/* vi: set sw=4 ts=4: */ /* * Gzip implementation for busybox * * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly. * * Originally adjusted for busybox by Charles P. Wright * "this is a stripped down version of gzip I put into busybox, it does * only standard in to standard out with -9 compression. It also requires * the zcat module for some important functions." * * Adjusted further by Erik Andersen to support * files as well as stdin/stdout, and to generally behave itself wrt * command line handling. * * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ #define SMALL_MEM #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "busybox.h" typedef unsigned char uch; typedef unsigned short ush; typedef unsigned long ulg; /* Return codes from gzip */ #define OK 0 #define ERROR 1 #define WARNING 2 /* Compression methods (see algorithm.doc) */ /* Only STORED and DEFLATED are supported by this BusyBox module */ #define STORED 0 /* methods 4 to 7 reserved */ #define DEFLATED 8 /* To save memory for 16 bit systems, some arrays are overlaid between * the various modules: * deflate: prev+head window d_buf l_buf outbuf * unlzw: tab_prefix tab_suffix stack inbuf outbuf * For compression, input is done in window[]. For decompression, output * is done in window except for unlzw. */ #ifndef INBUFSIZ # ifdef SMALL_MEM # define INBUFSIZ 0x2000 /* input buffer size */ # else # define INBUFSIZ 0x8000 /* input buffer size */ # endif #endif #define INBUF_EXTRA 64 /* required by unlzw() */ #ifndef OUTBUFSIZ # ifdef SMALL_MEM # define OUTBUFSIZ 8192 /* output buffer size */ # else # define OUTBUFSIZ 16384 /* output buffer size */ # endif #endif #define OUTBUF_EXTRA 2048 /* required by unlzw() */ #ifndef DIST_BUFSIZE # ifdef SMALL_MEM # define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */ # else # define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */ # endif #endif # define DECLARE(type, array, size) static type * array # define ALLOC(type, array, size) { \ array = (type*)xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)); \ } # define FREE(array) {free(array), array=NULL;} #define tab_suffix window #define tab_prefix prev /* hash link (see deflate.c) */ #define head (prev+WSIZE) /* hash head (see deflate.c) */ static long bytes_in; /* number of input bytes */ #define isize bytes_in /* for compatibility with old zip sources (to be cleaned) */ typedef int file_t; /* Do not use stdio */ #define NO_FILE (-1) /* in memory compression */ #define PACK_MAGIC "\037\036" /* Magic header for packed files */ #define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */ #define OLD_GZIP_MAGIC "\037\236" /* Magic header for gzip 0.5 = freeze 1.x */ #define LZH_MAGIC "\037\240" /* Magic header for SCO LZH Compress files */ #define PKZIP_MAGIC "\120\113\003\004" /* Magic header for pkzip files */ /* gzip flag byte */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ #define COMMENT 0x10 /* bit 4 set: file comment present */ #define RESERVED 0xC0 /* bit 6,7: reserved */ /* internal file attribute */ #define UNKNOWN 0xffff #define BINARY 0 #define ASCII 1 #ifndef WSIZE # define WSIZE 0x8000 /* window size--must be a power of two, and */ #endif /* at least 32K for zip's deflate method */ #define MIN_MATCH 3 #define MAX_MATCH 258 /* The minimum and maximum match lengths */ #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) /* Minimum amount of lookahead, except at the end of the input file. * See deflate.c for comments about the MIN_MATCH+1. */ #define MAX_DIST (WSIZE-MIN_LOOKAHEAD) /* In order to simplify the code, particularly on 16 bit machines, match * distances are limited to MAX_DIST instead of WSIZE. */ /* put_byte is used for the compressed output */ #define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\ flush_outbuf();} /* Output a 32 bit value to the bit stream, lsb first */ #if 0 #define put_long(n) { \ put_short((n) & 0xffff); \ put_short(((ulg)(n)) >> 16); \ } #endif #define seekable() 0 /* force sequential output */ #define translate_eol 0 /* no option -a yet */ /* Diagnostic functions */ #ifdef DEBUG # define Assert(cond,msg) {if(!(cond)) bb_error_msg(msg);} # define Trace(x) fprintf x # define Tracev(x) {if (verbose) fprintf x ;} # define Tracevv(x) {if (verbose>1) fprintf x ;} # define Tracec(c,x) {if (verbose && (c)) fprintf x ;} # define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;} #else # define Assert(cond,msg) # define Trace(x) # define Tracev(x) # define Tracevv(x) # define Tracec(c,x) # define Tracecv(c,x) #endif #define WARN(msg) {if (!quiet) fprintf msg ; \ if (exit_code == OK) exit_code = WARNING;} #ifndef MAX_PATH_LEN # define MAX_PATH_LEN 1024 /* max pathname length */ #endif /* from zip.c: */ static int zip(int in, int out); static int file_read(char *buf, unsigned size); /* from deflate.c */ static void lm_init(ush * flags); static ulg deflate(void); /* from trees.c */ static void ct_init(ush * attr, int *methodp); static int ct_tally(int dist, int lc); static ulg flush_block(char *buf, ulg stored_len, int eof); /* from bits.c */ static void bi_init(file_t zipfile); static void send_bits(int value, int length); static unsigned bi_reverse(unsigned value, int length); static void bi_windup(void); static void copy_block(char *buf, unsigned len, int header); static int (*read_buf) (char *buf, unsigned size); /* from util.c: */ static void flush_outbuf(void); /* lzw.h -- define the lzw functions. * Copyright (C) 1992-1993 Jean-loup Gailly. * This is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License, see the file COPYING. */ #ifndef BITS # define BITS 16 #endif #define INIT_BITS 9 /* Initial number of bits per code */ #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */ /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free. * It's a pity that old uncompress does not check bit 0x20. That makes * extension of the format actually undesirable because old compress * would just crash on the new format instead of giving a meaningful * error message. It does check the number of bits, but it's more * helpful to say "unsupported format, get a new version" than * "can only handle 16 bits". */ /* tailor.h -- target dependent definitions * Copyright (C) 1992-1993 Jean-loup Gailly. * This is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License, see the file COPYING. */ /* The target dependent definitions should be defined here only. * The target dependent functions should be defined in tailor.c. */ /* Common defaults */ #ifndef OS_CODE # define OS_CODE 0x03 /* assume Unix */ #endif #ifndef PATH_SEP # define PATH_SEP '/' #endif #ifndef OPTIONS_VAR # define OPTIONS_VAR "GZIP" #endif #ifndef Z_SUFFIX # define Z_SUFFIX ".gz" #endif #ifdef MAX_EXT_CHARS # define MAX_SUFFIX MAX_EXT_CHARS #else # define MAX_SUFFIX 30 #endif /* global buffers */ DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA); DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA); DECLARE(ush, d_buf, DIST_BUFSIZE); DECLARE(uch, window, 2L * WSIZE); DECLARE(ush, tab_prefix, 1L << BITS); static int foreground; /* set if program run in foreground */ static int method = DEFLATED; /* compression method */ static int exit_code = OK; /* program exit code */ static int part_nb; /* number of parts in .gz file */ static long time_stamp; /* original time stamp (modification time) */ static long ifile_size; /* input file size, -1 for devices (debug only) */ static char z_suffix[MAX_SUFFIX + 1]; /* default suffix (can be set with --suffix) */ static int z_len; /* strlen(z_suffix) */ static int ifd; /* input file descriptor */ static int ofd; /* output file descriptor */ static unsigned insize; /* valid bytes in inbuf */ static unsigned outcnt; /* bytes in output buffer */ static uint32_t *crc_32_tab; /* Output a 16 bit value, lsb first */ static void put_short(ush w) { if (outcnt < OUTBUFSIZ - 2) { outbuf[outcnt++] = (uch) ((w) & 0xff); outbuf[outcnt++] = (uch) ((ush) (w) >> 8); } else { put_byte((uch) ((w) & 0xff)); put_byte((uch) ((ush) (w) >> 8)); } } /* ======================================================================== * Signal and error handler. */ static void abort_gzip(int ATTRIBUTE_UNUSED ignored) { exit(ERROR); } /* =========================================================================== * Clear input and output buffers */ static void clear_bufs(void) { outcnt = 0; insize = 0; bytes_in = 0L; } /* =========================================================================== * Does the same as write(), but also handles partial pipe writes