1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Gzip implementation for busybox
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4 | *
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5 | * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly.
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6 | *
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7 | * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com>
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8 | * "this is a stripped down version of gzip I put into busybox, it does
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9 | * only standard in to standard out with -9 compression. It also requires
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10 | * the zcat module for some important functions."
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11 | *
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12 | * Adjusted further by Erik Andersen <andersen@codepoet.org> to support
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13 | * files as well as stdin/stdout, and to generally behave itself wrt
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14 | * command line handling.
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15 | *
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16 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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17 | */
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18 |
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19 | #define SMALL_MEM
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20 |
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21 | #include <stdlib.h>
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22 | #include <stdio.h>
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23 | #include <string.h>
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24 | #include <unistd.h>
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25 | #include <errno.h>
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26 | #include <sys/types.h>
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27 | #include <signal.h>
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28 | #include <utime.h>
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29 | #include <ctype.h>
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30 | #include <sys/types.h>
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31 | #include <unistd.h>
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32 | #include <dirent.h>
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33 | #include <fcntl.h>
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34 | #include <time.h>
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35 | #include "busybox.h"
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36 |
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37 | typedef unsigned char uch;
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38 | typedef unsigned short ush;
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39 | typedef unsigned long ulg;
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40 |
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41 | /* Return codes from gzip */
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42 | #define OK 0
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43 | #define ERROR 1
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44 | #define WARNING 2
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45 |
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46 | /* Compression methods (see algorithm.doc) */
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47 | /* Only STORED and DEFLATED are supported by this BusyBox module */
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48 | #define STORED 0
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49 | /* methods 4 to 7 reserved */
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50 | #define DEFLATED 8
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51 |
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52 | /* To save memory for 16 bit systems, some arrays are overlaid between
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53 | * the various modules:
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54 | * deflate: prev+head window d_buf l_buf outbuf
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55 | * unlzw: tab_prefix tab_suffix stack inbuf outbuf
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56 | * For compression, input is done in window[]. For decompression, output
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57 | * is done in window except for unlzw.
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58 | */
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59 |
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60 | #ifndef INBUFSIZ
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61 | # ifdef SMALL_MEM
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62 | # define INBUFSIZ 0x2000 /* input buffer size */
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63 | # else
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64 | # define INBUFSIZ 0x8000 /* input buffer size */
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65 | # endif
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66 | #endif
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67 | #define INBUF_EXTRA 64 /* required by unlzw() */
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68 |
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69 | #ifndef OUTBUFSIZ
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70 | # ifdef SMALL_MEM
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71 | # define OUTBUFSIZ 8192 /* output buffer size */
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72 | # else
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73 | # define OUTBUFSIZ 16384 /* output buffer size */
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74 | # endif
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75 | #endif
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76 | #define OUTBUF_EXTRA 2048 /* required by unlzw() */
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77 |
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78 | #ifndef DIST_BUFSIZE
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79 | # ifdef SMALL_MEM
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80 | # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
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81 | # else
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82 | # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
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83 | # endif
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84 | #endif
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85 |
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86 | # define DECLARE(type, array, size) static type * array
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87 | # define ALLOC(type, array, size) { \
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88 | array = (type*)xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)); \
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89 | }
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90 | # define FREE(array) {free(array), array=NULL;}
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91 |
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92 | #define tab_suffix window
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93 | #define tab_prefix prev /* hash link (see deflate.c) */
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94 | #define head (prev+WSIZE) /* hash head (see deflate.c) */
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95 |
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96 | static long bytes_in; /* number of input bytes */
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97 |
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98 | #define isize bytes_in
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99 | /* for compatibility with old zip sources (to be cleaned) */
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100 |
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101 | typedef int file_t; /* Do not use stdio */
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102 |
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103 | #define NO_FILE (-1) /* in memory compression */
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104 |
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105 |
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106 | #define PACK_MAGIC "\037\036" /* Magic header for packed files */
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107 | #define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
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108 | #define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */
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109 | #define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files */
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110 | #define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */
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111 |
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112 | /* gzip flag byte */
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113 | #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
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114 | #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
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115 | #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
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116 | #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
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117 | #define COMMENT 0x10 /* bit 4 set: file comment present */
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118 | #define RESERVED 0xC0 /* bit 6,7: reserved */
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119 |
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120 | /* internal file attribute */
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121 | #define UNKNOWN 0xffff
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122 | #define BINARY 0
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123 | #define ASCII 1
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124 |
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125 | #ifndef WSIZE
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126 | # define WSIZE 0x8000 /* window size--must be a power of two, and */
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127 | #endif /* at least 32K for zip's deflate method */
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128 |
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129 | #define MIN_MATCH 3
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130 | #define MAX_MATCH 258
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131 | /* The minimum and maximum match lengths */
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132 |
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133 | #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
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134 | /* Minimum amount of lookahead, except at the end of the input file.
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135 | * See deflate.c for comments about the MIN_MATCH+1.
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136 | */
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137 |
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138 | #define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
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139 | /* In order to simplify the code, particularly on 16 bit machines, match
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140 | * distances are limited to MAX_DIST instead of WSIZE.
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141 | */
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142 |
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143 | /* put_byte is used for the compressed output */
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144 | #define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
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145 | flush_outbuf();}
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146 |
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147 |
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148 | /* Output a 32 bit value to the bit stream, lsb first */
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149 | #if 0
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150 | #define put_long(n) { \
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151 | put_short((n) & 0xffff); \
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152 | put_short(((ulg)(n)) >> 16); \
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153 | }
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154 | #endif
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155 |
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156 | #define seekable() 0 /* force sequential output */
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157 | #define translate_eol 0 /* no option -a yet */
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158 |
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159 | /* Diagnostic functions */
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160 | #ifdef DEBUG
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161 | # define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);}
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162 | # define Trace(x) fprintf x
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163 | # define Tracev(x) {if (verbose) fprintf x ;}
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164 | # define Tracevv(x) {if (verbose>1) fprintf x ;}
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165 | # define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
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166 | # define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
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167 | #else
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168 | # define Assert(cond,msg)
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169 | # define Trace(x)
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170 | # define Tracev(x)
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171 | # define Tracevv(x)
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172 | # define Tracec(c,x)
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173 | # define Tracecv(c,x)
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174 | #endif
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175 |
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176 | #define WARN(msg) {if (!quiet) fprintf msg ; \
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177 | if (exit_code == OK) exit_code = WARNING;}
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178 |
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179 | #ifndef MAX_PATH_LEN
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180 | # define MAX_PATH_LEN 1024 /* max pathname length */
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181 | #endif
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182 |
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183 |
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184 | /* from zip.c: */
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185 | static int zip(int in, int out);
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186 | static int file_read(char *buf, unsigned size);
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187 |
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188 | /* from deflate.c */
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189 | static void lm_init(ush * flags);
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190 | static ulg deflate(void);
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191 |
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192 | /* from trees.c */
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193 | static void ct_init(ush * attr, int *methodp);
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194 | static int ct_tally(int dist, int lc);
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195 | static ulg flush_block(char *buf, ulg stored_len, int eof);
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196 |
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197 | /* from bits.c */
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198 | static void bi_init(file_t zipfile);
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199 | static void send_bits(int value, int length);
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200 | static unsigned bi_reverse(unsigned value, int length);
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201 | static void bi_windup(void);
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202 | static void copy_block(char *buf, unsigned len, int header);
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203 | static int (*read_buf) (char *buf, unsigned size);
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204 |
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205 | /* from util.c: */
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206 | static void flush_outbuf(void);
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207 |
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208 | /* lzw.h -- define the lzw functions.
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209 | * Copyright (C) 1992-1993 Jean-loup Gailly.
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210 | * This is free software; you can redistribute it and/or modify it under the
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211 | * terms of the GNU General Public License, see the file COPYING.
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212 | */
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213 |
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214 | #ifndef BITS
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215 | # define BITS 16
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216 | #endif
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217 | #define INIT_BITS 9 /* Initial number of bits per code */
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218 |
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219 | #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
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220 | /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
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221 | * It's a pity that old uncompress does not check bit 0x20. That makes
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222 | * extension of the format actually undesirable because old compress
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223 | * would just crash on the new format instead of giving a meaningful
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224 | * error message. It does check the number of bits, but it's more
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225 | * helpful to say "unsupported format, get a new version" than
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226 | * "can only handle 16 bits".
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227 | */
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228 |
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229 | /* tailor.h -- target dependent definitions
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230 | * Copyright (C) 1992-1993 Jean-loup Gailly.
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231 | * This is free software; you can redistribute it and/or modify it under the
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232 | * terms of the GNU General Public License, see the file COPYING.
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233 | */
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234 |
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235 | /* The target dependent definitions should be defined here only.
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236 | * The target dependent functions should be defined in tailor.c.
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237 | */
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238 |
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239 |
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240 | /* Common defaults */
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241 |
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242 | #ifndef OS_CODE
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243 | # define OS_CODE 0x03 /* assume Unix */
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244 | #endif
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245 |
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246 | #ifndef PATH_SEP
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247 | # define PATH_SEP '/'
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248 | #endif
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249 |
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250 | #ifndef OPTIONS_VAR
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251 | # define OPTIONS_VAR "GZIP"
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252 | #endif
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253 |
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254 | #ifndef Z_SUFFIX
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255 | # define Z_SUFFIX ".gz"
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256 | #endif
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257 |
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258 | #ifdef MAX_EXT_CHARS
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259 | # define MAX_SUFFIX MAX_EXT_CHARS
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260 | #else
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261 | # define MAX_SUFFIX 30
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262 | #endif
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263 |
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264 | /* global buffers */
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265 |
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266 | DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
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267 | DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
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268 | DECLARE(ush, d_buf, DIST_BUFSIZE);
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269 | DECLARE(uch, window, 2L * WSIZE);
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270 | DECLARE(ush, tab_prefix, 1L << BITS);
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271 |
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272 | static int foreground; /* set if program run in foreground */
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273 | static int method = DEFLATED; /* compression method */
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274 | static int exit_code = OK; /* program exit code */
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275 | static int part_nb; /* number of parts in .gz file */
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276 | static long time_stamp; /* original time stamp (modification time) */
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277 | static long ifile_size; /* input file size, -1 for devices (debug only) */
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278 | static char z_suffix[MAX_SUFFIX + 1]; /* default suffix (can be set with --suffix) */
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279 | static int z_len; /* strlen(z_suffix) */
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280 |
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281 | static int ifd; /* input file descriptor */
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282 | static int ofd; /* output file descriptor */
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283 | static unsigned insize; /* valid bytes in inbuf */
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284 | static unsigned outcnt; /* bytes in output buffer */
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285 |
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286 | static uint32_t *crc_32_tab;
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287 |
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288 | /* Output a 16 bit value, lsb first */
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289 | static void put_short(ush w)
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290 | {
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291 | if (outcnt < OUTBUFSIZ - 2) {
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292 | outbuf[outcnt++] = (uch) ((w) & 0xff);
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293 | outbuf[outcnt++] = (uch) ((ush) (w) >> 8);
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294 | } else {
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295 | put_byte((uch) ((w) & 0xff));
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296 | put_byte((uch) ((ush) (w) >> 8));
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297 | }
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298 | }
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299 |
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300 | /* ========================================================================
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301 | * Signal and error handler.
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302 | */
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303 | static void abort_gzip(int ATTRIBUTE_UNUSED ignored)
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304 | {
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305 | exit(ERROR);
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306 | }
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307 |
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308 | /* ===========================================================================
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309 | * Clear input and output buffers
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310 | */
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311 | static void clear_bufs(void)
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312 | {
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313 | outcnt = 0;
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314 | insize = 0;
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315 | bytes_in = 0L;
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316 | }
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317 |
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318 | /* ===========================================================================
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319 | * Does the same as write(), but also handles partial pipe writes and checks
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320 | * for error return.
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321 | */
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322 | static void write_buf(int fd, void *buf, unsigned cnt)
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323 | {
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324 | unsigned n;
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325 |
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326 | while ((n = write(fd, buf, cnt)) != cnt) {
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327 | if (n == (unsigned) (-1)) bb_error_msg_and_die(bb_msg_write_error);
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328 | cnt -= n;
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329 | buf = (void *) ((char *) buf + n);
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330 | }
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331 | }
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332 |
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333 | /* ===========================================================================
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334 | * Run a set of bytes through the crc shift register. If s is a NULL
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335 | * pointer, then initialize the crc shift register contents instead.
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336 | * Return the current crc in either case.
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337 | */
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338 | static uint32_t updcrc(uch * s, unsigned n)
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339 | {
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340 | static uint32_t crc = ~0; /* shift register contents */
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341 | uint32_t c; /* temporary variable */
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342 |
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343 | if (s == NULL) {
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344 | c = ~0;
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345 | } else {
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346 | c = crc;
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347 | if (n)
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348 | do {
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349 | c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8);
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350 | } while (--n);
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351 | }
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352 | crc = c;
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353 | return ~c;
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354 | }
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355 |
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356 | /* bits.c -- output variable-length bit strings
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357 | * Copyright (C) 1992-1993 Jean-loup Gailly
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358 | * This is free software; you can redistribute it and/or modify it under the
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359 | * terms of the GNU General Public License, see the file COPYING.
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360 | */
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361 |
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362 |
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363 | /*
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364 | * PURPOSE
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365 | *
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366 | * Output variable-length bit strings. Compression can be done
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367 | * to a file or to memory. (The latter is not supported in this version.)
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368 | *
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369 | * DISCUSSION
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370 | *
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371 | * The PKZIP "deflate" file format interprets compressed file data
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372 | * as a sequence of bits. Multi-bit strings in the file may cross
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373 | * byte boundaries without restriction.
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374 | *
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375 | * The first bit of each byte is the low-order bit.
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376 | *
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377 | * The routines in this file allow a variable-length bit value to
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378 | * be output right-to-left (useful for literal values). For
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379 | * left-to-right output (useful for code strings from the tree routines),
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380 | * the bits must have been reversed first with bi_reverse().
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381 | *
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382 | * For in-memory compression, the compressed bit stream goes directly
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383 | * into the requested output buffer. The input data is read in blocks
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384 | * by the mem_read() function. The buffer is limited to 64K on 16 bit
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385 | * machines.
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386 | *
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387 | * INTERFACE
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388 | *
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389 | * void bi_init (FILE *zipfile)
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390 | * Initialize the bit string routines.
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391 | *
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392 | * void send_bits (int value, int length)
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393 | * Write out a bit string, taking the source bits right to
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394 | * left.
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395 | *
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396 | * int bi_reverse (int value, int length)
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397 | * Reverse the bits of a bit string, taking the source bits left to
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398 | * right and emitting them right to left.
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399 | *
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400 | * void bi_windup (void)
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401 | * Write out any remaining bits in an incomplete byte.
