X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=trees.c;h=50cf4b4571cfec347ce5891b76fcb6675fcb580d;hb=e00a2bd392ca51351ecee55dbeee803f6ebda2f5;hp=56e9bb1c115e81082f58a89b003b766760e12a12;hpb=9712272c78b9d9c93746d9c8e156a3728c65ca72;p=zlib.git diff --git a/trees.c b/trees.c index 56e9bb1..50cf4b4 100644 --- a/trees.c +++ b/trees.c @@ -1,5 +1,5 @@ /* trees.c -- output deflated data using Huffman coding - * Copyright (C) 1995-2010 Jean-loup Gailly + * Copyright (C) 1995-2017 Jean-loup Gailly * detect_data_type() function provided freely by Cosmin Truta, 2006 * For conditions of distribution and use, see copyright notice in zlib.h */ @@ -36,7 +36,7 @@ #include "deflate.h" -#ifdef DEBUG +#ifdef ZLIB_DEBUG # include #endif @@ -74,11 +74,6 @@ local const uch bl_order[BL_CODES] * 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. */ @@ -127,13 +122,13 @@ struct static_tree_desc_s { int max_length; /* max bit length for the codes */ }; -local static_tree_desc static_l_desc = +local const static_tree_desc static_l_desc = {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; -local static_tree_desc static_d_desc = +local const static_tree_desc static_d_desc = {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; -local static_tree_desc static_bl_desc = +local const static_tree_desc static_bl_desc = {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; /* =========================================================================== @@ -151,24 +146,22 @@ 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 compress_block OF((deflate_state *s, const ct_data *ltree, + const ct_data *dtree)); local int detect_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 +#ifndef ZLIB_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 */ +#else /* !ZLIB_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); } @@ -187,7 +180,7 @@ local void gen_trees_header OF((void)); * Send a value on a given number of bits. * IN assertion: length <= 16 and value fits in length bits. */ -#ifdef DEBUG +#ifdef ZLIB_DEBUG local void send_bits OF((deflate_state *s, int value, int length)); local void send_bits(s, value, length) @@ -213,12 +206,12 @@ local void send_bits(s, value, length) s->bi_valid += length; } } -#else /* !DEBUG */ +#else /* !ZLIB_DEBUG */ #define send_bits(s, value, length) \ { int len = length;\ if (s->bi_valid > (int)Buf_size - len) {\ - int val = value;\ + int val = (int)value;\ s->bi_buf |= (ush)val << s->bi_valid;\ put_short(s, s->bi_buf);\ s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ @@ -228,7 +221,7 @@ local void send_bits(s, value, length) s->bi_valid += len;\ }\ } -#endif /* DEBUG */ +#endif /* ZLIB_DEBUG */ /* the arguments must not have side effects */ @@ -322,7 +315,7 @@ local void tr_static_init() * Genererate the file trees.h describing the static trees. */ #ifdef GEN_TREES_H -# ifndef DEBUG +# ifndef ZLIB_DEBUG # include # endif @@ -399,8 +392,7 @@ void ZLIB_INTERNAL _tr_init(s) s->bi_buf = 0; s->bi_valid = 0; - s->last_eob_len = 8; /* enough lookahead for inflate */ -#ifdef DEBUG +#ifdef ZLIB_DEBUG s->compressed_len = 0L; s->bits_sent = 0L; #endif @@ -528,12 +520,12 @@ local void gen_bitlen(s, desc) xbits = 0; if (n >= base) xbits = extra[n-base]; f = tree[n].Freq; - s->opt_len += (ulg)f * (bits + xbits); - if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); + s->opt_len += (ulg)f * (unsigned)(bits + xbits); + if (stree) s->static_len += (ulg)f * (unsigned)(stree[n].Len + xbits); } if (overflow == 0) return; - Trace((stderr,"\nbit length overflow\n")); + Tracev((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: */ @@ -560,9 +552,8 @@ local void gen_bitlen(s, desc) m = s->heap[--h]; if (m > max_code) continue; if ((unsigned) 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; + Tracev((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); + s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq; tree[m].Len = (ush)bits; } n--; @@ -584,7 +575,7 @@ local void gen_codes (tree, max_code, bl_count) ushf *bl_count; /* number of codes at each bit length */ { ush next_code[MAX_BITS+1]; /* next code value for each bit length */ - ush code = 0; /* running code value */ + unsigned code = 0; /* running code value */ int bits; /* bit index */ int n; /* code index */ @@ -592,7 +583,8 @@ local void gen_codes (tree, max_code, bl_count) * without bit reversal. */ for (bits = 1; bits <= MAX_BITS; bits++) { - next_code[bits] = code = (code + bl_count[bits-1]) << 1; + code = (code + bl_count[bits-1]) << 1; + next_code[bits] = (ush)code; } /* Check that the bit counts in bl_count are consistent. The