/* trees.c -- output deflated data using Huffman coding | |
* Copyright (C) 1995-2010 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 | |
*/ | |
/* | |
* 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 <ctype.h> | |
#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 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 | |
# 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 |= (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 |= (ush)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 |= (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 |= (ush)(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() | |
{ | |
#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: */ | |
#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; | |
for (code = 0; code < LENGTH_CODES-1; code++) { | |
base_length[code] = length; | |
for (n = 0; n < (1<<extra_lbits[code]); n++) { | |
_length_code[length++] = (uch)code; | |
} | |
} | |
Assert (length == 256, "tr_static_init: length != 256"); | |
/* Note that the length 255 (match length 258) can be represented | |
* in two different ways: code 284 + 5 bits or code 285, so we | |
* overwrite length_code[255] to use the best encoding: | |
*/ | |
_length_code[length-1] = (uch)code; | |
/* Initialize the mapping dist (0..32K) -> dist code (0..29) */ | |
dist = 0; | |
for (code = 0 ; code < 16; code++) { | |
base_dist[code] = dist; | |
for (n = 0; n < (1<<extra_dbits[code]); n++) { | |
_dist_code[dist++] = (uch)code; | |
} | |
} | |
Assert (dist == 256, "tr_static_init: dist != 256"); | |
dist >>= 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 <stdio.h> | |
# 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 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 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)); | |
} | |
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 ZLIB_INTERNAL _tr_init(s) | |
deflate_state *s; | |
{ | |
tr_static_init(); | |
s->l_desc.dyn_tree = s->dyn_ltree; | |
s->l_desc.stat_desc = &static_l_desc; | |
s->d_desc.dyn_tree = s->dyn_dtree; | |
s->d_desc.stat_desc = &static_d_desc; | |
s->bl_desc.dyn_tree = s->bl_tree; | |
s->bl_desc.stat_desc = &static_bl_desc; | |
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; | |
#endif | |
/* Initialize the first block of the first file: */ | |
init_block(s); | |
} | |
/* =========================================================================== | |
* Initialize a new block. | |
*/ | |
local void init_block(s) | |
deflate_state *s; | |
{ | |
int n; /* iterates over tree elements */ | |
/* Initialize the trees. */ | |
for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; | |
for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; | |
for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; | |
s->dyn_ltree[END_BLOCK].Freq = 1; | |
s->opt_len = s->static_len = 0L; | |
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 */ | |
{ | |
int v = s->heap[k]; | |
int j = k << 1; /* left son of k */ | |
while (j <= s->heap_len) { | |
/* Set j to the smallest of the two sons: */ | |
if (j < s->heap_len && | |
smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { | |
j++; | |
} | |
/* Exit if v is smaller than both sons */ | |
if (smaller(tree, v, s->heap[j], s->depth)) break; | |
/* Exchange v with the smallest son */ | |
s->heap[k] = s->heap[j]; k = j; | |
/* And continue down the tree, setting j to the left son of k */ | |
j <<= 1; | |
} | |
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 */ | |
{ | |
ct_data *tree = desc->dyn_tree; | |
int max_code = desc->max_code; | |
const ct_data *stree = desc->stat_desc->static_tree; | |
const intf *extra = desc->stat_desc->extra_bits; | |
int base = desc->stat_desc->extra_base; | |
int max_length = desc->stat_desc->max_length; | |
int h; /* heap index */ | |
int n, m; /* iterate over the tree elements */ | |
int bits; /* bit length */ | |
int xbits; /* extra bits */ | |
ush f; /* frequency */ | |
int overflow = 0; /* number of elements with bit length too large */ | |
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). | |
*/ | |
tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ | |
for (h = s->heap_max+1; h < HEAP_SIZE; h++) { | |
n = s->heap[h]; | |
bits = tree[tree[n].Dad].Len + 1; | |
if (bits > max_length) bits = max_length, overflow++; | |
tree[n].Len = (ush)bits; | |
/* We overwrite tree[n].Dad which is no longer needed */ | |
if (n > max_code) continue; /* not a leaf node */ | |
s->bl_count[bits]++; | |
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); | |
} | |
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 ((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; | |
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 */ | |
{ | |
ush next_code[MAX_BITS+1]; /* next code value for each bit length */ | |
ush code = 0; /* running code value */ | |
int bits; /* bit index */ | |
int n; /* code index */ | |
/* The distribution counts are first used to generate the code values | |
* without bit reversal. | |
*/ | |
for (bits = 1; bits <= MAX_BITS; bits++) { | |
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<<MAX_BITS)-1, | |
"inconsistent bit counts"); | |
Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); | |
for (n = 0; n <= max_code; n++) { | |
int len = tree[n].Len; | |
if (len == 0) continue; | |
/* Now reverse the bits */ | |
tree[n].Code = 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)); | |
} | |
} | |
/* =========================================================================== | |
