/* trees.c -- output deflated data using Huffman coding * Copyright (C) 1995-2003 Jean-loup Gailly * For conditions of distribution and use, see copyright notice in zlib.h */ /* * ALGORITHM * * The "deflation" process uses several Huffman trees. The more * common source values are represented by shorter bit sequences. * * Each code tree is stored in a compressed form which is itself * a Huffman encoding of the lengths of all the code strings (in * ascending order by source values). The actual code strings are * reconstructed from the lengths in the inflate process, as described * in the deflate specification. * * REFERENCES * * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc * * Storer, James A. * Data Compression: Methods and Theory, pp. 49-50. * Computer Science Press, 1988. ISBN 0-7167-8156-5. * * Sedgewick, R. * Algorithms, p290. * Addison-Wesley, 1983. ISBN 0-201-06672-6. */ /* @(#) $Id$ */ /* #define GEN_TREES_H */ #include "deflate.h" #ifdef DEBUG # include #endif /* =========================================================================== * Constants */ #define MAX_BL_BITS 7 /* Bit length codes must not exceed MAX_BL_BITS bits */ #define END_BLOCK 256 /* end of block literal code */ #define REP_3_6 16 /* repeat previous bit length 3-6 times (2 bits of repeat count) */ #define REPZ_3_10 17 /* repeat a zero length 3-10 times (3 bits of repeat count) */ #define REPZ_11_138 18 /* repeat a zero length 11-138 times (7 bits of repeat count) */ local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ = {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}; local const int extra_dbits[D_CODES] /* extra bits for each distance code */ = {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}; local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; local const uch bl_order[BL_CODES] = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; /* The lengths of the bit length codes are sent in order of decreasing * probability, to avoid transmitting the lengths for unused bit length codes. */ #define Buf_size (8 * 2*sizeof(char)) /* Number of bits used within bi_buf. (bi_buf might be implemented on * more than 16 bits on some systems.) */ /* =========================================================================== * Local data. These are initialized only once. */ #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ #if defined(GEN_TREES_H) || !defined(STDC) /* non ANSI compilers may not accept trees.h */ local ct_data static_ltree[L_CODES+2]; /* The static literal tree. Since the bit lengths are imposed, there is no * need for the L_CODES extra codes used during heap construction. However * The codes 286 and 287 are needed to build a canonical tree (see _tr_init * below). */ local ct_data static_dtree[D_CODES]; /* The static distance tree. (Actually a trivial tree since all codes use * 5 bits.) */ uch _dist_code[DIST_CODE_LEN]; /* Distance codes. The first 256 values correspond to the distances * 3 .. 258, the last 256 values correspond to the top 8 bits of * the 15 bit distances. */ uch _length_code[MAX_MATCH-MIN_MATCH+1]; /* length code for each normalized match length (0 == MIN_MATCH) */ local int base_length[LENGTH_CODES]; /* First normalized length for each code (0 = MIN_MATCH) */ local int base_dist[D_CODES]; /* First normalized distance for each code (0 = distance of 1) */ #else # include "trees.h" #endif /* GEN_TREES_H */ struct static_tree_desc_s { const ct_data *static_tree; /* static tree or NULL */ const intf *extra_bits; /* extra bits for each code or NULL */ int extra_base; /* base index for extra_bits */ int elems; /* max number of elements in the tree */ int max_length; /* max bit length for the codes */ }; local static_tree_desc static_l_desc = {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; local static_tree_desc static_d_desc = {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; local static_tree_desc static_bl_desc = {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; /* =========================================================================== * Local (static) routines in this file. */ local void tr_static_init OF((void)); local void init_block OF((deflate_state *s)); local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); local void build_tree OF((deflate_state *s, tree_desc *desc)); local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); local int build_bl_tree OF((deflate_state *s)); local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, int blcodes)); local void compress_block OF((deflate_state *s, ct_data *ltree, ct_data *dtree)); local void set_data_type OF((deflate_state *s)); local unsigned bi_reverse OF((unsigned value, int length)); local void bi_windup OF((deflate_state *s)); local void bi_flush OF((deflate_state *s)); local void copy_block OF((deflate_state *s, charf *buf, unsigned len, int header)); #ifdef GEN_TREES_H local void gen_trees_header OF((void)); #endif #ifndef DEBUG # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) /* Send a code of the given tree. c and tree must not have side effects */ #else /* DEBUG */ # define send_code(s, c, tree) \ { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ send_bits(s, tree[c].Code, tree[c].Len); } #endif /* =========================================================================== * Output a short LSB first on the stream. * IN assertion: there is enough room in pendingBuf. */ #define put_short(s, w) { \ put_byte(s, (uch)((w) & 0xff)); \ put_byte(s, (uch)((ush)(w) >> 8)); \ } /* =========================================================================== * Send a value on a given number of bits. * IN assertion: length <= 16 and value fits in length bits. */ #ifdef DEBUG local void send_bits OF((deflate_state *s, int value, int length)); local void send_bits(s, value, length) deflate_state *s; int value; /* value to send */ int length; /* number of bits */ { Tracevv((stderr," l %2d v %4x ", length, value)); Assert(length > 0 && length <= 15, "invalid length"); s->bits_sent += (ulg)length; /* If not enough room in bi_buf, use (valid) bits from bi_buf and * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) * unused bits in value. */ if (s->bi_valid > (int)Buf_size - length) { s->bi_buf |= (value << s->bi_valid); put_short(s, s->bi_buf); s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); s->bi_valid += length - Buf_size; } else { s->bi_buf |= value << s->bi_valid; s->bi_valid += length; } } #else /* !DEBUG */ #define send_bits(s, value, length) \ { int len = length;\ if (s->bi_valid > (int)Buf_size - len) {\ int val = value;\ s->bi_buf |= (val << s->bi_valid);\ put_short(s, s->bi_buf);\ s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ s->bi_valid += len - Buf_size;\ } else {\ s->bi_buf |= (value) << s->bi_valid;\ s->bi_valid += len;\ }\ } #endif /* DEBUG */ /* the arguments must not have side effects */ /* =========================================================================== * Initialize the various 'constant' tables. */ local void tr_static_init() 70 { #if defined(GEN_TREES_H) || !defined(STDC) static int static_init_done = 0; int n; /* iterates over tree elements */ int bits; /* bit counter */ int length; /* length value */ int code; /* code value */ int dist; /* distance index */ ush bl_count[MAX_BITS+1]; /* number of codes at each bit length for an optimal tree */ if (static_init_done) return; /* For some embedded targets, global variables are not initialized: */ static_l_desc.static_tree = static_ltree; static_l_desc.extra_bits = extra_lbits; static_d_desc.static_tree = static_dtree; static_d_desc.extra_bits = extra_dbits; static_bl_desc.extra_bits = extra_blbits; /* Initialize the mapping length (0..255) -> length code (0..28) */ length = 0; for (code = 0; code < LENGTH_CODES-1; code++) { base_length[code] = length; for (n = 0; n < (1< dist code (0..29) */ dist = 0; for (code = 0 ; code < 16; code++) { base_dist[code] = dist; for (n = 0; n < (1<>= 7; /* from now on, all distances are divided by 128 */ for ( ; code < D_CODES; code++) { base_dist[code] = dist << 7; for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { _dist_code[256 + dist++] = (uch)code; } } Assert (dist == 256, "tr_static_init: 256+dist != 512"); /* Construct the codes of the static literal tree */ for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; n = 0; while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; /* Codes 286 and 287 do not exist, but we must include them in the * tree construction to get a canonical Huffman tree (longest code * all ones) */ gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); /* The static distance tree is trivial: */ for (n = 0; n < D_CODES; n++) { static_dtree[n].Len = 5; static_dtree[n].Code = bi_reverse((unsigned)n, 5); } static_init_done = 1; # ifdef GEN_TREES_H gen_trees_header(); # endif #endif /* defined(GEN_TREES_H) || !defined(STDC) */ } /* =========================================================================== * Genererate the file trees.h describing the static trees. */ #ifdef GEN_TREES_H # ifndef DEBUG # include # endif # define SEPARATOR(i, last, width) \ ((i) == (last)? "\n};\n\n" : \ ((i) % (width) == (width)-1 ? ",\n" : ", ")) void gen_trees_header() { FILE *header = fopen("trees.h", "w"); int i; Assert (header != NULL, "Can't open trees.h"); fprintf(header, "/* header created automatically with -DGEN_TREES_H */\n\n"); fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); for (i = 0; i < L_CODES+2; i++) { fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); } fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); for (i = 0; i < D_CODES; i++) { fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); } fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); for (i = 0; i < DIST_CODE_LEN; i++) { fprintf(header, "%2u%s", _dist_code[i], SEPARATOR(i, DIST_CODE_LEN-1, 20)); } fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { fprintf(header, "%2u%s", _length_code[i], SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); } fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); for (i = 0; i < LENGTH_CODES; i++) { fprintf(header, "%1u%s", base_length[i], SEPARATOR(i, LENGTH_CODES-1, 20)); } fprintf(header, "local const int base_dist[D_CODES] = {\n"); for (i = 0; i < D_CODES; i++) { fprintf(header, "%5u%s", base_dist[i], SEPARATOR(i, D_CODES-1, 10)); } fclose(header); } #endif /* GEN_TREES_H */ /* =========================================================================== * Initialize the tree data structures for a new zlib stream. */ void _tr_init(s) deflate_state *s; 70 { 70 tr_static_init(); 70 s->l_desc.dyn_tree = s->dyn_ltree; 70 s->l_desc.stat_desc = &static_l_desc; 70 s->d_desc.dyn_tree = s->dyn_dtree; 70 s->d_desc.stat_desc = &static_d_desc; 70 s->bl_desc.dyn_tree = s->bl_tree; 70 s->bl_desc.stat_desc = &static_bl_desc; 70 s->bi_buf = 0; 70 s->bi_valid = 0; 70 s->last_eob_len = 8; /* enough lookahead for inflate */ #ifdef DEBUG s->compressed_len = 0L; s->bits_sent = 0L; #endif /* Initialize the first block of the first file: */ 70 init_block(s); } /* =========================================================================== * Initialize a new block. */ local void init_block(s) deflate_state *s; 146 { 146 int n; /* iterates over tree elements */ /* Initialize the trees. */ 146 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 146 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 146 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 146 s->dyn_ltree[END_BLOCK].Freq = 1; 146 s->opt_len = s->static_len = 0L; 146 s->last_lit = s->matches = 0; } #define SMALLEST 1 /* Index within the heap array of least frequent node in the Huffman tree */ /* =========================================================================== * Remove the smallest element from the heap and recreate the heap with * one less element. Updates heap and heap_len. */ #define pqremove(s, tree, top) \ {\ top = s->heap[SMALLEST]; \ s->heap[SMALLEST] = s->heap[s->heap_len--]; \ pqdownheap(s, tree, SMALLEST); \ } /* =========================================================================== * Compares to subtrees, using the tree depth as tie breaker when * the subtrees have equal frequency. This minimizes the worst case length. */ #define smaller(tree, n, m, depth) \ (tree[n].Freq < tree[m].Freq || \ (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) /* =========================================================================== * Restore the heap property by moving down the tree starting at node k, * exchanging a node with the smallest of its two sons if necessary, stopping * when the heap property is re-established (each father smaller than its * two sons). */ local void pqdownheap(s, tree, k) deflate_state *s; ct_data *tree; /* the tree to restore */ int k; /* node to move down */ 7800 { 7800 int v = s->heap[k]; 7800 int j = k << 1; /* left son of k */ 32572 while (j <= s->heap_len) { /* Set j to the smallest of the two sons: */ 26878 if (j < s->heap_len && smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 12810 j++; } /* Exit if v is smaller than both sons */ 26878 if (smaller(tree, v, s->heap[j], s->depth)) break; /* Exchange v with the smallest son */ 24772 s->heap[k] = s->heap[j]; k = j; /* And continue down the tree, setting j to the left son of k */ 24772 j <<= 1; } 7800 s->heap[k] = v; } /* =========================================================================== * Compute the optimal bit lengths for a tree and update the total bit length * for the current block. * IN assertion: the fields freq and dad are set, heap[heap_max] and * above are the tree nodes sorted by increasing frequency. * OUT assertions: the field len is set to the