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402 | *
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403 | * void copy_block(char *buf, unsigned len, int header)
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404 | * Copy a stored block to the zip file, storing first the length and
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405 | * its one's complement if requested.
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406 | *
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407 | */
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408 |
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409 | /* ===========================================================================
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410 | * Local data used by the "bit string" routines.
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411 | */
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412 |
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413 | static file_t zfile; /* output gzip file */
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414 |
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415 | static unsigned short bi_buf;
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416 |
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417 | /* Output buffer. bits are inserted starting at the bottom (least significant
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418 | * bits).
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419 | */
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420 |
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421 | #define Buf_size (8 * 2*sizeof(char))
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422 | /* Number of bits used within bi_buf. (bi_buf might be implemented on
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423 | * more than 16 bits on some systems.)
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424 | */
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425 |
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426 | static int bi_valid;
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427 |
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428 | /* Current input function. Set to mem_read for in-memory compression */
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429 |
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430 | #ifdef DEBUG
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431 | ulg bits_sent; /* bit length of the compressed data */
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432 | #endif
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433 |
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434 | /* ===========================================================================
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435 | * Initialize the bit string routines.
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436 | */
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437 | static void bi_init(file_t zipfile)
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438 | {
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439 | zfile = zipfile;
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440 | bi_buf = 0;
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441 | bi_valid = 0;
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442 | #ifdef DEBUG
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443 | bits_sent = 0L;
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444 | #endif
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445 |
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446 | /* Set the defaults for file compression. They are set by memcompress
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447 | * for in-memory compression.
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448 | */
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449 | if (zfile != NO_FILE) {
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450 | read_buf = file_read;
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451 | }
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452 | }
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453 |
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454 | /* ===========================================================================
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455 | * Send a value on a given number of bits.
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456 | * IN assertion: length <= 16 and value fits in length bits.
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457 | */
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458 | static void send_bits(int value, int length)
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459 | {
|
---|
460 | #ifdef DEBUG
|
---|
461 | Tracev((stderr, " l %2d v %4x ", length, value));
|
---|
462 | Assert(length > 0 && length <= 15, "invalid length");
|
---|
463 | bits_sent += (ulg) length;
|
---|
464 | #endif
|
---|
465 | /* If not enough room in bi_buf, use (valid) bits from bi_buf and
|
---|
466 | * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
|
---|
467 | * unused bits in value.
|
---|
468 | */
|
---|
469 | if (bi_valid > (int) Buf_size - length) {
|
---|
470 | bi_buf |= (value << bi_valid);
|
---|
471 | put_short(bi_buf);
|
---|
472 | bi_buf = (ush) value >> (Buf_size - bi_valid);
|
---|
473 | bi_valid += length - Buf_size;
|
---|
474 | } else {
|
---|
475 | bi_buf |= value << bi_valid;
|
---|
476 | bi_valid += length;
|
---|
477 | }
|
---|
478 | }
|
---|
479 |
|
---|
480 | /* ===========================================================================
|
---|
481 | * Reverse the first len bits of a code, using straightforward code (a faster
|
---|
482 | * method would use a table)
|
---|
483 | * IN assertion: 1 <= len <= 15
|
---|
484 | */
|
---|
485 | static unsigned bi_reverse(unsigned code, int len)
|
---|
486 | {
|
---|
487 | register unsigned res = 0;
|
---|
488 |
|
---|
489 | do {
|
---|
490 | res |= code & 1;
|
---|
491 | code >>= 1, res <<= 1;
|
---|
492 | } while (--len > 0);
|
---|
493 | return res >> 1;
|
---|
494 | }
|
---|
495 |
|
---|
496 | /* ===========================================================================
|
---|
497 | * Write out any remaining bits in an incomplete byte.
|
---|
498 | */
|
---|
499 | static void bi_windup(void)
|
---|
500 | {
|
---|
501 | if (bi_valid > 8) {
|
---|
502 | put_short(bi_buf);
|
---|
503 | } else if (bi_valid > 0) {
|
---|
504 | put_byte(bi_buf);
|
---|
505 | }
|
---|
506 | bi_buf = 0;
|
---|
507 | bi_valid = 0;
|
---|
508 | #ifdef DEBUG
|
---|
509 | bits_sent = (bits_sent + 7) & ~7;
|
---|
510 | #endif
|
---|
511 | }
|
---|
512 |
|
---|
513 | /* ===========================================================================
|
---|
514 | * Copy a stored block to the zip file, storing first the length and its
|
---|
515 | * one's complement if requested.
|
---|
516 | */
|
---|
517 | static void copy_block(char *buf, unsigned len, int header)
|
---|
518 | {
|
---|
519 | bi_windup(); /* align on byte boundary */
|
---|
520 |
|
---|
521 | if (header) {
|
---|
522 | put_short((ush) len);
|
---|
523 | put_short((ush) ~ len);
|
---|
524 | #ifdef DEBUG
|
---|
525 | bits_sent += 2 * 16;
|
---|
526 | #endif
|
---|
527 | }
|
---|
528 | #ifdef DEBUG
|
---|
529 | bits_sent += (ulg) len << 3;
|
---|
530 | #endif
|
---|
531 | while (len--) {
|
---|
532 | put_byte(*buf++);
|
---|
533 | }
|
---|
534 | }
|
---|
535 |
|
---|
536 | /* deflate.c -- compress data using the deflation algorithm
|
---|
537 | * Copyright (C) 1992-1993 Jean-loup Gailly
|
---|
538 | * This is free software; you can redistribute it and/or modify it under the
|
---|
539 | * terms of the GNU General Public License, see the file COPYING.
|
---|
540 | */
|
---|
541 |
|
---|
542 | /*
|
---|
543 | * PURPOSE
|
---|
544 | *
|
---|
545 | * Identify new text as repetitions of old text within a fixed-
|
---|
546 | * length sliding window trailing behind the new text.
|
---|
547 | *
|
---|
548 | * DISCUSSION
|
---|
549 | *
|
---|
550 | * The "deflation" process depends on being able to identify portions
|
---|
551 | * of the input text which are identical to earlier input (within a
|
---|
552 | * sliding window trailing behind the input currently being processed).
|
---|
553 | *
|
---|
554 | * The most straightforward technique turns out to be the fastest for
|
---|
555 | * most input files: try all possible matches and select the longest.
|
---|
556 | * The key feature of this algorithm is that insertions into the string
|
---|
557 | * dictionary are very simple and thus fast, and deletions are avoided
|
---|
558 | * completely. Insertions are performed at each input character, whereas
|
---|
559 | * string matches are performed only when the previous match ends. So it
|
---|
560 | * is preferable to spend more time in matches to allow very fast string
|
---|
561 | * insertions and avoid deletions. The matching algorithm for small
|
---|
562 | * strings is inspired from that of Rabin & Karp. A brute force approach
|
---|
563 | * is used to find longer strings when a small match has been found.
|
---|
564 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
|
---|
565 | * (by Leonid Broukhis).
|
---|
566 | * A previous version of this file used a more sophisticated algorithm
|
---|
567 | * (by Fiala and Greene) which is guaranteed to run in linear amortized
|
---|
568 | * time, but has a larger average cost, uses more memory and is patented.
|
---|
569 | * However the F&G algorithm may be faster for some highly redundant
|
---|
570 | * files if the parameter max_chain_length (described below) is too large.
|
---|
571 | *
|
---|
572 | * ACKNOWLEDGMENTS
|
---|
573 | *
|
---|
574 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
|
---|
575 | * I found it in 'freeze' written by Leonid Broukhis.
|
---|
576 | * Thanks to many info-zippers for bug reports and testing.
|
---|
577 | *
|
---|
578 | * REFERENCES
|
---|
579 | *
|
---|
580 | * APPNOTE.TXT documentation file in PKZIP 1.93a distribution.
|
---|
581 | *
|
---|
582 | * A description of the Rabin and Karp algorithm is given in the book
|
---|
583 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
|
---|
584 | *
|
---|
585 | * Fiala,E.R., and Greene,D.H.
|
---|
586 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
|
---|
587 | *
|
---|
588 | * INTERFACE
|
---|
589 | *
|
---|
590 | * void lm_init (int pack_level, ush *flags)
|
---|
591 | * Initialize the "longest match" routines for a new file
|
---|
592 | *
|
---|
593 | * ulg deflate (void)
|
---|
594 | * Processes a new input file and return its compressed length. Sets
|
---|
595 | * the compressed length, crc, deflate flags and internal file
|
---|
596 | * attributes.
|
---|
597 | */
|
---|
598 |
|
---|
599 |
|
---|
600 | /* ===========================================================================
|
---|
601 | * Configuration parameters
|
---|
602 | */
|
---|
603 |
|
---|
604 | /* Compile with MEDIUM_MEM to reduce the memory requirements or
|
---|
605 | * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the
|
---|
606 | * entire input file can be held in memory (not possible on 16 bit systems).
|
---|
607 | * Warning: defining these symbols affects HASH_BITS (see below) and thus
|
---|
608 | * affects the compression ratio. The compressed output
|
---|
609 | * is still correct, and might even be smaller in some cases.
|
---|
610 | */
|
---|
611 |
|
---|
612 | #ifdef SMALL_MEM
|
---|
613 | # define HASH_BITS 13 /* Number of bits used to hash strings */
|
---|
614 | #endif
|
---|
615 | #ifdef MEDIUM_MEM
|
---|
616 | # define HASH_BITS 14
|
---|
617 | #endif
|
---|
618 | #ifndef HASH_BITS
|
---|
619 | # define HASH_BITS 15
|
---|
620 | /* For portability to 16 bit machines, do not use values above 15. */
|
---|
621 | #endif
|
---|
622 |
|
---|
623 | /* To save space (see unlzw.c), we overlay prev+head with tab_prefix and
|
---|
624 | * window with tab_suffix. Check that we can do this:
|
---|
625 | */
|
---|
626 | #if (WSIZE<<1) > (1<<BITS)
|
---|
627 | # error cannot overlay window with tab_suffix and prev with tab_prefix0
|
---|
628 | #endif
|
---|
629 | #if HASH_BITS > BITS-1
|
---|
630 | # error cannot overlay head with tab_prefix1
|
---|
631 | #endif
|
---|
632 | #define HASH_SIZE (unsigned)(1<<HASH_BITS)
|
---|
633 | #define HASH_MASK (HASH_SIZE-1)
|
---|
634 | #define WMASK (WSIZE-1)
|
---|
635 | /* HASH_SIZE and WSIZE must be powers of two */
|
---|
636 | #define NIL 0
|
---|
637 | /* Tail of hash chains */
|
---|
638 | #define FAST 4
|
---|
639 | #define SLOW 2
|
---|
640 | /* speed options for the general purpose bit flag */
|
---|
641 | #ifndef TOO_FAR
|
---|
642 | # define TOO_FAR 4096
|
---|
643 | #endif
|
---|
644 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
|
---|
645 | /* ===========================================================================
|
---|
646 | * Local data used by the "longest match" routines.
|
---|
647 | */
|
---|
648 | typedef ush Pos;
|
---|
649 | typedef unsigned IPos;
|
---|
650 |
|
---|
651 | /* A Pos is an index in the character window. We use short instead of int to
|
---|
652 | * save space in the various tables. IPos is used only for parameter passing.
|
---|
653 | */
|
---|
654 |
|
---|
655 | /* DECLARE(uch, window, 2L*WSIZE); */
|
---|
656 | /* Sliding window. Input bytes are read into the second half of the window,
|
---|
657 | * and move to the first half later to keep a dictionary of at least WSIZE
|
---|
658 | * bytes. With this organization, matches are limited to a distance of
|
---|
659 | * WSIZE-MAX_MATCH bytes, but this ensures that IO is always
|
---|
660 | * performed with a length multiple of the block size. Also, it limits
|
---|
661 | * the window size to 64K, which is quite useful on MSDOS.
|
---|
662 | * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would
|
---|
663 | * be less efficient).
|
---|
664 | */
|
---|
665 |
|
---|
666 | /* DECLARE(Pos, prev, WSIZE); */
|
---|
667 | /* Link to older string with same hash index. To limit the size of this
|
---|
668 | * array to 64K, this link is maintained only for the last 32K strings.
|
---|
669 | * An index in this array is thus a window index modulo 32K.
|
---|
670 | */
|
---|
671 |
|
---|
672 | /* DECLARE(Pos, head, 1<<HASH_BITS); */
|
---|
673 | /* Heads of the hash chains or NIL. */
|
---|
674 |
|
---|
675 | static const ulg window_size = (ulg) 2 * WSIZE;
|
---|
676 |
|
---|
677 | /* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
|
---|
678 | * input file length plus MIN_LOOKAHEAD.
|
---|
679 | */
|
---|
680 |
|
---|
681 | static long block_start;
|
---|
682 |
|
---|
683 | /* window position at the beginning of the current output block. Gets
|
---|
684 | * negative when the window is moved backwards.
|
---|
685 | */
|
---|
686 |
|
---|
687 | static unsigned ins_h; /* hash index of string to be inserted */
|
---|
688 |
|
---|
689 | #define H_SHIFT ((HASH_BITS+MIN_MATCH-1)/MIN_MATCH)
|
---|
690 | /* Number of bits by which ins_h and del_h must be shifted at each
|
---|
691 | * input step. It must be such that after MIN_MATCH steps, the oldest
|
---|
692 | * byte no longer takes part in the hash key, that is:
|
---|
693 | * H_SHIFT * MIN_MATCH >= HASH_BITS
|
---|
694 | */
|
---|
695 |
|
---|
696 | static unsigned int prev_length;
|
---|
697 |
|
---|
698 | /* Length of the best match at previous step. Matches not greater than this
|
---|
699 | * are discarded. This is used in the lazy match evaluation.
|
---|
700 | */
|
---|
701 |
|
---|
702 | static unsigned strstart; /* start of string to insert */
|
---|
703 | static unsigned match_start; /* start of matching string */
|
---|
704 | static int eofile; /* flag set at end of input file */
|
---|
705 | static unsigned lookahead; /* number of valid bytes ahead in window */
|
---|
706 |
|
---|
707 | enum {
|
---|
708 | max_chain_length = 4096,
|
---|
709 |
|
---|
710 | /* To speed up deflation, hash chains are never searched beyond this length.
|
---|
711 | * A higher limit improves compression ratio but degrades the speed.
|
---|
712 | */
|
---|
713 |
|
---|
714 | max_lazy_match = 258,
|
---|
715 |
|
---|
716 | /* Attempt to find a better match only when the current match is strictly
|
---|
717 | * smaller than this value. This mechanism is used only for compression
|
---|
718 | * levels >= 4.
|
---|
719 | */
|
---|
720 | max_insert_length = max_lazy_match,
|
---|
721 | /* Insert new strings in the hash table only if the match length
|
---|
722 | * is not greater than this length. This saves time but degrades compression.
