1 | /* lzo1x_9x.c -- implementation of the LZO1X-999 compression algorithm
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2 |
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3 | This file is part of the LZO real-time data compression library.
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4 |
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5 | Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
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6 | Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
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7 | Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
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8 | Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
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9 | Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
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10 | Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
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11 | Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
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12 | Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
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13 | Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
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14 | Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
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15 | Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
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16 | Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
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17 | Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
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18 | All Rights Reserved.
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19 |
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20 | The LZO library is free software; you can redistribute it and/or
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21 | modify it under the terms of the GNU General Public License as
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22 | published by the Free Software Foundation; either version 2 of
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23 | the License, or (at your option) any later version.
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24 |
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25 | The LZO library is distributed in the hope that it will be useful,
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26 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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27 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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28 | GNU General Public License for more details.
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29 |
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30 | You should have received a copy of the GNU General Public License
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31 | along with the LZO library; see the file COPYING.
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32 | If not, write to the Free Software Foundation, Inc.,
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33 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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34 |
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35 | Markus F.X.J. Oberhumer
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36 | <markus@oberhumer.com>
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37 | http://www.oberhumer.com/opensource/lzo/
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38 | */
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39 | #include "libbb.h"
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40 |
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41 | /* The following is probably only safe on Intel-compatible processors ... */
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42 | #define LZO_UNALIGNED_OK_2
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43 | #define LZO_UNALIGNED_OK_4
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44 |
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45 | #include "liblzo.h"
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46 |
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47 | #define LZO_MAX(a,b) ((a) >= (b) ? (a) : (b))
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48 | #define LZO_MIN(a,b) ((a) <= (b) ? (a) : (b))
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49 | #define LZO_MAX3(a,b,c) ((a) >= (b) ? LZO_MAX(a,c) : LZO_MAX(b,c))
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50 |
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51 | /***********************************************************************
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52 | //
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53 | ************************************************************************/
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54 | #define SWD_N M4_MAX_OFFSET /* size of ring buffer */
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55 | #define SWD_F 2048 /* upper limit for match length */
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56 |
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57 | #define SWD_BEST_OFF (LZO_MAX3(M2_MAX_LEN, M3_MAX_LEN, M4_MAX_LEN) + 1)
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58 |
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59 | typedef struct {
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60 | int init;
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61 |
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62 | unsigned look; /* bytes in lookahead buffer */
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63 |
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64 | unsigned m_len;
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65 | unsigned m_off;
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66 |
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67 | const uint8_t *bp;
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68 | const uint8_t *ip;
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69 | const uint8_t *in;
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70 | const uint8_t *in_end;
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71 | uint8_t *out;
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72 |
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73 | unsigned r1_lit;
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74 |
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75 | } lzo1x_999_t;
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76 |
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77 | #define getbyte(c) ((c).ip < (c).in_end ? *((c).ip)++ : (-1))
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78 |
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79 | /* lzo_swd.c -- sliding window dictionary */
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80 |
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81 | /***********************************************************************
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82 | //
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83 | ************************************************************************/
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84 | #define SWD_UINT_MAX USHRT_MAX
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85 |
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86 | #ifndef SWD_HSIZE
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87 | # define SWD_HSIZE 16384
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88 | #endif
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89 | #ifndef SWD_MAX_CHAIN
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90 | # define SWD_MAX_CHAIN 2048
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91 | #endif
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92 |
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93 | #define HEAD3(b, p) \
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94 | ( ((0x9f5f * ((((b[p]<<5)^b[p+1])<<5) ^ b[p+2])) >> 5) & (SWD_HSIZE-1) )
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95 |
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96 | #if defined(LZO_UNALIGNED_OK_2)
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97 | # define HEAD2(b,p) (* (uint16_t *) &(b[p]))
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98 | #else
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99 | # define HEAD2(b,p) (b[p] ^ ((unsigned)b[p+1]<<8))
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100 | #endif
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101 | #define NIL2 SWD_UINT_MAX
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102 |
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103 | typedef struct lzo_swd {
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104 | /* public - "built-in" */
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105 |
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106 | /* public - configuration */
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107 | unsigned max_chain;
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108 | int use_best_off;
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109 |
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110 | /* public - output */
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111 | unsigned m_len;
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112 | unsigned m_off;
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113 | unsigned look;
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114 | int b_char;
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115 | #if defined(SWD_BEST_OFF)
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116 | unsigned best_off[SWD_BEST_OFF];
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117 | #endif
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118 |
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119 | /* semi public */
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120 | lzo1x_999_t *c;
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121 | unsigned m_pos;
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122 | #if defined(SWD_BEST_OFF)
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123 | unsigned best_pos[SWD_BEST_OFF];
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124 | #endif
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125 |
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126 | /* private */
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127 | unsigned ip; /* input pointer (lookahead) */
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128 | unsigned bp; /* buffer pointer */
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129 | unsigned rp; /* remove pointer */
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130 |
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131 | unsigned node_count;
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132 | unsigned first_rp;
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133 |
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134 | uint8_t b[SWD_N + SWD_F];
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135 | uint8_t b_wrap[SWD_F]; /* must follow b */
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136 | uint16_t head3[SWD_HSIZE];
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137 | uint16_t succ3[SWD_N + SWD_F];
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138 | uint16_t best3[SWD_N + SWD_F];
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139 | uint16_t llen3[SWD_HSIZE];
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140 | #ifdef HEAD2
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141 | uint16_t head2[65536L];
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142 | #endif
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143 | } lzo_swd_t, *lzo_swd_p;
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144 |
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145 | #define SIZEOF_LZO_SWD_T (sizeof(lzo_swd_t))
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146 |
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147 |
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148 | /* Access macro for head3.