and checks * for error return. */ static void write_buf(int fd, void *buf, unsigned cnt) { unsigned n; while ((n = write(fd, buf, cnt)) != cnt) { if (n == (unsigned) (-1)) bb_error_msg_and_die(bb_msg_write_error); cnt -= n; buf = (void *) ((char *) buf + n); } } /* =========================================================================== * Run a set of bytes through the crc shift register. If s is a NULL * pointer, then initialize the crc shift register contents instead. * Return the current crc in either case. */ static uint32_t updcrc(uch * s, unsigned n) { static uint32_t crc = ~0; /* shift register contents */ uint32_t c; /* temporary variable */ if (s == NULL) { c = ~0; } else { c = crc; if (n) do { c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8); } while (--n); } crc = c; return ~c; } /* bits.c -- output variable-length bit strings * Copyright (C) 1992-1993 Jean-loup Gailly * This is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License, see the file COPYING. */ /* * PURPOSE * * Output variable-length bit strings. Compression can be done * to a file or to memory. (The latter is not supported in this version.) * * DISCUSSION * * The PKZIP "deflate" file format interprets compressed file data * as a sequence of bits. Multi-bit strings in the file may cross * byte boundaries without restriction. * * The first bit of each byte is the low-order bit. * * The routines in this file allow a variable-length bit value to * be output right-to-left (useful for literal values). For * left-to-right output (useful for code strings from the tree routines), * the bits must have been reversed first with bi_reverse(). * * For in-memory compression, the compressed bit stream goes directly * into the requested output buffer. The input data is read in blocks * by the mem_read() function. The buffer is limited to 64K on 16 bit * machines. * * INTERFACE * * void bi_init (FILE *zipfile) * Initialize the bit string routines. * * void send_bits (int value, int length) * Write out a bit string, taking the source bits right to * left. * * int bi_reverse (int value, int length) * Reverse the bits of a bit string, taking the source bits left to * right and emitting them right to left. * * void bi_windup (void) * Write out any remaining bits in an incomplete byte. * * void copy_block(char *buf, unsigned len, int header) * Copy a stored block to the zip file, storing first the length and * its one's complement if requested. * */ /* =========================================================================== * Local data used by the "bit string" routines. */ static file_t zfile; /* output gzip file */ static unsigned short bi_buf; /* Output buffer. bits are inserted starting at the bottom (least significant * bits). */ #define Buf_size (8 * 2*sizeof(char)) /* Number of bits used within bi_buf. (bi_buf might be implemented on * more than 16 bits on some systems.) */ static int bi_valid; /* Current input function. Set to mem_read for in-memory compression */ #ifdef DEBUG ulg bits_sent; /* bit length of the compressed data */ #endif /* =========================================================================== * Initialize the bit string routines. */ static void bi_init(file_t zipfile) { zfile = zipfile; bi_buf = 0; bi_valid = 0; #ifdef DEBUG bits_sent = 0L; #endif /* Set the defaults for file compression. They are set by memcompress * for in-memory compression. */ if (zfile != NO_FILE) { read_buf = file_read; } } /* =========================================================================== * Send a value on a given number of bits. * IN assertion: length <= 16 and value fits in length bits. */ static void send_bits(int value, int length) { #ifdef DEBUG Tracev((stderr, " l %2d v %4x ", length, value)); Assert(length > 0 && length <= 15, "invalid length"); bits_sent += (ulg) length; #endif /* If not enough room in bi_buf, use (valid) bits from bi_buf and * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) * unused bits in value. */ if (bi_valid > (int) Buf_size - length) { bi_buf |= (value << bi_valid); put_short(bi_buf); bi_buf = (ush) value >> (Buf_size - bi_valid); bi_valid += length - Buf_size; } else { bi_buf |= value << bi_valid; bi_valid += length; } } /* =========================================================================== * Reverse the first len bits of a code, using straightforward code (a faster * method would use a table) * IN assertion: 1 <= len <= 15 */ static unsigned bi_reverse(unsigned code, int len) { register unsigned res = 0; do { res |= code & 1; code >>= 1, res <<= 1; } while (--len > 0); return res >> 1; } /* =========================================================================== * Write out any remaining bits in an incomplete byte. */ static void bi_windup(void) { if (bi_valid > 8) { put_short(bi_buf); } else if (bi_valid > 0) { put_byte(bi_buf); } bi_buf = 0; bi_valid = 0; #ifdef DEBUG bits_sent = (bits_sent + 7) & ~7; #endif } /* =========================================================================== * Copy a stored block to the zip file, storing first the length and its * one's complement if requested. */ static void copy_block(char *buf, unsigned len, int header) { bi_windup(); /* align on byte boundary */ if (header) { put_short((ush) len); put_short((ush) ~ len); #ifdef DEBUG bits_sent += 2 * 16; #endif } #ifdef DEBUG bits_sent += (ulg) len << 3; #endif while (len--) { put_byte(*buf++); } } /* deflate.c -- compress data using the deflation algorithm * Copyright (C) 1992-1993 Jean-loup Gailly * This is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License, see the file COPYING. */ /* * PURPOSE * * Identify new text as repetitions of old text within a fixed- * length sliding window trailing behind the new text. * * DISCUSSION * * The "deflation" process depends on being able to identify portions * of the input text which are identical to earlier input (within a * sliding window trailing behind the input currently being processed). * * The most straightforward technique turns out to be the fastest for * most input files: try all possible matches and select the longest. * The key feature of this algorithm is that insertions into the string * dictionary are very simple and thus fast, and deletions are avoided * completely. Insertions are performed at each input character, whereas * string matches are performed only when the previous match ends. So it * is preferable to spend more time in matches to allow very fast string * insertions and avoid deletions. The matching algorithm for small * strings is inspired from that of Rabin & Karp. A brute force approach * is used to find longer strings when a small match has been found. * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze * (by Leonid Broukhis). * A previous version of this file used a more sophisticated algorithm * (by Fiala and Greene) which is guaranteed to run in linear amortized * time, but has a larger average cost, uses more memory and is patented. * However the F&G algorithm may be faster for some highly redundant * files if the parameter max_chain_length (described below) is too large. * * ACKNOWLEDGMENTS * * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and * I found it in 'freeze' written by Leonid Broukhis. * Thanks to many info-zippers for bug reports and testing. * * REFERENCES * * APPNOTE.TXT documentation file in PKZIP 1.93a distribution. * * A description of the Rabin and Karp algorithm is given in the book * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. * * Fiala,E.R., and Greene,D.H. * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 * * INTERFACE * * void lm_init (int pack_level, ush *flags) * Initialize the "longest match" routines for a new file * * ulg deflate (void) * Processes a new input file and return its compressed length. Sets * the compressed length, crc, deflate flags and internal file * attributes. */ /* =========================================================================== * Configuration parameters */ /* Compile with MEDIUM_MEM to reduce the memory requirements or * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the * entire input file can be held in memory (not possible on 16 bit systems). * Warning: defining these symbols affects HASH_BITS (see below) and thus * affects the compression ratio. The compressed output * is still correct, and might even be smaller in some cases. */ #ifdef SMALL_MEM # define HASH_BITS 13 /* Number of bits used to hash strings */ #endif #ifdef MEDIUM_MEM # define HASH_BITS 14 #endif #ifndef HASH_BITS # define HASH_BITS 15 /* For portability to 16 bit machines, do not use values above 15. */ #endif /* To save space (see unlzw.c), we overlay prev+head with tab_prefix and * window with tab_suffix. Check that we can do this: */ #if (WSIZE<<1) > (1< BITS-1 # error cannot overlay head with tab_prefix1 #endif #define HASH_SIZE (unsigned)(1<= HASH_BITS */ static unsigned int prev_length; /* Length of the best match at previous step. Matches not greater than this * are discarded. This is used in the lazy match evaluation. */ static unsigned strstart; /* start of string to insert */ static unsigned match_start; /* start of matching string */ static int eofile; /* flag set at end of input file */ static unsigned lookahead; /* number of valid bytes ahead in window */ enum { max_chain_length = 4096, /* To speed up deflation, hash chains are never searched beyond this length. * A higher limit improves compression ratio but degrades the speed. */ max_lazy_match = 258, /* Attempt to find a better match only when the current match is strictly * smaller than this value. This mechanism is used only for compression * levels >= 4. */ max_insert_length = max_lazy_match, /* Insert new strings in the hash table only if the match length * is not greater than this length. This saves time but degrades compression. * max_insert_length is used only for compression levels <= 3. */ good_match = 32, /* Use a faster search when the previous match is longer than this */ /* Values for max_lazy_match, good_match and max_chain_length, depending on * the desired pack level (0..9). The values given below have been tuned to * exclude worst case performance for pathological files. Better values may be * found for specific files. */ nice_match = 258 /* Stop searching when current match exceeds this */ /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different * meaning. */ }; #define EQUAL 0 /* result of memcmp for equal strings */ /* =========================================================================== * Prototypes for local functions. */ static void fill_window(void); static int longest_match(IPos cur_match); #ifdef DEBUG static void check_match(IPos start, IPos match, int length); #endif /* =========================================================================== * Update a hash value with the given input byte * IN assertion: all calls to to UPDATE_HASH are made with consecutive * input characters, so that a running hash key can be computed from the * previous key instead of complete recalculation each time. */ #define UPDATE_HASH(h,c) (h = (((h)<= 1 */ /* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or * match.s. The code is functionally equivalent, so you can use the C version * if desired. */ static int longest_match(IPos cur_match) { unsigned chain_length = max_chain_length; /* max hash chain length */ register uch *scan = window + strstart; /* current string */ register uch *match; /* matched string */ register int len; /* length of current match */ int best_len = prev_length; /* best match length so far */ IPos limit = strstart > (IPos) MAX_DIST ? strstart - (IPos) MAX_DIST : NIL; /* Stop when cur_match becomes <= limit. To simplify the code, * we prevent matches with the string of window index 0. */ /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. * It is easy to get rid of this optimization if necessary. */ #if HASH_BITS < 8 || MAX_MATCH != 258 # error Code too clever #endif register uch *strend = window + strstart + MAX_MATCH; register uch scan_end1 = scan[best_len - 1]; register uch scan_end = scan[best_len]; /* Do not waste too much time if we already have a good match: */ if (prev_length >= good_match) { chain_length >>= 2; } Assert(strstart <= window_size - MIN_LOOKAHEAD, "insufficient lookahead"); do { Assert(cur_match < strstart, "no future"); match = window + cur_match; /* Skip to next match if the match length cannot increase * or if the match length is less than 2: */ if (match[best_len] != scan_end || match[best_len - 1] != scan_end1 || *match != *scan || *++match != scan[1]) continue; /* The check at best_len-1 can be removed because it will be made * again later. (This heuristic is not always a win.) * It is not necessary to compare scan[2] and match[2] since they * are always equal when the other bytes match, given that * the hash keys are equal and that HASH_BITS >= 8. */ scan += 2, match++; /* We check for insufficient lookahead only every 8th comparison; * the 256th check will be made at strstart+258. */ do { } while (*++scan == *++match && *++scan == *++match && *++scan == *++match && *++scan == *++match && *++scan == *++match && *++scan == *++match && *++scan == *++match && *++scan == *++match && scan < strend); len = MAX_MATCH - (int) (strend - scan); scan = strend - MAX_MATCH; if (len > best_len) { match_start = cur_match; best_len = len; if (len >= nice_match) break; scan_end1 = scan[best_len - 1]; scan_end = scan[best_len]; } } while ((cur_match = prev[cur_match & WMASK]) > limit && --chain_length != 0); return best_len; } #ifdef DEBUG /* =========================================================================== * Check that the match at match_start is indeed a match. */ static void check_match(IPos start, IPos match, int length) { /* check that the match is indeed a match */ if (memcmp((char *) window + match, (char *) window + start, length) != EQUAL) { bb_error_msg(" start %d, match %d, length %d", start, match, length); bb_error_msg("invalid match"); } if (verbose > 1) { bb_error_msg("\\[%d,%d]", start - match, length); do { putc(window[start++], stderr); } while (--length != 0); } } #else # define check_match(start, match, length) #endif /* =========================================================================== * Fill the window when the lookahead becomes insufficient. * Updates strstart and lookahead, and sets eofile if end of input file. * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0 * OUT assertions: at least one byte has been read, or eofile is set; * file reads are performed for at least two bytes (required for the * translate_eol option). */ static void fill_window(void) { register unsigned n, m; unsigned more = (unsigned) (window_size - (ulg) lookahead - (ulg) strstart); /* Amount of free space at the end of the window. */ /* If the window is almost full and there is insufficient lookahead, * move the upper half to the lower one to make room in the upper half. */ if (more == (unsigned) EOF) { /* Very unlikely, but possible on 16 bit machine if strstart == 0 * and lookahead == 1 (input done one byte at time) */ more--; } else if (strstart >= WSIZE + MAX_DIST) { /* By the IN assertion, the window is not empty so we can't confuse * more == 0 with more == 64K on a 16 bit machine. */ Assert(window_size == (ulg) 2 * WSIZE, "no sliding with BIG_MEM"); memcpy((char *) window, (char *) window + WSIZE, (unsigned) WSIZE); match_start -= WSIZE; strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */ block_start -= (long) WSIZE; for (n = 0; n < HASH_SIZE; n++) { m = head[n]; head[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL); } for (n = 0; n < WSIZE; n++) { m = prev[n]; prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : NIL); /* If n is not on any hash chain, prev[n] is garbage but * its value will never be used. */ } more += WSIZE; } /* At this point, more >= 2 */ if (!eofile) { n = read_buf((char *) window + strstart + lookahead, more); if (n == 0 || n == (unsigned) EOF) { eofile = 1; } else { lookahead += n; } } } /* =========================================================================== * Flush the current block, with given end-of-file flag. * IN assertion: strstart is set to the end of the current match. */ #define FLUSH_BLOCK(eof) \ flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \ (char*)NULL, (long)strstart - block_start, (eof)) /* =========================================================================== * Same as above, but achieves better compression. We use a lazy * evaluation for matches: a match is finally adopted only if there is * no better match at the next window position. */ static ulg deflate(void) { IPos hash_head; /* head of hash chain */ IPos prev_match; /* previous match */ int flush; /* set if current block must be flushed */ int match_available = 0; /* set if previous match exists */ register unsigned match_length = MIN_MATCH - 1; /* length of best match */ /* Process the input block. */ while (lookahead != 0) { /* Insert the string window[strstart .. strstart+2] in the * dictionary, and set hash_head to the head of the hash chain: */ INSERT_STRING(strstart, hash_head); /* Find the longest match, discarding those <= prev_length. */ prev_length = match_length, prev_match = match_start; match_length = MIN_MATCH - 1; if (hash_head != NIL && prev_length < max_lazy_match && strstart - hash_head <= MAX_DIST) { /* To simplify the code, we prevent matches with the string * of window index 0 (in particular we have to avoid a match * of the string with itself at the start of the input file). */ match_length = longest_match(hash_head); /* longest_match() sets match_start */ if (match_length > lookahead) match_length = lookahead; /* Ignore a length 3 match if it is too distant: */ if (match_length == MIN_MATCH && strstart - match_start > TOO_FAR) { /* If prev_match is also MIN_MATCH, match_start is garbage * but we will ignore the current match anyway. */ match_length--; } } /* If there was a match at the previous step and the current * match is not better, output the previous match: */ if (prev_length >= MIN_MATCH && match_length <= prev_length) { check_match(strstart - 1, prev_match, prev_length); flush = ct_tally(strstart - 1 - prev_match, prev_length - MIN_MATCH); /* Insert in hash table all strings up to the end of the match. * strstart-1 and strstart are already inserted. */ lookahead -= prev_length - 1; prev_length -= 2; do { strstart++; INSERT_STRING(strstart, hash_head); /* strstart never exceeds WSIZE-MAX_MATCH, so there are * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH * these bytes are garbage, but it does not matter since the * next lookahead bytes will always be emitted as literals. */ } while (--prev_length != 0); match_available = 0; match_length = MIN_MATCH - 1; strstart++; if (flush) FLUSH_BLOCK(0), block_start = strstart; } else if (match_available) { /* If there was no match at the previous position, output a * single literal. If there was a match but the current match * is longer, truncate the previous match to a single literal. */ Tracevv((stderr, "%c", window[strstart - 1])); if (ct_tally(0, window[strstart - 1])) { FLUSH_BLOCK(0), block_start = strstart; } strstart++; lookahead--; } else { /* There is no previous match to compare with, wait for * the next step to decide. */ match_available = 1; strstart++; lookahead--; } Assert(strstart <= isize && lookahead <= isize, "a bit too far"); /* Make sure that we always have enough lookahead, except * at the end of the input file. We need MAX_MATCH bytes * for the next match, plus MIN_MATCH bytes to insert the * string following the next match. */ while (lookahead < MIN_LOOKAHEAD && !eofile) fill_window(); } if (match_available) ct_tally(0, window[strstart - 1]); return FLUSH_BLOCK(1); /* eof */ } /* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface * Copyright (C) 1992-1993 Jean-loup Gailly * The unzip code was written and put in the public domain by Mark Adler. * Portions of the lzw code are derived from the public domain 'compress' * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies, * Ken Turkowski, Dave Mack and Peter Jannesen. * * See the license_msg below and the file COPYING for the software license. * See the file algorithm.doc for the compression algorithms and file formats. */ /* Compress files with zip algorithm and 'compress' interface. * See usage() and help() functions below for all options. * Outputs: * file.gz: compressed file with same mode, owner, and utimes * or stdout with -c option or if stdin used as input. * If the output file name had to be truncated, the original name is kept * in the compressed file. */ /* configuration */ typedef struct dirent dir_type; /* ======================================================================== */ int gzip_main(int argc, char **argv) { int result; int inFileNum; int outFileNum; struct stat statBuf; char *delFileName; int tostdout = 0; int force = 0; int opt; while ((opt = getopt(argc, argv, "cf123456789dq")) != -1) { switch (opt) { case 'c': tostdout = 1; break; case 'f': force = 1; break; /* Ignore 1-9 (compression level) options */ case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': break; case 'q': break; #ifdef CONFIG_GUNZIP case 'd': optind = 1; return gunzip_main(argc, argv); #endif default: bb_show_usage(); } } foreground = signal(SIGINT, SIG_IGN) != SIG_IGN; if (foreground) { (void) signal(SIGINT, abort_gzip); } #ifdef SIGTERM if (signal(SIGTERM, SIG_IGN) != SIG_IGN) { (void) signal(SIGTERM, abort_gzip); } #endif #ifdef SIGHUP if (signal(SIGHUP, SIG_IGN) != SIG_IGN) { (void) signal(SIGHUP, abort_gzip); } #endif strncpy(z_suffix, Z_SUFFIX, sizeof(z_suffix) - 1); z_len = strlen(z_suffix); /* Allocate all global buffers (for DYN_ALLOC option) */ ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA); ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA); ALLOC(ush, d_buf, DIST_BUFSIZE); ALLOC(uch, window, 2L * WSIZE); ALLOC(ush, tab_prefix, 1L << BITS); /* Initialise the CRC32 table */ crc_32_tab = bb_crc32_filltable(0); clear_bufs(); part_nb = 0; if (optind == argc) { time_stamp = 0; ifile_size = -1L; zip(STDIN_FILENO, STDOUT_FILENO); } else { int i; for (i = optind; i < argc; i++) { char *path = NULL; clear_bufs(); if (strcmp(argv[i], "-") == 0) { time_stamp = 0; ifile_size = -1L; inFileNum = STDIN_FILENO; outFileNum = STDOUT_FILENO; } else { inFileNum = bb_xopen3(argv[i], O_RDONLY, 0); if (fstat(inFileNum, &statBuf) < 0) bb_perror_msg_and_die("%s", argv[i]); time_stamp = statBuf.st_ctime; ifile_size = statBuf.st_size; if (!tostdout) { path = xmalloc(strlen(argv[i]) + 4); strcpy(path, argv[i]); strcat(path, ".gz"); /* Open output file */ #if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1) && defined O_NOFOLLOW outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW); #else outFileNum = open(path, O_RDWR | O_CREAT | O_EXCL); #endif if (outFileNum < 0) { bb_perror_msg("%s", path); free(path); continue; } /* Set permissions on the file */ fchmod(outFileNum, statBuf.st_mode); } else outFileNum = STDOUT_FILENO; } if (path == NULL && isatty(outFileNum) && force == 0) { bb_error_msg ("compressed data not written to a terminal. Use -f to force compression."); free(path); continue; } result = zip(inFileNum, outFileNum); if (path != NULL) { close(inFileNum); close(outFileNum); /* Delete the original file */ if (result == OK) delFileName = argv[i]; else delFileName = path; if (unlink(delFileName) < 0) bb_perror_msg("%s", delFileName); } free(path); } } return (exit_code); } /* trees.c -- output deflated data using Huffman coding * Copyright (C) 1992-1993 Jean-loup Gailly * This is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License, see the file COPYING. */ /* * PURPOSE * * Encode various sets of source values using variable-length * binary code trees. * * DISCUSSION * * The PKZIP "deflation" process uses several Huffman trees. The more * common source values are represented by shorter bit sequences. * * Each code tree is stored in the ZIP file in a compressed form * which is itself a Huffman encoding of the lengths of * all the code strings (in ascending order by source values). * The actual code strings are reconstructed from the lengths in * the UNZIP process, as described in the "application note" * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program. * * REFERENCES * * Lynch, Thomas J. * Data Compression: Techniques and Applications, pp. 53-55. * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7. * * Storer, James A. * Data Compression: Methods and Theory, pp. 49-50. * Computer Science Press, 1988. ISBN 0-7167-8156-5. * * Sedgewick, R. * Algorithms, p290. * Addison-Wesley, 1983. ISBN 0-201-06672-6. * * INTERFACE * * void ct_init (ush *attr, int *methodp) * Allocate the match buffer, initialize the various tables and save * the location of the internal file attribute (ascii/binary) and * method (DEFLATE/STORE) * * void ct_tally (int dist, int lc); * Save the match info and tally the frequency counts. * * long flush_block (char *buf, ulg stored_len, int eof) * Determine the best encoding for the current block: dynamic trees, * static trees or store, and output the encoded block to the zip * file. Returns the total compressed length for the file so far. * */ /* =========================================================================== * Constants */ #define MAX_BITS 15 /* All codes must not exceed MAX_BITS bits */ #define MAX_BL_BITS 7 /* Bit length codes must not exceed MAX_BL_BITS bits */ #define LENGTH_CODES 29 /* number of length