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/* trees.c -- output deflated data using Huffman coding |
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* Copyright (C) 1995-2026 Jean-loup Gailly |
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* detect_data_type() function provided freely by Cosmin Truta, 2006 |
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* For conditions of distribution and use, see copyright notice in zlib.h |
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*/ |
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/* |
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* ALGORITHM |
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* |
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* The "deflation" process uses several Huffman trees. The more |
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* common source values are represented by shorter bit sequences. |
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* |
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* Each code tree is stored in a compressed form which is itself |
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* a Huffman encoding of the lengths of all the code strings (in |
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* ascending order by source values). The actual code strings are |
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* reconstructed from the lengths in the inflate process, as described |
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* in the deflate specification. |
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* |
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* REFERENCES |
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* |
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* Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". |
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* Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc |
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* |
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* Storer, James A. |
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* Data Compression: Methods and Theory, pp. 49-50. |
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* Computer Science Press, 1988. ISBN 0-7167-8156-5. |
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* |
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* Sedgewick, R. |
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* Algorithms, p290. |
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* Addison-Wesley, 1983. ISBN 0-201-06672-6. |
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*/ |
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/* @(#) $Id$ */ |
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/* #define GEN_TREES_H */ |
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#include "deflate.h" |
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#ifdef ZLIB_DEBUG |
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# include <ctype.h> |
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#endif |
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/* =========================================================================== |
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* Constants |
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*/ |
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#define MAX_BL_BITS 7 |
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/* Bit length codes must not exceed MAX_BL_BITS bits */ |
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#define END_BLOCK 256 |
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/* end of block literal code */ |
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52
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#define REP_3_6 16 |
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/* repeat previous bit length 3-6 times (2 bits of repeat count) */ |
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#define REPZ_3_10 17 |
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/* repeat a zero length 3-10 times (3 bits of repeat count) */ |
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#define REPZ_11_138 18 |
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/* repeat a zero length 11-138 times (7 bits of repeat count) */ |
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61
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local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ |
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= {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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local const int extra_dbits[D_CODES] /* extra bits for each distance code */ |
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= {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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local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ |
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= {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; |
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local const uch bl_order[BL_CODES] |
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= {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; |
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/* The lengths of the bit length codes are sent in order of decreasing |
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* probability, to avoid transmitting the lengths for unused bit length codes. |
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*/ |
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/* =========================================================================== |
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* Local data. These are initialized only once. |
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*/ |
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#define DIST_CODE_LEN 512 /* see definition of array dist_code below */ |
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#if defined(GEN_TREES_H) || !defined(STDC) |
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/* non ANSI compilers may not accept trees.h */ |
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local ct_data static_ltree[L_CODES+2]; |
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/* The static literal tree. Since the bit lengths are imposed, there is no |
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* need for the L_CODES extra codes used during heap construction. However |
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* The codes 286 and 287 are needed to build a canonical tree (see _tr_init |
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* below). |
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*/ |
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local ct_data static_dtree[D_CODES]; |
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/* The static distance tree. (Actually a trivial tree since all codes use |
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* 5 bits.) |
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*/ |
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97
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uch _dist_code[DIST_CODE_LEN]; |
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/* Distance codes. The first 256 values correspond to the distances |
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* 3 .. 258, the last 256 values correspond to the top 8 bits of |
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* the 15 bit distances. |
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*/ |
