sl@0: /* trees.c -- output deflated data using Huffman coding sl@0: * Copyright (C) 1995-1998 Jean-loup Gailly sl@0: * For conditions of distribution and use, see copyright notice in zlib.h sl@0: */ sl@0: sl@0: /* sl@0: * ALGORITHM sl@0: * sl@0: * The "deflation" process uses several Huffman trees. The more sl@0: * common source values are represented by shorter bit sequences. sl@0: * sl@0: * Each code tree is stored in a compressed form which is itself sl@0: * a Huffman encoding of the lengths of all the code strings (in sl@0: * ascending order by source values). The actual code strings are sl@0: * reconstructed from the lengths in the inflate process, as described sl@0: * in the deflate specification. sl@0: * sl@0: * REFERENCES sl@0: * sl@0: * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". sl@0: * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc sl@0: * sl@0: * Storer, James A. sl@0: * Data Compression: Methods and Theory, pp. 49-50. sl@0: * Computer Science Press, 1988. ISBN 0-7167-8156-5. sl@0: * sl@0: * Sedgewick, R. sl@0: * Algorithms, p290. sl@0: * Addison-Wesley, 1983. ISBN 0-201-06672-6. sl@0: */ sl@0: sl@0: /* @(#) $Id$ */ sl@0: sl@0: /* #define GEN_TREES_H */ sl@0: sl@0: #include sl@0: sl@0: #include "deflate.h" sl@0: sl@0: #ifdef DEBUG sl@0: # include sl@0: #endif sl@0: sl@0: /* =========================================================================== sl@0: * Constants sl@0: */ sl@0: sl@0: #define MAX_BL_BITS 7 sl@0: /* Bit length codes must not exceed MAX_BL_BITS bits */ sl@0: sl@0: #define END_BLOCK 256 sl@0: /* end of block literal code */ sl@0: sl@0: #define REP_3_6 16 sl@0: /* repeat previous bit length 3-6 times (2 bits of repeat count) */ sl@0: sl@0: #define REPZ_3_10 17 sl@0: /* repeat a zero length 3-10 times (3 bits of repeat count) */ sl@0: sl@0: #define REPZ_11_138 18 sl@0: /* repeat a zero length 11-138 times (7 bits of repeat count) */ sl@0: sl@0: local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ sl@0: = {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}; sl@0: sl@0: local const int extra_dbits[D_CODES] /* extra bits for each distance code */ sl@0: = {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}; sl@0: sl@0: local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ sl@0: = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; sl@0: sl@0: local const uch bl_order[BL_CODES] sl@0: = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; sl@0: /* The lengths of the bit length codes are sent in order of decreasing sl@0: * probability, to avoid transmitting the lengths for unused bit length codes. sl@0: */ sl@0: sl@0: #define Buf_size (8 * 2*sizeof(char)) sl@0: /* Number of bits used within bi_buf. (bi_buf might be implemented on sl@0: * more than 16 bits on some systems.) sl@0: */ sl@0: sl@0: /* =========================================================================== sl@0: * Local data. These are initialized only once. sl@0: */ sl@0: sl@0: #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ sl@0: sl@0: #if defined(GEN_TREES_H) || !defined(STDC) sl@0: /* non ANSI compilers may not accept trees.h */ sl@0: sl@0: local ct_data static_ltree[L_CODES+2]; sl@0: /* The static literal tree. Since the bit lengths are imposed, there is no sl@0: * need for the L_CODES extra codes used during heap construction. However sl@0: * The codes 286 and 287 are needed to build a canonical tree (see _tr_init sl@0: * below). sl@0: */ sl@0: sl@0: local ct_data static_dtree[D_CODES]; sl@0: /* The static distance tree. (Actually a trivial tree since all codes use sl@0: * 5 bits.) sl@0: */ sl@0: sl@0: uch _dist_code[DIST_CODE_LEN]; sl@0: /* Distance codes. The first 256 values correspond to the distances sl@0: * 3 .. 258, the last 256 values correspond to the top 8 bits of sl@0: * the 15 bit distances. sl@0: */ sl@0: sl@0: uch _length_code[MAX_MATCH-MIN_MATCH+1]; sl@0: /* length code for each normalized match length (0 == MIN_MATCH) */ sl@0: sl@0: local int base_length[LENGTH_CODES]; sl@0: /* First normalized length for each code (0 = MIN_MATCH) */ sl@0: sl@0: local int base_dist[D_CODES]; sl@0: /* First normalized distance for each code (0 = distance of 1) */ sl@0: sl@0: #else sl@0: # include "trees.h" sl@0: #endif /* GEN_TREES_H */ sl@0: sl@0: struct static_tree_desc_s { sl@0: const ct_data *static_tree; /* static tree or NULL */ sl@0: const intf *extra_bits; /* extra bits for each code or NULL */ sl@0: int extra_base; /* base index for extra_bits */ sl@0: int elems; /* max number of elements in the tree */ sl@0: int max_length; /* max bit length for the codes */ sl@0: }; sl@0: sl@0: const local static_tree_desc static_l_desc = sl@0: {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; sl@0: sl@0: const local static_tree_desc static_d_desc = sl@0: {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; sl@0: sl@0: const local static_tree_desc static_bl_desc = sl@0: {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; sl@0: sl@0: /* =========================================================================== sl@0: * Local (static) routines in this file. sl@0: */ sl@0: sl@0: local void tr_static_init OF((void)); sl@0: local void init_block OF((deflate_state *s)); sl@0: local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); sl@0: local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); sl@0: local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); sl@0: local void build_tree OF((deflate_state *s, tree_desc *desc)); sl@0: local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); sl@0: local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); sl@0: local int build_bl_tree OF((deflate_state *s)); sl@0: local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, sl@0: int blcodes)); sl@0: local void compress_block OF((deflate_state *s, ct_data *ltree, sl@0: ct_data *dtree)); sl@0: local void set_data_type OF((deflate_state *s)); sl@0: local unsigned bi_reverse OF((unsigned value, int length)); sl@0: local void bi_windup OF((deflate_state *s)); sl@0: local void bi_flush OF((deflate_state *s)); sl@0: local void copy_block OF((deflate_state *s, charf *buf, unsigned len, sl@0: int header)); sl@0: sl@0: #ifdef GEN_TREES_H sl@0: local void gen_trees_header OF((void)); sl@0: #endif sl@0: sl@0: #ifndef DEBUG sl@0: # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) sl@0: /* Send a code of the given tree. c and tree must not have side effects */ sl@0: sl@0: #else /* DEBUG */ sl@0: # define send_code(s, c, tree) \ sl@0: { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ sl@0: send_bits(s, tree[c].Code, tree[c].Len); } sl@0: #endif sl@0: sl@0: /* =========================================================================== sl@0: * Output a short LSB first on the stream. sl@0: * IN assertion: there is enough room in pendingBuf. sl@0: */ sl@0: #define put_short(s, w) { \ sl@0: put_byte(s, (uch)((w) & 0xff)); \ sl@0: put_byte(s, (uch)((ush)(w) >> 8)); \ sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Send a value on a given number of bits. sl@0: * IN assertion: length <= 16 and value fits in length bits. sl@0: */ sl@0: #ifdef DEBUG sl@0: local void send_bits OF((deflate_state *s, int value, int length)); sl@0: sl@0: local void send_bits( sl@0: deflate_state *s, sl@0: int value, /* value to send */ sl@0: int length) /* number of bits */ sl@0: { sl@0: Tracevv((stderr," l %2d v %4x ", length, value)); sl@0: Assert(length > 0 && length <= 15, "invalid length"); sl@0: s->bits_sent += (ulg)length; sl@0: sl@0: /* If not enough room in bi_buf, use (valid) bits from bi_buf and sl@0: * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) sl@0: * unused bits in value. sl@0: */ sl@0: if (s->bi_valid > (int)Buf_size - length) { sl@0: s->bi_buf |= (value << s->bi_valid); sl@0: put_short(s, s->bi_buf); sl@0: s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); sl@0: s->bi_valid += length - Buf_size; sl@0: } else { sl@0: s->bi_buf |= value << s->bi_valid; sl@0: s->bi_valid += length; sl@0: } sl@0: } sl@0: #else /* !DEBUG */ sl@0: sl@0: #define send_bits(s, value, length) \ sl@0: { int len = length;\ sl@0: if (s->bi_valid > (int)Buf_size - len) {\ sl@0: int val = value;\ sl@0: s->bi_buf |= (val << s->bi_valid);\ sl@0: put_short(s, s->bi_buf);\ sl@0: s->bi_buf = STATIC_CAST(ush,val >> (Buf_size - s->bi_valid));\ sl@0: s->bi_valid += len - Buf_size;\ sl@0: } else {\ sl@0: s->bi_buf |= (value) << s->bi_valid;\ sl@0: s->bi_valid += len;\ sl@0: }\ sl@0: } sl@0: #endif /* DEBUG */ sl@0: sl@0: sl@0: #define MAX(a,b) (a >= b ? a : b) sl@0: /* the arguments must not have side effects */ sl@0: sl@0: /* =========================================================================== sl@0: * Initialize the various 'constant' tables. sl@0: */ sl@0: local void tr_static_init() sl@0: { sl@0: #if defined(GEN_TREES_H) || !defined(STDC) sl@0: static int static_init_done = 0; sl@0: int n; /* iterates over tree elements */ sl@0: int bits; /* bit counter */ sl@0: int length; /* length value */ sl@0: int code; /* code value */ sl@0: int dist; /* distance index */ sl@0: ush bl_count[MAX_BITS+1]; sl@0: /* number of codes at each bit length for an optimal tree */ sl@0: sl@0: if (static_init_done) return; sl@0: sl@0: /* For some embedded targets, global variables are not initialized: */ sl@0: static_l_desc.static_tree = static_ltree; sl@0: static_l_desc.extra_bits = extra_lbits; sl@0: static_d_desc.static_tree = static_dtree; sl@0: static_d_desc.extra_bits = extra_dbits; sl@0: static_bl_desc.extra_bits = extra_blbits; sl@0: sl@0: /* Initialize the mapping length (0..255) -> length code (0..28) */ sl@0: length = 0; sl@0: for (code = 0; code < LENGTH_CODES-1; code++) { sl@0: base_length[code] = length; sl@0: for (n = 0; n < (1< dist code (0..29) */ sl@0: dist = 0; sl@0: for (code = 0 ; code < 16; code++) { sl@0: base_dist[code] = dist; sl@0: for (n = 0; n < (1<>= 7; /* from now on, all distances are divided by 128 */ sl@0: for ( ; code < D_CODES; code++) { sl@0: base_dist[code] = dist << 7; sl@0: for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { sl@0: _dist_code[256 + dist++] = (uch)code; sl@0: } sl@0: } sl@0: Assert (dist == 256, "tr_static_init: 256+dist != 512"); sl@0: sl@0: /* Construct the codes of the static literal tree */ sl@0: for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; sl@0: n = 0; sl@0: while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; sl@0: while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; sl@0: while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; sl@0: while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; sl@0: /* Codes 286 and 287 do not exist, but we must include them in the sl@0: * tree construction to get a canonical Huffman tree (longest code sl@0: * all ones) sl@0: */ sl@0: gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); sl@0: sl@0: /* The static distance tree is trivial: */ sl@0: for (n = 0; n < D_CODES; n++) { sl@0: static_dtree[n].Len = 5; sl@0: static_dtree[n].Code = bi_reverse((unsigned)n, 5); sl@0: } sl@0: static_init_done = 1; sl@0: sl@0: # ifdef GEN_TREES_H sl@0: gen_trees_header(); sl@0: # endif sl@0: #endif /* defined(GEN_TREES_H) || !defined(STDC) */ sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Genererate the file trees.h describing the static trees. sl@0: */ sl@0: #ifdef GEN_TREES_H sl@0: # ifndef DEBUG sl@0: # include sl@0: # endif sl@0: sl@0: # define SEPARATOR(i, last, width) \ sl@0: ((i) == (last)? "\n};\n\n" : \ sl@0: ((i) % (width) == (width)-1 ? ",\n" : ", ")) sl@0: sl@0: void gen_trees_header() sl@0: { sl@0: FILE *header = fopen("trees.h", "w"); sl@0: int i; sl@0: sl@0: Assert (header != NULL, "Can't open trees.h"); sl@0: fprintf(header, sl@0: "/* header created automatically with -DGEN_TREES_H */\n\n"); sl@0: sl@0: fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); sl@0: for (i = 0; i < L_CODES+2; i++) { sl@0: fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, sl@0: static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); sl@0: } sl@0: sl@0: fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); sl@0: for (i = 0; i < D_CODES; i++) { sl@0: fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, sl@0: static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); sl@0: } sl@0: sl@0: fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); sl@0: for (i = 0; i < DIST_CODE_LEN; i++) { sl@0: fprintf(header, "%2u%s", _dist_code[i], sl@0: SEPARATOR(i, DIST_CODE_LEN-1, 20)); sl@0: } sl@0: sl@0: fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); sl@0: for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { sl@0: fprintf(header, "%2u%s", _length_code[i], sl@0: SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); sl@0: } sl@0: sl@0: fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); sl@0: for (i = 0; i < LENGTH_CODES; i++) { sl@0: fprintf(header, "%1u%s", base_length[i], sl@0: SEPARATOR(i, LENGTH_CODES-1, 20)); sl@0: } sl@0: sl@0: fprintf(header, "local const int base_dist[D_CODES] = {\n"); sl@0: for (i = 0; i < D_CODES; i++) { sl@0: fprintf(header, "%5u%s", base_dist[i], sl@0: SEPARATOR(i, D_CODES-1, 10)); sl@0: } sl@0: sl@0: fclose(header); sl@0: } sl@0: #endif /* GEN_TREES_H */ sl@0: sl@0: /* =========================================================================== sl@0: * Initialize the tree data structures for a new zlib stream. sl@0: */ sl@0: void _tr_init( sl@0: deflate_state *s) sl@0: { sl@0: tr_static_init(); sl@0: sl@0: s->l_desc.dyn_tree = s->dyn_ltree; sl@0: s->l_desc.stat_desc = &static_l_desc; sl@0: sl@0: s->d_desc.dyn_tree = s->dyn_dtree; sl@0: s->d_desc.stat_desc = &static_d_desc; sl@0: sl@0: s->bl_desc.dyn_tree = s->bl_tree; sl@0: s->bl_desc.stat_desc = &static_bl_desc; sl@0: sl@0: s->bi_buf = 0; sl@0: s->bi_valid = 0; sl@0: s->last_eob_len = 8; /* enough lookahead for inflate */ sl@0: #ifdef DEBUG sl@0: s->compressed_len = 0L; sl@0: s->bits_sent = 0L; sl@0: #endif sl@0: sl@0: /* Initialize the first block of the first file: */ sl@0: init_block(s); sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Initialize a new block. sl@0: */ sl@0: local void init_block( sl@0: deflate_state *s) sl@0: { sl@0: int n; /* iterates over tree elements */ sl@0: sl@0: /* Initialize the trees. */ sl@0: for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; sl@0: for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; sl@0: for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; sl@0: sl@0: s->dyn_ltree[END_BLOCK].Freq = 1; sl@0: s->opt_len = s->static_len = 0L; sl@0: s->last_lit = s->matches = 0; sl@0: } sl@0: sl@0: #define SMALLEST 1 sl@0: /* Index within the heap array of least frequent node in the Huffman tree */ sl@0: sl@0: sl@0: /* =========================================================================== sl@0: * Remove the smallest element from the heap and recreate the heap with sl@0: * one less element. Updates heap and heap_len. sl@0: */ sl@0: #define pqremove(s, tree, top) \ sl@0: {\ sl@0: top = s->heap[SMALLEST]; \ sl@0: s->heap[SMALLEST] = s->heap[s->heap_len--]; \ sl@0: pqdownheap(s, tree, SMALLEST); \ sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Compares to subtrees, using the tree depth as tie breaker when sl@0: * the subtrees have equal frequency. This minimizes the worst case length. sl@0: */ sl@0: #define smaller(tree, n, m, depth) \ sl@0: (tree[n].Freq < tree[m].Freq || \ sl@0: (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) sl@0: sl@0: /* =========================================================================== sl@0: * Restore the heap property by moving down the tree starting at node k, sl@0: * exchanging a node with the smallest of its two sons if necessary, stopping sl@0: * when the heap property is re-established (each father smaller than its sl@0: * two sons). sl@0: */ sl@0: local void pqdownheap( sl@0: deflate_state *s, sl@0: ct_data *tree, /* the tree to restore */ sl@0: int k) /* node to move down */ sl@0: { sl@0: int v = s->heap[k]; sl@0: int j = k << 1; /* left son of k */ sl@0: while (j <= s->heap_len) { sl@0: /* Set j to the smallest of the two sons: */ sl@0: if (j < s->heap_len && sl@0: smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { sl@0: j++; sl@0: } sl@0: /* Exit if v is smaller than both sons */ sl@0: if (smaller(tree, v, s->heap[j], s->depth)) break; sl@0: sl@0: /* Exchange v with the smallest son */ sl@0: s->heap[k] = s->heap[j]; k = j; sl@0: sl@0: /* And continue down the tree, setting j to the left son of k */ sl@0: j <<= 1; sl@0: } sl@0: s->heap[k] = v; sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Compute the optimal bit lengths for a tree and update the total bit length sl@0: * for the current block. sl@0: * IN assertion: the fields freq and dad are set, heap[heap_max] and sl@0: * above are the tree nodes sorted by increasing frequency. sl@0: * OUT assertions: the field len is set to the optimal bit length, the sl@0: * array bl_count contains the frequencies for each bit length. sl@0: * The length opt_len is updated; static_len is also updated if stree is sl@0: * not null. sl@0: */ sl@0: local void gen_bitlen( sl@0: deflate_state *s, sl@0: tree_desc *desc) /* the tree descriptor */ sl@0: { sl@0: ct_data *tree = desc->dyn_tree; sl@0: int max_code = desc->max_code; sl@0: const ct_data *stree = desc->stat_desc->static_tree; sl@0: const intf *extra = desc->stat_desc->extra_bits; sl@0: int base = desc->stat_desc->extra_base; sl@0: int max_length = desc->stat_desc->max_length; sl@0: int h; /* heap index */ sl@0: int n, m; /* iterate over the tree elements */ sl@0: int bits; /* bit length */ sl@0: int xbits; /* extra bits */ sl@0: ush f; /* frequency */ sl@0: int overflow = 0; /* number of elements with bit length too large */ sl@0: sl@0: for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; sl@0: sl@0: /* In a first pass, compute the optimal bit lengths (which may sl@0: * overflow in the case of the bit length tree). sl@0: */ sl@0: tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ sl@0: sl@0: for (h = s->heap_max+1; h < HEAP_SIZE; h++) { sl@0: n = s->heap[h]; sl@0: bits = tree[tree[n].Dad].Len + 1; sl@0: if (bits > max_length) bits = max_length, overflow++; sl@0: tree[n].Len = (ush)bits; sl@0: /* We overwrite tree[n].Dad which is no longer needed */ sl@0: sl@0: if (n > max_code) continue; /* not a leaf node */ sl@0: sl@0: s->bl_count[bits]++; sl@0: xbits = 0; sl@0: if (n >= base) xbits = extra[n-base]; sl@0: f = tree[n].Freq; sl@0: s->opt_len += (ulg)f * (bits + xbits); sl@0: if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); sl@0: } sl@0: if (overflow == 0) return; sl@0: sl@0: Trace((stderr,"\nbit length overflow\n")); sl@0: /* This happens for example on obj2 and pic of the Calgary corpus */ sl@0: sl@0: /* Find the first bit length which could increase: */ sl@0: do { sl@0: bits = max_length-1; sl@0: while (s->bl_count[bits] == 0) bits--; sl@0: s->bl_count[bits]--; /* move one leaf down the tree */ sl@0: s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ sl@0: s->bl_count[max_length]--; sl@0: /* The brother of the overflow item also moves one step up, sl@0: * but this does not affect bl_count[max_length] sl@0: */ sl@0: overflow -= 2; sl@0: } while (overflow > 0); sl@0: sl@0: /* Now recompute all bit lengths, scanning in increasing frequency. sl@0: * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all sl@0: * lengths instead of fixing only the wrong ones. This idea is taken sl@0: * from 'ar' written by Haruhiko Okumura.) sl@0: */ sl@0: for (bits = max_length; bits != 0; bits--) { sl@0: n = s->bl_count[bits]; sl@0: while (n != 0) { sl@0: m = s->heap[--h]; sl@0: if (m > max_code) continue; sl@0: if (tree[m].Len != (unsigned) bits) { sl@0: Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); sl@0: s->opt_len += ((long)bits - (long)tree[m].Len) sl@0: *(long)tree[m].Freq; sl@0: tree[m].Len = (ush)bits; sl@0: } sl@0: n--; sl@0: } sl@0: } sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Generate the codes for a given tree and bit counts (which need not be sl@0: * optimal). sl@0: * IN assertion: the array bl_count contains the bit length statistics for sl@0: * the given tree and the field len is set for all tree elements. sl@0: * OUT assertion: the field code is set for all tree elements of non sl@0: * zero code length. sl@0: */ sl@0: local void gen_codes ( sl@0: ct_data *tree, /* the tree to decorate */ sl@0: int max_code, /* largest code with non zero frequency */ sl@0: ushf *bl_count) /* number of codes at each bit length */ sl@0: { sl@0: ush next_code[MAX_BITS+1]; /* next code value for each bit length */ sl@0: ush code = 0; /* running code value */ sl@0: int bits; /* bit index */ sl@0: int n; /* code index */ sl@0: sl@0: /* The distribution counts are first used to generate the code values sl@0: * without bit reversal. sl@0: */ sl@0: for (bits = 1; bits <= MAX_BITS; bits++) { sl@0: next_code[bits] = code = STATIC_CAST(ush,(code + bl_count[bits-1]) << 1); sl@0: } sl@0: /* Check that the bit counts in bl_count are consistent. The last code sl@0: * must be all ones. sl@0: */ sl@0: Assert (code + bl_count[MAX_BITS]-1 == (1<dyn_tree; sl@0: const ct_data *stree = desc->stat_desc->static_tree; sl@0: int elems = desc->stat_desc->elems; sl@0: int n, m; /* iterate over heap elements */ sl@0: int max_code = -1; /* largest code with non zero frequency */ sl@0: int node; /* new node being created */ sl@0: sl@0: /* Construct the initial heap, with least frequent element in sl@0: * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. sl@0: * heap[0] is not used. sl@0: */ sl@0: s->heap_len = 0, s->heap_max = HEAP_SIZE; sl@0: sl@0: for (n = 0; n < elems; n++) { sl@0: if (tree[n].Freq != 0) { sl@0: s->heap[++(s->heap_len)] = max_code = n; sl@0: s->depth[n] = 0; sl@0: } else { sl@0: tree[n].Len = 0; sl@0: } sl@0: } sl@0: sl@0: /* The pkzip format requires that at least one distance code exists, sl@0: * and that at least one bit should be sent even if there is only one sl@0: * possible code. So to avoid special checks later on we force at least sl@0: * two codes of non zero frequency. sl@0: */ sl@0: while (s->heap_len < 2) { sl@0: node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); sl@0: tree[node].Freq = 1; sl@0: s->depth[node] = 0; sl@0: s->opt_len--; if (stree) s->static_len -= stree[node].Len; sl@0: /* node is 0 or 1 so it does not have extra bits */ sl@0: } sl@0: desc->max_code = max_code; sl@0: sl@0: /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, sl@0: * establish sub-heaps of increasing lengths: sl@0: */ sl@0: for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); sl@0: sl@0: /* Construct the Huffman tree by repeatedly combining the least two sl@0: * frequent nodes. sl@0: */ sl@0: node = elems; /* next internal node of the tree */ sl@0: do { sl@0: pqremove(s, tree, n); /* n = node of least frequency */ sl@0: m = s->heap[SMALLEST]; /* m = node of next least frequency */ sl@0: sl@0: s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ sl@0: s->heap[--(s->heap_max)] = m; sl@0: sl@0: /* Create a new node father of n and m */ sl@0: tree[node].Freq = STATIC_CAST(ush,tree[n].Freq + tree[m].Freq); sl@0: s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1); sl@0: tree[n].Dad = tree[m].Dad = (ush)node; sl@0: #ifdef DUMP_BL_TREE sl@0: if (tree == s->bl_tree) { sl@0: fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", sl@0: node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); sl@0: } sl@0: #endif sl@0: /* and insert the new node in the heap */ sl@0: s->heap[SMALLEST] = node++; sl@0: pqdownheap(s, tree, SMALLEST); sl@0: sl@0: } while (s->heap_len >= 2); sl@0: sl@0: s->heap[--(s->heap_max)] = s->heap[SMALLEST]; sl@0: sl@0: /* At this point, the fields freq and dad are set. We can now sl@0: * generate the bit lengths. sl@0: */ sl@0: gen_bitlen(s, (tree_desc *)desc); sl@0: sl@0: /* The field len is now set, we can generate the bit codes */ sl@0: gen_codes ((ct_data *)tree, max_code, s->bl_count); sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Scan a literal or distance tree to determine the frequencies of the codes sl@0: * in the bit length tree. sl@0: */ sl@0: local void scan_tree ( sl@0: deflate_state *s, sl@0: ct_data *tree, /* the tree to be scanned */ sl@0: int max_code) /* and its largest code of non zero frequency */ sl@0: { sl@0: int n; /* iterates over all tree elements */ sl@0: int prevlen = -1; /* last emitted length */ sl@0: int curlen; /* length of current code */ sl@0: int nextlen = tree[0].Len; /* length of next code */ sl@0: int count = 0; /* repeat count of the current code */ sl@0: int max_count = 7; /* max repeat count */ sl@0: int min_count = 4; /* min repeat count */ sl@0: sl@0: if (nextlen == 0) max_count = 138, min_count = 3; sl@0: tree[max_code+1].Len = (ush)0xffff; /* guard */ sl@0: sl@0: for (n = 0; n <= max_code; n++) { sl@0: curlen = nextlen; nextlen = tree[n+1].Len; sl@0: if (++count < max_count && curlen == nextlen) { sl@0: continue; sl@0: } else if (count < min_count) { sl@0: s->bl_tree[curlen].Freq = STATIC_CAST(ush, s->bl_tree[curlen].Freq + count); sl@0: } else if (curlen != 0) { sl@0: if (curlen != prevlen) s->bl_tree[curlen].Freq++; sl@0: s->bl_tree[REP_3_6].Freq++; sl@0: } else if (count <= 10) { sl@0: s->bl_tree[REPZ_3_10].Freq++; sl@0: } else { sl@0: s->bl_tree[REPZ_11_138].Freq++; sl@0: } sl@0: count = 0; prevlen = curlen; sl@0: if (nextlen == 0) { sl@0: max_count = 138, min_count = 3; sl@0: } else if (curlen == nextlen) { sl@0: max_count = 6, min_count = 3; sl@0: } else { sl@0: max_count = 7, min_count = 4; sl@0: } sl@0: } sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Send a literal or distance tree in compressed form, using the codes in sl@0: * bl_tree. sl@0: */ sl@0: local void send_tree ( sl@0: deflate_state *s, sl@0: ct_data *tree, /* the tree to be scanned */ sl@0: int max_code) /* and its largest code of non zero frequency */ sl@0: { sl@0: int n; /* iterates over all tree elements */ sl@0: int prevlen = -1; /* last emitted length */ sl@0: int curlen; /* length of current code */ sl@0: int nextlen = tree[0].Len; /* length of next code */ sl@0: int count = 0; /* repeat count of the current code */ sl@0: int max_count = 7; /* max repeat count */ sl@0: int min_count = 4; /* min repeat count */ sl@0: sl@0: /* tree[max_code+1].Len = -1; */ /* guard already set */ sl@0: if (nextlen == 0) max_count = 138, min_count = 3; sl@0: sl@0: for (n = 0; n <= max_code; n++) { sl@0: curlen = nextlen; nextlen = tree[n+1].Len; sl@0: if (++count < max_count && curlen == nextlen) { sl@0: continue; sl@0: } else if (count < min_count) { sl@0: do { send_code(s, curlen, s->bl_tree); } while (--count != 0); sl@0: sl@0: } else if (curlen != 0) { sl@0: if (curlen != prevlen) { sl@0: send_code(s, curlen, s->bl_tree); count--; sl@0: } sl@0: Assert(count >= 3 && count <= 6, " 3_6?"); sl@0: send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); sl@0: sl@0: } else if (count <= 10) { sl@0: send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); sl@0: sl@0: } else { sl@0: send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); sl@0: } sl@0: count = 0; prevlen = curlen; sl@0: if (nextlen == 0) { sl@0: max_count = 138, min_count = 3; sl@0: } else if (curlen == nextlen) { sl@0: max_count = 6, min_count = 3; sl@0: } else { sl@0: max_count = 7, min_count = 4; sl@0: } sl@0: } sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Construct the Huffman tree for the bit lengths and return the index in sl@0: * bl_order of the last bit length code to send. sl@0: */ sl@0: local int build_bl_tree( sl@0: deflate_state *s) sl@0: { sl@0: int max_blindex; /* index of last bit length code of non zero freq */ sl@0: sl@0: /* Determine the bit length frequencies for literal and distance trees */ sl@0: scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); sl@0: scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); sl@0: sl@0: /* Build the bit length tree: */ sl@0: build_tree(s, (tree_desc *)(&(s->bl_desc))); sl@0: /* opt_len now includes the length of the tree representations, except sl@0: * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. sl@0: */ sl@0: sl@0: /* Determine the number of bit length codes to send. The pkzip format sl@0: * requires that at least 4 bit length codes be sent. (appnote.txt says sl@0: * 3 but the actual value used is 4.) sl@0: */ sl@0: for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { sl@0: if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; sl@0: } sl@0: /* Update opt_len to include the bit length tree and counts */ sl@0: s->opt_len += 3*(max_blindex+1) + 5+5+4; sl@0: Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", sl@0: s->opt_len, s->static_len)); sl@0: sl@0: return max_blindex; sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Send the header for a block using dynamic Huffman trees: the counts, the sl@0: * lengths of the bit length codes, the literal tree and the distance tree. sl@0: * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. sl@0: */ sl@0: local void send_all_trees( sl@0: deflate_state *s, sl@0: int lcodes, int dcodes, int blcodes) /* number of codes for each tree */ sl@0: { sl@0: int rank; /* index in bl_order */ sl@0: sl@0: Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); sl@0: Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, sl@0: "too many codes"); sl@0: Tracev((stderr, "\nbl counts: ")); sl@0: send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ sl@0: send_bits(s, dcodes-1, 5); sl@0: send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ sl@0: for (rank = 0; rank < blcodes; rank++) { sl@0: Tracev((stderr, "\nbl code %2d ", bl_order[rank])); sl@0: send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); sl@0: } sl@0: Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); sl@0: sl@0: send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ sl@0: Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); sl@0: sl@0: send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ sl@0: Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Send a stored block sl@0: */ sl@0: void _tr_stored_block( sl@0: deflate_state *s, sl@0: charf *buf, /* input block */ sl@0: ulg stored_len, /* length of input block */ sl@0: int eof) /* true if this is the last block for a file */ sl@0: { sl@0: send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ sl@0: #ifdef DEBUG sl@0: s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; sl@0: s->compressed_len += (stored_len + 4) << 3; sl@0: #endif sl@0: copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Send one empty static block to give enough lookahead for inflate. sl@0: * This takes 10 bits, of which 7 may remain in the bit buffer. sl@0: * The current inflate code requires 9 bits of lookahead. If the sl@0: * last two codes for the previous block (real code plus EOB) were coded sl@0: * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode sl@0: * the last real code. In this case we send two empty static blocks instead sl@0: * of one. (There are no problems if the previous block is stored or fixed.) sl@0: * To simplify the code, we assume the worst case of last real code encoded sl@0: * on one bit only. sl@0: */ sl@0: void _tr_align( sl@0: deflate_state *s) sl@0: { sl@0: send_bits(s, STATIC_TREES<<1, 3); sl@0: send_code(s, END_BLOCK, static_ltree); sl@0: #ifdef DEBUG sl@0: s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ sl@0: #endif sl@0: bi_flush(s); sl@0: /* Of the 10 bits for the empty block, we have already sent sl@0: * (10 - bi_valid) bits. The lookahead for the last real code (before sl@0: * the EOB of the previous block) was thus at least one plus the length sl@0: * of the EOB plus what