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0
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1 /* trees.c -- output deflated data using Huffman coding
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2 * Copyright (C) 1995-1998 Jean-loup Gailly
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3 * For conditions of distribution and use, see copyright notice in zlib.h
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4 */
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5
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6 /*
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7 * ALGORITHM
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8 *
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9 * The "deflation" process uses several Huffman trees. The more
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10 * common source values are represented by shorter bit sequences.
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11 *
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12 * Each code tree is stored in a compressed form which is itself
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13 * a Huffman encoding of the lengths of all the code strings (in
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14 * ascending order by source values). The actual code strings are
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15 * reconstructed from the lengths in the inflate process, as described
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16 * in the deflate specification.
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17 *
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18 * REFERENCES
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19 *
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20 * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
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21 * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
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22 *
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23 * Storer, James A.
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24 * Data Compression: Methods and Theory, pp. 49-50.
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25 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
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26 *
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27 * Sedgewick, R.
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28 * Algorithms, p290.
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29 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
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30 */
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31
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32 /* @(#) $Id$ */
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33
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34 /* #define GEN_TREES_H */
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35
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36 #include "deflate.h"
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37
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38 #ifdef DEBUG
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39 # include <ctype.h>
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40 #endif
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41
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42 /* ===========================================================================
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43 * Constants
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44 */
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45
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46 #define MAX_BL_BITS 7
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47 /* Bit length codes must not exceed MAX_BL_BITS bits */
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48
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49 #define END_BLOCK 256
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50 /* end of block literal code */
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51
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52 #define REP_3_6 16
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53 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
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54
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55 #define REPZ_3_10 17
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56 /* repeat a zero length 3-10 times (3 bits of repeat count) */
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57
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58 #define REPZ_11_138 18
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59 /* repeat a zero length 11-138 times (7 bits of repeat count) */
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60
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61 local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
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62 = {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};
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63
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64 local const int extra_dbits[D_CODES] /* extra bits for each distance code */
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65 = {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};
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66
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67 local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
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68 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
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69
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70 local const uch bl_order[BL_CODES]
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71 = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
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72 /* The lengths of the bit length codes are sent in order of decreasing
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73 * probability, to avoid transmitting the lengths for unused bit length codes.
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74 */
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75
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76 #define Buf_size (8 * 2*sizeof(char))
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77 /* Number of bits used within bi_buf. (bi_buf might be implemented on
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78 * more than 16 bits on some systems.)
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79 */
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80
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81 /* ===========================================================================
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82 * Local data. These are initialized only once.
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83 */
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84
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85 #define DIST_CODE_LEN 512 /* see definition of array dist_code below */
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86
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87 #if defined(GEN_TREES_H) || !defined(STDC)
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88 /* non ANSI compilers may not accept trees.h */
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89
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90 local ct_data static_ltree[L_CODES+2];
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91 /* The static literal tree. Since the bit lengths are imposed, there is no
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92 * need for the L_CODES extra codes used during heap construction. However
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93 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
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94 * below).
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95 */
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96
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97 local ct_data static_dtree[D_CODES];
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98 /* The static distance tree. (Actually a trivial tree since all codes use
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99 * 5 bits.)
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100 */
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101
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102 uch _dist_code[DIST_CODE_LEN];
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103 /* Distance codes. The first 256 values correspond to the distances
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104 * 3 .. 258, the last 256 values correspond to the top 8 bits of
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105 * the 15 bit distances.
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106 */
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107
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108 uch _length_code[MAX_MATCH-MIN_MATCH+1];
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109 /* length code for each normalized match length (0 == MIN_MATCH) */
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110
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111 local int base_length[LENGTH_CODES];
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112 /* First normalized length for each code (0 = MIN_MATCH) */
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113
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114 local int base_dist[D_CODES];
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115 /* First normalized distance for each code (0 = distance of 1) */
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116
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117 #else
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118 # include "trees.h"
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119 #endif /* GEN_TREES_H */
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120
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121 struct static_tree_desc_s {
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122 const ct_data *static_tree; /* static tree or NULL */
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123 const intf *extra_bits; /* extra bits for each code or NULL */
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124 int extra_base; /* base index for extra_bits */
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125 int elems; /* max number of elements in the tree */
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126 int max_length; /* max bit length for the codes */
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127 };
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128
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129 local static_tree_desc static_l_desc =
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130 {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
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131
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132 local static_tree_desc static_d_desc =
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133 {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
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134
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135 local static_tree_desc static_bl_desc =
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136 {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
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137
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138 /* ===========================================================================
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139 * Local (static) routines in this file.
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140 */
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141
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142 local void tr_static_init OF((void));
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143 local void init_block OF((deflate_state *s));
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144 local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
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145 local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
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146 local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
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147 local void build_tree OF((deflate_state *s, tree_desc *desc));
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148 local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
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149 local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
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150 local int build_bl_tree OF((deflate_state *s));
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151 local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
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152 int blcodes));
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153 local void compress_block OF((deflate_state *s, ct_data *ltree,
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154 ct_data *dtree));
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155 local void set_data_type OF((deflate_state *s));
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156 local unsigned bi_reverse OF((unsigned value, int length));
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157 local void bi_windup OF((deflate_state *s));
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158 local void bi_flush OF((deflate_state *s));
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159 local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
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160 int header));
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161
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162 #ifdef GEN_TREES_H
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163 local void gen_trees_header OF((void));
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164 #endif
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165
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166 #ifndef DEBUG
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167 # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
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168 /* Send a code of the given tree. c and tree must not have side effects */
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169
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170 #else /* DEBUG */
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171 # define send_code(s, c, tree) \
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172 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
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173 send_bits(s, tree[c].Code, tree[c].Len); }
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174 #endif
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175
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176 /* ===========================================================================
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177 * Output a short LSB first on the stream.
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178 * IN assertion: there is enough room in pendingBuf.
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179 */
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180 #define put_short(s, w) { \
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181 put_byte(s, (uch)((w) & 0xff)); \
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182 put_byte(s, (uch)((ush)(w) >> 8)); \
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183 }
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184
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185 /* ===========================================================================
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186 * Send a value on a given number of bits.
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187 * IN assertion: length <= 16 and value fits in length bits.
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188 */
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189 #ifdef DEBUG
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190 local void send_bits OF((deflate_state *s, int value, int length));
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191
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192 local void send_bits(s, value, length)
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193 deflate_state *s;
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194 int value; /* value to send */
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195 int length; /* number of bits */
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196 {
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197 Tracevv((stderr," l %2d v %4x ", length, value));
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198 Assert(length > 0 && length <= 15, "invalid length");
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199 s->bits_sent += (ulg)length;
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200
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201 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
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202 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
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203 * unused bits in value.