|
---|
723 | * max_insert_length is used only for compression levels <= 3.
|
---|
724 | */
|
---|
725 |
|
---|
726 | good_match = 32,
|
---|
727 |
|
---|
728 | /* Use a faster search when the previous match is longer than this */
|
---|
729 |
|
---|
730 |
|
---|
731 | /* Values for max_lazy_match, good_match and max_chain_length, depending on
|
---|
732 | * the desired pack level (0..9). The values given below have been tuned to
|
---|
733 | * exclude worst case performance for pathological files. Better values may be
|
---|
734 | * found for specific files.
|
---|
735 | */
|
---|
736 |
|
---|
737 | nice_match = 258 /* Stop searching when current match exceeds this */
|
---|
738 |
|
---|
739 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
|
---|
740 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
|
---|
741 | * meaning.
|
---|
742 | */
|
---|
743 | };
|
---|
744 |
|
---|
745 | #define EQUAL 0
|
---|
746 | /* result of memcmp for equal strings */
|
---|
747 |
|
---|
748 | /* ===========================================================================
|
---|
749 | * Prototypes for local functions.
|
---|
750 | */
|
---|
751 | static void fill_window(void);
|
---|
752 |
|
---|
753 | static int longest_match(IPos cur_match);
|
---|
754 |
|
---|
755 | #ifdef DEBUG
|
---|
756 | static void check_match(IPos start, IPos match, int length);
|
---|
757 | #endif
|
---|
758 |
|
---|
759 | /* ===========================================================================
|
---|
760 | * Update a hash value with the given input byte
|
---|
761 | * IN assertion: all calls to to UPDATE_HASH are made with consecutive
|
---|
762 | * input characters, so that a running hash key can be computed from the
|
---|
763 | * previous key instead of complete recalculation each time.
|
---|
764 | */
|
---|
765 | #define UPDATE_HASH(h,c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK)
|
---|
766 |
|
---|
767 | /* ===========================================================================
|
---|
768 | * Insert string s in the dictionary and set match_head to the previous head
|
---|
769 | * of the hash chain (the most recent string with same hash key). Return
|
---|
770 | * the previous length of the hash chain.
|
---|
771 | * IN assertion: all calls to to INSERT_STRING are made with consecutive
|
---|
772 | * input characters and the first MIN_MATCH bytes of s are valid
|
---|
773 | * (except for the last MIN_MATCH-1 bytes of the input file).
|
---|
774 | */
|
---|
775 | #define INSERT_STRING(s, match_head) \
|
---|
776 | (UPDATE_HASH(ins_h, window[(s) + MIN_MATCH-1]), \
|
---|
777 | prev[(s) & WMASK] = match_head = head[ins_h], \
|
---|
778 | head[ins_h] = (s))
|
---|
779 |
|
---|
780 | /* ===========================================================================
|
---|
781 | * Initialize the "longest match" routines for a new file
|
---|
782 | */
|
---|
783 | static void lm_init(ush * flags)
|
---|
784 | {
|
---|
785 | register unsigned j;
|
---|
786 |
|
---|
787 | /* Initialize the hash table. */
|
---|
788 | memset(head, 0, HASH_SIZE * sizeof(*head));
|
---|
789 | /* prev will be initialized on the fly */
|
---|
790 |
|
---|
791 | *flags |= SLOW;
|
---|
792 | /* ??? reduce max_chain_length for binary files */
|
---|
793 |
|
---|
794 | strstart = 0;
|
---|
795 | block_start = 0L;
|
---|
796 |
|
---|
797 | lookahead = read_buf((char *) window,
|
---|
798 | sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE);
|
---|
799 |
|
---|
800 | if (lookahead == 0 || lookahead == (unsigned) EOF) {
|
---|
801 | eofile = 1, lookahead = 0;
|
---|
802 | return;
|
---|
803 | }
|
---|
804 | eofile = 0;
|
---|
805 | /* Make sure that we always have enough lookahead. This is important
|
---|
806 | * if input comes from a device such as a tty.
|
---|
807 | */
|
---|
808 | while (lookahead < MIN_LOOKAHEAD && !eofile)
|
---|
809 | fill_window();
|
---|
810 |
|
---|
811 | ins_h = 0;
|
---|
812 | for (j = 0; j < MIN_MATCH - 1; j++)
|
---|
813 | UPDATE_HASH(ins_h, window[j]);
|
---|
814 | /* If lookahead < MIN_MATCH, ins_h is garbage, but this is
|
---|
815 | * not important since only literal bytes will be emitted.
|
---|
816 | */
|
---|
817 | }
|
---|
818 |
|
---|
819 | /* ===========================================================================
|
---|
820 | * Set match_start to the longest match starting at the given string and
|
---|
821 | * return its length. Matches shorter or equal to prev_length are discarded,
|
---|
822 | * in which case the result is equal to prev_length and match_start is
|
---|
823 | * garbage.
|
---|
824 | * IN assertions: cur_match is the head of the hash chain for the current
|
---|
825 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
|
---|
826 | */
|
---|
827 |
|
---|
828 | /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or
|
---|
829 | * match.s. The code is functionally equivalent, so you can use the C version
|
---|
830 | * if desired.
|
---|
831 | */
|
---|
832 | static int longest_match(IPos cur_match)
|
---|
833 | {
|
---|
834 | unsigned chain_length = max_chain_length; /* max hash chain length */
|
---|
835 | register uch *scan = window + strstart; /* current string */
|
---|
836 | register uch *match; /* matched string */
|
---|
837 | register int len; /* length of current match */
|
---|
838 | int best_len = prev_length; /* best match length so far */
|
---|
839 | IPos limit =
|
---|
840 | strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : NIL;
|
---|
841 | /* Stop when cur_match becomes <= limit. To simplify the code,
|
---|
842 | * we prevent matches with the string of window index 0.
|
---|
843 | */
|
---|
844 |
|
---|
845 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
|
---|
846 | * It is easy to get rid of this optimization if necessary.
|
---|
847 | */
|
---|
848 | #if HASH_BITS < 8 || MAX_MATCH != 258
|
---|
849 | # error Code too clever
|
---|
850 | #endif
|
---|
851 | register uch *strend = window + strstart + MAX_MATCH;
|
---|
852 | register uch scan_end1 = scan[best_len - 1];
|
---|
853 | register uch scan_end = scan[best_len];
|
---|
854 |
|
---|
855 | /* Do not waste too much time if we already have a good match: */
|
---|
856 | if (prev_length >= good_match) {
|
---|
857 | chain_length >>= 2;
|
---|
858 | }
|
---|
859 | Assert(strstart <= window_size - MIN_LOOKAHEAD, "insufficient lookahead");
|
---|
860 |
|
---|
861 | do {
|
---|
862 | Assert(cur_match < strstart, "no future");
|
---|
863 | match = window + cur_match;
|
---|
864 |
|
---|
865 | /* Skip to next match if the match length cannot increase
|
---|
866 | * or if the match length is less than 2:
|
---|
867 | */
|
---|
868 | if (match[best_len] != scan_end ||
|
---|
869 | match[best_len - 1] != scan_end1 ||
|
---|
870 | *match != *scan || *++match != scan[1])
|
---|
871 | continue;
|
---|
872 |
|
---|
873 | /* The check at best_len-1 can be removed because it will be made
|
---|
874 | * again later. (This heuristic is not always a win.)
|
---|
875 | * It is not necessary to compare scan[2] and match[2] since they
|
---|
876 | * are always equal when the other bytes match, given that
|
---|
877 | * the hash keys are equal and that HASH_BITS >= 8.
|
---|
878 | */
|
---|
879 | scan += 2, match++;
|
---|
880 |
|
---|
881 | /* We check for insufficient lookahead only every 8th comparison;
|
---|
882 | * the 256th check will be made at strstart+258.
|
---|
883 | */
|
---|
884 | do {
|
---|
885 | } while (*++scan == *++match && *++scan == *++match &&
|
---|
886 | *++scan == *++match && *++scan == *++match &&
|
---|
887 | *++scan == *++match && *++scan == *++match &&
|
---|
888 | *++scan == *++match && *++scan == *++match && scan < strend);
|
---|
889 |
|
---|
890 | len = MAX_MATCH - (int) (strend - scan);
|
---|
891 | scan = strend - MAX_MATCH;
|
---|
892 |
|
---|
893 | if (len > best_len) {
|
---|
894 | match_start = cur_match;
|
---|
895 | best_len = len;
|
---|
896 | if (len >= nice_match)
|
---|
897 | break;
|
---|
898 | scan_end1 = scan[best_len - 1];
|
---|
899 | scan_end = scan[best_len];
|
---|
900 | }
|
---|
901 | } while ((cur_match = prev[cur_match & WMASK]) > limit
|
---|
902 | && --chain_length != 0);
|
---|
903 |
|
---|
904 | return best_len;
|
---|
905 | }
|
---|
906 |
|
---|
907 | #ifdef DEBUG
|
---|
908 | /* ===========================================================================
|
---|
909 | * Check that the match at match_start is indeed a match.
|
---|
910 | */
|
---|
911 | static void check_match(IPos start, IPos match, int length)
|
---|
912 | {
|
---|
913 | /* check that the match is indeed a match */
|
---|
914 | if (memcmp((char *) window + match,
|
---|
915 | (char *) window + start, length) != EQUAL) {
|
---|
916 | bb_error_msg(" start %d, match %d, length %d", start, match, length);
|
---|
917 | bb_error_msg("invalid match");
|
---|
918 | }
|
---|
919 | if (verbose > 1) {
|
---|
920 | bb_error_msg("\\[%d,%d]", start - match, length);
|
---|
921 | do {
|
---|
922 | putc(window[start++], stderr);
|
---|
923 | } while (--length != 0);
|
---|
924 | }
|
---|
925 | }
|
---|
926 | #else
|
---|
927 | # define check_match(start, match, length)
|
---|
928 | #endif
|
---|
929 |
|
---|
930 | /* ===========================================================================
|
---|
931 | * Fill the window when the lookahead becomes insufficient.
|
---|
932 | * Updates strstart and lookahead, and sets eofile if end of input file.
|
---|
933 | * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0
|
---|
934 | * OUT assertions: at least one byte has been read, or eofile is set;
|
---|
935 | * file reads are performed for at least two bytes (required for the
|
---|
936 | * translate_eol option).
|
---|
937 | */
|
---|
938 | static void fill_window(void)
|
---|
939 | {
|
---|
940 | register unsigned n, m;
|
---|
941 | unsigned more =
|
---|
942 | (unsigned) (window_size - (ulg) lookahead - (ulg) strstart);
|
---|
943 | /* Amount of free space at the end of the window. */
|
---|
944 |
|
---|
945 | /* If the window is almost full and there is insufficient lookahead,
|
---|
946 | * move the upper half to the lower one to make room in the upper half.
|
---|
947 | */
|
---|
948 | if (more == (unsigned) EOF) {
|
---|
949 | /* Very unlikely, but possible on 16 bit machine if strstart == 0
|
---|
950 | * and lookahead == 1 (input done one byte at time)
|
---|
951 | */
|
---|
952 | more--;
|
---|
953 | } else if (strstart >= WSIZE + MAX_DIST) {
|
---|
954 | /* By the IN assertion, the window is not empty so we can't confuse
|
---|
955 | * more == 0 with more == 64K on a 16 bit machine.
|
---|
956 | */
|
---|
957 | Assert(window_size == (ulg) 2 * WSIZE, "no sliding with BIG_MEM");
|
---|
958 |
|
---|
959 | memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE);
|
---|
960 | match_start -= WSIZE;
|
---|
961 | strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
|
---|
962 |
|
---|
963 | block_start -= (long) WSIZE;
|
---|
964 |
|
---|
965 | for (n = 0; n < HASH_SIZE; n++) {
|
---|
966 | m = head[n];
|
---|
967 | head[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
|
---|
968 | }
|
---|
969 | for (n = 0; n < WSIZE; n++) {
|
---|
970 | m = prev[n];
|
---|
971 | prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL);
|
---|
972 | /* If n is not on any hash chain, prev[n] is garbage but
|
---|
973 | * its value will never be used.
|
---|
974 | */
|
---|
975 | }
|
---|
976 | more += WSIZE;
|
---|
977 | }
|
---|
978 | /* At this point, more >= 2 */
|
---|
979 | if (!eofile) {
|
---|
980 | n = read_buf((char *) window + strstart + lookahead, more);
|
---|
981 | if (n == 0 || n == (unsigned) EOF) {
|
---|
982 | eofile = 1;
|
---|
983 | } else {
|
---|
984 | lookahead += n;
|
---|
985 | }
|
---|
986 | }
|
---|
987 | }
|
---|
988 |
|
---|
989 | /* ===========================================================================
|
---|
990 | * Flush the current block, with given end-of-file flag.
|
---|
991 | * IN assertion: strstart is set to the end of the current match.
|
---|
992 | */
|
---|
993 | #define FLUSH_BLOCK(eof) \
|
---|
994 | flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
|
---|
995 | (char*)NULL, (long)strstart - block_start, (eof))
|
---|
996 |
|
---|
997 | /* ===========================================================================
|
---|
998 | * Same as above, but achieves better compression. We use a lazy
|
---|
999 | * evaluation for matches: a match is finally adopted only if there is
|
---|
1000 | * no better match at the next window position.
|
---|
1001 | */
|
---|
1002 | static ulg deflate(void)
|
---|
1003 | {
|
---|
1004 | IPos hash_head; /* head of hash chain */
|
---|
1005 | IPos prev_match; /* previous match */
|
---|
1006 | int flush; /* set if current block must be flushed */
|
---|
1007 | int match_available = 0; /* set if previous match exists */
|
---|
1008 | register unsigned match_length = MIN_MATCH - 1; /* length of best match */
|
---|
1009 |
|
---|
1010 | /* Process the input block. */
|
---|
1011 | while (lookahead != 0) {
|
---|
1012 | /* Insert the string window[strstart .. strstart+2] in the
|
---|
1013 | * dictionary, and set hash_head to the head of the hash chain:
|
---|
1014 | */
|
---|
1015 | INSERT_STRING(strstart, hash_head);
|
---|
1016 |
|
---|
1017 | /* Find the longest match, discarding those <= prev_length.
|
---|
1018 | */
|
---|
1019 | prev_length = match_length, prev_match = match_start;
|
---|
1020 | match_length = MIN_MATCH - 1;
|
---|
1021 |
|
---|
1022 | if (hash_head != NIL && prev_length < max_lazy_match &&
|
---|
1023 | strstart - hash_head <= MAX_DIST) {
|
---|
1024 | /* To simplify the code, we prevent matches with the string
|
---|
1025 | * of window index 0 (in particular we have to avoid a match
|
---|
1026 | * of the string with itself at the start of the input file).