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uch _length_code[MAX_MATCH-MIN_MATCH+1]; |
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/* length code for each normalized match length (0 == MIN_MATCH) */ |
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local int base_length[LENGTH_CODES]; |
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/* First normalized length for each code (0 = MIN_MATCH) */ |
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local int base_dist[D_CODES]; |
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/* First normalized distance for each code (0 = distance of 1) */ |
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112
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#else |
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# include "trees.h" |
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#endif /* defined(GEN_TREES_H) || !defined(STDC) */ |
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struct static_tree_desc_s { |
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const ct_data *static_tree; /* static tree or NULL */ |
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const intf *extra_bits; /* extra bits for each code or NULL */ |
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int extra_base; /* base index for extra_bits */ |
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int elems; /* max number of elements in the tree */ |
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int max_length; /* max bit length for the codes */ |
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}; |
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#ifdef NO_INIT_GLOBAL_POINTERS |
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# define TCONST |
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#else |
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# define TCONST const |
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#endif |
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local TCONST static_tree_desc static_l_desc = |
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{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; |
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local TCONST static_tree_desc static_d_desc = |
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{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; |
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136
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local TCONST static_tree_desc static_bl_desc = |
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{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; |
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139
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140
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/* =========================================================================== |
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* Output a short LSB first on the stream. |
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142
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* IN assertion: there is enough room in pendingBuf. |
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*/ |
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#define put_short(s, w) { \ |
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put_byte(s, (uch)((w) & 0xff)); \ |
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put_byte(s, (uch)((ush)(w) >> 8)); \ |
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} |
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148
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149
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/* =========================================================================== |
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150
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* Reverse the first len bits of a code, using straightforward code (a faster |
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151
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* method would use a table) |
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152
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* IN assertion: 1 <= len <= 15 |
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153
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*/ |
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154
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local unsigned bi_reverse(unsigned code, int len) { |
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155
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unsigned res = 0; |
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156
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do { |
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157
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res |= code & 1; |
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code >>= 1, res <<= 1; |
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159
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} while (--len > 0); |
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160
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return res >> 1; |
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161
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} |
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162
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163
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/* =========================================================================== |
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164
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* Flush the bit buffer, keeping at most 7 bits in it. |
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165
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*/ |
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166
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local void bi_flush(deflate_state *s) { |
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167
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if (s->bi_valid == 16) { |
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put_short(s, s->bi_buf); |
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s->bi_buf = 0; |
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170
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s->bi_valid = 0; |
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} else if (s->bi_valid >= 8) { |
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put_byte(s, (Byte)s->bi_buf); |
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s->bi_buf >>= 8; |
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s->bi_valid -= 8; |
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} |
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} |
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177
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178
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/* =========================================================================== |
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179
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* Flush the bit buffer and align the output on a byte boundary |
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180
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*/ |
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181
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local void bi_windup(deflate_state *s) { |
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if (s->bi_valid > 8) { |
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put_short(s, s->bi_buf); |