codes, not counting the special END_BLOCK code */ #define LITERALS 256 /* number of literal bytes 0..255 */ #define END_BLOCK 256 /* end of block literal code */ #define L_CODES (LITERALS+1+LENGTH_CODES) /* number of Literal or Length codes, including the END_BLOCK code */ #define D_CODES 30 /* number of distance codes */ #define BL_CODES 19 /* number of codes used to transfer the bit lengths */ typedef uch extra_bits_t; /* extra bits for each length code */ static const extra_bits_t extra_lbits[LENGTH_CODES] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 }; /* extra bits for each distance code */ static const extra_bits_t extra_dbits[D_CODES] = { 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13 }; /* extra bits for each bit length code */ static const extra_bits_t extra_blbits[BL_CODES] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 }; #define STORED_BLOCK 0 #define STATIC_TREES 1 #define DYN_TREES 2 /* The three kinds of block type */ #ifndef LIT_BUFSIZE # ifdef SMALL_MEM # define LIT_BUFSIZE 0x2000 # else # ifdef MEDIUM_MEM # define LIT_BUFSIZE 0x4000 # else # define LIT_BUFSIZE 0x8000 # endif # endif #endif #ifndef DIST_BUFSIZE # define DIST_BUFSIZE LIT_BUFSIZE #endif /* Sizes of match buffers for literals/lengths and distances. There are * 4 reasons for limiting LIT_BUFSIZE to 64K: * - frequencies can be kept in 16 bit counters * - if compression is not successful for the first block, all input data is * still in the window so we can still emit a stored block even when input * comes from standard input. (This can also be done for all blocks if * LIT_BUFSIZE is not greater than 32K.) * - if compression is not successful for a file smaller than 64K, we can * even emit a stored file instead of a stored block (saving 5 bytes). * - creating new Huffman trees less frequently may not provide fast * adaptation to changes in the input data statistics. (Take for * example a binary file with poorly compressible code followed by * a highly compressible string table.) Smaller buffer sizes give * fast adaptation but have of course the overhead of transmitting trees * more frequently. * - I can't count above 4 * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save * memory at the expense of compression). Some optimizations would be possible * if we rely on DIST_BUFSIZE == LIT_BUFSIZE. */ #if LIT_BUFSIZE > INBUFSIZ #error cannot overlay l_buf and inbuf #endif #define REP_3_6 16 /* repeat previous bit length 3-6 times (2 bits of repeat count) */ #define REPZ_3_10 17 /* repeat a zero length 3-10 times (3 bits of repeat count) */ #define REPZ_11_138 18 /* repeat a zero length 11-138 times (7 bits of repeat count) */ /* =========================================================================== * Local data */ /* Data structure describing a single value and its code string. */ typedef struct ct_data { union { ush freq; /* frequency count */ ush code; /* bit string */ } fc; union { ush dad; /* father node in Huffman tree */ ush len; /* length of bit string */ } dl; } ct_data; #define Freq fc.freq #define Code fc.code #define Dad dl.dad #define Len dl.len #define HEAP_SIZE (2*L_CODES+1) /* maximum heap size */ static ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */ static ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */ static ct_data static_ltree[L_CODES + 2]; /* The static literal tree. Since the bit lengths are imposed, there is no * need for the L_CODES extra codes used during heap construction. However * The codes 286 and 287 are needed to build a canonical tree (see ct_init * below). */ static ct_data static_dtree[D_CODES]; /* The static distance tree. (Actually a trivial tree since all codes use * 5 bits.) */ static ct_data bl_tree[2 * BL_CODES + 1]; /* Huffman tree for the bit lengths */ typedef struct tree_desc { ct_data *dyn_tree; /* the dynamic tree */ ct_data *static_tree; /* corresponding static tree or NULL */ const extra_bits_t *extra_bits; /* extra bits for each code or NULL */ int extra_base; /* base index for extra_bits */ int elems; /* max number of elements in the tree */ int max_length; /* max bit length for the codes */ int max_code; /* largest code with non zero frequency */ } tree_desc; static tree_desc l_desc = { dyn_ltree, static_ltree, extra_lbits, LITERALS + 1, L_CODES, MAX_BITS, 0 }; static tree_desc d_desc = { dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0 }; static tree_desc bl_desc = { bl_tree, (ct_data *) 0, extra_blbits, 0, BL_CODES, MAX_BL_BITS, 0 }; static ush bl_count[MAX_BITS + 1]; /* number of codes at each bit length for an optimal tree */ static const uch bl_order[BL_CODES] = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; /* The lengths of the bit length codes are sent in order of decreasing * probability, to avoid transmitting the lengths for unused bit length codes. */ static int heap[2 * L_CODES + 1]; /* heap used to build the Huffman trees */ static int heap_len; /* number of elements in the heap */ static int heap_max; /* element of largest frequency */ /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used. * The same heap array is used to build all trees. */ static uch depth[2 * L_CODES + 1]; /* Depth of each subtree used as tie breaker for trees of equal frequency */ static uch length_code[MAX_MATCH - MIN_MATCH + 1]; /* length code for each normalized match length (0 == MIN_MATCH) */ static uch dist_code[512]; /* distance codes. The first 256 values correspond to the distances * 3 .. 258, the last 256 values correspond to the top 8 bits of * the 15 bit distances. */ static int base_length[LENGTH_CODES]; /* First normalized length for each code (0 = MIN_MATCH) */ static int base_dist[D_CODES]; /* First normalized distance for each code (0 = distance of 1) */ #define l_buf inbuf /* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */ /* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */ static uch flag_buf[(LIT_BUFSIZE / 8)]; /* flag_buf is a bit array distinguishing literals from lengths in * l_buf, thus indicating the presence or absence of a distance. */ static unsigned last_lit; /* running index in l_buf */ static unsigned last_dist; /* running index in d_buf */ static unsigned last_flags; /* running index in flag_buf */ static uch flags; /* current flags not yet saved in flag_buf */ static uch flag_bit; /* current bit used in flags */ /* bits are filled in flags starting at bit 0 (least significant). * Note: these flags are overkill in the current code since we don't * take advantage of DIST_BUFSIZE == LIT_BUFSIZE. */ static ulg opt_len; /* bit length of current block with optimal trees */ static ulg static_len; /* bit length of current block with static trees */ static ulg compressed_len; /* total bit length of compressed file */ static ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */ static int *file_method; /* pointer to DEFLATE or STORE */ /* =========================================================================== * Local (static) routines in this file. */ static void init_block(void); static void pqdownheap(ct_data * tree, int k); static void gen_bitlen(tree_desc * desc); static void gen_codes(ct_data * tree, int max_code); static void build_tree(tree_desc * desc); static void scan_tree(ct_data * tree, int max_code); static void send_tree(ct_data * tree, int max_code); static int build_bl_tree(void); static void send_all_trees(int lcodes, int dcodes, int blcodes); static void compress_block(ct_data * ltree, ct_data * dtree); static void set_file_type(void); #ifndef DEBUG # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len) /* Send a code of the given tree. c and tree must not have side effects */ #else /* DEBUG */ # define send_code(c, tree) \ { if (verbose>1) bb_error_msg("\ncd %3d ",(c)); \ send_bits(tree[c].Code, tree[c].Len); } #endif #define d_code(dist) \ ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)]) /* Mapping from a distance to a distance code. dist is the distance - 1 and * must not have side effects. dist_code[256] and dist_code[257] are never * used. */ /* the arguments must not have side effects */ /* =========================================================================== * Allocate the match buffer, initialize the various tables and save the * location of the internal file attribute (ascii/binary) and method * (DEFLATE/STORE). */ static void ct_init(ush * attr, int *methodp) { int n; /* iterates over tree elements */ int bits; /* bit counter */ int length; /* length value */ int code; /* code value */ int dist; /* distance