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204 */
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205 if (s->bi_valid > (int)Buf_size - length) {
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206 s->bi_buf |= (value << s->bi_valid);
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207 put_short(s, s->bi_buf);
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208 s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
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209 s->bi_valid += length - Buf_size;
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210 } else {
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211 s->bi_buf |= value << s->bi_valid;
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212 s->bi_valid += length;
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213 }
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214 }
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215 #else /* !DEBUG */
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216
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217 #define send_bits(s, value, length) \
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218 { int len = length;\
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219 if (s->bi_valid > (int)Buf_size - len) {\
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220 int val = value;\
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221 s->bi_buf |= (val << s->bi_valid);\
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222 put_short(s, s->bi_buf);\
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223 s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
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224 s->bi_valid += len - Buf_size;\
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225 } else {\
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226 s->bi_buf |= (value) << s->bi_valid;\
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227 s->bi_valid += len;\
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228 }\
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229 }
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230 #endif /* DEBUG */
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231
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232
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233 #define MAX(a,b) (a >= b ? a : b)
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234 /* the arguments must not have side effects */
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235
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236 /* ===========================================================================
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237 * Initialize the various 'constant' tables.
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238 */
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239 local void tr_static_init()
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240 {
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241 #if defined(GEN_TREES_H) || !defined(STDC)
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242 static int static_init_done = 0;
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243 int n; /* iterates over tree elements */
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244 int bits; /* bit counter */
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245 int length; /* length value */
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246 int code; /* code value */
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247 int dist; /* distance index */
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248 ush bl_count[MAX_BITS+1];
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249 /* number of codes at each bit length for an optimal tree */
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250
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251 if (static_init_done) return;
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252
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253 /* For some embedded targets, global variables are not initialized: */
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254 static_l_desc.static_tree = static_ltree;
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255 static_l_desc.extra_bits = extra_lbits;
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256 static_d_desc.static_tree = static_dtree;
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257 static_d_desc.extra_bits = extra_dbits;
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258 static_bl_desc.extra_bits = extra_blbits;
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259
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260 /* Initialize the mapping length (0..255) -> length code (0..28) */
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261 length = 0;
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262 for (code = 0; code < LENGTH_CODES-1; code++) {
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263 base_length[code] = length;
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264 for (n = 0; n < (1<<extra_lbits[code]); n++) {
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265 _length_code[length++] = (uch)code;
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266 }
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267 }
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268 Assert (length == 256, "tr_static_init: length != 256");
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269 /* Note that the length 255 (match length 258) can be represented
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270 * in two different ways: code 284 + 5 bits or code 285, so we
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271 * overwrite length_code[255] to use the best encoding:
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272 */
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273 _length_code[length-1] = (uch)code;
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274
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275 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
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276 dist = 0;
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277 for (code = 0 ; code < 16; code++) {
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278 base_dist[code] = dist;
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279 for (n = 0; n < (1<<extra_dbits[code]); n++) {
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280 _dist_code[dist++] = (uch)code;
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281 }
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282 }
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283 Assert (dist == 256, "tr_static_init: dist != 256");
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284 dist >>= 7; /* from now on, all distances are divided by 128 */
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285 for ( ; code < D_CODES; code++) {
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286 base_dist[code] = dist << 7;
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287 for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
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288 _dist_code[256 + dist++] = (uch)code;
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289 }
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290 }
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291 Assert (dist == 256, "tr_static_init: 256+dist != 512");
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292
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293 /* Construct the codes of the static literal tree */
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294 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
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295 n = 0;
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296 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
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297 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
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298 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
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299 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
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300 /* Codes 286 and 287 do not exist, but we must include them in the
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301 * tree construction to get a canonical Huffman tree (longest code
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302 * all ones)
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303 */
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304 gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
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305
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306 /* The static distance tree is trivial: */
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307 for (n = 0; n < D_CODES; n++) {
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308 static_dtree[n].Len = 5;
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309 static_dtree[n].Code = bi_reverse((unsigned)n, 5);
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310 }
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311 static_init_done = 1;
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312
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313 # ifdef GEN_TREES_H
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314 gen_trees_header();
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315 # endif
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316 #endif /* defined(GEN_TREES_H) || !defined(STDC) */
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317 }
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318
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319 /* ===========================================================================
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320 * Genererate the file trees.h describing the static trees.
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321 */
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322 #ifdef GEN_TREES_H
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323 # ifndef DEBUG
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324 # include <stdio.h>
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325 # endif
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326
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327 # define SEPARATOR(i, last, width) \
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328 ((i) == (last)? "\n};\n\n" : \
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329 ((i) % (width) == (width)-1 ? ",\n" : ", "))
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330
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331 void gen_trees_header()
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332 {
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333 FILE *header = fopen("trees.h", "w");
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334 int i;
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335
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336 Assert (header != NULL, "Can't open trees.h");
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337 fprintf(header,
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338 "/* header created automatically with -DGEN_TREES_H */\n\n");
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339
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340 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
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341 for (i = 0; i < L_CODES+2; i++) {
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342 fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
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343 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
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344 }
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345
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346 fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
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347 for (i = 0; i < D_CODES; i++) {
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348 fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
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349 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
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350 }
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351
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352 fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n");
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353 for (i = 0; i < DIST_CODE_LEN; i++) {
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354 fprintf(header, "%2u%s", _dist_code[i],
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355 SEPARATOR(i, DIST_CODE_LEN-1, 20));
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356 }
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357
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358 fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
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359 for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
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360 fprintf(header, "%2u%s", _length_code[i],
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361 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
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362 }
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363
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364 fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
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365 for (i = 0; i < LENGTH_CODES; i++) {
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366 fprintf(header, "%1u%s", base_length[i],
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367 SEPARATOR(i, LENGTH_CODES-1, 20));
|
|
|
368 }
|
|
|
369
|
|
|
370 fprintf(header, "local const int base_dist[D_CODES] = {\n");
|
|
|
371 for (i = 0; i < D_CODES; i++) {
|
|
|
372 fprintf(header, "%5u%s", base_dist[i],
|
|
|
373 SEPARATOR(i, D_CODES-1, 10));
|
|
|
374 }
|
|
|
375
|
|
|
376 fclose(header);
|
|
|
377 }
|
|
|
378 #endif /* GEN_TREES_H */
|
|
|
379
|
|
|
380 /* ===========================================================================
|
|
|
381 * Initialize the tree data structures for a new zlib stream.