|
---|
1027 | */
|
---|
1028 | match_length = longest_match(hash_head);
|
---|
1029 | /* longest_match() sets match_start */
|
---|
1030 | if (match_length > lookahead)
|
---|
1031 | match_length = lookahead;
|
---|
1032 |
|
---|
1033 | /* Ignore a length 3 match if it is too distant: */
|
---|
1034 | if (match_length == MIN_MATCH && strstart - match_start > TOO_FAR) {
|
---|
1035 | /* If prev_match is also MIN_MATCH, match_start is garbage
|
---|
1036 | * but we will ignore the current match anyway.
|
---|
1037 | */
|
---|
1038 | match_length--;
|
---|
1039 | }
|
---|
1040 | }
|
---|
1041 | /* If there was a match at the previous step and the current
|
---|
1042 | * match is not better, output the previous match:
|
---|
1043 | */
|
---|
1044 | if (prev_length >= MIN_MATCH && match_length <= prev_length) {
|
---|
1045 |
|
---|
1046 | check_match(strstart - 1, prev_match, prev_length);
|
---|
1047 |
|
---|
1048 | flush =
|
---|
1049 | ct_tally(strstart - 1 - prev_match, prev_length - MIN_MATCH);
|
---|
1050 |
|
---|
1051 | /* Insert in hash table all strings up to the end of the match.
|
---|
1052 | * strstart-1 and strstart are already inserted.
|
---|
1053 | */
|
---|
1054 | lookahead -= prev_length - 1;
|
---|
1055 | prev_length -= 2;
|
---|
1056 | do {
|
---|
1057 | strstart++;
|
---|
1058 | INSERT_STRING(strstart, hash_head);
|
---|
1059 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are
|
---|
1060 | * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
|
---|
1061 | * these bytes are garbage, but it does not matter since the
|
---|
1062 | * next lookahead bytes will always be emitted as literals.
|
---|
1063 | */
|
---|
1064 | } while (--prev_length != 0);
|
---|
1065 | match_available = 0;
|
---|
1066 | match_length = MIN_MATCH - 1;
|
---|
1067 | strstart++;
|
---|
1068 | if (flush)
|
---|
1069 | FLUSH_BLOCK(0), block_start = strstart;
|
---|
1070 |
|
---|
1071 | } else if (match_available) {
|
---|
1072 | /* If there was no match at the previous position, output a
|
---|
1073 | * single literal. If there was a match but the current match
|
---|
1074 | * is longer, truncate the previous match to a single literal.
|
---|
1075 | */
|
---|
1076 | Tracevv((stderr, "%c", window[strstart - 1]));
|
---|
1077 | if (ct_tally(0, window[strstart - 1])) {
|
---|
1078 | FLUSH_BLOCK(0), block_start = strstart;
|
---|
1079 | }
|
---|
1080 | strstart++;
|
---|
1081 | lookahead--;
|
---|
1082 | } else {
|
---|
1083 | /* There is no previous match to compare with, wait for
|
---|
1084 | * the next step to decide.
|
---|
1085 | */
|
---|
1086 | match_available = 1;
|
---|
1087 | strstart++;
|
---|
1088 | lookahead--;
|
---|
1089 | }
|
---|
1090 | Assert(strstart <= isize && lookahead <= isize, "a bit too far");
|
---|
1091 |
|
---|
1092 | /* Make sure that we always have enough lookahead, except
|
---|
1093 | * at the end of the input file. We need MAX_MATCH bytes
|
---|
1094 | * for the next match, plus MIN_MATCH bytes to insert the
|
---|
1095 | * string following the next match.
|
---|
1096 | */
|
---|
1097 | while (lookahead < MIN_LOOKAHEAD && !eofile)
|
---|
1098 | fill_window();
|
---|
1099 | }
|
---|
1100 | if (match_available)
|
---|
1101 | ct_tally(0, window[strstart - 1]);
|
---|
1102 |
|
---|
1103 | return FLUSH_BLOCK(1); /* eof */
|
---|
1104 | }
|
---|
1105 |
|
---|
1106 | /* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
|
---|
1107 | * Copyright (C) 1992-1993 Jean-loup Gailly
|
---|
1108 | * The unzip code was written and put in the public domain by Mark Adler.
|
---|
1109 | * Portions of the lzw code are derived from the public domain 'compress'
|
---|
1110 | * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
|
---|
1111 | * Ken Turkowski, Dave Mack and Peter Jannesen.
|
---|
1112 | *
|
---|
1113 | * See the license_msg below and the file COPYING for the software license.
|
---|
1114 | * See the file algorithm.doc for the compression algorithms and file formats.
|
---|
1115 | */
|
---|
1116 |
|
---|
1117 | /* Compress files with zip algorithm and 'compress' interface.
|
---|
1118 | * See usage() and help() functions below for all options.
|
---|
1119 | * Outputs:
|
---|
1120 | * file.gz: compressed file with same mode, owner, and utimes
|
---|
1121 | * or stdout with -c option or if stdin used as input.
|
---|
1122 | * If the output file name had to be truncated, the original name is kept
|
---|
1123 | * in the compressed file.
|
---|
1124 | */
|
---|
1125 |
|
---|
1126 | /* configuration */
|
---|
1127 |
|
---|
1128 | typedef struct dirent dir_type;
|
---|
1129 |
|
---|
1130 | /* ======================================================================== */
|
---|
1131 | int gzip_main(int argc, char **argv)
|
---|
1132 | {
|
---|
1133 | int result;
|
---|
1134 | int inFileNum;
|
---|
1135 | int outFileNum;
|
---|
1136 | struct stat statBuf;
|
---|
1137 | char *delFileName;
|
---|
1138 | int tostdout = 0;
|
---|
1139 | int force = 0;
|
---|
1140 | int opt;
|
---|
1141 |
|
---|
1142 | while ((opt = getopt(argc, argv, "cf123456789dq")) != -1) {
|
---|
1143 | switch (opt) {
|
---|
1144 | case 'c':
|
---|
1145 | tostdout = 1;
|
---|
1146 | break;
|
---|
1147 | case 'f':
|
---|
1148 | force = 1;
|
---|
1149 | break;
|
---|
1150 | /* Ignore 1-9 (compression level) options */
|
---|
1151 | case '1':
|
---|
1152 | case '2':
|
---|
1153 | case '3':
|
---|
1154 | case '4':
|
---|
1155 | case '5':
|
---|
1156 | case '6':
|
---|
1157 | case '7':
|
---|
1158 | case '8':
|
---|
1159 | case '9':
|
---|
1160 | break;
|
---|
1161 | case 'q':
|
---|
1162 | break;
|
---|
1163 | #ifdef CONFIG_GUNZIP
|
---|
1164 | case 'd':
|
---|
1165 | optind = 1;
|
---|
1166 | return gunzip_main(argc, argv);
|
---|
1167 | #endif
|
---|
1168 | default:
|
---|
1169 | bb_show_usage();
|
---|
1170 | }
|
---|
1171 | }
|
---|
1172 |
|
---|
1173 | foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
|
---|
1174 | if (foreground) {
|
---|
1175 | (void) signal(SIGINT, abort_gzip);
|
---|
1176 | }
|
---|
1177 | #ifdef SIGTERM
|
---|
1178 | if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
|
---|
1179 | (void) signal(SIGTERM, abort_gzip);
|
---|
1180 | }
|
---|
1181 | #endif
|
---|
1182 | #ifdef SIGHUP
|
---|
1183 | if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
|
---|
1184 | (void) signal(SIGHUP, abort_gzip);
|
---|
1185 | }
|
---|
1186 | #endif
|
---|
1187 |
|
---|
1188 | strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1);
|
---|
1189 | z_len = strlen(z_suffix);
|
---|
1190 |
|
---|
1191 | /* Allocate all global buffers (for DYN_ALLOC option) */
|
---|
1192 | ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
|
---|
1193 | ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
|
---|
1194 | ALLOC(ush, d_buf, DIST_BUFSIZE);
|
---|
1195 | ALLOC(uch, window, 2L * WSIZE);
|
---|
1196 | ALLOC(ush, tab_prefix, 1L << BITS);
|
---|
1197 |
|
---|
1198 | /* Initialise the CRC32 table */
|
---|
1199 | crc_32_tab = bb_crc32_filltable(0);
|
---|
1200 |
|
---|
1201 | clear_bufs();
|
---|
1202 | part_nb = 0;
|
---|
1203 |
|
---|
1204 | if (optind == argc) {
|
---|
1205 | time_stamp = 0;
|
---|
1206 | ifile_size = -1L;
|
---|
1207 | zip(STDIN_FILENO, STDOUT_FILENO);
|
---|
1208 | } else {
|
---|
1209 | int i;
|
---|
1210 |
|
---|
1211 | for (i = optind; i < argc; i++) {
|
---|
1212 | char *path = NULL;
|
---|
1213 |
|
---|
1214 | clear_bufs();
|
---|
1215 | if (strcmp(argv[i], "-") == 0) {
|
---|
1216 | time_stamp = 0;
|
---|
1217 | ifile_size = -1L;
|
---|
1218 | inFileNum = STDIN_FILENO;
|
---|
1219 | outFileNum = STDOUT_FILENO;
|
---|
1220 | } else {
|
---|
1221 | inFileNum = bb_xopen3(argv[i], O_RDONLY, 0);
|
---|
1222 | if (fstat(inFileNum, &statBuf) < 0)
|
---|
1223 | bb_perror_msg_and_die("%s", argv[i]);
|
---|
1224 | time_stamp = statBuf.st_ctime;
|
---|
1225 | ifile_size = statBuf.st_size;
|
---|
1226 |
|
---|
1227 | if (!tostdout) {
|
---|
1228 | path = xmalloc(strlen(argv[i]) + 4);
|
---|
1229 | strcpy(path, argv[i]);
|
---|
1230 | strcat(path, ".gz");
|
---|
1231 |
|
---|
1232 | /* Open output file */
|
---|
1233 | #if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) && defined O_NOFOLLOW
|
---|
1234 | outFileNum =
|
---|
1235 | open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
|
---|
1236 | #else
|
---|
1237 | outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL);
|
---|
1238 | #endif
|
---|
1239 | if (outFileNum < 0) {
|
---|
1240 | bb_perror_msg("%s", path);
|
---|
1241 | free(path);
|
---|
1242 | continue;
|
---|
1243 | }
|
---|
1244 |
|
---|
1245 | /* Set permissions on the file */
|
---|
1246 | fchmod(outFileNum, statBuf.st_mode);
|
---|
1247 | } else
|
---|
1248 | outFileNum = STDOUT_FILENO;
|
---|
1249 | }
|
---|
1250 |
|
---|
1251 | if (path == NULL && isatty(outFileNum) && force == 0) {
|
---|
1252 | bb_error_msg
|
---|
1253 | ("compressed data not written to a terminal. Use -f to force compression.");
|
---|
1254 | free(path);
|
---|
1255 | continue;
|
---|
1256 | }
|
---|
1257 |
|
---|
1258 | result = zip(inFileNum, outFileNum);
|
---|
1259 |
|
---|
1260 | if (path != NULL) {
|
---|
1261 | close(inFileNum);
|
---|
1262 | close(outFileNum);
|
---|
1263 |
|
---|
1264 | /* Delete the original file */
|
---|
1265 | if (result == OK)
|
---|
1266 | delFileName = argv[i];
|
---|
1267 | else
|
---|
1268 | delFileName = path;
|
---|
1269 |
|
---|
1270 | if (unlink(delFileName) < 0)
|
---|
1271 | bb_perror_msg("%s", delFileName);
|
---|
1272 | }
|
---|
1273 |
|
---|
1274 | free(path);
|
---|
1275 | }
|
---|
1276 | }
|
---|
1277 |
|
---|
1278 | return (exit_code);
|
---|
1279 | }
|
---|
1280 |
|
---|
1281 | /* trees.c -- output deflated data using Huffman coding
|
---|
1282 | * Copyright (C) 1992-1993 Jean-loup Gailly
|
---|
1283 | * This is free software; you can redistribute it and/or modify it under the
|
---|
1284 | * terms of the GNU General Public License, see the file COPYING.
|
---|
1285 | */
|
---|
1286 |
|
---|
1287 | /*
|
---|
1288 | * PURPOSE
|
---|
1289 | *
|
---|
1290 | * Encode various sets of source values using variable-length
|
---|
1291 | * binary code trees.
|
---|
1292 | *
|
---|
1293 | * DISCUSSION
|
---|
1294 | *
|
---|
1295 | * The PKZIP "deflation" process uses several Huffman trees. The more
|
---|
1296 | * common source values are represented by shorter bit sequences.
|
---|
1297 | *
|
---|
1298 | * Each code tree is stored in the ZIP file in a compressed form
|
---|
1299 | * which is itself a Huffman encoding of the lengths of
|
---|
1300 | * all the code strings (in ascending order by source values).
|
---|
1301 | * The actual code strings are reconstructed from the lengths in
|
---|
1302 | * the UNZIP process, as described in the "application note"
|
---|
1303 | * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program.
|
---|
1304 | *
|
---|
1305 | * REFERENCES
|
---|
1306 | *
|
---|
1307 | * Lynch, Thomas J.
|
---|
1308 | * Data Compression: Techniques and Applications, pp. 53-55.
|
---|
1309 | * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7.
|
---|
1310 | *
|
---|
1311 | * Storer, James A.
|
---|
1312 | * Data Compression: Methods and Theory, pp. 49-50.
|
---|
1313 | * Computer Science Press, 1988. ISBN 0-7167-8156-5.
|
---|
1314 | *
|
---|
1315 | * Sedgewick, R.
|
---|
1316 | * Algorithms, p290.
|
---|
1317 | * Addison-Wesley, 1983. ISBN 0-201-06672-6.
|
---|
1318 | *
|
---|
1319 | * INTERFACE
|
---|
1320 | *
|
---|
1321 | * void ct_init (ush *attr, int *methodp)
|
---|
1322 | * Allocate the match buffer, initialize the various tables and save
|
---|
1323 | * the location of the internal file attribute (ascii/binary) and
|
---|
1324 | * method (DEFLATE/STORE)
|
---|
1325 | *
|
---|
1326 | * void ct_tally (int dist, int lc);
|
---|
1327 | * Save the match info and tally the frequency counts.
|
---|
1328 | *
|
---|
1329 | * long flush_block (char *buf, ulg stored_len, int eof)
|
---|
1330 | * Determine the best encoding for the current block: dynamic trees,
|
---|
1331 | * static trees or store, and output the encoded block to the zip
|
---|
1332 | * file. Returns the total compressed length for the file so far.