* Construct one Huffman tree and assigns the code bit strings and lengths. | |
* Update the total bit length for the current block. | |
* IN assertion: the field freq is set for all tree elements. | |
* OUT assertions: the fields len and code are set to the optimal bit length | |
* and corresponding code. The length opt_len is updated; static_len is | |
* also updated if stree is not null. The field max_code is set. | |
*/ | |
local void build_tree(s, desc) | |
deflate_state *s; | |
tree_desc *desc; /* the tree descriptor */ | |
{ | |
ct_data *tree = desc->dyn_tree; | |
const ct_data *stree = desc->stat_desc->static_tree; | |
int elems = desc->stat_desc->elems; | |
int n, m; /* iterate over heap elements */ | |
int max_code = -1; /* largest code with non zero frequency */ | |
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. | |
*/ | |
s->heap_len = 0, s->heap_max = HEAP_SIZE; | |
for (n = 0; n < elems; n++) { | |
if (tree[n].Freq != 0) { | |
s->heap[++(s->heap_len)] = max_code = n; | |
s->depth[n] = 0; | |
} else { | |
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. | |
*/ | |
while (s->heap_len < 2) { | |
node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); | |
tree[node].Freq = 1; | |
s->depth[node] = 0; | |
s->opt_len--; if (stree) s->static_len -= stree[node].Len; | |
/* node is 0 or 1 so it does not have extra bits */ | |
} | |
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: | |
*/ | |
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. | |
*/ | |
node = elems; /* next internal node of the tree */ | |
do { | |
pqremove(s, tree, n); /* n = node of least frequency */ | |
m = s->heap[SMALLEST]; /* m = node of next least frequency */ | |
s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ | |
s->heap[--(s->heap_max)] = m; | |
/* Create a new node father of n and m */ | |
tree[node].Freq = tree[n].Freq + tree[m].Freq; | |
s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? | |
s->depth[n] : s->depth[m]) + 1); | |
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 */ | |
s->heap[SMALLEST] = node++; | |
pqdownheap(s, tree, SMALLEST); | |
} while (s->heap_len >= 2); | |
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. | |
*/ | |
gen_bitlen(s, (tree_desc *)desc); | |
/* The field len is now set, we can generate the bit codes */ | |
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 */ | |
{ | |
int n; /* iterates over all tree elements */ | |
int prevlen = -1; /* last emitted length */ | |
int curlen; /* length of current code */ | |
int nextlen = tree[0].Len; /* length of next code */ | |
int count = 0; /* repeat count of the current code */ | |
int max_count = 7; /* max repeat count */ | |
int min_count = 4; /* min repeat count */ | |
if (nextlen == 0) max_count = 138, min_count = 3; | |
tree[max_code+1].Len = (ush)0xffff; /* guard */ | |
for (n = 0; n <= max_code; n++) { | |
curlen = nextlen; nextlen = tree[n+1].Len; | |
if (++count < max_count && curlen == nextlen) { | |
continue; | |
} else if (count < min_count) { | |
s->bl_tree[curlen].Freq += count; | |
} else if (curlen != 0) { | |
if (curlen != prevlen) s->bl_tree[curlen].Freq++; | |
s->bl_tree[REP_3_6].Freq++; | |
} else if (count <= 10) { | |
s->bl_tree[REPZ_3_10].Freq++; | |
} else { | |
s->bl_tree[REPZ_11_138].Freq++; | |
} | |
count = 0; prevlen = curlen; | |
if (nextlen == 0) { | |
max_count = 138, min_count = 3; | |
} else if (curlen == nextlen) { | |
max_count = 6, min_count = 3; | |
} else { | |
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 */ | |
{ | |
int n; /* iterates over all tree elements */ | |
int prevlen = -1; /* last emitted length */ | |
int curlen; /* length of current code */ | |
int nextlen = tree[0].Len; /* length of next code */ | |
int count = 0; /* repeat count of the current code */ | |
int max_count = 7; /* max repeat count */ | |
int min_count = 4; /* min repeat count */ | |
/* tree[max_code+1].Len = -1; */ /* guard already set */ | |
if (nextlen == 0) max_count = 138, min_count = 3; | |
for (n = 0; n <= max_code; n++) { | |
curlen = nextlen; nextlen = tree[n+1].Len; | |
if (++count < max_count && curlen == nextlen) { | |
continue; | |
} else if (count < min_count) { | |
do { send_code(s, curlen, s->bl_tree); } while (--count != 0); | |
} else if (curlen != 0) { | |
if (curlen != prevlen) { | |
send_code(s, curlen, s->bl_tree); count--; | |
} | |
Assert(count >= 3 && count <= 6, " 3_6?"); | |
send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); | |
} else if (count <= 10) { | |
send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); | |
} else { | |
send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); | |
} | |
count = 0; prevlen = curlen; | |
if (nextlen == 0) { | |
max_count = 138, min_count = 3; | |
} else if (curlen == nextlen) { | |
max_count = 6, min_count = 3; | |
} else { | |
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; | |
{ | |
int max_blindex; /* index of last bit length code of non zero freq */ | |
/* Determine the bit length frequencies for literal and distance trees */ | |
scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); | |
scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); | |
/* Build the bit length tree: */ | |
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.) | |
*/ | |
for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { | |
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; | |
Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", | |
s->opt_len, s->static_len)); | |
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 */ | |