|
|
|
382 */
|
|
|
383 void _tr_init(s)
|
|
|
384 deflate_state *s;
|
|
|
385 {
|
|
|
386 tr_static_init();
|
|
|
387
|
|
|
388 s->l_desc.dyn_tree = s->dyn_ltree;
|
|
|
389 s->l_desc.stat_desc = &static_l_desc;
|
|
|
390
|
|
|
391 s->d_desc.dyn_tree = s->dyn_dtree;
|
|
|
392 s->d_desc.stat_desc = &static_d_desc;
|
|
|
393
|
|
|
394 s->bl_desc.dyn_tree = s->bl_tree;
|
|
|
395 s->bl_desc.stat_desc = &static_bl_desc;
|
|
|
396
|
|
|
397 s->bi_buf = 0;
|
|
|
398 s->bi_valid = 0;
|
|
|
399 s->last_eob_len = 8; /* enough lookahead for inflate */
|
|
|
400 #ifdef DEBUG
|
|
|
401 s->compressed_len = 0L;
|
|
|
402 s->bits_sent = 0L;
|
|
|
403 #endif
|
|
|
404
|
|
|
405 /* Initialize the first block of the first file: */
|
|
|
406 init_block(s);
|
|
|
407 }
|
|
|
408
|
|
|
409 /* ===========================================================================
|
|
|
410 * Initialize a new block.
|
|
|
411 */
|
|
|
412 local void init_block(s)
|
|
|
413 deflate_state *s;
|
|
|
414 {
|
|
|
415 int n; /* iterates over tree elements */
|
|
|
416
|
|
|
417 /* Initialize the trees. */
|
|
|
418 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
|
|
|
419 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
|
|
|
420 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
|
|
|
421
|
|
|
422 s->dyn_ltree[END_BLOCK].Freq = 1;
|
|
|
423 s->opt_len = s->static_len = 0L;
|
|
|
424 s->last_lit = s->matches = 0;
|
|
|
425 }
|
|
|
426
|
|
|
427 #define SMALLEST 1
|
|
|
428 /* Index within the heap array of least frequent node in the Huffman tree */
|
|
|
429
|
|
|
430
|
|
|
431 /* ===========================================================================
|
|
|
432 * Remove the smallest element from the heap and recreate the heap with
|
|
|
433 * one less element. Updates heap and heap_len.
|
|
|
434 */
|
|
|
435 #define pqremove(s, tree, top) \
|
|
|
436 {\
|
|
|
437 top = s->heap[SMALLEST]; \
|
|
|
438 s->heap[SMALLEST] = s->heap[s->heap_len--]; \
|
|
|
439 pqdownheap(s, tree, SMALLEST); \
|
|
|
440 }
|
|
|
441
|
|
|
442 /* ===========================================================================
|
|
|
443 * Compares to subtrees, using the tree depth as tie breaker when
|
|
|
444 * the subtrees have equal frequency. This minimizes the worst case length.
|
|
|
445 */
|
|
|
446 #define smaller(tree, n, m, depth) \
|
|
|
447 (tree[n].Freq < tree[m].Freq || \
|
|
|
448 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
|
|
|
449
|
|
|
450 /* ===========================================================================
|
|
|
451 * Restore the heap property by moving down the tree starting at node k,
|
|
|
452 * exchanging a node with the smallest of its two sons if necessary, stopping
|
|
|
453 * when the heap property is re-established (each father smaller than its
|
|
|
454 * two sons).
|
|
|
455 */
|
|
|
456 local void pqdownheap(s, tree, k)
|
|
|
457 deflate_state *s;
|
|
|
458 ct_data *tree; /* the tree to restore */
|
|
|
459 int k; /* node to move down */
|
|
|
460 {
|
|
|
461 int v = s->heap[k];
|
|
|
462 int j = k << 1; /* left son of k */
|
|
|
463 while (j <= s->heap_len) {
|
|
|
464 /* Set j to the smallest of the two sons: */
|
|
|
465 if (j < s->heap_len &&
|
|
|
466 smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
|
|
|
467 j++;
|
|
|
468 }
|
|
|
469 /* Exit if v is smaller than both sons */
|
|
|
470 if (smaller(tree, v, s->heap[j], s->depth)) break;
|
|
|
471
|
|
|
472 /* Exchange v with the smallest son */
|
|
|
473 s->heap[k] = s->heap[j]; k = j;
|
|
|
474
|
|
|
475 /* And continue down the tree, setting j to the left son of k */
|
|
|
476 j <<= 1;
|
|
|
477 }
|
|
|
478 s->heap[k] = v;
|
|
|
479 }
|
|
|
480
|
|
|
481 /* ===========================================================================
|
|
|
482 * Compute the optimal bit lengths for a tree and update the total bit length
|
|
|
483 * for the current block.
|
|
|
484 * IN assertion: the fields freq and dad are set, heap[heap_max] and
|
|
|
485 * above are the tree nodes sorted by increasing frequency.
|
|
|
486 * OUT assertions: the field len is set to the optimal bit length, the
|
|
|
487 * array bl_count contains the frequencies for each bit length.
|
|
|
488 * The length opt_len is updated; static_len is also updated if stree is
|
|
|
489 * not null.
|
|
|
490 */
|
|
|
491 local void gen_bitlen(s, desc)
|
|
|
492 deflate_state *s;
|
|
|
493 tree_desc *desc; /* the tree descriptor */
|
|
|
494 {
|
|
|
495 ct_data *tree = desc->dyn_tree;
|
|
|
496 int max_code = desc->max_code;
|
|
|
497 const ct_data *stree = desc->stat_desc->static_tree;
|
|
|
498 const intf *extra = desc->stat_desc->extra_bits;
|
|
|
499 int base = desc->stat_desc->extra_base;
|
|
|
500 int max_length = desc->stat_desc->max_length;
|
|
|
501 int h; /* heap index */
|
|
|
502 int n, m; /* iterate over the tree elements */
|
|
|
503 int bits; /* bit length */
|
|
|
504 int xbits; /* extra bits */
|
|
|
505 ush f; /* frequency */
|
|
|
506 int overflow = 0; /* number of elements with bit length too large */
|
|
|
507
|
|
|
508 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
|
|
|
509
|
|
|
510 /* In a first pass, compute the optimal bit lengths (which may
|
|
|
511 * overflow in the case of the bit length tree).