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184
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} else if (s->bi_valid > 0) { |
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185
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put_byte(s, (Byte)s->bi_buf); |
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} |
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s->bi_used = ((s->bi_valid - 1) & 7) + 1; |
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188
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s->bi_buf = 0; |
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s->bi_valid = 0; |
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#ifdef ZLIB_DEBUG |
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s->bits_sent = (s->bits_sent + 7) & ~(ulg)7; |
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#endif |
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193
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} |
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194
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195
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/* =========================================================================== |
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196
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* Generate the codes for a given tree and bit counts (which need not be |
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197
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* optimal). |
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198
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* IN assertion: the array bl_count contains the bit length statistics for |
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199
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* the given tree and the field len is set for all tree elements. |
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200
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* OUT assertion: the field code is set for all tree elements of non |
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201
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* zero code length. |
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202
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*/ |
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203
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local void gen_codes(ct_data *tree, int max_code, ushf *bl_count) { |
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204
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ush next_code[MAX_BITS+1]; /* next code value for each bit length */ |
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205
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unsigned code = 0; /* running code value */ |
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206
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int bits; /* bit index */ |
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207
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int n; /* code index */ |
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208
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209
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/* The distribution counts are first used to generate the code values |
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210
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* without bit reversal. |
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211
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*/ |
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212
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for (bits = 1; bits <= MAX_BITS; bits++) { |
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213
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code = (code + bl_count[bits - 1]) << 1; |
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214
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next_code[bits] = (ush)code; |
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215
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} |
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216
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/* Check that the bit counts in bl_count are consistent. The last code |
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217
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* must be all ones. |
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218
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*/ |
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219
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Assert (code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1, |
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220
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"inconsistent bit counts"); |
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221
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Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); |
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222
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223
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for (n = 0; n <= max_code; n++) { |
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224
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int len = tree[n].Len; |
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225
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if (len == 0) continue; |
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226
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/* Now reverse the bits */ |
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227
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tree[n].Code = (ush)bi_reverse(next_code[len]++, len); |
|
228
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229
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Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", |
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230
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n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len] - 1)); |
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231
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} |
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232
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} |
|
233
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234
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#ifdef GEN_TREES_H |
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235
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local void gen_trees_header(void); |
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236
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#endif |
|
237
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238
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#ifndef ZLIB_DEBUG |
|
239
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# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) |
|
240
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/* Send a code of the given tree. c and tree must not have side effects */ |
|
241
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242
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#else /* !ZLIB_DEBUG */ |
|
243
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# define send_code(s, c, tree) \ |
|
244
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{ if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ |
|
245
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send_bits(s, tree[c].Code, tree[c].Len); } |