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149 | * head3[key] may be uninitialized, but then its value will never be used.
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150 | */
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151 | #define s_get_head3(s,key) s->head3[key]
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152 |
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153 |
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154 | /***********************************************************************
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155 | //
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156 | ************************************************************************/
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157 | #define B_SIZE (SWD_N + SWD_F)
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158 |
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159 | static int swd_init(lzo_swd_p s)
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160 | {
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161 | /* defaults */
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162 | s->node_count = SWD_N;
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163 |
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164 | memset(s->llen3, 0, sizeof(s->llen3[0]) * (unsigned)SWD_HSIZE);
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165 | #ifdef HEAD2
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166 | memset(s->head2, 0xff, sizeof(s->head2[0]) * 65536L);
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167 | assert(s->head2[0] == NIL2);
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168 | #endif
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169 |
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170 | s->ip = 0;
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171 | s->bp = s->ip;
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172 | s->first_rp = s->ip;
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173 |
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174 | assert(s->ip + SWD_F <= B_SIZE);
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175 | s->look = (unsigned) (s->c->in_end - s->c->ip);
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176 | if (s->look > 0) {
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177 | if (s->look > SWD_F)
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178 | s->look = SWD_F;
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179 | memcpy(&s->b[s->ip], s->c->ip, s->look);
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180 | s->c->ip += s->look;
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181 | s->ip += s->look;
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182 | }
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183 | if (s->ip == B_SIZE)
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184 | s->ip = 0;
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185 |
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186 | s->rp = s->first_rp;
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187 | if (s->rp >= s->node_count)
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188 | s->rp -= s->node_count;
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189 | else
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190 | s->rp += B_SIZE - s->node_count;
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191 |
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192 | return LZO_E_OK;
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193 | }
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194 |
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195 | #define swd_pos2off(s,pos) \
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196 | (s->bp > (pos) ? s->bp - (pos) : B_SIZE - ((pos) - s->bp))
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197 |
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198 |
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199 | /***********************************************************************
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200 | //
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201 | ************************************************************************/
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202 | static void swd_getbyte(lzo_swd_p s)
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203 | {
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204 | int c;
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205 |
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206 | if ((c = getbyte(*(s->c))) < 0) {
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207 | if (s->look > 0)
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208 | --s->look;
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209 | } else {
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210 | s->b[s->ip] = c;
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211 | if (s->ip < SWD_F)
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212 | s->b_wrap[s->ip] = c;
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213 | }
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214 | if (++s->ip == B_SIZE)
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215 | s->ip = 0;
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216 | if (++s->bp == B_SIZE)
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217 | s->bp = 0;
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218 | if (++s->rp == B_SIZE)
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219 | s->rp = 0;