|
|
|
512 */
|
|
|
513 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
|
|
|
514
|
|
|
515 for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
|
|
|
516 n = s->heap[h];
|
|
|
517 bits = tree[tree[n].Dad].Len + 1;
|
|
|
518 if (bits > max_length) bits = max_length, overflow++;
|
|
|
519 tree[n].Len = (ush)bits;
|
|
|
520 /* We overwrite tree[n].Dad which is no longer needed */
|
|
|
521
|
|
|
522 if (n > max_code) continue; /* not a leaf node */
|
|
|
523
|
|
|
524 s->bl_count[bits]++;
|
|
|
525 xbits = 0;
|
|
|
526 if (n >= base) xbits = extra[n-base];
|
|
|
527 f = tree[n].Freq;
|
|
|
528 s->opt_len += (ulg)f * (bits + xbits);
|
|
|
529 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
|
|
|
530 }
|
|
|
531 if (overflow == 0) return;
|
|
|
532
|
|
|
533 Trace((stderr,"\nbit length overflow\n"));
|
|
|
534 /* This happens for example on obj2 and pic of the Calgary corpus */
|
|
|
535
|
|
|
536 /* Find the first bit length which could increase: */
|
|
|
537 do {
|
|
|
538 bits = max_length-1;
|
|
|
539 while (s->bl_count[bits] == 0) bits--;
|
|
|
540 s->bl_count[bits]--; /* move one leaf down the tree */
|
|
|
541 s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
|
|
|
542 s->bl_count[max_length]--;
|
|
|
543 /* The brother of the overflow item also moves one step up,
|
|
|
544 * but this does not affect bl_count[max_length]
|
|
|
545 */
|
|
|
546 overflow -= 2;
|
|
|
547 } while (overflow > 0);
|
|
|
548
|
|
|
549 /* Now recompute all bit lengths, scanning in increasing frequency.
|
|
|
550 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
|
|
|
551 * lengths instead of fixing only the wrong ones. This idea is taken
|
|
|
552 * from 'ar' written by Haruhiko Okumura.)
|
|
|
553 */
|
|
|
554 for (bits = max_length; bits != 0; bits--) {
|
|
|
555 n = s->bl_count[bits];
|
|
|
556 while (n != 0) {
|
|
|
557 m = s->heap[--h];
|
|
|
558 if (m > max_code) continue;
|
|
|
559 if (tree[m].Len != (unsigned) bits) {
|
|
|
560 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
|
|
|
561 s->opt_len += ((long)bits - (long)tree[m].Len)
|
|
|
562 *(long)tree[m].Freq;
|
|
|
563 tree[m].Len = (ush)bits;
|
|
|
564 }
|
|
|
565 n--;
|
|
|
566 }
|
|
|
567 }
|
|
|
568 }
|
|
|
569
|
|
|
570 /* ===========================================================================
|
|
|
571 * Generate the codes for a given tree and bit counts (which need not be
|
|
|
572 * optimal).
|
|
|
573 * IN assertion: the array bl_count contains the bit length statistics for
|
|
|
574 * the given tree and the field len is set for all tree elements.
|
|
|
575 * OUT assertion: the field code is set for all tree elements of non
|
|
|
576 * zero code length.
|
|
|
577 */
|
|
|
578 local void gen_codes (tree, max_code, bl_count)
|
|
|
579 ct_data *tree; /* the tree to decorate */
|
|
|
580 int max_code; /* largest code with non zero frequency */
|
|
|
581 ushf *bl_count; /* number of codes at each bit length */
|
|
|
582 {
|
|
|
583 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
|
|
|
584 ush code = 0; /* running code value */
|
|
|
585 int bits; /* bit index */
|
|
|
586 int n; /* code index */
|
|
|
587
|
|
|
588 /* The distribution counts are first used to generate the code values
|
|
|
589 * without bit reversal.
|
|
|
590 */
|
|
|
591 for (bits = 1; bits <= MAX_BITS; bits++) {
|
|
|
592 next_code[bits] = code = (code + bl_count[bits-1]) << 1;
|
|
|
593 }
|
|
|
594 /* Check that the bit counts in bl_count are consistent. The last code
|
|
|
595 * must be all ones.
|
|
|
596 */
|
|
|
597 Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
|
|
|
598 "inconsistent bit counts");
|
|
|
599 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
|
|
|
600
|
|
|
601 for (n = 0; n <= max_code; n++) {
|
|
|
602 int len = tree[n].Len;
|
|
|
603 if (len == 0) continue;
|
|
|
604 /* Now reverse the bits */
|
|
|
605 tree[n].Code = bi_reverse(next_code[len]++, len);
|
|
|
606
|
|
|
607 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
|
|
|
608 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
|
|
|
609 }
|
|
|
610 }
|
|
|
611
|
|
|
612 /* ===========================================================================
|
|
|
613 * Construct one Huffman tree and assigns the code bit strings and lengths.
|
|
|
614 * Update the total bit length for the current block.
|
|
|
615 * IN assertion: the field freq is set for all tree elements.
|
|
|
616 * OUT assertions: the fields len and code are set to the optimal bit length
|
|
|
617 * and corresponding code. The length opt_len is updated; static_len is
|
|
|
618 * also updated if stree is not null. The field max_code is set.
|
|
|
619 */
|
|
|
620 local void build_tree(s, desc)
|
|
|
621 deflate_state *s;
|
|
|
622 tree_desc *desc; /* the tree descriptor */
|
|
|
623 {
|
|
|
624 ct_data *tree = desc->dyn_tree;
|
|
|
625 const ct_data *stree = desc->stat_desc->static_tree;
|
|
|
626 int elems = desc->stat_desc->elems;
|
|
|
627 int n, m; /* iterate over heap elements */
|
|
|
628 int max_code = -1; /* largest code with non zero frequency */
|
|
|
629 int node; /* new node being created */
|
|
|
630
|
|
|
631 /* Construct the initial heap, with least frequent element in
|
|
|
632 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
|
|
|
633 * heap[0] is not used.
|
|
|
634 */
|
|
|
635 s->heap_len = 0, s->heap_max = HEAP_SIZE;
|
|
|
636
|
|
|
637 for (n = 0; n < elems; n++) {
|
|
|
638 if (tree[n].Freq != 0) {
|
|
|
639 s->heap[++(s->heap_len)] = max_code = n;
|
|
|
640 s->depth[n] = 0;
|
|
|
641 } else {
|
|
|
642 tree[n].Len = 0;
|
|
|
643 }
|
|
|
644 }
|
|
|
645
|
|
|
646 /* The pkzip format requires that at least one distance code exists,
|
|
|
647 * and that at least one bit should be sent even if there is only one
|
|
|
648 * possible code. So to avoid special checks later on we force at least
|
|
|
649 * two codes of non zero frequency.
|
|
|
650 */
|
|
|
651 while (s->heap_len < 2) {
|
|
|
652 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
|
|
|
653 tree[node].Freq = 1;
|
|
|
654 s->depth[node] = 0;
|
|
|
655 s->opt_len--; if (stree) s->static_len -= stree[node].Len;
|
|
|
656 /* node is 0 or 1 so it does not have extra bits */
|
|
|
657 }
|
|
|
658 desc->max_code = max_code;
|
|
|
659
|
|
|
660 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
|
|
|
661 * establish sub-heaps of increasing lengths:
|
|
|
662 */
|
|
|
663 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
|
|
|
664
|
|
|
665 /* Construct the Huffman tree by repeatedly combining the least two
|
|
|
666 * frequent nodes.