last code * must be all ones. @@ -605,7 +597,7 @@ local void gen_codes (tree, max_code, bl_count) int len = tree[n].Len; if (len == 0) continue; /* Now reverse the bits */ - tree[n].Code = bi_reverse(next_code[len]++, len); + tree[n].Code = (ush)bi_reverse(next_code[len]++, len); Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); @@ -827,7 +819,7 @@ local int build_bl_tree(s) if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; } /* Update opt_len to include the bit length tree and counts */ - s->opt_len += 3*(max_blindex+1) + 5+5+4; + s->opt_len += 3*((ulg)max_blindex+1) + 5+5+4; Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", s->opt_len, s->static_len)); @@ -875,52 +867,46 @@ void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) int last; /* one if this is the last block for a file */ { send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ -#ifdef DEBUG + bi_windup(s); /* align on byte boundary */ + put_short(s, (ush)stored_len); + put_short(s, (ush)~stored_len); + zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len); + s->pending += stored_len; +#ifdef ZLIB_DEBUG s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; s->compressed_len += (stored_len + 4) << 3; + s->bits_sent += 2*16; + s->bits_sent += stored_len<<3; #endif - copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ +} + +/* =========================================================================== + * Flush the bits in the bit buffer to pending output (leaves at most 7 bits) + */ +void ZLIB_INTERNAL _tr_flush_bits(s) + deflate_state *s; +{ + bi_flush(s); } /* =========================================================================== * 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 ZLIB_INTERNAL _tr_align(s) deflate_state *s; { send_bits(s, STATIC_TREES<<1, 3); send_code(s, END_BLOCK, static_ltree); -#ifdef DEBUG +#ifdef ZLIB_DEBUG s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ #endif 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. - */ - 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); - } - 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. + * trees or store, and write out the encoded block. */ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) deflate_state *s; @@ -990,16 +976,18 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { #endif send_bits(s, (STATIC_TREES<<1)+last, 3); - compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); -#ifdef DEBUG + compress_block(s, (const ct_data *)static_ltree, + (const ct_data *)static_dtree); +#ifdef ZLIB_DEBUG s->compressed_len += 3 + s->static_len; #endif } else { send_bits(s, (DYN_TREES<<1)+last, 3); send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, max_blindex+1); - compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); -#ifdef DEBUG + compress_block(s, (const ct_data *)s->dyn_ltree, + (const ct_data *)s->dyn_dtree); +#ifdef ZLIB_DEBUG s->compressed_len += 3 + s->opt_len; #endif } @@ -1011,7 +999,7 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) if (last) { bi_windup(s); -#ifdef DEBUG +#ifdef ZLIB_DEBUG s->compressed_len += 7; /* align on byte boundary */ #endif } @@ -1075,8 +1063,8 @@ int ZLIB_INTERNAL _tr_tally (s, dist, lc) */ local void compress_block(s, ltree, dtree) deflate_state *s; - ct_data *ltree; /* literal tree */ - ct_data *dtree; /* distance tree */ + const ct_data *ltree; /* literal tree */ + const ct_data *dtree; /* distance tree */ { unsigned dist; /* distance of matched string */ int lc; /* match length or unmatched char (if dist == 0) */ @@ -1106,7 +1094,7 @@ local void compress_block(s, ltree, dtree) send_code(s, code, dtree); /* send the distance code */ extra = extra_dbits[code]; if (extra != 0) { - dist -= base_dist[code]; + dist -= (unsigned)base_dist[code]; send_bits(s, dist, extra); /* send the extra distance bits */ } } /* literal or match pair ? */ @@ -1118,7 +1106,6 @@ local void compress_block(s, ltree, dtree) } while (lx < s->last_lit); send_code(s, END_BLOCK, ltree); - s->last_eob_len = ltree[END_BLOCK].Len; } /* =========================================================================== @@ -1210,35 +1197,7 @@ local void bi_windup(s) } s->bi_buf = 0; s->bi_valid = 0; -#ifdef DEBUG +#ifdef ZLIB_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 */ -{ - bi_windup(s); /* align on byte boundary */ - s->last_eob_len = 8; /* enough lookahead for inflate */ - - if (header) { - put_short(s, (ush)len); - put_short(s, (ush)~len); -#ifdef DEBUG - s->bits_sent += 2*16; -#endif - } -#ifdef DEBUG - s->bits_sent += (ulg)len<<3; -#endif - while (len--) { - put_byte(s, *buf++); - } -}