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220 | }
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221 |
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222 |
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223 | /***********************************************************************
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224 | // remove node from lists
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225 | ************************************************************************/
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226 | static void swd_remove_node(lzo_swd_p s, unsigned node)
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227 | {
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228 | if (s->node_count == 0) {
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229 | unsigned key;
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230 |
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231 | key = HEAD3(s->b,node);
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232 | assert(s->llen3[key] > 0);
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233 | --s->llen3[key];
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234 |
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235 | #ifdef HEAD2
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236 | key = HEAD2(s->b,node);
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237 | assert(s->head2[key] != NIL2);
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238 | if ((unsigned) s->head2[key] == node)
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239 | s->head2[key] = NIL2;
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240 | #endif
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241 | } else
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242 | --s->node_count;
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243 | }
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244 |
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245 |
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246 | /***********************************************************************
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247 | //
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248 | ************************************************************************/
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249 | static void swd_accept(lzo_swd_p s, unsigned n)
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250 | {
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251 | assert(n <= s->look);
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252 |
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253 | while (n--) {
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254 | unsigned key;
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255 |
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256 | swd_remove_node(s,s->rp);
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257 |
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258 | /* add bp into HEAD3 */
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259 | key = HEAD3(s->b, s->bp);
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260 | s->succ3[s->bp] = s_get_head3(s, key);
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261 | s->head3[key] = s->bp;
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262 | s->best3[s->bp] = SWD_F + 1;
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263 | s->llen3[key]++;
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264 | assert(s->llen3[key] <= SWD_N);
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265 |
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266 | #ifdef HEAD2
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267 | /* add bp into HEAD2 */
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268 | key = HEAD2(s->b, s->bp);
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269 | s->head2[key] = s->bp;
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270 | #endif
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271 |
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272 | swd_getbyte(s);
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273 | }
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274 | }
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275 |
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276 |
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277 | /***********************************************************************
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278 | //
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279 | ************************************************************************/
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280 | static void swd_search(lzo_swd_p s, unsigned node, unsigned cnt)
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281 | {
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282 | const uint8_t *p1;
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283 | const uint8_t *p2;
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284 | const uint8_t *px;
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285 | unsigned m_len = s->m_len;
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286 | const uint8_t *b = s->b;
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287 | const uint8_t *bp = s->b + s->bp;
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288 | const uint8_t *bx = s->b + s->bp + s->look;
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289 | unsigned char scan_end1;
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290 |