|
|
|
667 */
|
|
|
668 node = elems; /* next internal node of the tree */
|
|
|
669 do {
|
|
|
670 pqremove(s, tree, n); /* n = node of least frequency */
|
|
|
671 m = s->heap[SMALLEST]; /* m = node of next least frequency */
|
|
|
672
|
|
|
673 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
|
|
|
674 s->heap[--(s->heap_max)] = m;
|
|
|
675
|
|
|
676 /* Create a new node father of n and m */
|
|
|
677 tree[node].Freq = tree[n].Freq + tree[m].Freq;
|
|
|
678 s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1);
|
|
|
679 tree[n].Dad = tree[m].Dad = (ush)node;
|
|
|
680 #ifdef DUMP_BL_TREE
|
|
|
681 if (tree == s->bl_tree) {
|
|
|
682 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
|
|
|
683 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
|
|
|
684 }
|
|
|
685 #endif
|
|
|
686 /* and insert the new node in the heap */
|
|
|
687 s->heap[SMALLEST] = node++;
|
|
|
688 pqdownheap(s, tree, SMALLEST);
|
|
|
689
|
|
|
690 } while (s->heap_len >= 2);
|
|
|
691
|
|
|
692 s->heap[--(s->heap_max)] = s->heap[SMALLEST];
|
|
|
693
|
|
|
694 /* At this point, the fields freq and dad are set. We can now
|
|
|
695 * generate the bit lengths.
|
|
|
696 */
|
|
|
697 gen_bitlen(s, (tree_desc *)desc);
|
|
|
698
|
|
|
699 /* The field len is now set, we can generate the bit codes */
|
|
|
700 gen_codes ((ct_data *)tree, max_code, s->bl_count);
|
|
|
701 }
|
|
|
702
|
|
|
703 /* ===========================================================================
|
|
|
704 * Scan a literal or distance tree to determine the frequencies of the codes
|
|
|
705 * in the bit length tree.
|
|
|
706 */
|
|
|
707 local void scan_tree (s, tree, max_code)
|
|
|
708 deflate_state *s;
|
|
|
709 ct_data *tree; /* the tree to be scanned */
|
|
|
710 int max_code; /* and its largest code of non zero frequency */
|
|
|
711 {
|
|
|
712 int n; /* iterates over all tree elements */
|
|
|
713 int prevlen = -1; /* last emitted length */
|
|
|
714 int curlen; /* length of current code */
|
|
|
715 int nextlen = tree[0].Len; /* length of next code */
|
|
|
716 int count = 0; /* repeat count of the current code */
|
|
|
717 int max_count = 7; /* max repeat count */
|
|
|
718 int min_count = 4; /* min repeat count */
|
|
|
719
|
|
|
720 if (nextlen == 0) max_count = 138, min_count = 3;
|
|
|
721 tree[max_code+1].Len = (ush)0xffff; /* guard */
|
|
|
722
|
|
|
723 for (n = 0; n <= max_code; n++) {
|
|
|
724 curlen = nextlen; nextlen = tree[n+1].Len;
|
|
|
725 if (++count < max_count && curlen == nextlen) {
|
|
|
726 continue;
|
|
|
727 } else if (count < min_count) {
|
|
|
728 s->bl_tree[curlen].Freq += count;
|
|
|
729 } else if (curlen != 0) {
|
|
|
730 if (curlen != prevlen) s->bl_tree[curlen].Freq++;
|
|
|
731 s->bl_tree[REP_3_6].Freq++;
|
|
|
732 } else if (count <= 10) {
|
|
|
733 s->bl_tree[REPZ_3_10].Freq++;
|
|
|
734 } else {
|
|
|
735 s->bl_tree[REPZ_11_138].Freq++;
|
|
|
736 }
|
|
|
737 count = 0; prevlen = curlen;
|
|
|
738 if (nextlen == 0) {
|
|
|
739 max_count = 138, min_count = 3;
|
|
|
740 } else if (curlen == nextlen) {
|
|
|
741 max_count = 6, min_count = 3;
|
|
|
742 } else {
|
|
|
743 max_count = 7, min_count = 4;
|
|
|
744 }
|
|
|
745 }
|
|
|
746 }
|
|
|
747
|
|
|
748 /* ===========================================================================
|
|
|
749 * Send a literal or distance tree in compressed form, using the codes in
|
|
|
750 * bl_tree.
|
|
|
751 */
|
|
|
752 local void send_tree (s, tree, max_code)
|
|
|
753 deflate_state *s;
|
|
|
754 ct_data *tree; /* the tree to be scanned */
|
|
|
755 int max_code; /* and its largest code of non zero frequency */
|
|
|
756 {
|
|
|
757 int n; /* iterates over all tree elements */
|
|
|
758 int prevlen = -1; /* last emitted length */
|
|
|
759 int curlen; /* length of current code */
|
|
|
760 int nextlen = tree[0].Len; /* length of next code */
|
|
|
761 int count = 0; /* repeat count of the current code */
|
|
|
762 int max_count = 7; /* max repeat count */
|
|
|
763 int min_count = 4; /* min repeat count */
|
|
|
764
|
|
|
765 /* tree[max_code+1].Len = -1; */ /* guard already set */
|
|
|
766 if (nextlen == 0) max_count = 138, min_count = 3;
|
|
|
767
|
|
|
768 for (n = 0; n <= max_code; n++) {
|
|
|
769 curlen = nextlen; nextlen = tree[n+1].Len;
|
|
|
770 if (++count < max_count && curlen == nextlen) {
|
|
|
771 continue;
|
|
|
772 } else if (count < min_count) {
|
|
|
773 do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
|
|
|
774
|
|
|
775 } else if (curlen != 0) {
|
|
|
776 if (curlen != prevlen) {
|
|
|
777 send_code(s, curlen, s->bl_tree); count--;
|
|
|
778 }
|
|
|
779 Assert(count >= 3 && count <= 6, " 3_6?");
|
|
|
780 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
|
|
|
781
|
|
|
782 } else if (count <= 10) {
|
|
|
783 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
|
|
|
784
|
|
|
785 } else {
|
|
|
786 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
|
|
|
787 }
|
|
|
788 count = 0; prevlen = curlen;
|
|
|
789 if (nextlen == 0) {
|
|
|
790 max_count = 138, min_count = 3;
|
|
|
791 } else if (curlen == nextlen) {
|
|
|
792 max_count = 6, min_count = 3;
|
|
|
793 } else {
|
|
|
794 max_count = 7, min_count = 4;
|
|
|
795 }
|
|
|
796 }
|
|
|
797 }
|
|
|
798
|
|
|
799 /* ===========================================================================
|
|
|
800 * Construct the Huffman tree for the bit lengths and return the index in
|
|
|
801 * bl_order of the last bit length code to send.