|
246
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#endif |
|
247
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|
|
248
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/* =========================================================================== |
|
249
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* Send a value on a given number of bits. |
|
250
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* IN assertion: length <= 16 and value fits in length bits. |
|
251
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*/ |
|
252
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#ifdef ZLIB_DEBUG |
|
253
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local void send_bits(deflate_state *s, int value, int length) { |
|
254
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Tracevv((stderr," l %2d v %4x ", length, value)); |
|
255
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Assert(length > 0 && length <= 15, "invalid length"); |
|
256
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s->bits_sent += (ulg)length; |
|
257
|
|
|
258
|
/* If not enough room in bi_buf, use (valid) bits from bi_buf and |
|
259
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* (16 - bi_valid) bits from value, leaving (width - (16 - bi_valid)) |
|
260
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* unused bits in value. |
|
261
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*/ |
|
262
|
if (s->bi_valid > (int)Buf_size - length) { |
|
263
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s->bi_buf |= (ush)value << s->bi_valid; |
|
264
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put_short(s, s->bi_buf); |
|
265
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s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); |
|
266
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s->bi_valid += length - Buf_size; |
|
267
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} else { |
|
268
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s->bi_buf |= (ush)value << s->bi_valid; |
|
269
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s->bi_valid += length; |
|
270
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} |
|
271
|
} |
|
272
|
#else /* !ZLIB_DEBUG */ |
|
273
|
|
|
274
|
#define send_bits(s, value, length) \ |
|
275
|
{ int len = length;\ |
|
276
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if (s->bi_valid > (int)Buf_size - len) {\ |
|
277
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int val = (int)value;\ |
|
278
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s->bi_buf |= (ush)val << s->bi_valid;\ |
|
279
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put_short(s, s->bi_buf);\ |
|
280
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s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ |
|
281
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s->bi_valid += len - Buf_size;\ |
|
282
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} else {\ |
|
283
|
s->bi_buf |= (ush)(value) << s->bi_valid;\ |
|
284
|
s->bi_valid += len;\ |
|
285
|
}\ |
|
286
|
} |
|
287
|
#endif /* ZLIB_DEBUG */ |
|
288
|
|
|
289
|
|
|
290
|
/* the arguments must not have side effects */ |
|
291
|
|
|
292
|
/* =========================================================================== |
|
293
|
* Initialize the various 'constant' tables. |
|
294
|
*/ |
|
295
|
local void tr_static_init(void) { |
|
296
|
#if defined(GEN_TREES_H) || !defined(STDC) |
|
297
|
static int static_init_done = 0; |
|
298
|
int n; /* iterates over tree elements */ |
|
299
|
int bits; /* bit counter */ |
|
300
|
int length; /* length value */ |
|
301
|
int code; /* code value */ |
|
302
|
int dist; /* distance index */ |
|
303
|
ush bl_count[MAX_BITS+1]; |
|
304
|
/* number of codes at each bit length for an optimal tree */ |
|
305
|
|
|
306
|
if (static_init_done) return; |
|
307
|
|
|
308
|
/* For some embedded targets, global variables are not initialized: */ |
|
309
|
#ifdef NO_INIT_GLOBAL_POINTERS |
|
310
|
static_l_desc.static_tree = static_ltree; |
|
311
|
static_l_desc.extra_bits = extra_lbits; |
|
312
|
static_d_desc.static_tree = static_dtree; |
|
313
|
static_d_desc.extra_bits = extra_dbits; |
|
314
|
static_bl_desc.extra_bits = extra_blbits; |
|
315
|
#endif |
|
316
|
|
|
317
|
/* Initialize the mapping length (0..255) -> length code (0..28) */ |
|
318
|
length = 0; |
|
319
|
for (code = 0; code < LENGTH_CODES-1; code++) { |
|
320
|
base_length[code] = length; |
|
321
|
for (n = 0; n < (1 << extra_lbits[code]); n++) { |
|
322
|
_length_code[length++] = (uch)code; |
|
323
|
} |
|
324
|
} |
|
325
|
Assert (length == 256, "tr_static_init: length != 256"); |
|
326
|
/* Note that the length 255 (match length 258) can be represented |
|
327
|
* in two different ways: code 284 + 5 bits or code 285, so we |
|
328
|
* overwrite length_code[255] to use the best encoding: |
|
329
|
*/ |
|
330
|
_length_code[length - 1] = (uch)code; |
|
331
|
|
|
332
|
/* Initialize the mapping dist (0..32K) -> dist code (0..29) */ |
|
333
|
dist = 0; |
|
334
|
for (code = 0 ; code < 16; code++) { |
|
335
|
base_dist[code] = dist; |
|
336
|
for (n = 0; n < (1 << extra_dbits[code]); n++) { |
|
337
|
_dist_code[dist++] = (uch)code; |
|
338
|
} |
|
339
|
} |
|
340
|
Assert (dist == 256, "tr_static_init: dist != 256"); |
|
341
|
dist >>= 7; /* from now on, all distances are divided by 128 */ |
|
342
|
for ( ; code < D_CODES; code++) { |
|
343
|
base_dist[code] = dist << 7; |
|
344
|
for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { |
|
345
|
_dist_code[256 + dist++] = (uch)code; |
|
346
|
} |
|
347
|
} |
|
348
|
Assert (dist == 256, "tr_static_init: 256 + dist != 512"); |
|
349
|
|
|
350
|
/* Construct the codes of the static literal tree */ |
|
351
|
for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; |
|
352
|
n = 0; |
|
353
|
while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; |
|
354
|
while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; |
|
355
|
while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; |
|
356
|
while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; |
|
357
|
/* Codes 286 and 287 do not exist, but we must include them in the |
|
358
|
* tree construction to get a canonical Huffman tree (longest code |
|
359
|
* all ones) |
|
360
|
*/ |
|
361
|
gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); |
|
362
|
|
|
363
|
/* The static distance tree is trivial: */ |
|
364
|
for (n = 0; n < D_CODES; n++) { |
|
365
|
static_dtree[n].Len = 5; |
|
366
|
static_dtree[n].Code = bi_reverse((unsigned)n, 5); |
|
367
|
} |
|
368
|
static_init_done = 1; |
|
369
|
|
|
370
|
# ifdef GEN_TREES_H |
|
371
|
gen_trees_header(); |
|
372
|
# endif |
|
373
|
#endif /* defined(GEN_TREES_H) || !defined(STDC) */ |
|
374
|
} |
|
375
|
|
|
376
|
/* =========================================================================== |
|
377
|
* Generate the file trees.h describing the static trees. |
|
378
|
*/ |
|
379
|
#ifdef GEN_TREES_H |
|
380
|
# ifndef ZLIB_DEBUG |
|
381
|
# include <stdio.h> |
|
382
|
# endif |
|
383
|
|
|
384
|
# define SEPARATOR(i, last, width) \ |
|
385
|
((i) == (last)? "\n};\n\n" : \ |
|
386
|
((i) % (width) == (width) - 1 ? ",\n" : ", ")) |
|
387
|
|
|
388
|
void gen_trees_header(void) { |
|
389
|
FILE *header = fopen("trees.h", "w"); |
|
390
|
int i; |
|
391
|
|
|
392
|
Assert (header != NULL, "Can't open trees.h"); |
|
393
|
fprintf(header, |
|
394
|
"/* header created automatically with -DGEN_TREES_H */\n\n"); |
|
395
|
|
|
396
|
fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); |
|
397
|
for (i = 0; i < L_CODES+2; i++) { |
|
398
|
fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, |