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291 | assert(s->m_len > 0);
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292 |
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293 | scan_end1 = bp[m_len - 1];
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294 | for ( ; cnt-- > 0; node = s->succ3[node]) {
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295 | p1 = bp;
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296 | p2 = b + node;
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297 | px = bx;
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298 |
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299 | assert(m_len < s->look);
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300 |
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301 | if (p2[m_len - 1] == scan_end1
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302 | && p2[m_len] == p1[m_len]
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303 | && p2[0] == p1[0]
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304 | && p2[1] == p1[1]
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305 | ) {
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306 | unsigned i;
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307 | assert(lzo_memcmp(bp, &b[node], 3) == 0);
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308 |
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309 | p1 += 2; p2 += 2;
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310 | do {} while (++p1 < px && *p1 == *++p2);
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311 | i = p1-bp;
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312 |
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313 | assert(lzo_memcmp(bp, &b[node], i) == 0);
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314 |
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315 | #if defined(SWD_BEST_OFF)
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316 | if (i < SWD_BEST_OFF) {
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317 | if (s->best_pos[i] == 0)
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318 | s->best_pos[i] = node + 1;
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319 | }
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320 | #endif
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321 | if (i > m_len) {
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322 | s->m_len = m_len = i;
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323 | s->m_pos = node;
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324 | if (m_len == s->look)
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325 | return;
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326 | if (m_len >= SWD_F)
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327 | return;
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328 | if (m_len > (unsigned) s->best3[node])
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329 | return;
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330 | scan_end1 = bp[m_len - 1];
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331 | }
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332 | }
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333 | }
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334 | }
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335 |
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336 |
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337 | /***********************************************************************
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338 | //
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339 | ************************************************************************/
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340 | #ifdef HEAD2
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341 |
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342 | static int swd_search2(lzo_swd_p s)
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343 | {
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344 | unsigned key;
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345 |
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346 | assert(s->look >= 2);
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347 | assert(s->m_len > 0);
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348 |
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349 | key = s->head2[HEAD2(s->b, s->bp)];
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350 | if (key == NIL2)
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351 | return 0;
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352 | assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0);
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353 | #if defined(SWD_BEST_OFF)
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354 | if (s->best_pos[2] == 0)
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355 | s->best_pos[2] = key + 1;
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356 | #endif
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357 |
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358 | if (s->m_len < 2) {
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359 | s->m_len = 2;
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360 | s->m_pos = key;
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361 | }
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362 | return 1;
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363 | }
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364 |
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365 | #endif