|
---|
1333 | *
|
---|
1334 | */
|
---|
1335 |
|
---|
1336 | /* ===========================================================================
|
---|
1337 | * Constants
|
---|
1338 | */
|
---|
1339 |
|
---|
1340 | #define MAX_BITS 15
|
---|
1341 | /* All codes must not exceed MAX_BITS bits */
|
---|
1342 |
|
---|
1343 | #define MAX_BL_BITS 7
|
---|
1344 | /* Bit length codes must not exceed MAX_BL_BITS bits */
|
---|
1345 |
|
---|
1346 | #define LENGTH_CODES 29
|
---|
1347 | /* number of length codes, not counting the special END_BLOCK code */
|
---|
1348 |
|
---|
1349 | #define LITERALS 256
|
---|
1350 | /* number of literal bytes 0..255 */
|
---|
1351 |
|
---|
1352 | #define END_BLOCK 256
|
---|
1353 | /* end of block literal code */
|
---|
1354 |
|
---|
1355 | #define L_CODES (LITERALS+1+LENGTH_CODES)
|
---|
1356 | /* number of Literal or Length codes, including the END_BLOCK code */
|
---|
1357 |
|
---|
1358 | #define D_CODES 30
|
---|
1359 | /* number of distance codes */
|
---|
1360 |
|
---|
1361 | #define BL_CODES 19
|
---|
1362 | /* number of codes used to transfer the bit lengths */
|
---|
1363 |
|
---|
1364 | typedef uch extra_bits_t;
|
---|
1365 |
|
---|
1366 | /* extra bits for each length code */
|
---|
1367 | static const extra_bits_t extra_lbits[LENGTH_CODES]
|
---|
1368 | = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4,
|
---|
1369 | 4, 4, 5, 5, 5, 5, 0
|
---|
1370 | };
|
---|
1371 |
|
---|
1372 | /* extra bits for each distance code */
|
---|
1373 | static const extra_bits_t extra_dbits[D_CODES]
|
---|
1374 | = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,
|
---|
1375 | 10, 10, 11, 11, 12, 12, 13, 13
|
---|
1376 | };
|
---|
1377 |
|
---|
1378 | /* extra bits for each bit length code */
|
---|
1379 | static const extra_bits_t extra_blbits[BL_CODES]
|
---|
1380 | = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 };
|
---|
1381 |
|
---|
1382 | #define STORED_BLOCK 0
|
---|
1383 | #define STATIC_TREES 1
|
---|
1384 | #define DYN_TREES 2
|
---|
1385 | /* The three kinds of block type */
|
---|
1386 |
|
---|
1387 | #ifndef LIT_BUFSIZE
|
---|
1388 | # ifdef SMALL_MEM
|
---|
1389 | # define LIT_BUFSIZE 0x2000
|
---|
1390 | # else
|
---|
1391 | # ifdef MEDIUM_MEM
|
---|
1392 | # define LIT_BUFSIZE 0x4000
|
---|
1393 | # else
|
---|
1394 | # define LIT_BUFSIZE 0x8000
|
---|
1395 | # endif
|
---|
1396 | # endif
|
---|
1397 | #endif
|
---|
1398 | #ifndef DIST_BUFSIZE
|
---|
1399 | # define DIST_BUFSIZE LIT_BUFSIZE
|
---|
1400 | #endif
|
---|
1401 | /* Sizes of match buffers for literals/lengths and distances. There are
|
---|
1402 | * 4 reasons for limiting LIT_BUFSIZE to 64K:
|
---|
1403 | * - frequencies can be kept in 16 bit counters
|
---|
1404 | * - if compression is not successful for the first block, all input data is
|
---|
1405 | * still in the window so we can still emit a stored block even when input
|
---|
1406 | * comes from standard input. (This can also be done for all blocks if
|
---|
1407 | * LIT_BUFSIZE is not greater than 32K.)
|
---|
1408 | * - if compression is not successful for a file smaller than 64K, we can
|
---|
1409 | * even emit a stored file instead of a stored block (saving 5 bytes).
|
---|
1410 | * - creating new Huffman trees less frequently may not provide fast
|
---|
1411 | * adaptation to changes in the input data statistics. (Take for
|
---|
1412 | * example a binary file with poorly compressible code followed by
|
---|
1413 | * a highly compressible string table.) Smaller buffer sizes give
|
---|
1414 | * fast adaptation but have of course the overhead of transmitting trees
|
---|
1415 | * more frequently.
|
---|
1416 | * - I can't count above 4
|
---|
1417 | * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save
|
---|
1418 | * memory at the expense of compression). Some optimizations would be possible
|
---|
1419 | * if we rely on DIST_BUFSIZE == LIT_BUFSIZE.
|
---|
1420 | */
|
---|
1421 | #if LIT_BUFSIZE > INBUFSIZ
|
---|
1422 | #error cannot overlay l_buf and inbuf
|
---|
1423 | #endif
|
---|
1424 | #define REP_3_6 16
|
---|
1425 | /* repeat previous bit length 3-6 times (2 bits of repeat count) */
|
---|
1426 | #define REPZ_3_10 17
|
---|
1427 | /* repeat a zero length 3-10 times (3 bits of repeat count) */
|
---|
1428 | #define REPZ_11_138 18
|
---|
1429 | /* repeat a zero length 11-138 times (7 bits of repeat count) */
|
---|
1430 |
|
---|
1431 | /* ===========================================================================
|
---|
1432 | * Local data
|
---|
1433 | */
|
---|
1434 |
|
---|
1435 | /* Data structure describing a single value and its code string. */
|
---|
1436 | typedef struct ct_data {
|
---|
1437 | union {
|
---|
1438 | ush freq; /* frequency count */
|
---|
1439 | ush code; /* bit string */
|
---|
1440 | } fc;
|
---|
1441 | union {
|
---|
1442 | ush dad; /* father node in Huffman tree */
|
---|
1443 | ush len; /* length of bit string */
|
---|
1444 | } dl;
|
---|
1445 | } ct_data;
|
---|
1446 |
|
---|
1447 | #define Freq fc.freq
|
---|
1448 | #define Code fc.code
|
---|
1449 | #define Dad dl.dad
|
---|
1450 | #define Len dl.len
|
---|
1451 |
|
---|
1452 | #define HEAP_SIZE (2*L_CODES+1)
|
---|
1453 | /* maximum heap size */
|
---|
1454 |
|
---|
1455 | static ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */
|
---|
1456 | static ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */
|
---|
1457 |
|
---|
1458 | static ct_data static_ltree[L_CODES + 2];
|
---|
1459 |
|
---|
1460 | /* The static literal tree. Since the bit lengths are imposed, there is no
|
---|
1461 | * need for the L_CODES extra codes used during heap construction. However
|
---|
1462 | * The codes 286 and 287 are needed to build a canonical tree (see ct_init
|
---|
1463 | * below).
|
---|
1464 | */
|
---|
1465 |
|
---|
1466 | static ct_data static_dtree[D_CODES];
|
---|
1467 |
|
---|
1468 | /* The static distance tree. (Actually a trivial tree since all codes use
|
---|
1469 | * 5 bits.)
|
---|
1470 | */
|
---|
1471 |
|
---|
1472 | static ct_data bl_tree[2 * BL_CODES + 1];
|
---|
1473 |
|
---|
1474 | /* Huffman tree for the bit lengths */
|
---|
1475 |
|
---|
1476 | typedef struct tree_desc {
|
---|
1477 | ct_data *dyn_tree; /* the dynamic tree */
|
---|
1478 | ct_data *static_tree; /* corresponding static tree or NULL */
|
---|
1479 | const extra_bits_t *extra_bits; /* extra bits for each code or NULL */
|
---|
1480 | int extra_base; /* base index for extra_bits */
|
---|
1481 | int elems; /* max number of elements in the tree */
|
---|
1482 | int max_length; /* max bit length for the codes */
|
---|
1483 | int max_code; /* largest code with non zero frequency */
|
---|
1484 | } tree_desc;
|
---|
1485 |
|
---|
1486 | static tree_desc l_desc =
|
---|
1487 | { dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES,
|
---|
1488 | MAX_BITS, 0
|
---|
1489 | };
|
---|
1490 |
|
---|
1491 | static tree_desc d_desc =
|
---|
1492 | { dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 };
|
---|
1493 |
|
---|
1494 | static tree_desc bl_desc =
|
---|
1495 | { bl_tree, (ct_data *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS,
|
---|
1496 | 0
|
---|
1497 | };
|
---|
1498 |
|
---|
1499 |
|
---|
1500 | static ush bl_count[MAX_BITS + 1];
|
---|
1501 |
|
---|
1502 | /* number of codes at each bit length for an optimal tree */
|
---|
1503 |
|
---|
1504 | static const uch bl_order[BL_CODES]
|
---|
1505 | = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
|
---|
1506 |
|
---|
1507 | /* The lengths of the bit length codes are sent in order of decreasing
|
---|
1508 | * probability, to avoid transmitting the lengths for unused bit length codes.
|
---|
1509 | */
|
---|
1510 |
|
---|
1511 | static int heap[2 * L_CODES + 1]; /* heap used to build the Huffman trees */
|
---|
1512 | static int heap_len; /* number of elements in the heap */
|
---|
1513 | static int heap_max; /* element of largest frequency */
|
---|
1514 |
|
---|
1515 | /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
|
---|
1516 | * The same heap array is used to build all trees.
|
---|
1517 | */
|
---|
1518 |
|
---|
1519 | static uch depth[2 * L_CODES + 1];
|
---|
1520 |
|
---|
1521 | /* Depth of each subtree used as tie breaker for trees of equal frequency */
|
---|
1522 |
|
---|
1523 | static uch length_code[MAX_MATCH - MIN_MATCH + 1];
|
---|
1524 |
|
---|
1525 | /* length code for each normalized match length (0 == MIN_MATCH) */
|
---|
1526 |
|
---|
1527 | static uch dist_code[512];
|
---|
1528 |
|
---|
1529 | /* distance codes. The first 256 values correspond to the distances
|
---|
1530 | * 3 .. 258, the last 256 values correspond to the top 8 bits of
|
---|
1531 | * the 15 bit distances.
|
---|
1532 | */
|
---|
1533 |
|
---|
1534 | static int base_length[LENGTH_CODES];
|
---|
1535 |
|
---|
1536 | /* First normalized length for each code (0 = MIN_MATCH) */
|
---|
1537 |
|
---|
1538 | static int base_dist[D_CODES];
|
---|
1539 |
|
---|
1540 | /* First normalized distance for each code (0 = distance of 1) */
|
---|
1541 |
|
---|
1542 | #define l_buf inbuf
|
---|
1543 | /* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */
|
---|
1544 |
|
---|
1545 | /* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */
|
---|
1546 |
|
---|
1547 | static uch flag_buf[(LIT_BUFSIZE / 8)];
|
---|
1548 |
|
---|
1549 | /* flag_buf is a bit array distinguishing literals from lengths in
|
---|
1550 | * l_buf, thus indicating the presence or absence of a distance.
|
---|
1551 | */
|
---|
1552 |
|
---|
1553 | static unsigned last_lit; /* running index in l_buf */
|
---|
1554 | static unsigned last_dist; /* running index in d_buf */
|
---|
1555 | static unsigned last_flags; /* running index in flag_buf */
|
---|
1556 | static uch flags; /* current flags not yet saved in flag_buf */
|
---|
1557 | static uch flag_bit; /* current bit used in flags */
|
---|
1558 |
|
---|
1559 | /* bits are filled in flags starting at bit 0 (least significant).
|
---|
1560 | * Note: these flags are overkill in the current code since we don't
|
---|
1561 | * take advantage of DIST_BUFSIZE == LIT_BUFSIZE.
|
---|
1562 | */
|
---|
1563 |
|
---|
1564 | static ulg opt_len; /* bit length of current block with optimal trees */
|
---|
1565 | static ulg static_len; /* bit length of current block with static trees */
|
---|
1566 |
|
---|
1567 | static ulg compressed_len; /* total bit length of compressed file */
|
---|
1568 |
|
---|
1569 |
|
---|
1570 | static ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */
|
---|
1571 | static int *file_method; /* pointer to DEFLATE or STORE */
|
---|
1572 |
|
---|
1573 | /* ===========================================================================
|
---|
1574 | * Local (static) routines in this file.
|
---|
1575 | */
|
---|
1576 |
|
---|
1577 | static void init_block(void);
|
---|
1578 | static void pqdownheap(ct_data * tree, int k);
|
---|
1579 | static void gen_bitlen(tree_desc * desc);
|
---|
1580 | static void gen_codes(ct_data * tree, int max_code);
|
---|
1581 | static void build_tree(tree_desc * desc);
|
---|
1582 | static void scan_tree(ct_data * tree, int max_code);
|
---|
1583 | static void send_tree(ct_data * tree, int max_code);
|
---|
1584 | static int build_bl_tree(void);
|
---|
1585 | static void send_all_trees(int lcodes, int dcodes, int blcodes);
|
---|
1586 | static void compress_block(ct_data * ltree, ct_data * dtree);
|
---|
1587 | static void set_file_type(void);
|
---|
1588 |
|
---|
1589 |
|
---|
1590 | #ifndef DEBUG
|
---|
1591 | # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len)
|
---|
1592 | /* Send a code of the given tree. c and tree must not have side effects */
|
---|
1593 |
|
---|
1594 | #else /* DEBUG */
|
---|
1595 | # define send_code(c, tree) \
|
---|
1596 | { if (verbose>1) bb_error_msg("\ncd %3d ",(c)); \
|
---|
1597 | send_bits(tree[c].Code, tree[c].Len); }
|
---|
1598 | #endif
|
---|
1599 |
|
---|
1600 | #define d_code(dist) \
|
---|
1601 | ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
|
---|
1602 | /* Mapping from a distance to a distance code. dist is the distance - 1 and
|
---|
1603 | * must not have side effects. dist_code[256] and dist_code[257] are never
|
---|
1604 | * used.
|
---|
1605 | */
|
---|
1606 |
|
---|
1607 | /* the arguments must not have side effects */
|
---|
1608 |
|
---|
1609 | /* ===========================================================================
|
---|
1610 | * Allocate the match buffer, initialize the various tables and save the
|
---|
1611 | * location of the internal file attribute (ascii/binary) and method
|
---|
1612 | * (DEFLATE/STORE).