|
399
|
static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); |
|
400
|
} |
|
401
|
|
|
402
|
fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); |
|
403
|
for (i = 0; i < D_CODES; i++) { |
|
404
|
fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, |
|
405
|
static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); |
|
406
|
} |
|
407
|
|
|
408
|
fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n"); |
|
409
|
for (i = 0; i < DIST_CODE_LEN; i++) { |
|
410
|
fprintf(header, "%2u%s", _dist_code[i], |
|
411
|
SEPARATOR(i, DIST_CODE_LEN-1, 20)); |
|
412
|
} |
|
413
|
|
|
414
|
fprintf(header, |
|
415
|
"const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); |
|
416
|
for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { |
|
417
|
fprintf(header, "%2u%s", _length_code[i], |
|
418
|
SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); |
|
419
|
} |
|
420
|
|
|
421
|
fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); |
|
422
|
for (i = 0; i < LENGTH_CODES; i++) { |
|
423
|
fprintf(header, "%1u%s", base_length[i], |
|
424
|
SEPARATOR(i, LENGTH_CODES-1, 20)); |
|
425
|
} |
|
426
|
|
|
427
|
fprintf(header, "local const int base_dist[D_CODES] = {\n"); |
|
428
|
for (i = 0; i < D_CODES; i++) { |
|
429
|
fprintf(header, "%5u%s", base_dist[i], |
|
430
|
SEPARATOR(i, D_CODES-1, 10)); |
|
431
|
} |
|
432
|
|
|
433
|
fclose(header); |
|
434
|
} |
|
435
|
#endif /* GEN_TREES_H */ |
|
436
|
|
|
437
|
/* =========================================================================== |
|
438
|
* Initialize a new block. |
|
439
|
*/ |
|
440
|
local void init_block(deflate_state *s) { |
|
441
|
int n; /* iterates over tree elements */ |
|
442
|
|
|
443
|
/* Initialize the trees. */ |
|
444
|
for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; |
|
445
|
for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; |
|
446
|
for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; |
|
447
|
|
|
448
|
s->dyn_ltree[END_BLOCK].Freq = 1; |
|
449
|
s->opt_len = s->static_len = 0L; |
|
450
|
s->sym_next = s->matches = 0; |
|
451
|
} |
|
452
|
|
|
453
|
/* =========================================================================== |
|
454
|
* Initialize the tree data structures for a new zlib stream. |
|
455
|
*/ |
|
456
|
void ZLIB_INTERNAL _tr_init(deflate_state *s) { |
|
457
|
tr_static_init(); |
|
458
|
|
|
459
|
s->l_desc.dyn_tree = s->dyn_ltree; |
|
460
|
s->l_desc.stat_desc = &static_l_desc; |
|
461
|
|
|
462
|
s->d_desc.dyn_tree = s->dyn_dtree; |
|
463
|
s->d_desc.stat_desc = &static_d_desc; |
|
464
|
|
|
465
|
s->bl_desc.dyn_tree = s->bl_tree; |
|
466
|
s->bl_desc.stat_desc = &static_bl_desc; |
|
467
|
|
|
468
|
s->bi_buf = 0; |
|
469
|
s->bi_valid = 0; |
|
470
|
s->bi_used = 0; |
|
471
|
#ifdef ZLIB_DEBUG |
|
472
|
s->compressed_len = 0L; |
|
473
|
s->bits_sent = 0L; |
|
474
|
#endif |
|
475
|
|
|
476
|
/* Initialize the first block of the first file: */ |
|
477
|
init_block(s); |
|
478
|
} |
|
479
|
|
|
480
|
#define SMALLEST 1 |
|
481
|
/* Index within the heap array of least frequent node in the Huffman tree */ |
|
482
|
|
|
483
|
|
|
484
|
/* =========================================================================== |
|
485
|
* Remove the smallest element from the heap and recreate the heap with |
|
486
|
* one less element. Updates heap and heap_len. |
|
487
|
*/ |
|
488
|
#define pqremove(s, tree, top) \ |
|
489
|
{\ |
|
490
|
top = s->heap[SMALLEST]; \ |
|
491
|
s->heap[SMALLEST] = s->heap[s->heap_len--]; \ |
|
492
|
pqdownheap(s, tree, SMALLEST); \ |
|
493
|
} |
|
494
|
|
|
495
|
/* =========================================================================== |
|
496
|
* Compares to subtrees, using the tree depth as tie breaker when |
|
497
|
* the subtrees have equal frequency. This minimizes the worst case length. |
|
498
|
*/ |
|
499
|
#define smaller(tree, n, m, depth) \ |
|
500
|
(tree[n].Freq < tree[m].Freq || \ |
|
501
|
(tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) |
|
502
|
|
|
503
|
/* =========================================================================== |
|
504
|
* Restore the heap property by moving down the tree starting at node k, |
|
505
|
* exchanging a node with the smallest of its two sons if necessary, stopping |
|
506
|
* when the heap property is re-established (each father smaller than its |
|
507
|
* two sons). |
|
508
|
*/ |
|
509
|
local void pqdownheap(deflate_state *s, ct_data *tree, int k) { |
|
510
|
int v = s->heap[k]; |
|
511
|
int j = k << 1; /* left son of k */ |
|
512
|
while (j <= s->heap_len) { |
|
513
|
/* Set j to the smallest of the two sons: */ |
|
514
|
if (j < s->heap_len && |
|
515
|
smaller(tree, s->heap[j + 1], s->heap[j], s->depth)) { |
|
516
|
j++; |
|
517
|
} |
|
518
|
/* Exit if v is smaller than both sons */ |
|
519
|
if (smaller(tree, v, s->heap[j], s->depth)) break; |
|
520
|
|
|
521
|
/* Exchange v with the smallest son */ |
|
522
|
s->heap[k] = s->heap[j]; k = j; |
|
523
|
|
|
524
|
/* And continue down the tree, setting j to the left son of k */ |
|
525
|
j <<= 1; |
|
526
|
} |
|
527
|
s->heap[k] = v; |
|
528
|
} |
|
529
|
|
|
530
|
/* =========================================================================== |
|
531
|
* Compute the optimal bit lengths for a tree and update the total bit length |
|
532
|
* for the current block. |
|
533
|
* IN assertion: the fields freq and dad are set, heap[heap_max] and |
|
534
|
* above are the tree nodes sorted by increasing frequency. |
|
535
|
* OUT assertions: the field len is set to the optimal bit length, the |
|
536
|
* array bl_count contains the frequencies for each bit length. |
|
537
|
* The length opt_len is updated; static_len is also updated if stree is |
|
538
|
* not null. |
|
539
|
*/ |
|
540
|
local void gen_bitlen(deflate_state *s, tree_desc *desc) { |
|
541
|
ct_data *tree = desc->dyn_tree; |
|
542
|
int max_code = desc->max_code; |
|
543
|
const ct_data *stree = desc->stat_desc->static_tree; |
|
544
|
const intf *extra = desc->stat_desc->extra_bits; |
|
545
|
int base = desc->stat_desc->extra_base; |
|
546
|
int max_length = desc->stat_desc->max_length; |
|
547
|
int h; /* heap index */ |
|
548
|
int n, m; /* iterate over the tree elements */ |
|
549
|
int bits; /* bit length */ |
|
550
|
int xbits; /* extra bits */ |
|
551
|
ush f; /* frequency */ |
|
552
|
int overflow = 0; /* number of elements with bit length too large */ |
|
553
|
|
|
554
|
for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; |
|
555
|
|
|
556
|
/* In a first pass, compute the optimal bit lengths (which may |
|
557
|
* overflow in the case of the bit length tree). |
|
558
|
*/ |
|
559
|
tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ |
|
560
|
|
|
561
|
for (h = s->heap_max + 1; h < HEAP_SIZE; h++) { |
|
562
|
n = s->heap[h]; |
|
563
|
bits = tree[tree[n].Dad].Len + 1; |
|
564
|
if (bits > max_length) bits = max_length, overflow++; |
|
565
|
tree[n].Len = (ush)bits; |
|
566
|
/* We overwrite tree[n].Dad which is no longer needed */ |
|
567
|
|
|
568
|
if (n > max_code) continue; /* not a leaf node */ |
|
569
|
|
|
570
|
s->bl_count[bits]++; |
|
571
|
xbits = 0; |
|
572
|
if (n >= base) xbits = extra[n - base]; |
|
573
|
f = tree[n].Freq; |
|
574
|
s->opt_len += (ulg)f * (unsigned)(bits + xbits); |
|
575
|
if (stree) s->static_len += (ulg)f * (unsigned)(stree[n].Len + xbits); |
|
576
|
} |
|
577
|
if (overflow == 0) return; |
|
578
|
|
|
579
|
Tracev((stderr,"\nbit length overflow\n")); |
|
580
|
/* This happens for example on obj2 and pic of the Calgary corpus */ |
|
581
|
|
|
582
|
/* Find the first bit length which could increase: */ |
|
583
|
do { |
|
584
|
bits = max_length - 1; |
|
585
|
while (s->bl_count[bits] == 0) bits--; |