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366 |
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367 |
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368 | /***********************************************************************
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369 | //
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370 | ************************************************************************/
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371 | static void swd_findbest(lzo_swd_p s)
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372 | {
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373 | unsigned key;
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374 | unsigned cnt, node;
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375 | unsigned len;
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376 |
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377 | assert(s->m_len > 0);
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378 |
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379 | /* get current head, add bp into HEAD3 */
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380 | key = HEAD3(s->b,s->bp);
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381 | node = s->succ3[s->bp] = s_get_head3(s, key);
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382 | cnt = s->llen3[key]++;
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383 | assert(s->llen3[key] <= SWD_N + SWD_F);
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384 | if (cnt > s->max_chain)
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385 | cnt = s->max_chain;
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386 | s->head3[key] = s->bp;
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387 |
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388 | s->b_char = s->b[s->bp];
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389 | len = s->m_len;
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390 | if (s->m_len >= s->look) {
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391 | if (s->look == 0)
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392 | s->b_char = -1;
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393 | s->m_off = 0;
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394 | s->best3[s->bp] = SWD_F + 1;
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395 | } else {
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396 | #ifdef HEAD2
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397 | if (swd_search2(s))
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398 | #endif
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399 | if (s->look >= 3)
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400 | swd_search(s, node, cnt);
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401 | if (s->m_len > len)
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402 | s->m_off = swd_pos2off(s,s->m_pos);
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403 | s->best3[s->bp] = s->m_len;
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404 |
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405 | #if defined(SWD_BEST_OFF)
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406 | if (s->use_best_off) {
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407 | int i;
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408 | for (i = 2; i < SWD_BEST_OFF; i++) {
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409 | if (s->best_pos[i] > 0)
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410 | s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1);
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411 | else
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412 | s->best_off[i] = 0;
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413 | }
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414 | }
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415 | #endif
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416 | }
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417 |
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418 | swd_remove_node(s,s->rp);
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419 |
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420 | #ifdef HEAD2
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421 | /* add bp into HEAD2 */
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422 | key = HEAD2(s->b, s->bp);
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423 | s->head2[key] = s->bp;
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424 | #endif
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425 | }
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426 |
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427 | #undef HEAD3
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428 | #undef HEAD2
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429 | #undef s_get_head3
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430 |
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431 |
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432 | /***********************************************************************
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433 | //
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434 | ************************************************************************/
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435 | static int init_match(lzo1x_999_t *c, lzo_swd_p s, uint32_t use_best_off)
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436 | {
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437 | int r;
