diff options
Diffstat (limited to 'zlib/trees.c')
| -rw-r--r-- | zlib/trees.c | 131 |
1 files changed, 68 insertions, 63 deletions
diff --git a/zlib/trees.c b/zlib/trees.c index b5ccd84d4..459282d34 100644 --- a/zlib/trees.c +++ b/zlib/trees.c @@ -1,5 +1,6 @@ /* trees.c -- output deflated data using Huffman coding - * Copyright (C) 1995-2005 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 */ @@ -75,11 +76,6 @@ 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. */ @@ -154,7 +150,7 @@ 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 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)); @@ -205,12 +201,12 @@ local void send_bits(s, value, length) * unused bits in value. */ if (s->bi_valid > (int)Buf_size - length) { - s->bi_buf |= (value << s->bi_valid); + s->bi_buf |= (ush)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_buf |= (ush)value << s->bi_valid; s->bi_valid += length; } } @@ -220,12 +216,12 @@ local void 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);\ + s->bi_buf |= (ush)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_buf |= (ush)(value) << s->bi_valid;\ s->bi_valid += len;\ }\ } @@ -252,11 +248,13 @@ local void tr_static_init() if (static_init_done) return; /* For some embedded targets, global variables are not initialized: */ +#ifdef NO_INIT_GLOBAL_POINTERS 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; +#endif /* Initialize the mapping length (0..255) -> length code (0..28) */ length = 0; @@ -350,13 +348,14 @@ void gen_trees_header() static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); } - fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); + fprintf(header, "const uch ZLIB_INTERNAL _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"); + fprintf(header, + "const uch ZLIB_INTERNAL _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)); @@ -381,7 +380,7 @@ void gen_trees_header() /* =========================================================================== * Initialize the tree data structures for a new zlib stream. */ -void _tr_init(s) +void ZLIB_INTERNAL _tr_init(s) deflate_state *s; { tr_static_init(); @@ -397,7 +396,6 @@ void _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; @@ -866,13 +864,13 @@ local void send_all_trees(s, lcodes, dcodes, blcodes) /* =========================================================================== * Send a stored block */ -void _tr_stored_block(s, buf, stored_len, eof) +void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) 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 */ + int last; /* one if this is the last block for a file */ { - send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ + send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ #ifdef DEBUG s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; s->compressed_len += (stored_len + 4) << 3; @@ -881,17 +879,19 @@ void _tr_stored_block(s, buf, stored_len, eof) } /* =========================================================================== + * 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 _tr_align(s) +void ZLIB_INTERNAL _tr_align(s) deflate_state *s; { send_bits(s, STATIC_TREES<<1, 3); @@ -900,31 +900,17 @@ void _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; } /* =========================================================================== * 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) +void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 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 */ + int last; /* one if this is the last block for a file */ { ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ int max_blindex = 0; /* index of last bit length code of non zero freq */ @@ -933,8 +919,8 @@ void _tr_flush_block(s, buf, stored_len, eof) if (s->level > 0) { /* Check if the file is binary or text */ - if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN) - set_data_type(s); + if (s->strm->data_type == Z_UNKNOWN) + s->strm->data_type = detect_data_type(s); /* Construct the literal and distance trees */ build_tree(s, (tree_desc *)(&(s->l_desc))); @@ -980,20 +966,20 @@ void _tr_flush_block(s, buf, stored_len, eof) * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to * transform a block into a stored block. */ - _tr_stored_block(s, buf, stored_len, eof); + _tr_stored_block(s, buf, stored_len, last); #ifdef FORCE_STATIC } else if (static_lenb >= 0) { /* force static trees */ #else } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { #endif - send_bits(s, (STATIC_TREES<<1)+eof, 3); + send_bits(s, (STATIC_TREES<<1)+last, 3); compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); #ifdef DEBUG s->compressed_len += 3 + s->static_len; #endif } else { - send_bits(s, (DYN_TREES<<1)+eof, 3); + 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); @@ -1007,21 +993,21 @@ void _tr_flush_block(s, buf, stored_len, eof) */ init_block(s); - if (eof) { + if (last) { 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)); + s->compressed_len-7*last)); } /* =========================================================================== * Save the match info and tally the frequency counts. Return true if * the current block must be flushed. */ -int _tr_tally (s, dist, lc) +int ZLIB_INTERNAL _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) */ @@ -1116,28 +1102,48 @@ 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; } /* =========================================================================== - * Set the data type to BINARY or TEXT, using a crude approximation: - * set it to Z_TEXT if all symbols are either printable characters (33 to 255) - * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise. + * Check if the data type is TEXT or BINARY, using the following algorithm: + * - TEXT if the two conditions below are satisfied: + * a) There are no non-portable control characters belonging to the + * "black list" (0..6, 14..25, 28..31). + * b) There is at least one printable character belonging to the + * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). + * - BINARY otherwise. + * - The following partially-portable control characters form a + * "gray list" that is ignored in this detection algorithm: + * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). * IN assertion: the fields Freq of dyn_ltree are set. */ -local void set_data_type(s) +local int detect_data_type(s) deflate_state *s; { + /* black_mask is the bit mask of black-listed bytes + * set bits 0..6, 14..25, and 28..31 + * 0xf3ffc07f = binary 11110011111111111100000001111111 + */ + unsigned long black_mask = 0xf3ffc07fUL; int n; - for (n = 0; n < 9; n++) + /* Check for non-textual ("black-listed") bytes. */ + for (n = 0; n <= 31; n++, black_mask >>= 1) + if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0)) + return Z_BINARY; + + /* Check for textual ("white-listed") bytes. */ + if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 + || s->dyn_ltree[13].Freq != 0) + return Z_TEXT; + for (n = 32; n < LITERALS; n++) if (s->dyn_ltree[n].Freq != 0) - break; - if (n == 9) - for (n = 14; n < 32; n++) - if (s->dyn_ltree[n].Freq != 0) - break; - s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY; + return Z_TEXT; + + /* There are no "black-listed" or "white-listed" bytes: + * this stream either is empty or has tolerated ("gray-listed") bytes only. + */ + return Z_BINARY; } /* =========================================================================== @@ -1203,7 +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); |