|
586
|
s->bl_count[bits]--; /* move one leaf down the tree */ |
|
587
|
s->bl_count[bits + 1] += 2; /* move one overflow item as its brother */ |
|
588
|
s->bl_count[max_length]--; |
|
589
|
/* The brother of the overflow item also moves one step up, |
|
590
|
* but this does not affect bl_count[max_length] |
|
591
|
*/ |
|
592
|
overflow -= 2; |
|
593
|
} while (overflow > 0); |
|
594
|
|
|
595
|
/* Now recompute all bit lengths, scanning in increasing frequency. |
|
596
|
* h is still equal to HEAP_SIZE. (It is simpler to reconstruct all |
|
597
|
* lengths instead of fixing only the wrong ones. This idea is taken |
|
598
|
* from 'ar' written by Haruhiko Okumura.) |
|
599
|
*/ |
|
600
|
for (bits = max_length; bits != 0; bits--) { |
|
601
|
n = s->bl_count[bits]; |
|
602
|
while (n != 0) { |
|
603
|
m = s->heap[--h]; |
|
604
|
if (m > max_code) continue; |
|
605
|
if ((unsigned) tree[m].Len != (unsigned) bits) { |
|
606
|
Tracev((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); |
|
607
|
s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq; |
|
608
|
tree[m].Len = (ush)bits; |
|
609
|
} |
|
610
|
n--; |
|
611
|
} |
|
612
|
} |
|
613
|
} |
|
614
|
|
|
615
|
#ifdef DUMP_BL_TREE |
|
616
|
# include <stdio.h> |
|
617
|
#endif |
|
618
|
|
|
619
|
/* =========================================================================== |
|
620
|
* Construct one Huffman tree and assigns the code bit strings and lengths. |
|
621
|
* Update the total bit length for the current block. |
|
622
|
* IN assertion: the field freq is set for all tree elements. |
|
623
|
* OUT assertions: the fields len and code are set to the optimal bit length |
|
624
|
* and corresponding code. The length opt_len is updated; static_len is |
|
625
|
* also updated if stree is not null. The field max_code is set. |
|
626
|
*/ |
|
627
|
local void build_tree(deflate_state *s, tree_desc *desc) { |
|
628
|
ct_data *tree = desc->dyn_tree; |
|
629
|
const ct_data *stree = desc->stat_desc->static_tree; |
|
630
|
int elems = desc->stat_desc->elems; |
|
631
|
int n, m; /* iterate over heap elements */ |
|
632
|
int max_code = -1; /* largest code with non zero frequency */ |
|
633
|
int node; /* new node being created */ |
|
634
|
|
|
635
|
/* Construct the initial heap, with least frequent element in |
|
636
|
* heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n + 1]. |
|
637
|
* heap[0] is not used. |
|
638
|
*/ |
|
639
|
s->heap_len = 0, s->heap_max = HEAP_SIZE; |
|
640
|
|
|
641
|
for (n = 0; n < elems; n++) { |
|
642
|
if (tree[n].Freq != 0) { |
|
643
|
s->heap[++(s->heap_len)] = max_code = n; |
|
644
|
s->depth[n] = 0; |
|
645
|
} else { |
|
646
|
tree[n].Len = 0; |
|
647
|
} |
|
648
|
} |
|
649
|
|
|
650
|
/* The pkzip format requires that at least one distance code exists, |
|
651
|
* and that at least one bit should be sent even if there is only one |
|
652
|
* possible code. So to avoid special checks later on we force at least |
|
653
|
* two codes of non zero frequency. |
|
654
|
*/ |
|
655
|
while (s->heap_len < 2) { |
|
656
|
node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); |
|
657
|
tree[node].Freq = 1; |
|
658
|
s->depth[node] = 0; |
|
659
|
s->opt_len--; if (stree) s->static_len -= stree[node].Len; |
|
660
|
/* node is 0 or 1 so it does not have extra bits */ |
|
661
|
} |
|
662
|
desc->max_code = max_code; |
|
663
|
|
|
664
|
/* The elements heap[heap_len/2 + 1 .. heap_len] are leaves of the tree, |
|
665
|
* establish sub-heaps of increasing lengths: |
|
666
|
*/ |
|
667
|
for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); |
|
668
|
|
|
669
|
/* Construct the Huffman tree by repeatedly combining the least two |
|
670
|
* frequent nodes. |
|
671
|
*/ |
|
672
|
node = elems; /* next internal node of the tree */ |
|
673
|
do { |
|
674
|
pqremove(s, tree, n); /* n = node of least frequency */ |
|
675
|
m = s->heap[SMALLEST]; /* m = node of next least frequency */ |
|
676
|
|
|
677
|
s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ |
|
678
|
s->heap[--(s->heap_max)] = m; |
|
679
|
|
|
680
|
/* Create a new node father of n and m */ |
|
681
|
tree[node].Freq = tree[n].Freq + tree[m].Freq; |
|
682
|
s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? |
|
683
|
s->depth[n] : s->depth[m]) + 1); |
|
684
|
tree[n].Dad = tree[m].Dad = (ush)node; |
|
685
|
#ifdef DUMP_BL_TREE |
|
686
|
if (tree == s->bl_tree) { |
|
687
|
fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", |
|
688
|
node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); |
|
689
|
} |
|
690
|
#endif |
|
691
|
/* and insert the new node in the heap */ |
|
692
|
s->heap[SMALLEST] = node++; |
|
693
|
pqdownheap(s, tree, SMALLEST); |
|
694
|
|
|
695
|
} while (s->heap_len >= 2); |
|
696
|
|
|
697
|
s->heap[--(s->heap_max)] = s->heap[SMALLEST]; |
|
698
|
|
|
699
|
/* At this point, the fields freq and dad are set. We can now |
|
700
|
* generate the bit lengths. |
|
701
|
*/ |
|
702
|
gen_bitlen(s, (tree_desc *)desc); |
|
703
|
|
|
704
|
/* The field len is now set, we can generate the bit codes */ |
|
705
|
gen_codes ((ct_data *)tree, max_code, s->bl_count); |
|
706
|
} |
|
707
|
|
|
708
|
/* =========================================================================== |
|
709
|
* Scan a literal or distance tree to determine the frequencies of the codes |
|
710
|
* in the bit length tree. |
|
711
|
*/ |
|
712
|
local void scan_tree(deflate_state *s, ct_data *tree, int max_code) { |
|
713
|
int n; /* iterates over all tree elements */ |
|
714
|
int prevlen = -1; /* last emitted length */ |
|
715
|
int curlen; /* length of current code */ |
|
716
|
int nextlen = tree[0].Len; /* length of next code */ |
|
717
|
int count = 0; /* repeat count of the current code */ |
|
718
|
int max_count = 7; /* max repeat count */ |
|
719
|
int min_count = 4; /* min repeat count */ |
|
720
|
|
|
721
|
if (nextlen == 0) max_count = 138, min_count = 3; |
|
722
|
tree[max_code + 1].Len = (ush)0xffff; /* guard */ |
|
723
|
|
|
724
|
for (n = 0; n <= max_code; n++) { |
|
725
|
curlen = nextlen; nextlen = tree[n + 1].Len; |
|
726
|
if (++count < max_count && curlen == nextlen) { |
|
727
|
continue; |
|
728
|
} else if (count < min_count) { |
|
729
|
s->bl_tree[curlen].Freq += (ush)count; |
|
730
|
} else if (curlen != 0) { |
|
731
|
if (curlen != prevlen) s->bl_tree[curlen].Freq++; |
|
732
|
s->bl_tree[REP_3_6].Freq++; |
|
733
|
} else if (count <= 10) { |
|
734
|
s->bl_tree[REPZ_3_10].Freq++; |
|
735
|
} else { |
|
736
|
s->bl_tree[REPZ_11_138].Freq++; |
|
737
|
} |
|
738
|
count = 0; prevlen = curlen; |
|
739
|
if (nextlen == 0) { |
|
740
|
max_count = 138, min_count = 3; |
|
741
|
} else if (curlen == nextlen) { |
|
742
|
max_count = 6, min_count = 3; |
|
743
|
} else { |
|
744
|
max_count = 7, min_count = 4; |
|
745
|
} |
|
746
|
} |
|
747
|
} |
|
748
|
|
|
749
|
/* =========================================================================== |
|
750
|
* Send a literal or distance tree in compressed form, using the codes in |
|
751
|
* bl_tree. |
|
752
|
*/ |
|
753
|
local void send_tree(deflate_state *s, ct_data *tree, int max_code) { |
|
754
|
int n; /* iterates over all tree elements */ |
|
755
|
int prevlen = -1; /* last emitted length */ |
|
756
|
int curlen; /* length of current code */ |
|
757
|
int nextlen = tree[0].Len; /* length of next code */ |
|
758
|
int count = 0; /* repeat count of the current code */ |
|
759
|
int max_count = 7; /* max repeat count */ |
|
760
|
int min_count = 4; /* min repeat count */ |
|
761
|
|
|
762
|
/* tree[max_code + 1].Len = -1; */ /* guard already set */ |
|
763
|
if (nextlen == 0) max_count = 138, min_count = 3; |
|
764
|
|
|
765
|
for (n = 0; n <= max_code; n++) { |
|
766
|