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438 |
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439 | assert(!c->init);
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440 | c->init = 1;
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441 |
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442 | s->c = c;
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443 |
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444 | r = swd_init(s);
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445 | if (r != 0)
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446 | return r;
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447 |
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448 | s->use_best_off = use_best_off;
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449 | return r;
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450 | }
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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 | ************************************************************************/
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456 | static int find_match(lzo1x_999_t *c, lzo_swd_p s,
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457 | unsigned this_len, unsigned skip)
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458 | {
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459 | assert(c->init);
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460 |
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461 | if (skip > 0) {
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462 | assert(this_len >= skip);
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463 | swd_accept(s, this_len - skip);
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464 | } else {
|
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465 | assert(this_len <= 1);
|
---|
466 | }
|
---|
467 |
|
---|
468 | s->m_len = 1;
|
---|
469 | s->m_len = 1;
|
---|
470 | #ifdef SWD_BEST_OFF
|
---|
471 | if (s->use_best_off)
|
---|
472 | memset(s->best_pos, 0, sizeof(s->best_pos));
|
---|
473 | #endif
|
---|
474 | swd_findbest(s);
|
---|
475 | c->m_len = s->m_len;
|
---|
476 | c->m_off = s->m_off;
|
---|
477 |
|
---|
478 | swd_getbyte(s);
|
---|
479 |
|
---|
480 | if (s->b_char < 0) {
|
---|
481 | c->look = 0;
|
---|
482 | c->m_len = 0;
|
---|
483 | } else {
|
---|
484 | c->look = s->look + 1;
|
---|
485 | }
|
---|
486 | c->bp = c->ip - c->look;
|
---|
487 |
|
---|
488 | return LZO_E_OK;
|
---|
489 | }
|
---|
490 |
|
---|
491 | /* this is a public functions, but there is no prototype in a header file */
|
---|
492 | static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len,
|
---|
493 | uint8_t *out, unsigned *out_len,
|
---|
494 | void *wrkmem,
|
---|
495 | unsigned good_length,
|
---|
496 | unsigned max_lazy,
|
---|
497 | unsigned max_chain,
|
---|
498 | uint32_t use_best_off);
|
---|
499 |
|
---|
500 |
|
---|
501 | /***********************************************************************
|
---|
502 | //
|
---|
503 | ************************************************************************/
|
---|
504 | static uint8_t *code_match(lzo1x_999_t *c,
|
---|
505 | uint8_t *op, unsigned m_len, unsigned m_off)
|
---|
506 | {
|
---|
507 | assert(op > c->out);
|
---|
508 | if (m_len == 2) {
|
---|
509 | assert(m_off <= M1_MAX_OFFSET);
|
---|
510 | assert(c->r1_lit > 0);
|
---|
511 | assert(c->r1_lit < 4);
|
---|
512 | m_off -= 1;
|
---|
513 | *op++ = M1_MARKER | ((m_off & 3) << 2);
|
---|
514 | *op++ = m_off >> 2;
|
---|
515 | } else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
|
---|
516 | assert(m_len >= 3);
|
---|
517 | m_off -= 1;
|
---|
518 | *op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2);
|
---|
519 | *op++ = m_off >> 3;
|
---|
520 | assert(op[-2] >= M2_MARKER);
|
---|
521 | } else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) {
|
---|
522 | assert(m_len == 3);
|
---|
523 | assert(m_off > M2_MAX_OFFSET);
|
---|
524 | m_off -= 1 + M2_MAX_OFFSET;
|
---|
525 | *op++ = M1_MARKER | ((m_off & 3) << 2);
|
---|
526 | *op++ = m_off >> 2;
|
---|
527 | } else if (m_off <= M3_MAX_OFFSET) {
|
---|
528 | assert(m_len >= 3);
|
---|
529 | m_off -= 1;
|
---|
530 | if (m_len <= M3_MAX_LEN)
|
---|
531 | *op++ = M3_MARKER | (m_len - 2);
|
---|
532 | else {
|
---|
533 | m_len -= M3_MAX_LEN;
|
---|
534 | *op++ = M3_MARKER | 0;
|
---|
535 | while (m_len > 255) {
|
---|
536 | m_len -= 255;
|
---|
537 | *op++ = 0;
|
---|
538 | }
|
---|
539 | assert(m_len > 0);
|
---|
540 | *op++ = m_len;
|
---|
541 | }
|
---|
542 | *op++ = m_off << 2;
|
---|
543 | *op++ = m_off >> 6;
|
---|
544 | } else {
|
---|
545 | unsigned k;
|
---|
546 |
|
---|
547 | assert(m_len >= 3);
|
---|
548 | assert(m_off > 0x4000);
|
---|
549 | assert(m_off <= 0xbfff);
|
---|
550 | m_off -= 0x4000;
|
---|
551 | k = (m_off & 0x4000) >> 11;
|
---|
552 | if (m_len <= M4_MAX_LEN)
|
---|
553 | *op++ = M4_MARKER | k | (m_len - 2);
|
---|
554 | else {
|
---|
555 | m_len -= M4_MAX_LEN;
|
---|
556 | *op++ = M4_MARKER | k | 0;
|
---|
557 | while (m_len > 255) {
|
---|
558 | m_len -= 255;
|
---|
559 | *op++ = 0;
|
---|
560 | }
|
---|
561 | assert(m_len > 0);
|
---|
562 | *op++ = m_len;
|
---|
563 | }
|
---|
564 | *op++ = m_off << 2;
|
---|
565 | *op++ = m_off >> 6;
|
---|
566 | }
|
---|
567 |
|
---|
568 | return op;
|
---|
569 | }
|
---|
570 |
|
---|
571 |
|
---|
572 | static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op,
|
---|
573 | const uint8_t *ii, unsigned t)
|
---|
574 | {
|
---|
575 | if (op == c->out && t <= 238) {
|
---|
576 | *op++ = 17 + t;
|
---|
577 | } else if (t <= 3) {
|
---|
578 | op[-2] |= t;
|
---|
579 | } else if (t <= 18) {