|
---|
1613 | */
|
---|
1614 | static void ct_init(ush * attr, int *methodp)
|
---|
1615 | {
|
---|
1616 | int n; /* iterates over tree elements */
|
---|
1617 | int bits; /* bit counter */
|
---|
1618 | int length; /* length value */
|
---|
1619 | int code; /* code value */
|
---|
1620 | int dist; /* distance index */
|
---|
1621 |
|
---|
1622 | file_type = attr;
|
---|
1623 | file_method = methodp;
|
---|
1624 | compressed_len = 0L;
|
---|
1625 |
|
---|
1626 | if (static_dtree[0].Len != 0)
|
---|
1627 | return; /* ct_init already called */
|
---|
1628 |
|
---|
1629 | /* Initialize the mapping length (0..255) -> length code (0..28) */
|
---|
1630 | length = 0;
|
---|
1631 | for (code = 0; code < LENGTH_CODES - 1; code++) {
|
---|
1632 | base_length[code] = length;
|
---|
1633 | for (n = 0; n < (1 << extra_lbits[code]); n++) {
|
---|
1634 | length_code[length++] = (uch) code;
|
---|
1635 | }
|
---|
1636 | }
|
---|
1637 | Assert(length == 256, "ct_init: length != 256");
|
---|
1638 | /* Note that the length 255 (match length 258) can be represented
|
---|
1639 | * in two different ways: code 284 + 5 bits or code 285, so we
|
---|
1640 | * overwrite length_code[255] to use the best encoding:
|
---|
1641 | */
|
---|
1642 | length_code[length - 1] = (uch) code;
|
---|
1643 |
|
---|
1644 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
|
---|
1645 | dist = 0;
|
---|
1646 | for (code = 0; code < 16; code++) {
|
---|
1647 | base_dist[code] = dist;
|
---|
1648 | for (n = 0; n < (1 << extra_dbits[code]); n++) {
|
---|
1649 | dist_code[dist++] = (uch) code;
|
---|
1650 | }
|
---|
1651 | }
|
---|
1652 | Assert(dist == 256, "ct_init: dist != 256");
|
---|
1653 | dist >>= 7; /* from now on, all distances are divided by 128 */
|
---|
1654 | for (; code < D_CODES; code++) {
|
---|
1655 | base_dist[code] = dist << 7;
|
---|
1656 | for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
|
---|
1657 | dist_code[256 + dist++] = (uch) code;
|
---|
1658 | }
|
---|
1659 | }
|
---|
1660 | Assert(dist == 256, "ct_init: 256+dist != 512");
|
---|
1661 |
|
---|
1662 | /* Construct the codes of the static literal tree */
|
---|
1663 | for (bits = 0; bits <= MAX_BITS; bits++)
|
---|
1664 | bl_count[bits] = 0;
|
---|
1665 | n = 0;
|
---|
1666 | while (n <= 143)
|
---|
1667 | static_ltree[n++].Len = 8, bl_count[8]++;
|
---|
1668 | while (n <= 255)
|
---|
1669 | static_ltree[n++].Len = 9, bl_count[9]++;
|
---|
1670 | while (n <= 279)
|
---|
1671 | static_ltree[n++].Len = 7, bl_count[7]++;
|
---|
1672 | while (n <= 287)
|
---|
1673 | static_ltree[n++].Len = 8, bl_count[8]++;
|
---|
1674 | /* Codes 286 and 287 do not exist, but we must include them in the
|
---|
1675 | * tree construction to get a canonical Huffman tree (longest code
|
---|
1676 | * all ones)
|
---|
1677 | */
|
---|
1678 | gen_codes((ct_data *) static_ltree, L_CODES + 1);
|
---|
1679 |
|
---|
1680 | /* The static distance tree is trivial: */
|
---|
1681 | for (n = 0; n < D_CODES; n++) {
|
---|
1682 | static_dtree[n].Len = 5;
|
---|
1683 | static_dtree[n].Code = bi_reverse(n, 5);
|
---|
1684 | }
|
---|
1685 |
|
---|
1686 | /* Initialize the first block of the first file: */
|
---|
1687 | init_block();
|
---|
1688 | }
|
---|
1689 |
|
---|
1690 | /* ===========================================================================
|
---|
1691 | * Initialize a new block.
|
---|
1692 | */
|
---|
1693 | static void init_block(void)
|
---|
1694 | {
|
---|
1695 | int n; /* iterates over tree elements */
|
---|
1696 |
|
---|
1697 | /* Initialize the trees. */
|
---|
1698 | for (n = 0; n < L_CODES; n++)
|
---|
1699 | dyn_ltree[n].Freq = 0;
|
---|
1700 | for (n = 0; n < D_CODES; n++)
|
---|
1701 | dyn_dtree[n].Freq = 0;
|
---|
1702 | for (n = 0; n < BL_CODES; n++)
|
---|
1703 | bl_tree[n].Freq = 0;
|
---|
1704 |
|
---|
1705 | dyn_ltree[END_BLOCK].Freq = 1;
|
---|
1706 | opt_len = static_len = 0L;
|
---|
1707 | last_lit = last_dist = last_flags = 0;
|
---|
1708 | flags = 0;
|
---|
1709 | flag_bit = 1;
|
---|
1710 | }
|
---|
1711 |
|
---|
1712 | #define SMALLEST 1
|
---|
1713 | /* Index within the heap array of least frequent node in the Huffman tree */
|
---|
1714 |
|
---|
1715 |
|
---|
1716 | /* ===========================================================================
|
---|
1717 | * Remove the smallest element from the heap and recreate the heap with
|
---|
1718 | * one less element. Updates heap and heap_len.
|
---|
1719 | */
|
---|
1720 | #define pqremove(tree, top) \
|
---|
1721 | {\
|
---|
1722 | top = heap[SMALLEST]; \
|
---|
1723 | heap[SMALLEST] = heap[heap_len--]; \
|
---|
1724 | pqdownheap(tree, SMALLEST); \
|
---|
1725 | }
|
---|
1726 |
|
---|
1727 | /* ===========================================================================
|
---|
1728 | * Compares to subtrees, using the tree depth as tie breaker when
|
---|
1729 | * the subtrees have equal frequency. This minimizes the worst case length.
|
---|
1730 | */
|
---|
1731 | #define smaller(tree, n, m) \
|
---|
1732 | (tree[n].Freq < tree[m].Freq || \
|
---|
1733 | (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
|
---|
1734 |
|
---|
1735 | /* ===========================================================================
|
---|
1736 | * Restore the heap property by moving down the tree starting at node k,
|
---|
1737 | * exchanging a node with the smallest of its two sons if necessary, stopping
|
---|
1738 | * when the heap property is re-established (each father smaller than its
|
---|
1739 | * two sons).
|
---|
1740 | */
|
---|
1741 | static void pqdownheap(ct_data * tree, int k)
|
---|
1742 | {
|
---|
1743 | int v = heap[k];
|
---|
1744 | int j = k << 1; /* left son of k */
|
---|
1745 |
|
---|
1746 | while (j <= heap_len) {
|
---|
1747 | /* Set j to the smallest of the two sons: */
|
---|
1748 | if (j < heap_len && smaller(tree, heap[j + 1], heap[j]))
|
---|
1749 | j++;
|
---|
1750 |
|
---|
1751 | /* Exit if v is smaller than both sons */
|
---|
1752 | if (smaller(tree, v, heap[j]))
|
---|
1753 | break;
|
---|
1754 |
|
---|
1755 | /* Exchange v with the smallest son */
|
---|
1756 | heap[k] = heap[j];
|
---|
1757 | k = j;
|
---|
1758 |
|
---|
1759 | /* And continue down the tree, setting j to the left son of k */
|
---|
1760 | j <<= 1;
|
---|
1761 | }
|
---|
1762 | heap[k] = v;
|
---|
1763 | }
|
---|
1764 |
|
---|
1765 | /* ===========================================================================
|
---|
1766 | * Compute the optimal bit lengths for a tree and update the total bit length
|
---|
1767 | * for the current block.
|
---|
1768 | * IN assertion: the fields freq and dad are set, heap[heap_max] and
|
---|
1769 | * above are the tree nodes sorted by increasing frequency.
|
---|
1770 | * OUT assertions: the field len is set to the optimal bit length, the
|
---|
1771 | * array bl_count contains the frequencies for each bit length.
|
---|
1772 | * The length opt_len is updated; static_len is also updated if stree is
|
---|
1773 | * not null.
|
---|
1774 | */
|
---|
1775 | static void gen_bitlen(tree_desc * desc)
|
---|
1776 | {
|
---|
1777 | ct_data *tree = desc->dyn_tree;
|
---|
1778 | const extra_bits_t *extra = desc->extra_bits;
|
---|
1779 | int base = desc->extra_base;
|
---|
1780 | int max_code = desc->max_code;
|
---|
1781 | int max_length = desc->max_length;
|
---|
1782 | ct_data *stree = desc->static_tree;
|
---|
1783 | int h; /* heap index */
|
---|
1784 | int n, m; /* iterate over the tree elements */
|
---|
1785 | int bits; /* bit length */
|
---|
1786 | int xbits; /* extra bits */
|
---|
1787 | ush f; /* frequency */
|
---|
1788 | int overflow = 0; /* number of elements with bit length too large */
|
---|
1789 |
|
---|
1790 | for (bits = 0; bits <= MAX_BITS; bits++)
|
---|
1791 | bl_count[bits] = 0;
|
---|
1792 |
|
---|
1793 | /* In a first pass, compute the optimal bit lengths (which may
|
---|
1794 | * overflow in the case of the bit length tree).
|
---|
1795 | */
|
---|
1796 | tree[heap[heap_max]].Len = 0; /* root of the heap */
|
---|
1797 |
|
---|
1798 | for (h = heap_max + 1; h < HEAP_SIZE; h++) {
|
---|
1799 | n = heap[h];
|
---|
1800 | bits = tree[tree[n].Dad].Len + 1;
|
---|
1801 | if (bits > max_length)
|
---|
1802 | bits = max_length, overflow++;
|
---|
1803 | tree[n].Len = (ush) bits;
|
---|
1804 | /* We overwrite tree[n].Dad which is no longer needed */
|
---|
1805 |
|
---|
1806 | if (n > max_code)
|
---|
1807 | continue; /* not a leaf node */
|
---|
1808 |
|
---|
1809 | bl_count[bits]++;
|
---|
1810 | xbits = 0;
|
---|
1811 | if (n >= base)
|
---|
1812 | xbits = extra[n - base];
|
---|
1813 | f = tree[n].Freq;
|
---|
1814 | opt_len += (ulg) f *(bits + xbits);
|
---|
1815 |
|
---|
1816 | if (stree)
|
---|
1817 | static_len += (ulg) f *(stree[n].Len + xbits);
|
---|
1818 | }
|
---|
1819 | if (overflow == 0)
|
---|
1820 | return;
|
---|
1821 |
|
---|
1822 | Trace((stderr, "\nbit length overflow\n"));
|
---|
1823 | /* This happens for example on obj2 and pic of the Calgary corpus */
|
---|
1824 |
|
---|
1825 | /* Find the first bit length which could increase: */
|
---|
1826 | do {
|
---|
1827 | bits = max_length - 1;
|
---|
1828 | while (bl_count[bits] == 0)
|
---|
1829 | bits--;
|
---|
1830 | bl_count[bits]--; /* move one leaf down the tree */
|
---|
1831 | bl_count[bits + 1] += 2; /* move one overflow item as its brother */
|
---|
1832 | bl_count[max_length]--;
|
---|
1833 | /* The brother of the overflow item also moves one step up,
|
---|
1834 | * but this does not affect bl_count[max_length]
|
---|
1835 | */
|
---|
1836 | overflow -= 2;
|
---|
1837 | } while (overflow > 0);
|
---|
1838 |
|
---|
1839 | /* Now recompute all bit lengths, scanning in increasing frequency.
|
---|
1840 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
|
---|
1841 | * lengths instead of fixing only the wrong ones. This idea is taken
|
---|
1842 | * from 'ar' written by Haruhiko Okumura.)
|
---|
1843 | */
|
---|
1844 | for (bits = max_length; bits != 0; bits--) {
|
---|
1845 | n = bl_count[bits];
|
---|
1846 | while (n != 0) {
|
---|
1847 | m = heap[--h];
|
---|
1848 | if (m > max_code)
|
---|
1849 | continue;
|
---|
1850 | if (tree[m].Len != (unsigned) bits) {
|
---|
1851 | Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len,
|
---|
1852 | bits));
|
---|
1853 | opt_len +=
|
---|
1854 | ((long) bits - (long) tree[m].Len) * (long) tree[m].Freq;
|
---|
1855 | tree[m].Len = (ush) bits;
|
---|
1856 | }
|
---|
1857 | n--;
|
---|
1858 | }
|
---|
1859 | }
|
---|
1860 | }
|
---|
1861 |
|
---|
1862 | /* ===========================================================================
|
---|
1863 | * Generate the codes for a given tree and bit counts (which need not be
|
---|
1864 | * optimal).
|
---|
1865 | * IN assertion: the array bl_count contains the bit length statistics for
|
---|
1866 | * the given tree and the field len is set for all tree elements.
|
---|
1867 | * OUT assertion: the field code is set for all tree elements of non
|
---|
1868 | * zero code length.
|
---|
1869 | */
|
---|
1870 | static void gen_codes(ct_data * tree, int max_code)
|
---|
1871 | {
|
---|
1872 | ush next_code[MAX_BITS + 1]; /* next code value for each bit length */
|
---|
1873 | ush code = 0; /* running code value */
|
---|
1874 | int bits; /* bit index */
|
---|
1875 | int n; /* code index */
|
---|
1876 |
|
---|
1877 | /* The distribution counts are first used to generate the code values
|
---|
1878 | * without bit reversal.
|
---|
1879 | */
|
---|
1880 | for (bits = 1; bits <= MAX_BITS; bits++) {
|
---|
1881 | next_code[bits] = code = (code + bl_count[bits - 1]) << 1;
|
---|
1882 | }
|
---|
1883 | /* Check that the bit counts in bl_count are consistent. The last code
|
---|
1884 | * must be all ones.
|
---|
1885 | */
|
---|
1886 | Assert(code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
|
---|
1887 | "inconsistent bit counts");
|
---|
1888 | Tracev((stderr, "\ngen_codes: max_code %d ", max_code));
|
---|
1889 |
|
---|
1890 | for (n = 0; n <= max_code; n++) {
|
---|
1891 | int len = tree[n].Len;
|
---|
1892 |
|
---|
1893 | if (len == 0)
|
---|
1894 | continue;
|
---|
1895 | /* Now reverse the bits */
|
---|
1896 | tree[n].Code = bi_reverse(next_code[len]++, len);
|
---|
1897 |
|
---|
1898 | Tracec(tree != static_ltree,
|
---|
1899 | (stderr, "\nn %3d %c l %2d c %4x (%x) ", n,
|
---|
1900 | (isgraph(n) ? n : ' '), len, tree[n].Code,
|
---|
1901 | next_code[len] - 1));
|
---|
1902 | }
|
---|
1903 | }
|
---|
1904 |
|
---|
1905 | /* ===========================================================================
|
---|
1906 | * Construct one Huffman tree and assigns the code bit strings and lengths.
|
---|
1907 | * Update the total bit length for the current block.
|
---|
1908 | * IN assertion: the field freq is set for all tree elements.
|
---|
1909 | * OUT assertions: the fields len and code are set to the optimal bit length
|
---|
1910 | * and corresponding code. The length opt_len is updated; static_len is
|
---|
1911 | * also updated if stree is not null. The field max_code is set.