index */ file_type = attr; file_method = methodp; compressed_len = 0L; if (static_dtree[0].Len != 0) return; /* ct_init already called */ /* Initialize the mapping length (0..255) -> length code (0..28) */ length = 0; for (code = 0; code < LENGTH_CODES - 1; code++) { base_length[code] = length; for (n = 0; n < (1 << extra_lbits[code]); n++) { length_code[length++] = (uch) code; } } Assert(length == 256, "ct_init: length != 256"); /* Note that the length 255 (match length 258) can be represented * in two different ways: code 284 + 5 bits or code 285, so we * overwrite length_code[255] to use the best encoding: */ length_code[length - 1] = (uch) code; /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ dist = 0; for (code = 0; code < 16; code++) { base_dist[code] = dist; for (n = 0; n < (1 << extra_dbits[code]); n++) { dist_code[dist++] = (uch) code; } } Assert(dist == 256, "ct_init: dist != 256"); dist >>= 7; /* from now on, all distances are divided by 128 */ for (; code < D_CODES; code++) { base_dist[code] = dist << 7; for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { dist_code[256 + dist++] = (uch) code; } } Assert(dist == 256, "ct_init: 256+dist != 512"); /* Construct the codes of the static literal tree */ for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; n = 0; while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; /* Codes 286 and 287 do not exist, but we must include them in the * tree construction to get a canonical Huffman tree (longest code * all ones) */ gen_codes((ct_data *) static_ltree, L_CODES + 1); /* The static distance tree is trivial: */ for (n = 0; n < D_CODES; n++) { static_dtree[n].Len = 5; static_dtree[n].Code = bi_reverse(n, 5); } /* Initialize the first block of the first file: */ init_block(); } /* =========================================================================== * Initialize a new block. */ static void init_block(void) { int n; /* iterates over tree elements */ /* Initialize the trees. */ for (n = 0; n < L_CODES; n++) dyn_ltree[n].Freq = 0; for (n = 0; n < D_CODES; n++) dyn_dtree[n].Freq = 0; for (n = 0; n < BL_CODES; n++) bl_tree[n].Freq = 0; dyn_ltree[END_BLOCK].Freq = 1; opt_len = static_len = 0L; last_lit = last_dist = last_flags = 0; flags = 0; flag_bit = 1; } #define SMALLEST 1 /* Index within the heap array of least frequent node in the Huffman tree */ /* =========================================================================== * Remove the smallest element from the heap and recreate the heap with * one less element. Updates heap and heap_len. */ #define pqremove(tree, top) \ {\ top = heap[SMALLEST]; \ heap[SMALLEST] = heap[heap_len--]; \ pqdownheap(tree, SMALLEST); \ } /* =========================================================================== * Compares to subtrees, using the tree depth as tie breaker when * the subtrees have equal frequency. This minimizes the worst case length. */ #define smaller(tree, n, m) \ (tree[n].Freq < tree[m].Freq || \ (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) /* =========================================================================== * Restore the heap property by moving down the tree starting at node k, * exchanging a node with the smallest of its two sons if necessary, stopping * when the heap property is re-established (each father smaller than its * two sons). */ static void pqdownheap(ct_data * tree, int k) { int v = heap[k]; int j = k << 1; /* left son of k */ while (j <= heap_len) { /* Set j to the smallest of the two sons: */ if (j < heap_len && smaller(tree, heap[j + 1], heap[j])) j++; /* Exit if v is smaller than both sons */ if (smaller(tree, v, heap[j])) break; /* Exchange v with the smallest son */ heap[k] = heap[j]; k = j; /* And continue down the tree, setting j to the left son of k */ j <<= 1; } heap[k] = v; } /* =========================================================================== * Compute the optimal bit lengths for a tree and update the total bit length * for the current block. * IN assertion: the fields freq and dad are set, heap[heap_max] and * above are the tree nodes sorted by increasing frequency. * OUT assertions: the field len is set to the optimal bit length, the * array bl_count contains the frequencies for each bit length. * The length opt_len is updated; static_len is also updated if stree is * not null. */ static void gen_bitlen(tree_desc * desc) { ct_data *tree = desc->dyn_tree; const extra_bits_t *extra = desc->extra_bits; int base = desc->extra_base; int max_code = desc->max_code; int max_length = desc->max_length; ct_data *stree = desc->static_tree; int h; /* heap index */ int n, m; /* iterate over the tree elements */ int bits; /* bit length */ int xbits; /* extra bits */ ush f; /* frequency */ int overflow = 0; /* number of elements with bit length too large */ for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; /* In a first pass, compute the optimal bit lengths (which may * overflow in the case of the bit length tree). */ tree[heap[heap_max]].Len = 0; /* root of the heap */ for (h = heap_max + 1; h < HEAP_SIZE; h++) { n = heap[h]; bits = tree[tree[n].Dad].Len + 1; if (bits > max_length) bits = max_length, overflow++; tree[n].Len = (ush) bits; /* We overwrite tree[n].Dad which is no longer needed */ if (n > max_code) continue; /* not a leaf node */ bl_count[bits]++; xbits = 0; if (n >= base) xbits = extra[n - base]; f = tree[n].Freq; opt_len += (ulg) f *(bits + xbits); if (stree) static_len += (ulg) f *(stree[n].Len + xbits); } if (overflow == 0) return; Trace((stderr, "\nbit length overflow\n")); /* This happens for example on obj2 and pic of the Calgary corpus */ /* Find the first bit length which could increase: */ do { bits = max_length - 1; while (bl_count[bits] == 0) bits--; bl_count[bits]--; /* move one leaf down the tree */ bl_count[bits + 1] += 2; /* move one overflow item as its brother */ bl_count[max_length]--; /* The brother of the overflow item also moves one step up, * but this does not affect bl_count[max_length] */ overflow -= 2; } while (overflow > 0); /* Now recompute all bit lengths, scanning in increasing frequency. * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all * lengths instead of fixing only the wrong ones. This idea is taken * from 'ar' written by Haruhiko Okumura.) */ for (bits = max_length; bits != 0; bits--) { n = bl_count[bits]; while (n != 0) { m = heap[--h]; if (m > max_code) continue; if (tree[m].Len != (unsigned) bits) { Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len, bits)); opt_len += ((long) bits - (long) tree[m].Len) * (long) tree[m].Freq; tree[m].Len = (ush) bits; } n--; } } } /* =========================================================================== * Generate the codes for a given tree and bit counts (which need not be * optimal). * IN assertion: the array bl_count contains the bit length statistics for * the given tree and the field len is set for all tree elements. * OUT assertion: the field code is set for all tree elements of non * zero code length. */ static void gen_codes(ct_data * tree, int max_code) { ush next_code[MAX_BITS + 1]; /* next code value for each bit length */ ush code = 0; /* running code value */ int bits; /* bit index */ int n; /* code index */ /* The distribution counts are first used to generate the code values * without bit reversal. */ for (bits = 1; bits <= MAX_BITS; bits++) { next_code[bits] = code = (code + bl_count[bits - 1]) << 1; } /* Check that the bit counts in bl_count are consistent. The last code * must be all ones. */ Assert(code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1, "inconsistent bit counts"); Tracev((stderr, "\ngen_codes: max_code %d ", max_code)); for (n = 0; n <= max_code; n++) { int len = tree[n].Len; if (len == 0) continue; /* Now reverse the bits */ tree[n].Code = bi_reverse(next_code[len]++, len); Tracec(tree != static_ltree, (stderr, "\nn %3d %c l %2d c %4x (%x) ", n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len] - 1)); } } /* =========================================================================== * Construct one Huffman tree and assigns the code bit strings and lengths. * Update the total bit length for the current block. * IN assertion: the field freq is set for all tree elements. * OUT assertions: the fields len and code are set to the optimal bit length * and corresponding code. The length opt_len is updated; static_len is * also updated if stree is not null. The field max_code is set. */ static void build_tree(tree_desc * desc) { ct_data *tree = desc->dyn_tree; ct_data *stree = desc->static_tree; int elems = desc->elems; int n, m; /* iterate over heap elements */ int max_code = -1; /* largest code with non zero frequency */ int node = elems; /* next internal node of the tree */ /* Construct the initial heap, with least frequent element in * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. * heap[0] is not used. */ heap_len = 0, heap_max = HEAP_SIZE; for (n = 0; n < elems; n++) { if (tree[n].Freq != 0) { heap[++heap_len] = max_code = n; depth[n] = 0; } else { tree[n].Len = 0; } } /* The pkzip format requires that at least one distance code exists, * and that at least one bit should be sent even if there is only one * possible code. So to avoid special checks later on we force at least * two codes of non zero frequency. */ while (heap_len < 2) { int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0); tree[new].Freq = 1; depth[new] = 0; opt_len--; if (stree) static_len -= stree[new].Len; /* new is 0 or 1 so it does not have extra bits */ } desc->max_code = max_code; /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, * establish sub-heaps of increasing lengths: */ for (n = heap_len / 2; n >= 1; n--) pqdownheap(tree, n); /* Construct the Huffman tree by repeatedly combining the least two * frequent nodes. */ do { pqremove(tree, n); /* n = node of least frequency */ m = heap[SMALLEST]; /* m = node of next least frequency */ heap[--heap_max] = n; /* keep the nodes sorted by frequency */ heap[--heap_max] = m; /* Create a new node father of n and m */ tree[node].Freq = tree[n].Freq + tree[m].Freq; depth[node] = (uch) (MAX(depth[n], depth[m]) + 1); tree[n].Dad = tree[m].Dad = (ush) node; #ifdef DUMP_BL_TREE if (tree == bl_tree) { bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)", node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); } #endif /* and insert the new node in the heap */ heap[SMALLEST] = node++; pqdownheap(tree, SMALLEST); } while (heap_len >= 2); heap[--heap_max] = heap[SMALLEST]; /* At this point, the fields freq and dad are set. We can now * generate the bit lengths. */ gen_bitlen((tree_desc *) desc); /* The field len is now set, we can generate the bit codes */ gen_codes((ct_data *) tree, max_code); } /* =========================================================================== * Scan a literal or distance tree to determine the frequencies of the codes * in the bit length tree. Updates opt_len to take into account the repeat * counts. (The contribution of the bit length codes will be added later * during the construction of bl_tree.) */ static void scan_tree(ct_data * tree, int max_code) { int n; /* iterates over all tree elements */ int prevlen = -1; /* last emitted length */ int curlen; /* length of current code */ int nextlen = tree[0].Len; /* length of next code */ int count = 0; /* repeat count of the current code */ int max_count = 7; /* max repeat count */ int min_count = 4; /* min repeat count */ if (nextlen == 0) max_count = 138, min_count = 3; tree[max_code + 1].Len = (ush) 0xffff; /* guard */ for (n = 0; n <= max_code; n++) { curlen = nextlen; nextlen = tree[n + 1].Len; if (++count < max_count && curlen == nextlen) { continue; } else if (count < min_count) { bl_tree[curlen].Freq += count; } else if (curlen != 0) { if (curlen != prevlen) bl_tree[curlen].Freq++; bl_tree[REP_3_6].Freq++; } else if (count <= 10) { bl_tree[REPZ_3_10].Freq++; } else { bl_tree[REPZ_11_138].Freq++; } count = 0; prevlen = curlen; if (nextlen == 0) { max_count = 138, min_count = 3; } else if (curlen == nextlen) { max_count = 6, min_count = 3; } else { max_count = 7, min_count = 4; } } } /* =========================================================================== * Send a literal or distance tree in compressed form, using the codes in * bl_tree. */ static void send_tree(ct_data * tree, int max_code) { int n; /* iterates over all tree elements */ int prevlen = -1; /* last emitted length */ int curlen; /* length of current code */ int nextlen = tree[0].Len; /* length of next code */ int count = 0; /* repeat count of the current code */ int max_count = 7; /* max repeat count */ int min_count = 4; /* min repeat count */ /* tree[max_code+1].Len = -1; *//* guard already set */ if (nextlen == 0) max_count = 138, min_count = 3; for (n = 0; n <= max_code; n++) { curlen = nextlen; nextlen = tree[n + 1].Len; if (++count < max_count && curlen == nextlen) { continue; } else if (count < min_count) { do { send_code(curlen, bl_tree); } while (--count != 0); } else if (curlen != 0) { if (curlen != prevlen) { send_code(curlen, bl_tree); count--; } Assert(count >= 3 && count <= 6, " 3_6?"); send_code(REP_3_6, bl_tree); send_bits(count - 3, 2); } else if (count <= 10) { send_code(REPZ_3_10, bl_tree); send_bits(count - 3, 3); } else { send_code(REPZ_11_138, bl_tree); send_bits(count - 11, 7); } count = 0; prevlen = curlen; if (nextlen == 0) { max_count = 138, min_count = 3; } else if (curlen == nextlen) { max_count = 6, min_count = 3; } else { max_count = 7, min_count = 4; } } } /* =========================================================================== * Construct the Huffman tree for the bit lengths and return the index in * bl_order of the last bit length code to send. */ static int build_bl_tree(void) { int max_blindex; /* index of last bit length code of non zero freq */ /* Determine the bit length frequencies for literal and distance trees */ scan_tree((ct_data *) dyn_ltree, l_desc.max_code); scan_tree((ct_data *) dyn_dtree, d_desc.max_code); /* Build the bit length tree: */ build_tree((tree_desc *) (&bl_desc)); /* opt_len now includes the length of the tree representations, except * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. */ /* Determine the number of bit length codes to send. The pkzip format * requires that at least 4 bit length codes be sent. (appnote.txt says * 3 but the actual value used is 4.) */ for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) { if (bl_tree[bl_order[max_blindex]].Len != 0) break; } /* Update opt_len to include the bit length tree and counts */ opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4; Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len, static_len)); return max_blindex; } /* =========================================================================== * Send the header for a block using dynamic Huffman trees: the counts, the * lengths of the bit length codes, the literal tree and the distance tree. * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. */ static void send_all_trees(int lcodes, int dcodes, int blcodes) { int rank; /* index in bl_order */ Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); Assert(lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, "too many codes"); Tracev((stderr, "\nbl counts: ")); send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */ send_bits(dcodes - 1, 5); send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */ for (rank = 0; rank < blcodes; rank++) { Tracev((stderr, "\nbl code %2d ", bl_order[rank])); send_bits(bl_tree[bl_order[rank]].Len, 3); } Tracev((stderr, "\nbl tree: sent %ld", bits_sent)); send_tree((ct_data *) dyn_ltree, lcodes - 1); /* send the literal tree */ Tracev((stderr, "\nlit tree: sent %ld", bits_sent)); send_tree((ct_data *) dyn_dtree, dcodes - 1); /* send the distance tree */ Tracev((stderr, "\ndist tree: sent %ld", bits_sent)); } /* =========================================================================== * Determine the best encoding for the current block: dynamic trees, static * trees or store, and output the encoded block to the zip file. This function * returns the total compressed length for the file so far. */ static ulg flush_block(char *buf, ulg stored_len, int eof) { ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ int max_blindex; /* index of last bit length code of non zero freq */ flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */ /* Check if the file is ascii or binary */ if (*file_type == (ush) UNKNOWN) set_file_type(); /* Construct the literal and distance trees */ build_tree((tree_desc *) (&l_desc)); Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len)); build_tree((tree_desc *) (&d_desc)); Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len)); /* At this point, opt_len and static_len are the total bit lengths of * the compressed block data, excluding the tree representations. */ /* Build the bit length tree for the above two trees, and get the index * in bl_order of the last bit length code to send. */ max_blindex = build_bl_tree(); /* Determine the best encoding. Compute first the block length in bytes */ opt_lenb = (opt_len + 3 + 7) >> 3; static_lenb = (static_len + 3 + 7) >> 3; Trace((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ", opt_lenb, opt_len, static_lenb, static_len, stored_len, last_lit, last_dist)); if (static_lenb <= opt_lenb) opt_lenb = static_lenb; /* If compression failed and this is the first and last block, * and if the zip file can be seeked (to rewrite the local header), * the whole file is transformed into a stored file: */ if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) { /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */ if (buf == (char *) 0) bb_error_msg("block vanished"); copy_block(buf, (unsigned) stored_len, 0); /* without header */ compressed_len = stored_len << 3; *file_method = STORED; } else if (stored_len + 4 <= opt_lenb && buf != (char *) 0) { /* 4: two words for the lengths */ /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. * Otherwise we can't have processed more than WSIZE input bytes since * the last block flush, because compression would have been * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to * transform a block into a stored block. */ send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */ compressed_len = (compressed_len + 3 + 7) & ~7L; compressed_len += (stored_len + 4) << 3; copy_block(buf, (unsigned) stored_len, 1); /* with header */ } else if (static_lenb == opt_lenb) { send_bits((STATIC_TREES << 1) + eof, 3); compress_block((ct_data *) static_ltree, (ct_data *) static_dtree); compressed_len += 3 + static_len; } else { send_bits((DYN_TREES << 1) + eof, 3); send_all_trees(l_desc.max_code + 1, d_desc.max_code + 1, max_blindex + 1); compress_block((ct_data *) dyn_ltree, (ct_data *) dyn_dtree); compressed_len += 3 + opt_len; } Assert(compressed_len == bits_sent, "bad compressed size"); init_block(); if (eof) { bi_windup(); compressed_len += 7; /* align on byte boundary */ } Tracev((stderr, "\ncomprlen %lu(%lu) ", compressed_len >> 3, compressed_len - 7 * eof)); return compressed_len >> 3; } /* =========================================================================== * Save the match info and tally the frequency counts. Return true if * the current block must be flushed. */ static int ct_tally(int dist, int lc) { l_buf[last_lit++] = (uch) lc; if (dist == 0) { /* lc is the unmatched char */ dyn_ltree[lc].Freq++; } else { /* Here, lc is the match length - MIN_MATCH */ dist--; /* dist = match distance - 1 */ Assert((ush) dist < (ush) MAX_DIST && (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) && (ush) d_code(dist) < (ush) D_CODES, "ct_tally: bad match"); dyn_ltree[length_code[lc] + LITERALS + 1].Freq++; dyn_dtree[d_code(dist)].Freq++; d_buf[last_dist++] = (ush) dist; flags |= flag_bit; } flag_bit <<= 1; /* Output the flags if they fill a byte: */ if ((last_lit & 7) == 0) { flag_buf[last_flags++] = flags; flags = 0, flag_bit = 1; } /* Try to guess if it is profitable to stop the current block here */ if ((last_lit & 0xfff) == 0) { /* Compute an upper bound for the compressed length */ ulg out_length = (ulg) last_lit * 8L; ulg in_length = (ulg) strstart - block_start; int dcode; for (dcode = 0; dcode < D_CODES; dcode++) { out_length += (ulg) dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]); } out_length >>= 3; Trace((stderr, "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ", last_lit, last_dist, in_length, out_length, 100L - out_length * 100L / in_length)); if (last_dist < last_lit / 2 && out_length < in_length / 2) return 1; } return (last_lit == LIT_BUFSIZE - 1 || last_dist == DIST_BUFSIZE); /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K * on 16 bit machines and because stored blocks are restricted to * 64K-1 bytes. */ } /* =========================================================================== * Send the block data compressed using the given Huffman trees */ static void compress_block(ct_data * ltree, ct_data * dtree) { unsigned dist; /* distance of matched string */ int lc; /* match length or unmatched char (if dist == 0) */ unsigned lx = 0; /* running index in l_buf */ unsigned dx = 0; /* running index in d_buf */ unsigned fx = 0; /* running index in flag_buf */ uch flag = 0; /* current flags */ unsigned code; /* the code to send */ int extra; /* number of extra bits to send */ if (last_lit != 0) do { if ((lx & 7) == 0) flag = flag_buf[fx++]; lc = l_buf[lx++]; if ((flag & 1) == 0) { send_code(lc, ltree); /* send a literal byte */ Tracecv(isgraph(lc), (stderr, " '%c' ", lc)); } else { /* Here, lc is the match length - MIN_MATCH */ code = length_code[lc]; send_code(code + LITERALS + 1, ltree); /* send the length code */ extra = extra_lbits[code]; if (extra != 0) { lc -= base_length[code]; send_bits(lc, extra); /* send the extra length bits */ } dist = d_buf[dx++]; /* Here, dist is the match distance - 1 */ code = d_code(dist); Assert(code < D_CODES, "bad d_code"); send_code(code, dtree); /* send the distance code */ extra = extra_dbits[code]; if (extra != 0) { dist -= base_dist[code]; send_bits(dist, extra); /* send the extra distance bits */ } } /* literal or match pair ? */ flag >>= 1; } while (lx < last_lit); send_code(END_BLOCK, ltree); } /* =========================================================================== * Set the file type to ASCII or BINARY, using a crude approximation: * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. * IN assertion: the fields freq of dyn_ltree are set and the total of all * frequencies does not exceed 64K (to fit in an int on 16 bit machines). */ static void set_file_type(void) { int n = 0; unsigned ascii_freq = 0; unsigned bin_freq = 0; while (n < 7) bin_freq += dyn_ltree[n++].Freq; while (n < 128) ascii_freq += dyn_ltree[n++].Freq; while (n < LITERALS) bin_freq += dyn_ltree[n++].Freq; *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII; if (*file_type == BINARY && translate_eol) { bb_error_msg("-l used on binary file"); } } /* zip.c -- compress files to the gzip or pkzip format * Copyright (C) 1992-1993 Jean-loup Gailly * This is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License, see the file COPYING. */ static uint32_t crc; /* crc on uncompressed file data */ static long header_bytes; /* number of bytes in gzip header */ static void put_long(ulg n) { put_short((n) & 0xffff); put_short(((ulg) (n)) >> 16); } /* put_header_byte is used for the compressed output * - for the initial 4 bytes that can't overflow the buffer. */ #define put_header_byte(c) {outbuf[outcnt++]=(uch)(c);} /* =========================================================================== * Deflate in to out. * IN assertions: the input and output buffers are cleared. * The variables time_stamp and save_orig_name are initialized. */ static int zip(int in, int out) { uch my_flags = 0; /* general purpose bit flags */ ush attr = 0; /* ascii/binary flag */ ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */ ifd = in; ofd = out; outcnt = 0; /* Write the header to the gzip file. See algorithm.doc for the format */ method = DEFLATED; put_header_byte(GZIP_MAGIC[0]); /* magic header */ put_header_byte(GZIP_MAGIC[1]); put_header_byte(DEFLATED); /* compression method */ put_header_byte(my_flags); /* general flags */ put_long(time_stamp); /* Write deflated file to zip file */ crc = updcrc(0, 0); bi_init(out); ct_init(&attr, &method); lm_init(&deflate_flags); put_byte((uch) deflate_flags); /* extra flags */ put_byte(OS_CODE); /* OS identifier */ header_bytes = (long) outcnt; (void) deflate(); /* Write the crc and uncompressed size */ put_long(crc); put_long(isize); header_bytes += 2 * sizeof(long); flush_outbuf(); return OK; } /* =========================================================================== * Read a new buffer from the current input file, perform end-of-line * translation, and update the crc and input file size. * IN assertion: size >= 2 (for end-of-line translation) */ static int file_read(char *buf, unsigned size) { unsigned len; Assert(insize == 0, "inbuf not empty"); len = read(ifd, buf, size); if (len == (unsigned) (-1) || len == 0) return (int) len; crc = updcrc((uch *) buf, len); isize += (ulg) len; return (int) len; } /* =========================================================================== * Write the output buffer outbuf[0..outcnt-1] and update bytes_out. * (used for the compressed data only) */ static void flush_outbuf(void) { if (outcnt == 0) return; write_buf(ofd, (char *) outbuf, outcnt); outcnt = 0; }