curlen = nextlen; nextlen = tree[n + 1].Len; |
|
767
|
if (++count < max_count && curlen == nextlen) { |
|
768
|
continue; |
|
769
|
} else if (count < min_count) { |
|
770
|
do { send_code(s, curlen, s->bl_tree); } while (--count != 0); |
|
771
|
|
|
772
|
} else if (curlen != 0) { |
|
773
|
if (curlen != prevlen) { |
|
774
|
send_code(s, curlen, s->bl_tree); count--; |
|
775
|
} |
|
776
|
Assert(count >= 3 && count <= 6, " 3_6?"); |
|
777
|
send_code(s, REP_3_6, s->bl_tree); send_bits(s, count - 3, 2); |
|
778
|
|
|
779
|
} else if (count <= 10) { |
|
780
|
send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count - 3, 3); |
|
781
|
|
|
782
|
} else { |
|
783
|
send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count - 11, 7); |
|
784
|
} |
|
785
|
count = 0; prevlen = curlen; |
|
786
|
if (nextlen == 0) { |
|
787
|
max_count = 138, min_count = 3; |
|
788
|
} else if (curlen == nextlen) { |
|
789
|
max_count = 6, min_count = 3; |
|
790
|
} else { |
|
791
|
max_count = 7, min_count = 4; |
|
792
|
} |
|
793
|
} |
|
794
|
} |
|
795
|
|
|
796
|
/* =========================================================================== |
|
797
|
* Construct the Huffman tree for the bit lengths and return the index in |
|
798
|
* bl_order of the last bit length code to send. |
|
799
|
*/ |
|
800
|
local int build_bl_tree(deflate_state *s) { |
|
801
|
int max_blindex; /* index of last bit length code of non zero freq */ |
|
802
|
|
|
803
|
/* Determine the bit length frequencies for literal and distance trees */ |
|
804
|
scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); |
|
805
|
scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); |
|
806
|
|
|
807
|
/* Build the bit length tree: */ |
|
808
|
build_tree(s, (tree_desc *)(&(s->bl_desc))); |
|
809
|
/* opt_len now includes the length of the tree representations, except the |
|
810
|
* lengths of the bit lengths codes and the 5 + 5 + 4 bits for the counts. |
|
811
|
*/ |
|
812
|
|
|
813
|
/* Determine the number of bit length codes to send. The pkzip format |
|
814
|
* requires that at least 4 bit length codes be sent. (appnote.txt says |
|
815
|
* 3 but the actual value used is 4.) |
|
816
|
*/ |
|
817
|
for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { |
|
818
|
if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; |
|
819
|
} |
|
820
|
/* Update opt_len to include the bit length tree and counts */ |
|
821
|
s->opt_len += 3*((ulg)max_blindex + 1) + 5 + 5 + 4; |
|
822
|
Tracev((stderr, "\ndyn trees: dyn %lu, stat %lu", |
|
823
|
s->opt_len, s->static_len)); |
|
824
|
|
|
825
|
return max_blindex; |
|
826
|
} |
|
827
|
|
|
828
|
/* =========================================================================== |
|
829
|
* Send the header for a block using dynamic Huffman trees: the counts, the |
|
830
|
* lengths of the bit length codes, the literal tree and the distance tree. |
|
831
|
* IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. |
|
832
|
*/ |
|
833
|
local void send_all_trees(deflate_state *s, int lcodes, int dcodes, |
|
834
|
int blcodes) { |
|
835
|
int rank; /* index in bl_order */ |
|
836
|
|
|
837
|
Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); |
|
838
|
Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, |
|
839
|
"too many codes"); |
|
840
|
Tracev((stderr, "\nbl counts: ")); |
|
841
|
send_bits(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */ |
|
842
|
send_bits(s, dcodes - 1, 5); |
|
843
|
send_bits(s, blcodes - 4, 4); /* not -3 as stated in appnote.txt */ |
|
844
|
for (rank = 0; rank < blcodes; rank++) { |
|
845
|
Tracev((stderr, "\nbl code %2d ", bl_order[rank])); |
|
846
|
send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); |
|
847
|
} |
|
848
|
Tracev((stderr, "\nbl tree: sent %lu", s->bits_sent)); |
|
849
|
|
|
850
|
send_tree(s, (ct_data *)s->dyn_ltree, lcodes - 1); /* literal tree */ |
|
851
|
Tracev((stderr, "\nlit tree: sent %lu", s->bits_sent)); |
|
852
|
|
|
853
|
send_tree(s, (ct_data *)s->dyn_dtree, dcodes - 1); /* distance tree */ |
|
854
|
Tracev((stderr, "\ndist tree: sent %lu", s->bits_sent)); |
|
855
|
} |
|
856
|
|
|
857
|
/* =========================================================================== |
|
858
|
* Send a stored block |
|
859
|
*/ |
|
860
|
void ZLIB_INTERNAL _tr_stored_block(deflate_state *s, charf *buf, |
|
861
|
ulg stored_len, int last) { |
|
862
|
send_bits(s, (STORED_BLOCK<<1) + last, 3); /* send block type */ |
|
863
|
bi_windup(s); /* align on byte boundary */ |
|
864
|
put_short(s, (ush)stored_len); |
|
865
|
put_short(s, (ush)~stored_len); |
|
866
|
if (stored_len) |
|
867
|
zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len); |
|
868
|
s->pending += stored_len; |
|
869
|
#ifdef ZLIB_DEBUG |
|
870
|
s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; |
|
871
|
s->compressed_len += (stored_len + 4) << 3; |
|
872
|
s->bits_sent += 2*16; |
|
873
|
s->bits_sent += stored_len << 3; |
|
874
|
#endif |
|
875
|
} |
|
876
|
|
|
877
|
/* =========================================================================== |
|
878
|
* Flush the bits in the bit buffer to pending output (leaves at most 7 bits) |
|
879
|
*/ |
|
880
|
void ZLIB_INTERNAL _tr_flush_bits(deflate_state *s) { |
|
881
|
bi_flush(s); |
|
882
|
} |
|
883
|
|
|
884
|
/* =========================================================================== |
|
885
|
* Send one empty static block to give enough lookahead for inflate. |
|
886
|
* This takes 10 bits, of which 7 may remain in the bit buffer. |
|
887
|
*/ |
|
888
|
void ZLIB_INTERNAL _tr_align(deflate_state *s) { |
|
889
|
send_bits(s, STATIC_TREES<<1, 3); |
|
890
|
send_code(s, END_BLOCK, static_ltree); |
|
891
|
#ifdef ZLIB_DEBUG |
|
892
|
s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ |
|
893
|
#endif |
|
894
|
bi_flush(s); |
|
895
|
} |
|
896
|
|
|
897
|
/* =========================================================================== |
|
898
|
* Send the block data compressed using the given Huffman trees |
|
899
|
*/ |
|
900
|
local void compress_block(deflate_state *s, const ct_data *ltree, |
|
901
|
const ct_data *dtree) { |
|
902
|
unsigned dist; /* distance of matched string */ |
|
903
|
int lc; /* match length or unmatched char (if dist == 0) */ |
|
904
|
unsigned sx = 0; /* running index in symbol buffers */ |
|
905
|
unsigned code; /* the code to send */ |
|
906
|
int extra; /* number of extra bits to send */ |
|
907
|
|
|
908
|
if (s->sym_next != 0) do { |
|
909
|
#ifdef LIT_MEM |
|
910
|
dist = s->d_buf[sx]; |
|
911
|
lc = s->l_buf[sx++]; |
|
912
|
#else |
|
913
|
dist = s->sym_buf[sx++] & 0xff; |
|
914
|
dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8; |
|
915
|
lc = s->sym_buf[sx++]; |
|
916
|
#endif |
|
917
|
if (dist == 0) { |
|
918
|
send_code(s, lc, ltree); /* send a literal byte */ |
|
919
|
Tracecv(isgraph(lc), (stderr," '%c' ", lc)); |
|
920
|
} else { |
|
921
|
/* Here, lc is the match length - MIN_MATCH */ |
|
922
|
code = _length_code[lc]; |
|
923
|
send_code(s, code + LITERALS + 1, ltree); /* send length code */ |
|
924
|
extra = extra_lbits[code]; |
|
925
|
if (extra != 0) { |
|
926
|
lc -= base_length[code]; |
|
927
|
send_bits(s, lc, extra); /* send the extra length bits */ |
|
928
|
} |
|
929
|
dist--; /* dist is now the match distance - 1 */ |
|
930
|
code = d_code(dist); |
|
931
|
Assert (code < D_CODES, "bad d_code"); |
|
932
|
|
|
933
|
send_code(s, code, dtree); /* send the distance code */ |
|
934
|
extra = extra_dbits[code]; |
|
935
|
if (extra != 0) { |
|
936
|
dist -= (unsigned)base_dist[code]; |
|
937
|
send_bits(s, (int)dist, extra); /* send the extra bits */ |
|
938
|
} |
|
939
|
} /* literal or match pair ? */ |
|
940
|
|
|
941
|