|
---|
1912 | */
|
---|
1913 | static void build_tree(tree_desc * desc)
|
---|
1914 | {
|
---|
1915 | ct_data *tree = desc->dyn_tree;
|
---|
1916 | ct_data *stree = desc->static_tree;
|
---|
1917 | int elems = desc->elems;
|
---|
1918 | int n, m; /* iterate over heap elements */
|
---|
1919 | int max_code = -1; /* largest code with non zero frequency */
|
---|
1920 | int node = elems; /* next internal node of the tree */
|
---|
1921 |
|
---|
1922 | /* Construct the initial heap, with least frequent element in
|
---|
1923 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
|
---|
1924 | * heap[0] is not used.
|
---|
1925 | */
|
---|
1926 | heap_len = 0, heap_max = HEAP_SIZE;
|
---|
1927 |
|
---|
1928 | for (n = 0; n < elems; n++) {
|
---|
1929 | if (tree[n].Freq != 0) {
|
---|
1930 | heap[++heap_len] = max_code = n;
|
---|
1931 | depth[n] = 0;
|
---|
1932 | } else {
|
---|
1933 | tree[n].Len = 0;
|
---|
1934 | }
|
---|
1935 | }
|
---|
1936 |
|
---|
1937 | /* The pkzip format requires that at least one distance code exists,
|
---|
1938 | * and that at least one bit should be sent even if there is only one
|
---|
1939 | * possible code. So to avoid special checks later on we force at least
|
---|
1940 | * two codes of non zero frequency.
|
---|
1941 | */
|
---|
1942 | while (heap_len < 2) {
|
---|
1943 | int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0);
|
---|
1944 |
|
---|
1945 | tree[new].Freq = 1;
|
---|
1946 | depth[new] = 0;
|
---|
1947 | opt_len--;
|
---|
1948 | if (stree)
|
---|
1949 | static_len -= stree[new].Len;
|
---|
1950 | /* new is 0 or 1 so it does not have extra bits */
|
---|
1951 | }
|
---|
1952 | desc->max_code = max_code;
|
---|
1953 |
|
---|
1954 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
|
---|
1955 | * establish sub-heaps of increasing lengths:
|
---|
1956 | */
|
---|
1957 | for (n = heap_len / 2; n >= 1; n--)
|
---|
1958 | pqdownheap(tree, n);
|
---|
1959 |
|
---|
1960 | /* Construct the Huffman tree by repeatedly combining the least two
|
---|
1961 | * frequent nodes.
|
---|
1962 | */
|
---|
1963 | do {
|
---|
1964 | pqremove(tree, n); /* n = node of least frequency */
|
---|
1965 | m = heap[SMALLEST]; /* m = node of next least frequency */
|
---|
1966 |
|
---|
1967 | heap[--heap_max] = n; /* keep the nodes sorted by frequency */
|
---|
1968 | heap[--heap_max] = m;
|
---|
1969 |
|
---|
1970 | /* Create a new node father of n and m */
|
---|
1971 | tree[node].Freq = tree[n].Freq + tree[m].Freq;
|
---|
1972 | depth[node] = (uch) (MAX(depth[n], depth[m]) + 1);
|
---|
1973 | tree[n].Dad = tree[m].Dad = (ush) node;
|
---|
1974 | #ifdef DUMP_BL_TREE
|
---|
1975 | if (tree == bl_tree) {
|
---|
1976 | bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)",
|
---|
1977 | node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
|
---|
1978 | }
|
---|
1979 | #endif
|
---|
1980 | /* and insert the new node in the heap */
|
---|
1981 | heap[SMALLEST] = node++;
|
---|
1982 | pqdownheap(tree, SMALLEST);
|
---|
1983 |
|
---|
1984 | } while (heap_len >= 2);
|
---|
1985 |
|
---|
1986 | heap[--heap_max] = heap[SMALLEST];
|
---|
1987 |
|
---|
1988 | /* At this point, the fields freq and dad are set. We can now
|
---|
1989 | * generate the bit lengths.
|
---|
1990 | */
|
---|
1991 | gen_bitlen((tree_desc *) desc);
|
---|
1992 |
|
---|
1993 | /* The field len is now set, we can generate the bit codes */
|
---|
1994 | gen_codes((ct_data *) tree, max_code);
|
---|
1995 | }
|
---|
1996 |
|
---|
1997 | /* ===========================================================================
|
---|
1998 | * Scan a literal or distance tree to determine the frequencies of the codes
|
---|
1999 | * in the bit length tree. Updates opt_len to take into account the repeat
|
---|
2000 | * counts. (The contribution of the bit length codes will be added later
|
---|
2001 | * during the construction of bl_tree.)
|
---|
2002 | */
|
---|
2003 | static void scan_tree(ct_data * tree, int max_code)
|
---|
2004 | {
|
---|
2005 | int n; /* iterates over all tree elements */
|
---|
2006 | int prevlen = -1; /* last emitted length */
|
---|
2007 | int curlen; /* length of current code */
|
---|
2008 | int nextlen = tree[0].Len; /* length of next code */
|
---|
2009 | int count = 0; /* repeat count of the current code */
|
---|
2010 | int max_count = 7; /* max repeat count */
|
---|
2011 | int min_count = 4; /* min repeat count */
|
---|
2012 |
|
---|
2013 | if (nextlen == 0)
|
---|
2014 | max_count = 138, min_count = 3;
|
---|
2015 | tree[max_code + 1].Len = (ush) 0xffff; /* guard */
|
---|
2016 |
|
---|
2017 | for (n = 0; n <= max_code; n++) {
|
---|
2018 | curlen = nextlen;
|
---|
2019 | nextlen = tree[n + 1].Len;
|
---|
2020 | if (++count < max_count && curlen == nextlen) {
|
---|
2021 | continue;
|
---|
2022 | } else if (count < min_count) {
|
---|
2023 | bl_tree[curlen].Freq += count;
|
---|
2024 | } else if (curlen != 0) {
|
---|
2025 | if (curlen != prevlen)
|
---|
2026 | bl_tree[curlen].Freq++;
|
---|
2027 | bl_tree[REP_3_6].Freq++;
|
---|
2028 | } else if (count <= 10) {
|
---|
2029 | bl_tree[REPZ_3_10].Freq++;
|
---|
2030 | } else {
|
---|
2031 | bl_tree[REPZ_11_138].Freq++;
|
---|
2032 | }
|
---|
2033 | count = 0;
|
---|
2034 | prevlen = curlen;
|
---|
2035 | if (nextlen == 0) {
|
---|
2036 | max_count = 138, min_count = 3;
|
---|
2037 | } else if (curlen == nextlen) {
|
---|
2038 | max_count = 6, min_count = 3;
|
---|
2039 | } else {
|
---|
2040 | max_count = 7, min_count = 4;
|
---|
2041 | }
|
---|
2042 | }
|
---|
2043 | }
|
---|
2044 |
|
---|
2045 | /* ===========================================================================
|
---|
2046 | * Send a literal or distance tree in compressed form, using the codes in
|
---|
2047 | * bl_tree.
|
---|
2048 | */
|
---|
2049 | static void send_tree(ct_data * tree, int max_code)
|
---|
2050 | {
|
---|
2051 | int n; /* iterates over all tree elements */
|
---|
2052 | int prevlen = -1; /* last emitted length */
|
---|
2053 | int curlen; /* length of current code */
|
---|
2054 | int nextlen = tree[0].Len; /* length of next code */
|
---|
2055 | int count = 0; /* repeat count of the current code */
|
---|
2056 | int max_count = 7; /* max repeat count */
|
---|
2057 | int min_count = 4; /* min repeat count */
|
---|
2058 |
|
---|
2059 | /* tree[max_code+1].Len = -1; *//* guard already set */
|
---|
2060 | if (nextlen == 0)
|
---|
2061 | max_count = 138, min_count = 3;
|
---|
2062 |
|
---|
2063 | for (n = 0; n <= max_code; n++) {
|
---|
2064 | curlen = nextlen;
|
---|
2065 | nextlen = tree[n + 1].Len;
|
---|
2066 | if (++count < max_count && curlen == nextlen) {
|
---|
2067 | continue;
|
---|
2068 | } else if (count < min_count) {
|
---|
2069 | do {
|
---|
2070 | send_code(curlen, bl_tree);
|
---|
2071 | } while (--count != 0);
|
---|
2072 |
|
---|
2073 | } else if (curlen != 0) {
|
---|
2074 | if (curlen != prevlen) {
|
---|
2075 | send_code(curlen, bl_tree);
|
---|
2076 | count--;
|
---|
2077 | }
|
---|
2078 | Assert(count >= 3 && count <= 6, " 3_6?");
|
---|
2079 | send_code(REP_3_6, bl_tree);
|
---|
2080 | send_bits(count - 3, 2);
|
---|
2081 |
|
---|
2082 | } else if (count <= 10) {
|
---|
2083 | send_code(REPZ_3_10, bl_tree);
|
---|
2084 | send_bits(count - 3, 3);
|
---|
2085 |
|
---|
2086 | } else {
|
---|
2087 | send_code(REPZ_11_138, bl_tree);
|
---|
2088 | send_bits(count - 11, 7);
|
---|
2089 | }
|
---|
2090 | count = 0;
|
---|
2091 | prevlen = curlen;
|
---|
2092 | if (nextlen == 0) {
|
---|
2093 | max_count = 138, min_count = 3;
|
---|
2094 | } else if (curlen == nextlen) {
|
---|
2095 | max_count = 6, min_count = 3;
|
---|
2096 | } else {
|
---|
2097 | max_count = 7, min_count = 4;
|
---|
2098 | }
|
---|
2099 | }
|
---|
2100 | }
|
---|
2101 |
|
---|
2102 | /* ===========================================================================
|
---|
2103 | * Construct the Huffman tree for the bit lengths and return the index in
|
---|
2104 | * bl_order of the last bit length code to send.
|
---|
2105 | */
|
---|
2106 | static int build_bl_tree(void)
|
---|
2107 | {
|
---|
2108 | int max_blindex; /* index of last bit length code of non zero freq */
|
---|
2109 |
|
---|
2110 | /* Determine the bit length frequencies for literal and distance trees */
|
---|
2111 | scan_tree((ct_data *) dyn_ltree, l_desc.max_code);
|
---|
2112 | scan_tree((ct_data *) dyn_dtree, d_desc.max_code);
|
---|
2113 |
|
---|
2114 | /* Build the bit length tree: */
|
---|
2115 | build_tree((tree_desc *) (&bl_desc));
|
---|
2116 | /* opt_len now includes the length of the tree representations, except
|
---|
2117 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
|
---|
2118 | */
|
---|
2119 |
|
---|
2120 | /* Determine the number of bit length codes to send. The pkzip format
|
---|
2121 | * requires that at least 4 bit length codes be sent. (appnote.txt says
|
---|
2122 | * 3 but the actual value used is 4.)
|
---|
2123 | */
|
---|
2124 | for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) {
|
---|
2125 | if (bl_tree[bl_order[max_blindex]].Len != 0)
|
---|
2126 | break;
|
---|
2127 | }
|
---|
2128 | /* Update opt_len to include the bit length tree and counts */
|
---|
2129 | opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
|
---|
2130 | Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len, static_len));
|
---|
2131 |
|
---|
2132 | return max_blindex;
|
---|
2133 | }
|
---|
2134 |
|
---|
2135 | /* ===========================================================================
|
---|
2136 | * Send the header for a block using dynamic Huffman trees: the counts, the
|
---|
2137 | * lengths of the bit length codes, the literal tree and the distance tree.
|
---|
2138 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
|
---|
2139 | */
|
---|
2140 | static void send_all_trees(int lcodes, int dcodes, int blcodes)
|
---|
2141 | {
|
---|
2142 | int rank; /* index in bl_order */
|
---|
2143 |
|
---|
2144 | Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
|
---|
2145 | Assert(lcodes <= L_CODES && dcodes <= D_CODES
|
---|
2146 | && blcodes <= BL_CODES, "too many codes");
|
---|
2147 | Tracev((stderr, "\nbl counts: "));
|
---|
2148 | send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */
|
---|
2149 | send_bits(dcodes - 1, 5);
|
---|
2150 | send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */
|
---|
2151 | for (rank = 0; rank < blcodes; rank++) {
|
---|
2152 | Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
|
---|
2153 | send_bits(bl_tree[bl_order[rank]].Len, 3);
|
---|
2154 | }
|
---|
2155 | Tracev((stderr, "\nbl tree: sent %ld", bits_sent));
|
---|
2156 |
|
---|
2157 | send_tree((ct_data *) dyn_ltree, lcodes - 1); /* send the literal tree */
|
---|
2158 | Tracev((stderr, "\nlit tree: sent %ld", bits_sent));
|
---|
2159 |
|
---|
2160 | send_tree((ct_data *) dyn_dtree, dcodes - 1); /* send the distance tree */
|
---|
2161 | Tracev((stderr, "\ndist tree: sent %ld", bits_sent));
|
---|
2162 | }
|
---|
2163 |
|
---|
2164 | /* ===========================================================================
|
---|
2165 | * Determine the best encoding for the current block: dynamic trees, static
|
---|
2166 | * trees or store, and output the encoded block to the zip file. This function
|
---|
2167 | * returns the total compressed length for the file so far.
|
---|
2168 | */
|
---|
2169 | static ulg flush_block(char *buf, ulg stored_len, int eof)
|
---|
2170 | {
|
---|
2171 | ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
|
---|
2172 | int max_blindex; /* index of last bit length code of non zero freq */
|
---|
2173 |
|
---|
2174 | flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */
|
---|
2175 |
|
---|
2176 | /* Check if the file is ascii or binary */
|
---|
2177 | if (*file_type == (ush) UNKNOWN)
|
---|
2178 | set_file_type();
|
---|
2179 |
|
---|
2180 | /* Construct the literal and distance trees */
|
---|
2181 | build_tree((tree_desc *) (&l_desc));
|
---|
2182 | Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));
|
---|
2183 |
|
---|
2184 | build_tree((tree_desc *) (&d_desc));
|
---|
2185 | Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len));
|
---|
2186 | /* At this point, opt_len and static_len are the total bit lengths of
|
---|
2187 | * the compressed block data, excluding the tree representations.
|
---|
2188 | */
|
---|
2189 |
|
---|
2190 | /* Build the bit length tree for the above two trees, and get the index
|
---|
2191 | * in bl_order of the last bit length code to send.