|
|
|
802 */
|
|
|
803 local int build_bl_tree(s)
|
|
|
804 deflate_state *s;
|
|
|
805 {
|
|
|
806 int max_blindex; /* index of last bit length code of non zero freq */
|
|
|
807
|
|
|
808 /* Determine the bit length frequencies for literal and distance trees */
|
|
|
809 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
|
|
|
810 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
|
|
|
811
|
|
|
812 /* Build the bit length tree: */
|
|
|
813 build_tree(s, (tree_desc *)(&(s->bl_desc)));
|
|
|
814 /* opt_len now includes the length of the tree representations, except
|
|
|
815 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
|
|
|
816 */
|
|
|
817
|
|
|
818 /* Determine the number of bit length codes to send. The pkzip format
|
|
|
819 * requires that at least 4 bit length codes be sent. (appnote.txt says
|
|
|
820 * 3 but the actual value used is 4.)
|
|
|
821 */
|
|
|
822 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
|
|
|
823 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
|
|
|
824 }
|
|
|
825 /* Update opt_len to include the bit length tree and counts */
|
|
|
826 s->opt_len += 3*(max_blindex+1) + 5+5+4;
|
|
|
827 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
|
|
|
828 s->opt_len, s->static_len));
|
|
|
829
|
|
|
830 return max_blindex;
|
|
|
831 }
|
|
|
832
|
|
|
833 /* ===========================================================================
|
|
|
834 * Send the header for a block using dynamic Huffman trees: the counts, the
|
|
|
835 * lengths of the bit length codes, the literal tree and the distance tree.
|
|
|
836 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
|
|
|
837 */
|
|
|
838 local void send_all_trees(s, lcodes, dcodes, blcodes)
|
|
|
839 deflate_state *s;
|
|
|
840 int lcodes, dcodes, blcodes; /* number of codes for each tree */
|
|
|
841 {
|
|
|
842 int rank; /* index in bl_order */
|
|
|
843
|
|
|
844 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
|
|
|
845 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
|
|
|
846 "too many codes");
|
|
|
847 Tracev((stderr, "\nbl counts: "));
|
|
|
848 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
|
|
|
849 send_bits(s, dcodes-1, 5);
|
|
|
850 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
|
|
|
851 for (rank = 0; rank < blcodes; rank++) {
|
|
|
852 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
|
|
|
853 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
|
|
|
854 }
|
|
|
855 Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
|
|
|
856
|
|
|
857 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
|
|
|
858 Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
|
|
|
859
|
|
|
860 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
|
|
|
861 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
|
|
|
862 }
|
|
|
863
|
|
|
864 /* ===========================================================================
|
|
|
865 * Send a stored block
|
|
|
866 */
|
|
|
867 void _tr_stored_block(s, buf, stored_len, eof)
|
|
|
868 deflate_state *s;
|
|
|
869 charf *buf; /* input block */
|
|
|
870 ulg stored_len; /* length of input block */
|
|
|
871 int eof; /* true if this is the last block for a file */
|
|
|
872 {
|
|
|
873 send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */
|
|
|
874 #ifdef DEBUG
|
|
|
875 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
|
|
|
876 s->compressed_len += (stored_len + 4) << 3;
|
|
|
877 #endif
|
|
|
878 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
|
|
|
879 }
|
|
|
880
|
|
|
881 /* ===========================================================================
|
|
|
882 * Send one empty static block to give enough lookahead for inflate.
|
|
|
883 * This takes 10 bits, of which 7 may remain in the bit buffer.
|
|
|
884 * The current inflate code requires 9 bits of lookahead. If the
|
|
|
885 * last two codes for the previous block (real code plus EOB) were coded
|
|
|
886 * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
|
|
|
887 * the last real code. In this case we send two empty static blocks instead
|
|
|
888 * of one. (There are no problems if the previous block is stored or fixed.)
|
|
|
889 * To simplify the code, we assume the worst case of last real code encoded
|
|
|
890 * on one bit only.
|
|
|
891 */
|
|
|
892 void _tr_align(s)
|
|
|
893 deflate_state *s;
|
|
|
894 {
|
|
|
895 send_bits(s, STATIC_TREES<<1, 3);
|
|
|
896 send_code(s, END_BLOCK, static_ltree);
|
|
|
897 #ifdef DEBUG
|
|
|
898 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
|
|
|
899 #endif
|
|
|
900 bi_flush(s);
|
|
|
901 /* Of the 10 bits for the empty block, we have already sent
|
|
|
902 * (10 - bi_valid) bits. The lookahead for the last real code (before
|
|
|
903 * the EOB of the previous block) was thus at least one plus the length
|
|
|
904 * of the EOB plus what we have just sent of the empty static block.
|
|
|
905 */
|
|
|
906 if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
|
|
|
907 send_bits(s, STATIC_TREES<<1, 3);
|
|
|
908 send_code(s, END_BLOCK, static_ltree);
|
|
|
909 #ifdef DEBUG
|
|
|
910 s->compressed_len += 10L;
|
|
|
911 #endif
|
|
|
912 bi_flush(s);
|
|
|
913 }
|
|
|
914 s->last_eob_len = 7;
|
|
|
915 }
|
|
|
916
|
|
|
917 /* ===========================================================================
|
|
|
918 * Determine the best encoding for the current block: dynamic trees, static
|
|
|
919 * trees or store, and output the encoded block to the zip file.
|
|
|
920 */
|
|
|
921 void _tr_flush_block(s, buf, stored_len, eof)
|
|
|
922 deflate_state *s;
|
|
|
923 charf *buf; /* input block, or NULL if too old */
|
|
|
924 ulg stored_len; /* length of input block */
|
|
|
925 int eof; /* true if this is the last block for a file */
|
|
|
926 {
|
|
|
927 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
|
|
|
928 int max_blindex = 0; /* index of last bit length code of non zero freq */
|
|
|
929
|
|
|
930 /* Build the Huffman trees unless a stored block is forced */
|
|
|
931 if (s->level > 0) {
|
|
|
932
|
|
|
933 /* Check if the file is ascii or binary */
|
|
|
934 if (s->data_type == Z_UNKNOWN) set_data_type(s);
|
|
|
935
|
|
|
936 /* Construct the literal and distance trees */
|
|
|
937 build_tree(s, (tree_desc *)(&(s->l_desc)));
|
|
|
938 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
|
|
|
939 s->static_len));
|
|
|
940
|
|
|
941 build_tree(s, (tree_desc *)(&(s->d_desc)));
|
|
|
942 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
|
|
|
943 s->static_len));
|
|
|
944 /* At this point, opt_len and static_len are the total bit lengths of
|
|
|
945 * the compressed block data, excluding the tree representations.