|
---|
580 | *op++ = t - 3;
|
---|
581 | } else {
|
---|
582 | unsigned tt = t - 18;
|
---|
583 |
|
---|
584 | *op++ = 0;
|
---|
585 | while (tt > 255) {
|
---|
586 | tt -= 255;
|
---|
587 | *op++ = 0;
|
---|
588 | }
|
---|
589 | assert(tt > 0);
|
---|
590 | *op++ = tt;
|
---|
591 | }
|
---|
592 | do *op++ = *ii++; while (--t > 0);
|
---|
593 |
|
---|
594 | return op;
|
---|
595 | }
|
---|
596 |
|
---|
597 |
|
---|
598 | static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii,
|
---|
599 | unsigned lit)
|
---|
600 | {
|
---|
601 | if (lit > 0) {
|
---|
602 | assert(m_len >= 2);
|
---|
603 | op = STORE_RUN(c, op, ii, lit);
|
---|
604 | } else {
|
---|
605 | assert(m_len >= 3);
|
---|
606 | }
|
---|
607 | c->r1_lit = lit;
|
---|
608 |
|
---|
609 | return op;
|
---|
610 | }
|
---|
611 |
|
---|
612 |
|
---|
613 | /***********************************************************************
|
---|
614 | //
|
---|
615 | ************************************************************************/
|
---|
616 | static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit)
|
---|
617 | {
|
---|
618 | int n = 4;
|
---|
619 |
|
---|
620 | if (m_len < 2)
|
---|
621 | return -1;
|
---|
622 | if (m_len == 2)
|
---|
623 | return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1;
|
---|
624 | if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
|
---|
625 | return 2;
|
---|
626 | if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4)
|
---|
627 | return 2;
|
---|
628 | if (m_off <= M3_MAX_OFFSET) {
|
---|
629 | if (m_len <= M3_MAX_LEN)
|
---|
630 | return 3;
|
---|
631 | m_len -= M3_MAX_LEN;
|
---|
632 | } else if (m_off <= M4_MAX_OFFSET) {
|
---|
633 | if (m_len <= M4_MAX_LEN)
|
---|
634 | return 3;
|
---|
635 | m_len -= M4_MAX_LEN;
|
---|
636 | } else
|
---|
637 | return -1;
|
---|
638 | while (m_len > 255) {
|
---|
639 | m_len -= 255;
|
---|
640 | n++;
|
---|
641 | }
|
---|
642 | return n;
|
---|
643 | }
|
---|
644 |
|
---|
645 |
|
---|
646 | static int min_gain(unsigned ahead, unsigned lit1,
|
---|
647 | unsigned lit2, int l1, int l2, int l3)
|
---|
648 | {
|
---|
649 | int lazy_match_min_gain = 0;
|
---|
650 |
|
---|
651 | assert (ahead >= 1);
|
---|
652 | lazy_match_min_gain += ahead;
|
---|
653 |
|
---|
654 | if (lit1 <= 3)
|
---|
655 | lazy_match_min_gain += (lit2 <= 3) ? 0 : 2;
|
---|
656 | else if (lit1 <= 18)
|
---|
657 | lazy_match_min_gain += (lit2 <= 18) ? 0 : 1;
|
---|
658 |
|
---|
659 | lazy_match_min_gain += (l2 - l1) * 2;
|
---|
660 | if (l3 > 0)
|
---|
661 | lazy_match_min_gain -= (ahead - l3) * 2;
|
---|
662 |
|
---|
663 | if (lazy_match_min_gain < 0)
|
---|
664 | lazy_match_min_gain = 0;
|
---|
665 |
|
---|
666 | return lazy_match_min_gain;
|
---|
667 | }
|
---|
668 |
|
---|
669 |
|
---|
670 | /***********************************************************************
|
---|
671 | //
|
---|
672 | ************************************************************************/
|
---|
673 | #if defined(SWD_BEST_OFF)
|
---|
674 |
|
---|
675 | static void better_match(const lzo_swd_p swd,
|
---|
676 | unsigned *m_len, unsigned *m_off)
|
---|
677 | {
|
---|
678 | if (*m_len <= M2_MIN_LEN)
|
---|
679 | return;
|
---|
680 |
|
---|
681 | if (*m_off <= M2_MAX_OFFSET)
|
---|
682 | return;
|
---|
683 |
|
---|
684 | /* M3/M4 -> M2 */
|
---|
685 | if (*m_off > M2_MAX_OFFSET
|
---|
686 | && *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1
|
---|
687 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET
|
---|
688 | ) {
|
---|
689 | *m_len = *m_len - 1;
|
---|
690 | *m_off = swd->best_off[*m_len];
|
---|
691 | return;
|
---|
692 | }
|
---|
693 |
|
---|
694 | /* M4 -> M2 */
|
---|
695 | if (*m_off > M3_MAX_OFFSET
|
---|
696 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2
|
---|
697 | && swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET
|
---|
698 | ) {
|
---|
699 | *m_len = *m_len - 2;
|
---|
700 | *m_off = swd->best_off[*m_len];
|
---|
701 | return;
|
---|
702 | }
|
---|
703 | /* M4 -> M3 */
|
---|
704 | if (*m_off > M3_MAX_OFFSET
|
---|
705 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1
|
---|
706 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET
|
---|
707 | ) {
|
---|
708 | *m_len = *m_len - 1;
|
---|
709 | *m_off = swd->best_off[*m_len];
|
---|
710 | }
|
---|
711 | }
|
---|
712 |
|
---|
713 | #endif
|
---|
714 |
|
---|
715 |
|
---|
716 | /***********************************************************************
|
---|
717 | //
|
---|
718 | ************************************************************************/
|
---|
719 | static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len,
|
---|
720 | uint8_t *out, unsigned *out_len,
|
---|
721 | void *wrkmem,
|
---|
722 | unsigned good_length,
|
---|
723 | unsigned max_lazy,
|
---|
724 | unsigned max_chain,
|
---|
725 | uint32_t use_best_off)
|
---|
726 | {
|
---|
727 | uint8_t *op;
|
---|
728 | const uint8_t *ii;
|
---|
729 | unsigned lit;
|
---|
730 | unsigned m_len, m_off;
|
---|
731 | lzo1x_999_t cc;
|
---|
732 | lzo1x_999_t *const c = &cc;
|
---|
733 | const lzo_swd_p swd = (lzo_swd_p) wrkmem;
|
---|
734 | int r;
|
---|
735 |
|
---|
736 | c->init = 0;
|
---|
737 | c->ip = c->in = in;
|
---|
738 | c->in_end = in + in_len;
|
---|
739 | c->out = out;
|
---|
740 |
|
---|
741 | op = out;
|
---|
742 | ii = c->ip; /* point to start of literal run */
|
---|
743 | lit = 0;
|
---|
744 | c->r1_lit = 0;
|
---|
745 |
|
---|
746 | r = init_match(c, swd, use_best_off);
|
---|
747 | if (r != 0)
|
---|
748 | return r;
|
---|
749 | swd->max_chain = max_chain;
|
---|
750 |
|
---|
751 | r = find_match(c, swd, 0, 0);
|
---|
752 | if (r != 0)
|
---|
753 | return r;
|
---|
754 |
|
---|
755 | while (c->look > 0) {