{ | |
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: ")); | |
send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ | |
send_bits(s, dcodes-1, 5); | |
send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ | |
for (rank = 0; rank < blcodes; rank++) { | |
Tracev((stderr, "\nbl code %2d ", bl_order[rank])); | |
send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); | |
} | |
Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); | |
send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ | |
Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); | |
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 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 last; /* one if this is the last block for a file */ | |
{ | |
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; | |
#endif | |
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 ZLIB_INTERNAL _tr_align(s) | |
deflate_state *s; | |
{ | |
send_bits(s, STATIC_TREES<<1, 3); | |
send_code(s, END_BLOCK, static_ltree); | |
#ifdef 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. | |
*/ | |
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 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 */ | |
/* Build the Huffman trees unless a stored block is forced */ | |
if (s->level > 0) { | |
/* Check if the file is binary or text */ | |
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))); | |
Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, | |
s->static_len)); | |
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. | |
*/ | |
max_blindex = build_bl_tree(s); | |
/* Determine the best encoding. Compute the block lengths in bytes. */ | |
opt_lenb = (s->opt_len+3+7)>>3; | |
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)); | |
if (static_lenb <= opt_lenb) opt_lenb = static_lenb; | |
} else { | |
Assert(buf != (char*)0, "lost buf"); | |
opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ | |
} | |
#ifdef FORCE_STORED | |
if (buf != (char*)0) { /* force stored block */ | |
#else | |
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. | |
*/ | |
_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)+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)+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 | |
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. | |
*/ | |
init_block(s); | |
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*last)); | |
} | |
/* =========================================================================== | |
* Save the match info and tally the frequency counts. Return true if | |
* the current block must be flushed. | |
*/ | |
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) */ | |
{ | |
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 */ | |
{ | |
unsigned dist; /* distance of matched string */ | |
int lc; /* match length or unmatched char (if dist == 0) */ | |
unsigned lx = 0; /* running index in l_buf */ | |
unsigned code; /* the code to send */ | |
int extra; /* number of extra bits to send */ | |
if (s->last_lit != 0) do { | |
dist = s->d_buf[lx]; | |
lc = s->l_buf[lx++]; | |
if (dist == 0) { | |
send_code(s, lc, ltree); /* send a literal byte */ | |
Tracecv(isgraph(lc), (stderr," '%c' ", lc)); | |
} else { | |
/* Here, lc is the match length - MIN_MATCH */ | |
code = _length_code[lc]; | |
send_code(s, code+LITERALS+1, ltree); /* send the length code */ | |
extra = extra_lbits[code]; | |
if (extra != 0) { | |
lc -= base_length[code]; | |
send_bits(s, lc, extra); /* send the extra length bits */ | |
} | |
dist--; /* dist is now the match distance - 1 */ | |
code = d_code(dist); | |
Assert (code < D_CODES, "bad d_code"); | |
send_code(s, code, dtree); /* send the distance code */ | |
extra = extra_dbits[code]; | |
if (extra != 0) { | |
dist -= base_dist[code]; | |
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"); | |
} while (lx < s->last_lit); | |
send_code(s, END_BLOCK, ltree); | |
s->last_eob_len = ltree[END_BLOCK].Len; | |
} | |
/* =========================================================================== | |
* 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 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; | |
/* 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) | |
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; | |
} | |
/* =========================================================================== | |
* 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 */ | |
{ | |
register unsigned res = 0; | |
do { | |
res |= code & 1; | |
code >>= 1, res <<= 1; | |
} while (--len > 0); | |
return res >> 1; | |
} | |
/* =========================================================================== | |
* Flush the bit buffer, keeping at most 7 bits in it. | |
*/ | |
local void bi_flush(s) | |
deflate_state *s; | |
{ | |
if (s->bi_valid == 16) { | |
put_short(s, s->bi_buf); | |
s->bi_buf = 0; | |
s->bi_valid = 0; | |
} else if (s->bi_valid >= 8) { | |
put_byte(s, (Byte)s->bi_buf); | |
s->bi_buf >>= 8; | |
s->bi_valid -= 8; | |
} | |
} | |
/* =========================================================================== | |
* Flush the bit buffer and align the output on a byte boundary | |
*/ | |
local void bi_windup(s) | |
deflate_state *s; | |
{ | |
if (s->bi_valid > 8) { | |
put_short(s, s->bi_buf); | |
} else if (s->bi_valid > 0) { | |
put_byte(s, (Byte)s->bi_buf); | |
} | |
s->bi_buf = 0; | |
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 */ | |
{ | |
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++); | |
} | |
} |