optimal bit length, the * array bl_count contains the frequencies for each bit length. * The length opt_len is updated; static_len is also updated if stree is * not null. */ local void gen_bitlen(s, desc) deflate_state *s; tree_desc *desc; /* the tree descriptor */ 222 { 222 ct_data *tree = desc->dyn_tree; 222 int max_code = desc->max_code; 222 const ct_data *stree = desc->stat_desc->static_tree; 222 const intf *extra = desc->stat_desc->extra_bits; 222 int base = desc->stat_desc->extra_base; 222 int max_length = desc->stat_desc->max_length; 222 int h; /* heap index */ 222 int n, m; /* iterate over the tree elements */ 222 int bits; /* bit length */ 222 int xbits; /* extra bits */ 222 ush f; /* frequency */ 222 int overflow = 0; /* number of elements with bit length too large */ 222 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; /* In a first pass, compute the optimal bit lengths (which may * overflow in the case of the bit length tree). */ 222 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 6400 for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 6178 n = s->heap[h]; 6178 bits = tree[tree[n].Dad].Len + 1; 6178 if (bits > max_length) bits = max_length, overflow++; 6178 tree[n].Len = (ush)bits; /* We overwrite tree[n].Dad which is no longer needed */ 6178 if (n > max_code) continue; /* not a leaf node */ 3311 s->bl_count[bits]++; 3311 xbits = 0; 3311 if (n >= base) xbits = extra[n-base]; 3311 f = tree[n].Freq; 3311 s->opt_len += (ulg)f * (bits + xbits); 3311 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); } 222 if (overflow == 0) return; Trace((stderr,"\nbit length overflow\n")); /* This happens for example on obj2 and pic of the Calgary corpus */ /* Find the first bit length which could increase: */ ###### do { ###### bits = max_length-1; ###### while (s->bl_count[bits] == 0) bits--; ###### s->bl_count[bits]--; /* move one leaf down the tree */ ###### s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ ###### s->bl_count[max_length]--; /* The brother of the overflow item also moves one step up, * but this does not affect bl_count[max_length] */ ###### overflow -= 2; ###### } while (overflow > 0); /* Now recompute all bit lengths, scanning in increasing frequency. * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all * lengths instead of fixing only the wrong ones. This idea is taken * from 'ar' written by Haruhiko Okumura.) */ ###### for (bits = max_length; bits != 0; bits--) { ###### n = s->bl_count[bits]; ###### while (n != 0) { ###### m = s->heap[--h]; ###### if (m > max_code) continue; ###### if (tree[m].Len != (unsigned) bits) { Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); ###### s->opt_len += ((long)bits - (long)tree[m].Len) *(long)tree[m].Freq; ###### tree[m].Len = (ush)bits; } ###### n--; } } } /* =========================================================================== * Generate the codes for a given tree and bit counts (which need not be * optimal). * IN assertion: the array bl_count contains the bit length statistics for * the given tree and the field len is set for all tree elements. * OUT assertion: the field code is set for all tree elements of non * zero code length. */ local void gen_codes (tree, max_code, bl_count) ct_data *tree; /* the tree to decorate */ int max_code; /* largest code with non zero frequency */ ushf *bl_count; /* number of codes at each bit length */ 222 { 222 ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 222 ush code = 0; /* running code value */ 222 int bits; /* bit index */ 222 int n; /* code index */ /* The distribution counts are first used to generate the code values * without bit reversal. */ 3552 for (bits = 1; bits <= MAX_BITS; bits++) { 3330 next_code[bits] = code = (code + bl_count[bits-1]) << 1; } /* Check that the bit counts in bl_count are consistent. The last code * must be all ones. */ Assert (code + bl_count[MAX_BITS]-1 == (1<dyn_tree; 222 const ct_data *stree = desc->stat_desc->static_tree; 222 int elems = desc->stat_desc->elems; 222 int n, m; /* iterate over heap elements */ 222 int max_code = -1; /* largest code with non zero frequency */ 222 int node; /* new node being created */ /* Construct the initial heap, with least frequent element in * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. * heap[0] is not used. */ 222 s->heap_len = 0, s->heap_max = HEAP_SIZE; 25012 for (n = 0; n < elems; n++) { 24790 if (tree[n].Freq != 0) { 3200 s->heap[++(s->heap_len)] = max_code = n; 3200 s->depth[n] = 0; } else { 21590 tree[n].Len = 0; } } /* The pkzip format requires that at least