|
---|
2192 | */
|
---|
2193 | max_blindex = build_bl_tree();
|
---|
2194 |
|
---|
2195 | /* Determine the best encoding. Compute first the block length in bytes */
|
---|
2196 | opt_lenb = (opt_len + 3 + 7) >> 3;
|
---|
2197 | static_lenb = (static_len + 3 + 7) >> 3;
|
---|
2198 |
|
---|
2199 | Trace((stderr,
|
---|
2200 | "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",
|
---|
2201 | opt_lenb, opt_len, static_lenb, static_len, stored_len,
|
---|
2202 | last_lit, last_dist));
|
---|
2203 |
|
---|
2204 | if (static_lenb <= opt_lenb)
|
---|
2205 | opt_lenb = static_lenb;
|
---|
2206 |
|
---|
2207 | /* If compression failed and this is the first and last block,
|
---|
2208 | * and if the zip file can be seeked (to rewrite the local header),
|
---|
2209 | * the whole file is transformed into a stored file:
|
---|
2210 | */
|
---|
2211 | if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) {
|
---|
2212 | /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
|
---|
2213 | if (buf == (char *) 0)
|
---|
2214 | bb_error_msg("block vanished");
|
---|
2215 |
|
---|
2216 | copy_block(buf, (unsigned) stored_len, 0); /* without header */
|
---|
2217 | compressed_len = stored_len << 3;
|
---|
2218 | *file_method = STORED;
|
---|
2219 |
|
---|
2220 | } else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) {
|
---|
2221 | /* 4: two words for the lengths */
|
---|
2222 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
|
---|
2223 | * Otherwise we can't have processed more than WSIZE input bytes since
|
---|
2224 | * the last block flush, because compression would have been
|
---|
2225 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
|
---|
2226 | * transform a block into a stored block.
|
---|
2227 | */
|
---|
2228 | send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */
|
---|
2229 | compressed_len = (compressed_len + 3 + 7) & ~7L;
|
---|
2230 | compressed_len += (stored_len + 4) << 3;
|
---|
2231 |
|
---|
2232 | copy_block(buf, (unsigned) stored_len, 1); /* with header */
|
---|
2233 |
|
---|
2234 | } else if (static_lenb == opt_lenb) {
|
---|
2235 | send_bits((STATIC_TREES << 1) + eof, 3);
|
---|
2236 | compress_block((ct_data *) static_ltree, (ct_data *) static_dtree);
|
---|
2237 | compressed_len += 3 + static_len;
|
---|
2238 | } else {
|
---|
2239 | send_bits((DYN_TREES << 1) + eof, 3);
|
---|
2240 | send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1,
|
---|
2241 | max_blindex + 1);
|
---|
2242 | compress_block((ct_data *) dyn_ltree, (ct_data *) dyn_dtree);
|
---|
2243 | compressed_len += 3 + opt_len;
|
---|
2244 | }
|
---|
2245 | Assert(compressed_len == bits_sent, "bad compressed size");
|
---|
2246 | init_block();
|
---|
2247 |
|
---|
2248 | if (eof) {
|
---|
2249 | bi_windup();
|
---|
2250 | compressed_len += 7; /* align on byte boundary */
|
---|
2251 | }
|
---|
2252 | Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3,
|
---|
2253 | compressed_len - 7 * eof));
|
---|
2254 |
|
---|
2255 | return compressed_len >> 3;
|
---|
2256 | }
|
---|
2257 |
|
---|
2258 | /* ===========================================================================
|
---|
2259 | * Save the match info and tally the frequency counts. Return true if
|
---|
2260 | * the current block must be flushed.
|
---|
2261 | */
|
---|
2262 | static int ct_tally(int dist, int lc)
|
---|
2263 | {
|
---|
2264 | l_buf[last_lit++] = (uch) lc;
|
---|
2265 | if (dist == 0) {
|
---|
2266 | /* lc is the unmatched char */
|
---|
2267 | dyn_ltree[lc].Freq++;
|
---|
2268 | } else {
|
---|
2269 | /* Here, lc is the match length - MIN_MATCH */
|
---|
2270 | dist--; /* dist = match distance - 1 */
|
---|
2271 | Assert((ush) dist < (ush) MAX_DIST &&
|
---|
2272 | (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) &&
|
---|
2273 | (ush) d_code(dist) < (ush) D_CODES, "ct_tally: bad match");
|
---|
2274 |
|
---|
2275 | dyn_ltree[length_code[lc] + LITERALS + 1].Freq++;
|
---|
2276 | dyn_dtree[d_code(dist)].Freq++;
|
---|
2277 |
|
---|
2278 | d_buf[last_dist++] = (ush) dist;
|
---|
2279 | flags |= flag_bit;
|
---|
2280 | }
|
---|
2281 | flag_bit <<= 1;
|
---|
2282 |
|
---|
2283 | /* Output the flags if they fill a byte: */
|
---|
2284 | if ((last_lit & 7) == 0) {
|
---|
2285 | flag_buf[last_flags++] = flags;
|
---|
2286 | flags = 0, flag_bit = 1;
|
---|
2287 | }
|
---|
2288 | /* Try to guess if it is profitable to stop the current block here */
|
---|
2289 | if ((last_lit & 0xfff) == 0) {
|
---|
2290 | /* Compute an upper bound for the compressed length */
|
---|
2291 | ulg out_length = (ulg) last_lit * 8L;
|
---|
2292 | ulg in_length = (ulg) strstart - block_start;
|
---|
2293 | int dcode;
|
---|
2294 |
|
---|
2295 | for (dcode = 0; dcode < D_CODES; dcode++) {
|
---|
2296 | out_length +=
|
---|
2297 | (ulg) dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]);
|
---|
2298 | }
|
---|
2299 | out_length >>= 3;
|
---|
2300 | Trace((stderr,
|
---|
2301 | "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",
|
---|
2302 | last_lit, last_dist, in_length, out_length,
|
---|
2303 | 100L - out_length * 100L / in_length));
|
---|
2304 | if (last_dist < last_lit / 2 && out_length < in_length / 2)
|
---|
2305 | return 1;
|
---|
2306 | }
|
---|
2307 | return (last_lit == LIT_BUFSIZE - 1 || last_dist == DIST_BUFSIZE);
|
---|
2308 | /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K
|
---|
2309 | * on 16 bit machines and because stored blocks are restricted to
|
---|
2310 | * 64K-1 bytes.
|
---|
2311 | */
|
---|
2312 | }
|
---|
2313 |
|
---|
2314 | /* ===========================================================================
|
---|
2315 | * Send the block data compressed using the given Huffman trees
|
---|
2316 | */
|
---|
2317 | static void compress_block(ct_data * ltree, ct_data * dtree)
|
---|
2318 | {
|
---|
2319 | unsigned dist; /* distance of matched string */
|
---|
2320 | int lc; /* match length or unmatched char (if dist == 0) */
|
---|
2321 | unsigned lx = 0; /* running index in l_buf */
|
---|
2322 | unsigned dx = 0; /* running index in d_buf */
|
---|
2323 | unsigned fx = 0; /* running index in flag_buf */
|
---|
2324 | uch flag = 0; /* current flags */
|
---|
2325 | unsigned code; /* the code to send */
|
---|
2326 | int extra; /* number of extra bits to send */
|
---|
2327 |
|
---|
2328 | if (last_lit != 0)
|
---|
2329 | do {
|
---|
2330 | if ((lx & 7) == 0)
|
---|
2331 | flag = flag_buf[fx++];
|
---|
2332 | lc = l_buf[lx++];
|
---|
2333 | if ((flag & 1) == 0) {
|
---|
2334 | send_code(lc, ltree); /* send a literal byte */
|
---|
2335 | Tracecv(isgraph(lc), (stderr, " '%c' ", lc));
|
---|
2336 | } else {
|
---|
2337 | /* Here, lc is the match length - MIN_MATCH */
|
---|
2338 | code = length_code[lc];
|
---|
2339 | send_code(code + LITERALS + 1, ltree); /* send the length code */
|
---|
2340 | extra = extra_lbits[code];
|
---|
2341 | if (extra != 0) {
|
---|
2342 | lc -= base_length[code];
|
---|
2343 | send_bits(lc, extra); /* send the extra length bits */
|
---|
2344 | }
|
---|
2345 | dist = d_buf[dx++];
|
---|
2346 | /* Here, dist is the match distance - 1 */
|
---|
2347 | code = d_code(dist);
|
---|
2348 | Assert(code < D_CODES, "bad d_code");
|
---|
2349 |
|
---|
2350 | send_code(code, dtree); /* send the distance code */
|
---|
2351 | extra = extra_dbits[code];
|
---|
2352 | if (extra != 0) {
|
---|
2353 | dist -= base_dist[code];
|
---|
2354 | send_bits(dist, extra); /* send the extra distance bits */
|
---|
2355 | }
|
---|
2356 | } /* literal or match pair ? */
|
---|
2357 | flag >>= 1;
|
---|
2358 | } while (lx < last_lit);
|
---|
2359 |
|
---|
2360 | send_code(END_BLOCK, ltree);
|
---|
2361 | }
|
---|
2362 |
|
---|
2363 | /* ===========================================================================
|
---|
2364 | * Set the file type to ASCII or BINARY, using a crude approximation:
|
---|
2365 | * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
|
---|
2366 | * IN assertion: the fields freq of dyn_ltree are set and the total of all
|
---|
2367 | * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
|
---|
2368 | */
|
---|
2369 | static void set_file_type(void)
|
---|
2370 | {
|
---|
2371 | int n = 0;
|
---|
2372 | unsigned ascii_freq = 0;
|
---|
2373 | unsigned bin_freq = 0;
|
---|
2374 |
|
---|
2375 | while (n < 7)
|
---|
2376 | bin_freq += dyn_ltree[n++].Freq;
|
---|
2377 | while (n < 128)
|
---|
2378 | ascii_freq += dyn_ltree[n++].Freq;
|
---|
2379 | while (n < LITERALS)
|
---|
2380 | bin_freq += dyn_ltree[n++].Freq;
|
---|
2381 | *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;
|
---|
2382 | if (*file_type == BINARY && translate_eol) {
|
---|
2383 | bb_error_msg("-l used on binary file");
|
---|
2384 | }
|
---|
2385 | }
|
---|
2386 |
|
---|
2387 | /* zip.c -- compress files to the gzip or pkzip format
|
---|
2388 | * Copyright (C) 1992-1993 Jean-loup Gailly
|
---|
2389 | * This is free software; you can redistribute it and/or modify it under the
|
---|
2390 | * terms of the GNU General Public License, see the file COPYING.
|
---|
2391 | */
|
---|
2392 |
|
---|
2393 |
|
---|
2394 | static uint32_t crc; /* crc on uncompressed file data */
|
---|
2395 | static long header_bytes; /* number of bytes in gzip header */
|
---|
2396 |
|
---|
2397 | static void put_long(ulg n)
|
---|
2398 | {
|
---|
2399 | put_short((n) & 0xffff);
|
---|
2400 | put_short(((ulg) (n)) >> 16);
|
---|
2401 | }
|
---|
2402 |
|
---|
2403 | /* put_header_byte is used for the compressed output
|
---|
2404 | * - for the initial 4 bytes that can't overflow the buffer.
|
---|
2405 | */
|
---|
2406 | #define put_header_byte(c) {outbuf[outcnt++]=(uch)(c);}
|
---|
2407 |
|
---|
2408 | /* ===========================================================================
|
---|
2409 | * Deflate in to out.
|
---|
2410 | * IN assertions: the input and output buffers are cleared.
|
---|
2411 | * The variables time_stamp and save_orig_name are initialized.
|
---|
2412 | */
|
---|
2413 | static int zip(int in, int out)
|
---|
2414 | {
|
---|
2415 | uch my_flags = 0; /* general purpose bit flags */
|
---|
2416 | ush attr = 0; /* ascii/binary flag */
|
---|
2417 | ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
|
---|
2418 |
|
---|
2419 | ifd = in;
|
---|
2420 | ofd = out;
|
---|
2421 | outcnt = 0;
|
---|
2422 |
|
---|
2423 | /* Write the header to the gzip file. See algorithm.doc for the format */
|
---|
2424 |
|
---|
2425 |
|
---|
2426 | method = DEFLATED;
|
---|
2427 | put_header_byte(GZIP_MAGIC[0]); /* magic header */
|
---|
2428 | put_header_byte(GZIP_MAGIC[1]);
|
---|
2429 | put_header_byte(DEFLATED); /* compression method */
|
---|
2430 |
|
---|
2431 | put_header_byte(my_flags); /* general flags */
|
---|
2432 | put_long(time_stamp);
|
---|
2433 |
|
---|
2434 | /* Write deflated file to zip file */
|
---|
2435 | crc = updcrc(0, 0);
|
---|
2436 |
|
---|
2437 | bi_init(out);
|
---|
2438 | ct_init(&attr, &method);
|
---|
2439 | lm_init(&deflate_flags);
|
---|
2440 |
|
---|
2441 | put_byte((uch) deflate_flags); /* extra flags */
|
---|
2442 | put_byte(OS_CODE); /* OS identifier */
|
---|
2443 |
|
---|
2444 | header_bytes = (long) outcnt;
|
---|
2445 |
|
---|
2446 | (void) deflate();
|
---|
2447 |
|
---|
2448 | /* Write the crc and uncompressed size */
|
---|
2449 | put_long(crc);
|
---|
2450 | put_long(isize);
|
---|
2451 | header_bytes += 2 * sizeof(long);
|
---|
2452 |
|
---|
2453 | flush_outbuf();
|
---|
2454 | return OK;
|
---|
2455 | }
|
---|
2456 |
|
---|
2457 |
|
---|
2458 | /* ===========================================================================
|
---|
2459 | * Read a new buffer from the current input file, perform end-of-line
|
---|
2460 | * translation, and update the crc and input file size.
|
---|
2461 | * IN assertion: size >= 2 (for end-of-line translation)
|
---|
2462 | */
|
---|
2463 | static int file_read(char *buf, unsigned size)
|
---|
2464 | {
|
---|
2465 | unsigned len;
|
---|
2466 |
|
---|
2467 | Assert(insize == 0, "inbuf not empty");
|
---|
2468 |
|
---|
2469 | len = read(ifd, buf, size);
|
---|
2470 | if (len == (unsigned) (-1) || len == 0)
|
---|
2471 | return (int) len;
|
---|
2472 |
|
---|
2473 | crc = updcrc((uch *) buf, len);
|
---|
2474 | isize += (ulg) len;
|
---|
2475 | return (int) len;
|
---|
2476 | }
|
---|
2477 |
|
---|
2478 | /* ===========================================================================
|
---|
2479 | * Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
|
---|
2480 | * (used for the compressed data only)
|
---|
2481 | */
|
---|
2482 | static void flush_outbuf(void)
|
---|
2483 | {
|
---|
2484 | if (outcnt == 0)
|
---|
2485 | return;
|
---|
2486 |
|
---|
2487 | write_buf(ofd, (char *) outbuf, outcnt);
|
---|
2488 | outcnt = 0;
|
---|
2489 | }
|
---|