/* Check for no overlay of pending_buf on needed symbols */ |
|
942
|
#ifdef LIT_MEM |
|
943
|
Assert(s->pending < 2 * (s->lit_bufsize + sx), "pendingBuf overflow"); |
|
944
|
#else |
|
945
|
Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow"); |
|
946
|
#endif |
|
947
|
|
|
948
|
} while (sx < s->sym_next); |
|
949
|
|
|
950
|
send_code(s, END_BLOCK, ltree); |
|
951
|
} |
|
952
|
|
|
953
|
/* =========================================================================== |
|
954
|
* Check if the data type is TEXT or BINARY, using the following algorithm: |
|
955
|
* - TEXT if the two conditions below are satisfied: |
|
956
|
* a) There are no non-portable control characters belonging to the |
|
957
|
* "block list" (0..6, 14..25, 28..31). |
|
958
|
* b) There is at least one printable character belonging to the |
|
959
|
* "allow list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). |
|
960
|
* - BINARY otherwise. |
|
961
|
* - The following partially-portable control characters form a |
|
962
|
* "gray list" that is ignored in this detection algorithm: |
|
963
|
* (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). |
|
964
|
* IN assertion: the fields Freq of dyn_ltree are set. |
|
965
|
*/ |
|
966
|
local int detect_data_type(deflate_state *s) { |
|
967
|
/* block_mask is the bit mask of block-listed bytes |
|
968
|
* set bits 0..6, 14..25, and 28..31 |
|
969
|
* 0xf3ffc07f = binary 11110011111111111100000001111111 |
|
970
|
*/ |
|
971
|
unsigned long block_mask = 0xf3ffc07fUL; |
|
972
|
int n; |
|
973
|
|
|
974
|
/* Check for non-textual ("block-listed") bytes. */ |
|
975
|
for (n = 0; n <= 31; n++, block_mask >>= 1) |
|
976
|
if ((block_mask & 1) && (s->dyn_ltree[n].Freq != 0)) |
|
977
|
return Z_BINARY; |
|
978
|
|
|
979
|
/* Check for textual ("allow-listed") bytes. */ |
|
980
|
if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 |
|
981
|
|| s->dyn_ltree[13].Freq != 0) |
|
982
|
return Z_TEXT; |
|
983
|
for (n = 32; n < LITERALS; n++) |
|
984
|
if (s->dyn_ltree[n].Freq != 0) |
|
985
|
return Z_TEXT; |
|
986
|
|
|
987
|
/* There are no "block-listed" or "allow-listed" bytes: |
|
988
|
* this stream either is empty or has tolerated ("gray-listed") bytes only. |
|
989
|
*/ |
|
990
|
return Z_BINARY; |
|
991
|
} |
|
992
|
|
|
993
|
/* =========================================================================== |
|
994
|
* Determine the best encoding for the current block: dynamic trees, static |
|
995
|
* trees or store, and write out the encoded block. |
|
996
|
*/ |
|
997
|
void ZLIB_INTERNAL _tr_flush_block(deflate_state *s, charf *buf, |
|
998
|
ulg stored_len, int last) { |
|
999
|
ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ |
|
1000
|
int max_blindex = 0; /* index of last bit length code of non zero freq */ |
|
1001
|
|
|
1002
|
/* Build the Huffman trees unless a stored block is forced */ |
|
1003
|
if (s->level > 0) { |
|
1004
|
|
|
1005
|
/* Check if the file is binary or text */ |
|
1006
|
if (s->strm->data_type == Z_UNKNOWN) |
|
1007
|
s->strm->data_type = detect_data_type(s); |
|
1008
|
|
|
1009
|
/* Construct the literal and distance trees */ |
|
1010
|
build_tree(s, (tree_desc *)(&(s->l_desc))); |
|
1011
|
Tracev((stderr, "\nlit data: dyn %lu, stat %lu", s->opt_len, |
|
1012
|
s->static_len)); |
|
1013
|
|
|
1014
|
build_tree(s, (tree_desc *)(&(s->d_desc))); |
|
1015
|
Tracev((stderr, "\ndist data: dyn %lu, stat %lu", s->opt_len, |
|
1016
|
s->static_len)); |
|
1017
|
/* At this point, opt_len and static_len are the total bit lengths of |
|
1018
|
* the compressed block data, excluding the tree representations. |
|
1019
|
*/ |
|
1020
|
|
|
1021
|
/* Build the bit length tree for the above two trees, and get the index |
|
1022
|
* in bl_order of the last bit length code to send. |
|
1023
|
*/ |
|
1024
|
max_blindex = build_bl_tree(s); |
|
1025
|
|
|
1026
|
/* Determine the best encoding. Compute the block lengths in bytes. */ |
|
1027
|
opt_lenb = (s->opt_len + 3 + 7) >> 3; |
|
1028
|
static_lenb = (s->static_len + 3 + 7) >> 3; |
|
1029
|
|
|
1030
|
Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", |
|
1031
|
opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, |
|
1032
|
s->sym_next / 3)); |
|
1033
|
|
|
1034
|
#ifndef FORCE_STATIC |
|
1035
|
if (static_lenb <= opt_lenb || s->strategy == Z_FIXED) |
|
1036
|
#endif |
|
1037
|
opt_lenb = static_lenb; |
|
1038
|
|
|
1039
|
} else { |
|
1040
|
Assert(buf != (char*)0, "lost buf"); |
|
1041
|
opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ |
|
1042
|
} |
|
1043
|
|
|
1044
|
#ifdef FORCE_STORED |
|
1045
|
if (buf != (char*)0) { /* force stored block */ |
|
1046
|
#else |
|
1047
|
if (stored_len + 4 <= opt_lenb && buf != (char*)0) { |
|
1048
|
/* 4: two words for the lengths */ |
|
1049
|
#endif |
|
1050
|
/* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. |
|
1051
|
* Otherwise we can't have processed more than WSIZE input bytes since |
|
1052
|
* the last block flush, because compression would have been |
|
1053
|
* successful. If LIT_BUFSIZE <= WSIZE, it is never too late to |
|
1054
|
* transform a block into a stored block. |
|
1055
|
*/ |
|
1056
|
_tr_stored_block(s, buf, stored_len, last); |
|
1057
|
|
|
1058
|
} else if (static_lenb == opt_lenb) { |
|
1059
|
send_bits(s, (STATIC_TREES<<1) + last, 3); |
|
1060
|
compress_block(s, (const ct_data *)static_ltree, |
|
1061
|
(const ct_data *)static_dtree); |
|
1062
|
#ifdef ZLIB_DEBUG |
|
1063
|
s->compressed_len += 3 + s->static_len; |
|
1064
|
#endif |
|
1065
|
} else { |
|
1066
|
send_bits(s, (DYN_TREES<<1) + last, 3); |
|
1067
|
send_all_trees(s, s->l_desc.max_code + 1, s->d_desc.max_code + 1, |
|
1068
|
max_blindex + 1); |
|
1069
|
compress_block(s, (const ct_data *)s->dyn_ltree, |
|
1070
|
(const ct_data *)s->dyn_dtree); |
|
1071
|
#ifdef ZLIB_DEBUG |
|
1072
|
s->compressed_len += 3 + s->opt_len; |
|
1073
|
#endif |
|
1074
|
} |
|
1075
|
Assert (s->compressed_len == s->bits_sent, "bad compressed size"); |
|
1076
|
/* The above check is made mod 2^32, for files larger than 512 MB |
|
1077
|
* and uLong implemented on 32 bits. |
|
1078
|
*/ |
|
1079
|
init_block(s); |
|
1080
|
|
|
1081
|
if (last) { |
|
1082
|
bi_windup(s); |
|
1083
|
#ifdef ZLIB_DEBUG |
|
1084
|
s->compressed_len += 7; /* align on byte boundary */ |
|
1085
|
#endif |
|
1086
|
} |
|
1087
|
Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len >> 3, |
|
1088
|
s->compressed_len - 7*(ulg)last)); |
|
1089
|
} |
|
1090
|
|
|
1091
|
/* =========================================================================== |
|
1092
|
* Save the match info and tally the frequency counts. Return true if |
|
1093
|
* the current block must be flushed. |
|
1094
|
*/ |
|
1095
|
int ZLIB_INTERNAL _tr_tally(deflate_state *s, unsigned dist, unsigned lc) { |
|
1096
|
#ifdef LIT_MEM |
|
1097
|
s->d_buf[s->sym_next] = (ush)dist; |
|
1098
|
s->l_buf[s->sym_next++] = (uch)lc; |
|
1099
|
#else |
|
1100
|
s->sym_buf[s->sym_next++] = (uch)dist; |
|
1101
|
s->sym_buf[s->sym_next++] = (uch)(dist >> 8); |
|
1102
|
s->sym_buf[s->sym_next++] = (uch)lc; |
|
1103
|
#endif |
|
1104
|
if (dist == 0) { |
|
1105
|
/* lc is the unmatched char */ |
|
1106
|
s->dyn_ltree[lc].Freq++; |
|
1107
|
} else { |
|
1108
|
s->matches++; |
|
1109
|
/* Here, lc is the match length - MIN_MATCH */ |
|
1110
|
dist--; /* dist = match distance - 1 */ |
|
1111
|
Assert((ush)dist < (ush)MAX_DIST(s) && |
|
1112
|
(ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && |
|
1113
|
(ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); |
|
1114
|
|
|
1115
|
s->dyn_ltree[_length_code[lc] + LITERALS + 1].Freq++; |
|
1116
|
s->dyn_dtree[d_code(dist)].Freq++; |
|
1117
|
} |
|
1118
|
return (s->sym_next == s->sym_end); |
|
1119
|
} |
|
1120
|
|