one distance code exists, * and that at least one bit should be sent even if there is only one * possible code. So to avoid special checks later on we force at least * two codes of non zero frequency. */ 333 while (s->heap_len < 2) { 111 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 111 tree[node].Freq = 1; 111 s->depth[node] = 0; 111 s->opt_len--; if (stree) s->static_len -= stree[node].Len; /* node is 0 or 1 so it does not have extra bits */ } 222 desc->max_code = max_code; /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, * establish sub-heaps of increasing lengths: */ 222 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); /* Construct the Huffman tree by repeatedly combining the least two * frequent nodes. */ 222 node = elems; /* next internal node of the tree */ 3089 do { 3089 pqremove(s, tree, n); /* n = node of least frequency */ 3089 m = s->heap[SMALLEST]; /* m = node of next least frequency */ 3089 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 3089 s->heap[--(s->heap_max)] = m; /* Create a new node father of n and m */ 3089 tree[node].Freq = tree[n].Freq + tree[m].Freq; 3089 s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? s->depth[n] : s->depth[m]) + 1); 3089 tree[n].Dad = tree[m].Dad = (ush)node; #ifdef DUMP_BL_TREE if (tree == s->bl_tree) { fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); } #endif /* and insert the new node in the heap */ 3089 s->heap[SMALLEST] = node++; 3089 pqdownheap(s, tree, SMALLEST); 3089 } while (s->heap_len >= 2); 222 s->heap[--(s->heap_max)] = s->heap[SMALLEST]; /* At this point, the fields freq and dad are set. We can now * generate the bit lengths. */ 222 gen_bitlen(s, (tree_desc *)desc); /* The field len is now set, we can generate the bit codes */ 222 gen_codes ((ct_data *)tree, max_code, s->bl_count); } /* =========================================================================== * Scan a literal or distance tree to determine the frequencies of the codes * in the bit length tree. */ local void scan_tree (s, tree, max_code) deflate_state *s; ct_data *tree; /* the tree to be scanned */ int max_code; /* and its largest code of non zero frequency */ 148 { 148 int n; /* iterates over all tree elements */ 148 int prevlen = -1; /* last emitted length */ 148 int curlen; /* length of current code */ 148 int nextlen = tree[0].Len; /* length of next code */ 148 int count = 0; /* repeat count of the current code */ 148 int max_count = 7; /* max repeat count */ 148 int min_count = 4; /* min repeat count */ 148 if (nextlen == 0) max_count = 138, min_count = 3; 148 tree[max_code+1].Len = (ush)0xffff; /* guard */ 20058 for (n = 0; n <= max_code; n++) { 19910 curlen = nextlen; nextlen = tree[n+1].Len; 19910 if (++count < max_count && curlen == nextlen) { 17908 continue; 2002 } else if (count < min_count) { 1419 s->bl_tree[curlen].Freq += count; 583 } else if (curlen != 0) { 228 if (curlen != prevlen) s->bl_tree[curlen].Freq++; 228 s->bl_tree[REP_3_6].Freq++; 355 } else if (count <= 10) { 122 s->bl_tree[REPZ_3_10].Freq++; } else { 233 s->bl_tree[REPZ_11_138].Freq++; } 2002 count = 0; prevlen = curlen; 2002 if (nextlen == 0) { 452 max_count = 138, min_count = 3; 1550 } else if (curlen == nextlen) { 114 max_count = 6, min_count = 3; } else { 1436 max_count = 7, min_count = 4; } } } /* =========================================================================== * Send a literal or distance tree in compressed form, using the codes in * bl_tree. */ local void send_tree (s, tree, max_code) deflate_state *s; ct_data *tree; /* the tree to be scanned */ int max_code; /* and its largest code of non zero frequency */ 30 { 30 int n; /* iterates over all tree elements */ 30 int prevlen = -1; /* last emitted length */ 30 int curlen; /* length of current code */ 30 int nextlen = tree[0].Len; /* length of next code */ 30 int count = 0; /* repeat count of the current code */ 30 int max_count = 7; /* max repeat count */ 30 int min_count = 4; /* min repeat count */ /* tree[max_code+1].Len = -1; */ /* guard already set */ 30 if (nextlen == 0) max_count = 138, min_count = 3; 4396 for (n = 0; n <= max_code; n++) { 4366 curlen = nextlen; nextlen = tree[n+1].Len; 4366 if (++count < max_count && curlen == nextlen) { 3591 continue; 775 } else if (count < min_count) { 820 do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 133 } else if (curlen != 0) { 14 if (curlen != prevlen) { 14 send_code(s, curlen, s->bl_tree); count--; } Assert(count >= 3 && count <= 6, " 3_6?"); 14 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 119 } else if (count <= 10) { 60 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); } else { 59 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); } 775 count = 0; prevlen = curlen; 775 if (nextlen == 0) { 182 max_count = 138, min_count = 3; 593 } else if (curlen == nextlen) { ###### max_count = 6, min_count = 3; } else { 593 max_count = 7, min_count = 4; } } } /* =========================================================================== * Construct the Huffman tree for the bit lengths and return the index in * bl_order of the last bit length code to send. */ local int build_bl_tree(s) deflate_state *s; 74 { 74 int max_blindex; /* index of last bit length code of non zero freq */ /* Determine the bit length frequencies for literal and distance trees */ 74 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 74 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); /* Build the bit length tree: */ 74 build_tree(s, (tree_desc *)(&(s->bl_desc))); /* opt_len now includes the length of the tree representations, except * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. */ /* Determine the number of bit length codes to send. The pkzip format * requires that at least 4 bit length codes be sent. (appnote.txt says * 3 but the actual value used is 4.) */ 174 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 174 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; } /* Update opt_len to include the bit length tree and counts */ 74 s->opt_len += 3*(max_blindex+1) + 5+5+4; Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", s->opt_len, s->static_len)); 74 return max_blindex; } /* =========================================================================== * Send the header for a block using dynamic Huffman trees: the counts, the * lengths of the bit length codes, the literal tree and the distance tree. * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. */ local void send_all_trees(s, lcodes, dcodes, blcodes) deflate_state *s; int lcodes, dcodes, blcodes; /* number of codes for each tree */ 15 { 15 int rank; /* index in bl_order */ Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, "too many codes"); Tracev((stderr, "\nbl counts: ")); 15 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 15 send_bits(s, dcodes-1, 5); 15 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 263 for (rank = 0; rank < blcodes; rank++) { Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 248 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); } Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 15 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 15 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); } /* =========================================================================== * Send a stored block */ void _tr_stored_block(s, buf, stored_len, eof) deflate_state *s; charf *buf; /* input block */ ulg stored_len; /* length of input block */ int eof; /* true if this is the last block for a file */ 8 { 8 send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ #ifdef DEBUG s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; s->compressed_len += (stored_len + 4) << 3; #endif 8 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ } /* =========================================================================== * Send one empty static block to give enough lookahead for inflate. * This takes 10 bits, of which 7 may remain in the bit buffer. * The current inflate code requires 9 bits of lookahead. If the * last two codes for the previous block (real code plus EOB) were coded * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode * the last real code. In this case we send two empty static blocks instead * of one. (There are no problems if the previous block is stored or fixed.) * To simplify the code, we assume the worst case of last real code encoded * on one bit only. */ void _tr_align(s) deflate_state *s; 1 { 1 send_bits(s, STATIC_TREES<<1, 3); 1 send_code(s, END_BLOCK, static_ltree); #ifdef DEBUG s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ #endif 1 bi_flush(s); /* Of the 10 bits for the empty block, we have already sent * (10 - bi_valid) bits. The lookahead for the last real code (before * the EOB of the previous block) was thus at least one plus the length * of the EOB plus what we have just sent of the empty static block. */ 1 if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { ###### send_bits(s, STATIC_TREES<<1, 3); ###### send_code(s, END_BLOCK, static_ltree); #ifdef DEBUG s->compressed_len += 10L; #endif ###### bi_flush(s); } 1 s->last_eob_len = 