|
|
|
946 */
|
|
|
947
|
|
|
948 /* Build the bit length tree for the above two trees, and get the index
|
|
|
949 * in bl_order of the last bit length code to send.
|
|
|
950 */
|
|
|
951 max_blindex = build_bl_tree(s);
|
|
|
952
|
|
|
953 /* Determine the best encoding. Compute first the block length in bytes*/
|
|
|
954 opt_lenb = (s->opt_len+3+7)>>3;
|
|
|
955 static_lenb = (s->static_len+3+7)>>3;
|
|
|
956
|
|
|
957 Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
|
|
|
958 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
|
|
|
959 s->last_lit));
|
|
|
960
|
|
|
961 if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
|
|
|
962
|
|
|
963 } else {
|
|
|
964 Assert(buf != (char*)0, "lost buf");
|
|
|
965 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
|
|
|
966 }
|
|
|
967
|
|
|
968 #ifdef FORCE_STORED
|
|
|
969 if (buf != (char*)0) { /* force stored block */
|
|
|
970 #else
|
|
|
971 if (stored_len+4 <= opt_lenb && buf != (char*)0) {
|
|
|
972 /* 4: two words for the lengths */
|
|
|
973 #endif
|
|
|
974 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
|
|
|
975 * Otherwise we can't have processed more than WSIZE input bytes since
|
|
|
976 * the last block flush, because compression would have been
|
|
|
977 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
|
|
|
978 * transform a block into a stored block.
|
|
|
979 */
|
|
|
980 _tr_stored_block(s, buf, stored_len, eof);
|
|
|
981
|
|
|
982 #ifdef FORCE_STATIC
|
|
|
983 } else if (static_lenb >= 0) { /* force static trees */
|
|
|
984 #else
|
|
|
985 } else if (static_lenb == opt_lenb) {
|
|
|
986 #endif
|
|
|
987 send_bits(s, (STATIC_TREES<<1)+eof, 3);
|
|
|
988 compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
|
|
|
989 #ifdef DEBUG
|
|
|
990 s->compressed_len += 3 + s->static_len;
|
|
|
991 #endif
|
|
|
992 } else {
|
|
|
993 send_bits(s, (DYN_TREES<<1)+eof, 3);
|
|
|
994 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
|
|
|
995 max_blindex+1);
|
|
|
996 compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
|
|
|
997 #ifdef DEBUG
|
|
|
998 s->compressed_len += 3 + s->opt_len;
|
|
|
999 #endif
|
|
|
1000 }
|
|
|
1001 Assert (s->compressed_len == s->bits_sent, "bad compressed size");
|
|
|
1002 /* The above check is made mod 2^32, for files larger than 512 MB
|
|
|
1003 * and uLong implemented on 32 bits.
|
|
|
1004 */
|
|
|
1005 init_block(s);
|
|
|
1006
|
|
|
1007 if (eof) {
|
|
|
1008 bi_windup(s);
|
|
|
1009 #ifdef DEBUG
|
|
|
1010 s->compressed_len += 7; /* align on byte boundary */
|
|
|
1011 #endif
|
|
|
1012 }
|
|
|
1013 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
|
|
|
1014 s->compressed_len-7*eof));
|
|
|
1015 }
|
|
|
1016
|
|
|
1017 /* ===========================================================================
|
|
|
1018 * Save the match info and tally the frequency counts. Return true if
|
|
|
1019 * the current block must be flushed.
|
|
|
1020 */
|
|
|
1021 int _tr_tally (s, dist, lc)
|
|
|
1022 deflate_state *s;
|
|
|
1023 unsigned dist; /* distance of matched string */
|
|
|
1024 unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
|
|
|
1025 {
|
|
|
1026 s->d_buf[s->last_lit] = (ush)dist;
|
|
|
1027 s->l_buf[s->last_lit++] = (uch)lc;
|
|
|
1028 if (dist == 0) {
|
|
|
1029 /* lc is the unmatched char */
|
|
|
1030 s->dyn_ltree[lc].Freq++;
|
|
|
1031 } else {
|
|
|
1032 s->matches++;
|
|
|
1033 /* Here, lc is the match length - MIN_MATCH */
|
|
|
1034 dist--; /* dist = match distance - 1 */
|
|
|
1035 Assert((ush)dist < (ush)MAX_DIST(s) &&
|
|
|
1036 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
|
|
|
1037 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
|
|
|
1038
|
|
|
1039 s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
|
|
|
1040 s->dyn_dtree[d_code(dist)].Freq++;
|
|
|
1041 }
|
|
|
1042
|
|
|
1043 #ifdef TRUNCATE_BLOCK
|
|
|
1044 /* Try to guess if it is profitable to stop the current block here */
|
|
|
1045 if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
|
|
|
1046 /* Compute an upper bound for the compressed length */
|
|
|
1047 ulg out_length = (ulg)s->last_lit*8L;
|
|
|
1048 ulg in_length = (ulg)((long)s->strstart - s->block_start);
|
|
|
1049 int dcode;
|
|
|
1050 for (dcode = 0; dcode < D_CODES; dcode++) {
|
|
|
1051 out_length += (ulg)s->dyn_dtree[dcode].Freq *
|
|
|
1052 (5L+extra_dbits[dcode]);
|
|
|
1053 }
|
|
|
1054 out_length >>= 3;
|
|
|
1055 Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
|
|
|
1056 s->last_lit, in_length, out_length,
|
|
|
1057 100L - out_length*100L/in_length));
|
|
|
1058 if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
|
|
|
1059 }
|
|
|
1060 #endif
|
|
|
1061 return (s->last_lit == s->lit_bufsize-1);
|
|
|
1062 /* We avoid equality with lit_bufsize because of wraparound at 64K
|
|
|
1063 * on 16 bit machines and because stored blocks are restricted to
|
|
|
1064 * 64K-1 bytes.