we have just sent of the empty static block. sl@0: */ sl@0: if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { sl@0: send_bits(s, STATIC_TREES<<1, 3); sl@0: send_code(s, END_BLOCK, static_ltree); sl@0: #ifdef DEBUG sl@0: s->compressed_len += 10L; sl@0: #endif sl@0: bi_flush(s); sl@0: } sl@0: s->last_eob_len = 7; sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Determine the best encoding for the current block: dynamic trees, static sl@0: * trees or store, and output the encoded block to the zip file. sl@0: */ sl@0: void _tr_flush_block( sl@0: deflate_state *s, sl@0: charf *buf, /* input block, or NULL if too old */ sl@0: ulg stored_len, /* length of input block */ sl@0: int eof) /* true if this is the last block for a file */ sl@0: { sl@0: ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ sl@0: int max_blindex = 0; /* index of last bit length code of non zero freq */ sl@0: sl@0: /* Build the Huffman trees unless a stored block is forced */ sl@0: if (s->level > 0) { sl@0: sl@0: /* Check if the file is ascii or binary */ sl@0: if (s->data_type == Z_UNKNOWN) set_data_type(s); sl@0: sl@0: /* Construct the literal and distance trees */ sl@0: build_tree(s, (tree_desc *)(&(s->l_desc))); sl@0: Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, sl@0: s->static_len)); sl@0: sl@0: build_tree(s, (tree_desc *)(&(s->d_desc))); sl@0: Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, sl@0: s->static_len)); sl@0: /* At this point, opt_len and static_len are the total bit lengths of sl@0: * the compressed block data, excluding the tree representations. sl@0: */ sl@0: sl@0: /* Build the bit length tree for the above two trees, and get the index sl@0: * in bl_order of the last bit length code to send. sl@0: */ sl@0: max_blindex = build_bl_tree(s); sl@0: sl@0: /* Determine the best encoding. Compute first the block length in bytes*/ sl@0: opt_lenb = (s->opt_len+3+7)>>3; sl@0: static_lenb = (s->static_len+3+7)>>3; sl@0: sl@0: Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", sl@0: opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, sl@0: s->last_lit)); sl@0: sl@0: if (static_lenb <= opt_lenb) opt_lenb = static_lenb; sl@0: sl@0: } else { sl@0: Assert(buf != (char*)0, "lost buf"); sl@0: opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ sl@0: } sl@0: sl@0: #ifdef FORCE_STORED sl@0: if (buf != (char*)0) { /* force stored block */ sl@0: #else sl@0: if (stored_len+4 <= opt_lenb && buf != (char*)0) { sl@0: /* 4: two words for the lengths */ sl@0: #endif sl@0: /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. sl@0: * Otherwise we can't have processed more than WSIZE input bytes since sl@0: * the last block flush, because compression would have been sl@0: * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to sl@0: * transform a block into a stored block. sl@0: */ sl@0: _tr_stored_block(s, buf, stored_len, eof); sl@0: sl@0: #ifdef FORCE_STATIC sl@0: } else if (static_lenb >= 0) { /* force static trees */ sl@0: #else sl@0: } else if (static_lenb == opt_lenb) { sl@0: #endif sl@0: send_bits(s, (STATIC_TREES<<1)+eof, 3); sl@0: compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); sl@0: #ifdef DEBUG sl@0: s->compressed_len += 3 + s->static_len; sl@0: #endif sl@0: } else { sl@0: send_bits(s, (DYN_TREES<<1)+eof, 3); sl@0: send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, sl@0: max_blindex+1); sl@0: compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); sl@0: #ifdef DEBUG sl@0: s->compressed_len += 3 + s->opt_len; sl@0: #endif sl@0: } sl@0: Assert (s->compressed_len == s->bits_sent, "bad compressed size"); sl@0: /* The above check is made mod 2^32, for files larger than 512 MB sl@0: * and uLong implemented on 32 bits. sl@0: */ sl@0: init_block(s); sl@0: sl@0: if (eof) { sl@0: bi_windup(s); sl@0: #ifdef DEBUG sl@0: s->compressed_len += 7; /* align on byte boundary */ sl@0: #endif sl@0: } sl@0: Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, sl@0: s->compressed_len-7*eof)); sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Save the match info and tally the frequency counts. Return true if sl@0: * the current block must be flushed. sl@0: */ sl@0: int _tr_tally ( sl@0: deflate_state *s, sl@0: unsigned dist, /* distance of matched string */ sl@0: unsigned lc) /* match length-MIN_MATCH or unmatched char (if dist==0) */ sl@0: { sl@0: s->d_buf[s->last_lit] = (ush)dist; sl@0: s->l_buf[s->last_lit++] = (uch)lc; sl@0: if (dist == 0) { sl@0: /* lc is the unmatched char */ sl@0: s->dyn_ltree[lc].Freq++; sl@0: } else { sl@0: s->matches++; sl@0: /* Here, lc is the match length - MIN_MATCH */ sl@0: dist--; /* dist = match distance - 1 */ sl@0: Assert((ush)dist < (ush)MAX_DIST(s) && sl@0: (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && sl@0: (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); sl@0: sl@0: s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; sl@0: s->dyn_dtree[d_code(dist)].Freq++; sl@0: } sl@0: sl@0: #ifdef TRUNCATE_BLOCK sl@0: /* Try to guess if it is profitable to stop the current block here */ sl@0: if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { sl@0: /* Compute an upper bound for the compressed length */ sl@0: ulg out_length = (ulg)s->last_lit*8L; sl@0: ulg in_length = (ulg)((long)s->strstart - s->block_start); sl@0: int dcode; sl@0: for (dcode = 0; dcode < D_CODES; dcode++) { sl@0: out_length += (ulg)s->dyn_dtree[dcode].Freq * sl@0: (5L+extra_dbits[dcode]); sl@0: } sl@0: out_length >>= 3; sl@0: Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", sl@0: s->last_lit, in_length, out_length, sl@0: 100L - out_length*100L/in_length)); sl@0: if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; sl@0: } sl@0: #endif sl@0: return (s->last_lit == s->lit_bufsize-1); sl@0: /* We avoid equality with lit_bufsize because of wraparound at 64K sl@0: * on 16 bit machines and because stored blocks are restricted to sl@0: * 64K-1 bytes. sl@0: */ sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Send the block data compressed using the given Huffman trees sl@0: */ sl@0: local void compress_block( sl@0: deflate_state *s, sl@0: ct_data *ltree, /* literal tree */ sl@0: ct_data *dtree) /* distance tree */ sl@0: { sl@0: unsigned dist; /* distance of matched string */ sl@0: int lc; /* match length or unmatched char (if dist == 0) */ sl@0: unsigned lx = 0; /* running index in l_buf */ sl@0: unsigned code; /* the code to send */ sl@0: int extra; /* number of extra bits to send */ sl@0: sl@0: if (s->last_lit != 0) do { sl@0: dist = s->d_buf[lx]; sl@0: lc = s->l_buf[lx++]; sl@0: if (dist == 0) { sl@0: send_code(s, lc, ltree); /* send a literal byte */ sl@0: Tracecv(isgraph(lc), (stderr," '%c' ", lc)); sl@0: } else { sl@0: /* Here, lc is the match length - MIN_MATCH */ sl@0: code = _length_code[lc]; sl@0: send_code(s, code+LITERALS+1, ltree); /* send the length code */ sl@0: extra = extra_lbits[code]; sl@0: if (extra != 0) { sl@0: lc -= base_length[code]; sl@0: send_bits(s, lc, extra); /* send the extra length bits */ sl@0: } sl@0: dist--; /* dist is now the match distance - 1 */ sl@0: code = d_code(dist); sl@0: Assert (code < D_CODES, "bad d_code"); sl@0: sl@0: send_code(s, code, dtree); /* send the distance code */ sl@0: extra = extra_dbits[code]; sl@0: if (extra != 0) { sl@0: dist -= base_dist[code]; sl@0: send_bits(s, dist, extra); /* send the extra distance bits */ sl@0: } sl@0: } /* literal or match pair ? */ sl@0: sl@0: /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ sl@0: Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow"); sl@0: sl@0: } while (lx < s->last_lit); sl@0: sl@0: send_code(s, END_BLOCK, ltree); sl@0: s->last_eob_len = ltree[END_BLOCK].Len; sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Set the data type to ASCII or BINARY, using a crude approximation: sl@0: * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. sl@0: * IN assertion: the fields freq of dyn_ltree are set and the total of all sl@0: * frequencies does not exceed 64K (to fit in an int on 16 bit machines). sl@0: */ sl@0: local void set_data_type( sl@0: deflate_state *s) sl@0: { sl@0: int n = 0; sl@0: unsigned ascii_freq = 0; sl@0: unsigned bin_freq = 0; sl@0: while (n < 7) bin_freq += s->dyn_ltree[n++].Freq; sl@0: while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq; sl@0: while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq; sl@0: s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII); sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Reverse the first len bits of a code, using straightforward code (a faster sl@0: * method would use a table) sl@0: * IN assertion: 1 <= len <= 15 sl@0: */ sl@0: local unsigned bi_reverse( sl@0: unsigned code, /* the value to invert */ sl@0: int len) /* its bit length */ sl@0: { sl@0: register unsigned res = 0; sl@0: do { sl@0: res |= code & 1; sl@0: code >>= 1, res <<= 1; sl@0: } while (--len > 0); sl@0: return res >> 1; sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Flush the bit buffer, keeping at most 7 bits in it. sl@0: */ sl@0: local void bi_flush( sl@0: deflate_state *s) sl@0: { sl@0: if (s->bi_valid == 16) { sl@0: put_short(s, s->bi_buf); sl@0: s->bi_buf = 0; sl@0: s->bi_valid = 0; sl@0: } else if (s->bi_valid >= 8) { sl@0: put_byte(s, (Byte)s->bi_buf); sl@0: s->bi_buf >>= 8; sl@0: s->bi_valid -= 8; sl@0: } sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Flush the bit buffer and align the output on a byte boundary sl@0: */ sl@0: local void bi_windup( sl@0: deflate_state *s) sl@0: { sl@0: if (s->bi_valid > 8) { sl@0: put_short(s, s->bi_buf); sl@0: } else if (s->bi_valid > 0) { sl@0: put_byte(s, (Byte)s->bi_buf); sl@0: } sl@0: s->bi_buf = 0; sl@0: s->bi_valid = 0; sl@0: #ifdef DEBUG sl@0: s->bits_sent = (s->bits_sent+7) & ~7; sl@0: #endif sl@0: } sl@0: sl@0: /* =========================================================================== sl@0: * Copy a stored block, storing first the length and its sl@0: * one's complement if requested. sl@0: */ sl@0: local void copy_block( sl@0: deflate_state *s, sl@0: charf *buf, /* the input data */ sl@0: unsigned len, /* its length */ sl@0: int header) /* true if block header must be written */ sl@0: { sl@0: bi_windup(s); /* align on byte boundary */ sl@0: s->last_eob_len = 8; /* enough lookahead for inflate */ sl@0: sl@0: if (header) { sl@0: put_short(s, (ush)len); sl@0: put_short(s, (ush)~len); sl@0: #ifdef DEBUG sl@0: s->bits_sent += 2*16; sl@0: #endif sl@0: } sl@0: #ifdef DEBUG sl@0: s->bits_sent += (ulg)len<<3; sl@0: #endif sl@0: while (len--) { sl@0: put_byte(s, *buf++); sl@0: } sl@0: }