diff options
Diffstat (limited to 'trees.c')
| -rw-r--r-- | trees.c | 54 |
1 files changed, 18 insertions, 36 deletions
@@ -1,5 +1,5 @@ /* trees.c -- output deflated data using Huffman coding - * Copyright (C) 1995-2010 Jean-loup Gailly + * Copyright (C) 1995-2012 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 */ @@ -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. */ @@ -151,8 +146,8 @@ 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)); @@ -399,7 +394,6 @@ 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 s->compressed_len = 0L; s->bits_sent = 0L; @@ -883,15 +877,17 @@ void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) } /* =========================================================================== + * 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; @@ -902,20 +898,6 @@ void ZLIB_INTERNAL _tr_align(s) 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; } /* =========================================================================== @@ -990,7 +972,8 @@ 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); + compress_block(s, (const ct_data *)static_ltree, + (const ct_data *)static_dtree); #ifdef DEBUG s->compressed_len += 3 + s->static_len; #endif @@ -998,7 +981,8 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 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); + compress_block(s, (const ct_data *)s->dyn_ltree, + (const ct_data *)s->dyn_dtree); #ifdef DEBUG s->compressed_len += 3 + s->opt_len; #endif @@ -1075,8 +1059,8 @@ 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) */ @@ -1118,7 +1102,6 @@ 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; } /* =========================================================================== @@ -1226,7 +1209,6 @@ local void copy_block(s, buf, len, header) 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); |