|
---|
756 | unsigned ahead;
|
---|
757 | unsigned max_ahead;
|
---|
758 | int l1, l2, l3;
|
---|
759 |
|
---|
760 | m_len = c->m_len;
|
---|
761 | m_off = c->m_off;
|
---|
762 |
|
---|
763 | assert(c->bp == c->ip - c->look);
|
---|
764 | assert(c->bp >= in);
|
---|
765 | if (lit == 0)
|
---|
766 | ii = c->bp;
|
---|
767 | assert(ii + lit == c->bp);
|
---|
768 | assert(swd->b_char == *(c->bp));
|
---|
769 |
|
---|
770 | if (m_len < 2
|
---|
771 | || (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4))
|
---|
772 | /* Do not accept this match for compressed-data compatibility
|
---|
773 | * with LZO v1.01 and before
|
---|
774 | * [ might be a problem for decompress() and optimize() ]
|
---|
775 | */
|
---|
776 | || (m_len == 2 && op == out)
|
---|
777 | || (op == out && lit == 0)
|
---|
778 | ) {
|
---|
779 | /* a literal */
|
---|
780 | m_len = 0;
|
---|
781 | }
|
---|
782 | else if (m_len == M2_MIN_LEN) {
|
---|
783 | /* compression ratio improves if we code a literal in some cases */
|
---|
784 | if (m_off > MX_MAX_OFFSET && lit >= 4)
|
---|
785 | m_len = 0;
|
---|
786 | }
|
---|
787 |
|
---|
788 | if (m_len == 0) {
|
---|
789 | /* a literal */
|
---|
790 | lit++;
|
---|
791 | swd->max_chain = max_chain;
|
---|
792 | r = find_match(c, swd, 1, 0);
|
---|
793 | assert(r == 0);
|
---|
794 | continue;
|
---|
795 | }
|
---|
796 |
|
---|
797 | /* a match */
|
---|
798 | #if defined(SWD_BEST_OFF)
|
---|
799 | if (swd->use_best_off)
|
---|
800 | better_match(swd, &m_len, &m_off);
|
---|
801 | #endif
|
---|
802 |
|
---|
803 | /* shall we try a lazy match ? */
|
---|
804 | ahead = 0;
|
---|
805 | if (m_len >= max_lazy) {
|
---|
806 | /* no */
|
---|
807 | l1 = 0;
|
---|
808 | max_ahead = 0;
|
---|
809 | } else {
|
---|
810 | /* yes, try a lazy match */
|
---|
811 | l1 = len_of_coded_match(m_len, m_off, lit);
|
---|
812 | assert(l1 > 0);
|
---|
813 | max_ahead = LZO_MIN(2, (unsigned)l1 - 1);
|
---|
814 | }
|
---|
815 |
|
---|
816 |
|
---|
817 | while (ahead < max_ahead && c->look > m_len) {
|
---|
818 | int lazy_match_min_gain;
|
---|
819 |
|
---|
820 | if (m_len >= good_length)
|
---|
821 | swd->max_chain = max_chain >> 2;
|
---|
822 | else
|
---|
823 | swd->max_chain = max_chain;
|
---|
824 | r = find_match(c, swd, 1, 0);
|
---|
825 | ahead++;
|
---|
826 |
|
---|
827 | assert(r == 0);
|
---|
828 | assert(c->look > 0);
|
---|
829 | assert(ii + lit + ahead == c->bp);
|
---|
830 |
|
---|
831 | if (c->m_len < m_len)
|
---|
832 | continue;
|
---|
833 | if (c->m_len == m_len && c->m_off >= m_off)
|
---|
834 | continue;
|
---|
835 | #if defined(SWD_BEST_OFF)
|
---|
836 | if (swd->use_best_off)
|
---|
837 | better_match(swd, &c->m_len, &c->m_off);
|
---|
838 | #endif
|
---|
839 | l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead);
|
---|
840 | if (l2 < 0)
|
---|
841 | continue;
|
---|
842 |
|
---|
843 | /* compressed-data compatibility [see above] */
|
---|
844 | l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit);
|
---|
845 |
|
---|
846 | lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3);
|
---|
847 | if (c->m_len >= m_len + lazy_match_min_gain) {
|
---|
848 | if (l3 > 0) {
|
---|
849 | /* code previous run */
|
---|
850 | op = code_run(c, op, ii, lit);
|
---|
851 | lit = 0;
|
---|
852 | /* code shortened match */
|
---|
853 | op = code_match(c, op, ahead, m_off);
|
---|
854 | } else {
|
---|
855 | lit += ahead;
|
---|
856 | assert(ii + lit == c->bp);
|
---|
857 | }
|
---|
858 | goto lazy_match_done;
|
---|
859 | }
|
---|
860 | }
|
---|
861 |
|
---|
862 | assert(ii + lit + ahead == c->bp);
|
---|
863 |
|
---|
864 | /* 1 - code run */
|
---|
865 | op = code_run(c, op, ii, lit);
|
---|
866 | lit = 0;
|
---|
867 |
|
---|
868 | /* 2 - code match */
|
---|
869 | op = code_match(c, op, m_len, m_off);
|
---|
870 | swd->max_chain = max_chain;
|
---|
871 | r = find_match(c, swd, m_len, 1+ahead);
|
---|
872 | assert(r == 0);
|
---|
873 |
|
---|
874 | lazy_match_done: ;
|
---|
875 | }
|
---|
876 |
|
---|
877 | /* store final run */
|
---|
878 | if (lit > 0)
|
---|
879 | op = STORE_RUN(c, op, ii, lit);
|
---|
880 |
|
---|
881 | #if defined(LZO_EOF_CODE)
|
---|
882 | *op++ = M4_MARKER | 1;
|
---|
883 | *op++ = 0;
|
---|
884 | *op++ = 0;
|
---|
885 | #endif
|
---|
886 |
|
---|
887 | *out_len = op - out;
|
---|
888 |
|
---|
889 | return LZO_E_OK;
|
---|
890 | }
|
---|
891 |
|
---|
892 |
|
---|
893 | /***********************************************************************
|
---|
894 | //
|
---|
895 | ************************************************************************/
|
---|
896 | int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len,
|
---|
897 | uint8_t *out, unsigned *out_len,
|
---|
898 | void *wrkmem,
|
---|
899 | int compression_level)
|
---|
900 | {
|
---|
901 | static const struct {
|
---|
902 | uint16_t good_length;
|
---|
903 | uint16_t max_lazy;
|
---|
904 | uint16_t max_chain;
|
---|
905 | uint16_t use_best_off;
|
---|
906 | } c[3] = {
|
---|
907 | { 8, 32, 256, 0 },
|
---|
908 | { 32, 128, 2048, 1 },
|
---|
909 | { SWD_F, SWD_F, 4096, 1 } /* max. compression */
|
---|
910 | };
|
---|
911 |
|
---|
912 | if (compression_level < 7 || compression_level > 9)
|
---|
913 | return LZO_E_ERROR;
|
---|
914 |
|
---|
915 | compression_level -= 7;
|
---|
916 | return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem,
|
---|
917 | c[compression_level].good_length,
|
---|
918 | c[compression_level].max_lazy,
|
---|
919 | c[compression_level].max_chain,
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920 | c[compression_level].use_best_off);
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921 | }
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