7; } /* =========================================================================== * Determine the best encoding for the current block: dynamic trees, static * trees or store, and output the encoded block to the zip file. */ void _tr_flush_block(s, buf, stored_len, eof) deflate_state *s; charf *buf; /* input block, or NULL if too old */ ulg stored_len; /* length of input block */ int eof; /* true if this is the last block for a file */ 76 { 76 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 76 int max_blindex = 0; /* index of last bit length code of non zero freq */ /* Build the Huffman trees unless a stored block is forced */ 76 if (s->level > 0) { /* Check if the file is ascii or binary */ 74 if (s->strm->data_type == Z_UNKNOWN) set_data_type(s); /* Construct the literal and distance trees */ 74 build_tree(s, (tree_desc *)(&(s->l_desc))); Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, s->static_len)); 74 build_tree(s, (tree_desc *)(&(s->d_desc))); Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, s->static_len)); /* At this point, opt_len and static_len are the total bit lengths of * the compressed block data, excluding the tree representations. */ /* Build the bit length tree for the above two trees, and get the index * in bl_order of the last bit length code to send. */ 74 max_blindex = build_bl_tree(s); /* Determine the best encoding. Compute the block lengths in bytes. */ 74 opt_lenb = (s->opt_len+3+7)>>3; 74 static_lenb = (s->static_len+3+7)>>3; Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, s->last_lit)); 74 if (static_lenb <= opt_lenb) opt_lenb = static_lenb; } else { Assert(buf != (char*)0, "lost buf"); 2 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ } #ifdef FORCE_STORED if (buf != (char*)0) { /* force stored block */ #else 76 if (stored_len+4 <= opt_lenb && buf != (char*)0) { /* 4: two words for the lengths */ #endif /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. * Otherwise we can't have processed more than WSIZE input bytes since * the last block flush, because compression would have been * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to * transform a block into a stored block. */ 7 _tr_stored_block(s, buf, stored_len, eof); #ifdef FORCE_STATIC } else if (static_lenb >= 0) { /* force static trees */ #else 69 } else if (static_lenb == opt_lenb) { #endif 54 send_bits(s, (STATIC_TREES<<1)+eof, 3); 54 compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); #ifdef DEBUG s->compressed_len += 3 + s->static_len; #endif } else { 15 send_bits(s, (DYN_TREES<<1)+eof, 3); 15 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, max_blindex+1); 15 compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); #ifdef DEBUG s->compressed_len += 3 + s->opt_len; #endif } Assert (s->compressed_len == s->bits_sent, "bad compressed size"); /* The above check is made mod 2^32, for files larger than 512 MB * and uLong implemented on 32 bits. */ 76 init_block(s); 76 if (eof) { 70 bi_windup(s); #ifdef DEBUG s->compressed_len += 7; /* align on byte boundary */ #endif } Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, s->compressed_len-7*eof)); } /* =========================================================================== * Save the match info and tally the frequency counts. Return true if * the current block must be flushed. */ int _tr_tally (s, dist, lc) deflate_state *s; unsigned dist; /* distance of matched string */ unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ ###### { ###### s->d_buf[s->last_lit] = (ush)dist; ###### s->l_buf[s->last_lit++] = (uch)lc; ###### if (dist == 0) { /* lc is the unmatched char */ ###### s->dyn_ltree[lc].Freq++; } else { ###### s->matches++; /* Here, lc is the match length - MIN_MATCH */ ###### dist--; /* dist = match distance - 1 */ Assert((ush)dist < (ush)MAX_DIST(s) && (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); ###### s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; ###### s->dyn_dtree[d_code(dist)].Freq++; } #ifdef TRUNCATE_BLOCK /* Try to guess if it is profitable to stop the current block here */ if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { /* Compute an upper bound for the compressed length */ ulg out_length = (ulg)s->last_lit*8L; ulg in_length = (ulg)((long)s->strstart - s->block_start); int dcode; for (dcode = 0; dcode < D_CODES; dcode++) { out_length += (ulg)s->dyn_dtree[dcode].Freq * (5L+extra_dbits[dcode]); } out_length >>= 3; Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", s->last_lit, in_length, out_length, 100L - out_length*100L/in_length)); if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; } #endif ###### return (s->last_lit == s->lit_bufsize-1); /* We avoid equality with lit_bufsize because of wraparound at 64K * on 16 bit machines and because stored blocks are restricted to * 64K-1 bytes. */ } /* =========================================================================== * Send the block data compressed using the given Huffman trees */ local void compress_block(s, ltree, dtree) deflate_state *s; ct_data *ltree; /* literal tree */ ct_data *dtree; /* distance tree */ 69 { 69 unsigned dist; /* distance of matched string */ 69 int lc; /* match length or unmatched char (if dist == 0) */ 69 unsigned lx = 0; /* running index in l_buf */ 69 unsigned code; /* the code to send */ 69 int extra; /* number of extra bits to send */ 69 if (s->last_lit != 0) do { 68610 dist = s->d_buf[lx]; 68610 lc = s->l_buf[lx++]; 68610 if (dist == 0) { 58780 send_code(s, lc, ltree); /* send a literal byte */ Tracecv(isgraph(lc), (stderr," '%c' ", lc)); } else { /* Here, lc is the match length - MIN_MATCH */ 9830 code = _length_code[lc]; 9830 send_code(s, code+LITERALS+1, ltree); /* send the length code */ 9830 extra = extra_lbits[code]; 9830 if (extra != 0) { 1838 lc -= base_length[code]; 1838 send_bits(s, lc, extra); /* send the extra length bits */ } 9830 dist--; /* dist is now the match distance - 1 */ 9830 code = d_code(dist); Assert (code < D_CODES, "bad d_code"); 9830 send_code(s, code, dtree); /* send the distance code */ 9830 extra = extra_dbits[code]; 9830 if (extra != 0) { 9636 dist -= base_dist[code]; 9636 send_bits(s, dist, extra); /* send the extra distance bits */ } } /* literal or match pair ? */ /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, "pendingBuf overflow"); 68610 } while (lx < s->last_lit); 69 send_code(s, END_BLOCK, ltree); 69 s->last_eob_len = ltree[END_BLOCK].Len; } /* =========================================================================== * Set the data type to ASCII or BINARY, using a crude approximation: * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. * IN assertion: the fields freq of dyn_ltree are set and the total of all * frequencies does not exceed 64K (to fit in an int on 16 bit machines). */ local void set_data_type(s) deflate_state *s; 70 { 70 int n = 0; 70 unsigned ascii_freq = 0; 70 unsigned bin_freq = 0; 560 while (n < 7) bin_freq += s->dyn_ltree[n++].Freq; 8540 while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq; 9030 while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq; 70 s->strm->data_type = bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII; } /* =========================================================================== * Reverse the first len bits of a code, using straightforward code (a faster * method would use a table) * IN assertion: 1 <= len <= 15 */ local unsigned bi_reverse(code, len) unsigned code; /* the value to invert */ int len; /* its bit length */ 3311 { 3311 register unsigned res = 0; 20794 do { 20794 res |= code & 1; 20794 code >>= 1, res <<= 1; 20794 } while (--len > 0); 3311 return res >> 1; } /* =========================================================================== * Flush the bit buffer, keeping at most 7 bits in it. */ local void bi_flush(s) deflate_state *s; 1 { 1 if (s->bi_valid == 16) { ###### put_short(s, s->bi_buf); ###### s->bi_buf = 0; ###### s->bi_valid = 0; 1 } else if (s->bi_valid >= 8) { 1 put_byte(s, (Byte)s->bi_buf); 1 s->bi_buf >>= 8; 1 s->bi_valid -= 8; } } /* =========================================================================== * Flush the bit buffer and align the output on a byte boundary */ local void bi_windup(s) deflate_state *s; 78 { 78 if (s->bi_valid > 8) { 32 put_short(s, s->bi_buf); 46 } else if (s->bi_valid > 0) { 40 put_byte(s, (Byte)s->bi_buf); } 78 s->bi_buf = 0; 78 s->bi_valid = 0; #ifdef DEBUG s->bits_sent = (s->bits_sent+7) & ~7; #endif } /* =========================================================================== * Copy a stored block, storing first the length and its * one's complement if requested. */ local void copy_block(s, buf, len, header) deflate_state *s; charf *buf; /* the input data */ unsigned len; /* its length */ int header; /* true if block header must be written */ 8 { 8 bi_windup(s); /* align on byte boundary */ 8 s->last_eob_len = 8; /* enough lookahead for inflate */ 8 if (header) { 8 put_short(s, (ush)len); 8 put_short(s, (ush)~len); #ifdef DEBUG s->bits_sent += 2*16; #endif } #ifdef DEBUG s->bits_sent += (ulg)len<<3; #endif 77268 while (len--) { 77260 put_byte(s, *buf++); } }