|
|
|
1065 */
|
|
|
1066 }
|
|
|
1067
|
|
|
1068 /* ===========================================================================
|
|
|
1069 * Send the block data compressed using the given Huffman trees
|
|
|
1070 */
|
|
|
1071 local void compress_block(s, ltree, dtree)
|
|
|
1072 deflate_state *s;
|
|
|
1073 ct_data *ltree; /* literal tree */
|
|
|
1074 ct_data *dtree; /* distance tree */
|
|
|
1075 {
|
|
|
1076 unsigned dist; /* distance of matched string */
|
|
|
1077 int lc; /* match length or unmatched char (if dist == 0) */
|
|
|
1078 unsigned lx = 0; /* running index in l_buf */
|
|
|
1079 unsigned code; /* the code to send */
|
|
|
1080 int extra; /* number of extra bits to send */
|
|
|
1081
|
|
|
1082 if (s->last_lit != 0) do {
|
|
|
1083 dist = s->d_buf[lx];
|
|
|
1084 lc = s->l_buf[lx++];
|
|
|
1085 if (dist == 0) {
|
|
|
1086 send_code(s, lc, ltree); /* send a literal byte */
|
|
|
1087 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
|
|
|
1088 } else {
|
|
|
1089 /* Here, lc is the match length - MIN_MATCH */
|
|
|
1090 code = _length_code[lc];
|
|
|
1091 send_code(s, code+LITERALS+1, ltree); /* send the length code */
|
|
|
1092 extra = extra_lbits[code];
|
|
|
1093 if (extra != 0) {
|
|
|
1094 lc -= base_length[code];
|
|
|
1095 send_bits(s, lc, extra); /* send the extra length bits */
|
|
|
1096 }
|
|
|
1097 dist--; /* dist is now the match distance - 1 */
|
|
|
1098 code = d_code(dist);
|
|
|
1099 Assert (code < D_CODES, "bad d_code");
|
|
|
1100
|
|
|
1101 send_code(s, code, dtree); /* send the distance code */
|
|
|
1102 extra = extra_dbits[code];
|
|
|
1103 if (extra != 0) {
|
|
|
1104 dist -= base_dist[code];
|
|
|
1105 send_bits(s, dist, extra); /* send the extra distance bits */
|
|
|
1106 }
|
|
|
1107 } /* literal or match pair ? */
|
|
|
1108
|
|
|
1109 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
|
|
|
1110 Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow");
|
|
|
1111
|
|
|
1112 } while (lx < s->last_lit);
|
|
|
1113
|
|
|
1114 send_code(s, END_BLOCK, ltree);
|
|
|
1115 s->last_eob_len = ltree[END_BLOCK].Len;
|
|
|
1116 }
|
|
|
1117
|
|
|
1118 /* ===========================================================================
|
|
|
1119 * Set the data type to ASCII or BINARY, using a crude approximation:
|
|
|
1120 * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
|
|
|
1121 * IN assertion: the fields freq of dyn_ltree are set and the total of all
|
|
|
1122 * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
|
|
|
1123 */
|
|
|
1124 local void set_data_type(s)
|
|
|
1125 deflate_state *s;
|
|
|
1126 {
|
|
|
1127 int n = 0;
|
|
|
1128 unsigned ascii_freq = 0;
|
|
|
1129 unsigned bin_freq = 0;
|
|
|
1130 while (n < 7) bin_freq += s->dyn_ltree[n++].Freq;
|
|
|
1131 while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq;
|
|
|
1132 while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq;
|
|
|
1133 s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII);
|
|
|
1134 }
|
|
|
1135
|
|
|
1136 /* ===========================================================================
|
|
|
1137 * Reverse the first len bits of a code, using straightforward code (a faster
|
|
|
1138 * method would use a table)
|
|
|
1139 * IN assertion: 1 <= len <= 15
|
|
|
1140 */
|
|
|
1141 local unsigned bi_reverse(code, len)
|
|
|
1142 unsigned code; /* the value to invert */
|
|
|
1143 int len; /* its bit length */
|
|
|
1144 {
|
|
|
1145 register unsigned res = 0;
|
|
|
1146 do {
|
|
|
1147 res |= code & 1;
|
|
|
1148 code >>= 1, res <<= 1;
|
|
|
1149 } while (--len > 0);
|
|
|
1150 return res >> 1;
|
|
|
1151 }
|
|
|
1152
|
|
|
1153 /* ===========================================================================
|
|
|
1154 * Flush the bit buffer, keeping at most 7 bits in it.
|
|
|
1155 */
|
|
|
1156 local void bi_flush(s)
|
|
|
1157 deflate_state *s;
|
|
|
1158 {
|
|
|
1159 if (s->bi_valid == 16) {
|
|
|
1160 put_short(s, s->bi_buf);
|
|
|
1161 s->bi_buf = 0;
|
|
|
1162 s->bi_valid = 0;
|
|
|
1163 } else if (s->bi_valid >= 8) {
|
|
|
1164 put_byte(s, (Byte)s->bi_buf);
|
|
|
1165 s->bi_buf >>= 8;
|
|
|
1166 s->bi_valid -= 8;
|
|
|
1167 }
|
|
|
1168 }
|
|
|
1169
|
|
|
1170 /* ===========================================================================
|
|
|
1171 * Flush the bit buffer and align the output on a byte boundary
|
|
|
1172 */
|
|
|
1173 local void bi_windup(s)
|
|
|
1174 deflate_state *s;
|
|
|
1175 {
|
|
|
1176 if (s->bi_valid > 8) {
|
|
|
1177 put_short(s, s->bi_buf);
|
|
|
1178 } else if (s->bi_valid > 0) {
|
|
|
1179 put_byte(s, (Byte)s->bi_buf);
|
|
|
1180 }
|
|
|
1181 s->bi_buf = 0;
|
|
|
1182 s->bi_valid = 0;
|
|
|
1183 #ifdef DEBUG
|
|
|
1184 s->bits_sent = (s->bits_sent+7) & ~7;
|
|
|
1185 #endif
|
|
|
1186 }
|
|
|
1187
|
|
|
1188 /* ===========================================================================
|
|
|
1189 * Copy a stored block, storing first the length and its
|
|
|
1190 * one's complement if requested.
|
|
|
1191 */
|
|
|
1192 local void copy_block(s, buf, len, header)
|
|
|
1193 deflate_state *s;
|
|
|
1194 charf *buf; /* the input data */
|
|
|
1195 unsigned len; /* its length */
|
|
|
1196 int header; /* true if block header must be written */
|
|
|
1197 {
|
|
|
1198 bi_windup(s); /* align on byte boundary */
|
|
|
1199 s->last_eob_len = 8; /* enough lookahead for inflate */
|
|
|
1200
|
|
|
1201 if (header) {
|
|
|
1202 put_short(s, (ush)len);
|
|
|
1203 put_short(s, (ush)~len);
|
|
|
1204 #ifdef DEBUG
|
|
|
1205 s->bits_sent += 2*16;
|
|
|
1206 #endif
|
|
|
1207 }
|
|
|
1208 #ifdef DEBUG
|
|
|
1209 s->bits_sent += (ulg)len<<3;
|
|
|
1210 #endif
|
|
|
1211 while (len--) {
|
|
|
1212 put_byte(s, *buf++);
|
|
|
1213 }
|
|
|
1214 }
|
