1 |
745 |
jeremybenn |
/* trees.c -- output deflated data using Huffman coding
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* Copyright (C) 1995-2005 Jean-loup Gailly
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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/*
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* ALGORITHM
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*
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* The "deflation" process uses several Huffman trees. The more
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* common source values are represented by shorter bit sequences.
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*
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* Each code tree is stored in a compressed form which is itself
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* a Huffman encoding of the lengths of all the code strings (in
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* ascending order by source values). The actual code strings are
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* reconstructed from the lengths in the inflate process, as described
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* in the deflate specification.
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*
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18 |
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* REFERENCES
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*
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* Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
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* Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
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*
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* Storer, James A.
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* Data Compression: Methods and Theory, pp. 49-50.
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* Computer Science Press, 1988. ISBN 0-7167-8156-5.
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*
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* Sedgewick, R.
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* Algorithms, p290.
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* Addison-Wesley, 1983. ISBN 0-201-06672-6.
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*/
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/* @(#) $Id: trees.c,v 1.1.1.2 2002/03/11 21:53:27 tromey Exp $ */
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/* #define GEN_TREES_H */
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#include "deflate.h"
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#ifdef DEBUG
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# include <ctype.h>
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#endif
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/* ===========================================================================
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* Constants
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*/
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#define MAX_BL_BITS 7
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/* Bit length codes must not exceed MAX_BL_BITS bits */
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#define END_BLOCK 256
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/* end of block literal code */
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#define REP_3_6 16
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/* repeat previous bit length 3-6 times (2 bits of repeat count) */
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#define REPZ_3_10 17
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/* repeat a zero length 3-10 times (3 bits of repeat count) */
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#define REPZ_11_138 18
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/* repeat a zero length 11-138 times (7 bits of repeat count) */
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local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
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= {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};
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64 |
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local const int extra_dbits[D_CODES] /* extra bits for each distance code */
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= {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};
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67 |
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local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
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= {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
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70 |
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local const uch bl_order[BL_CODES]
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= {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
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/* The lengths of the bit length codes are sent in order of decreasing
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* probability, to avoid transmitting the lengths for unused bit length codes.
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*/
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#define Buf_size (8 * 2*sizeof(char))
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/* Number of bits used within bi_buf. (bi_buf might be implemented on
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* more than 16 bits on some systems.)
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*/
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/* ===========================================================================
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* Local data. These are initialized only once.
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*/
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#define DIST_CODE_LEN 512 /* see definition of array dist_code below */
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#if defined(GEN_TREES_H) || !defined(STDC)
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/* non ANSI compilers may not accept trees.h */
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89 |
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local ct_data static_ltree[L_CODES+2];
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/* The static literal tree. Since the bit lengths are imposed, there is no
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* need for the L_CODES extra codes used during heap construction. However
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* The codes 286 and 287 are needed to build a canonical tree (see _tr_init
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* below).
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*/
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local ct_data static_dtree[D_CODES];
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/* The static distance tree. (Actually a trivial tree since all codes use
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* 5 bits.)
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*/
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uch _dist_code[DIST_CODE_LEN];
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/* Distance codes. The first 256 values correspond to the distances
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* 3 .. 258, the last 256 values correspond to the top 8 bits of
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* the 15 bit distances.
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*/
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107 |
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uch _length_code[MAX_MATCH-MIN_MATCH+1];
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/* length code for each normalized match length (0 == MIN_MATCH) */
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local int base_length[LENGTH_CODES];
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/* First normalized length for each code (0 = MIN_MATCH) */
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local int base_dist[D_CODES];
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/* First normalized distance for each code (0 = distance of 1) */
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#else
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# include "trees.h"
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#endif /* GEN_TREES_H */
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struct static_tree_desc_s {
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const ct_data *static_tree; /* static tree or NULL */
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const intf *extra_bits; /* extra bits for each code or NULL */
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int extra_base; /* base index for extra_bits */
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int elems; /* max number of elements in the tree */
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int max_length; /* max bit length for the codes */
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};
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local static_tree_desc static_l_desc =
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{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
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local static_tree_desc static_d_desc =
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{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
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local static_tree_desc static_bl_desc =
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{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
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/* ===========================================================================
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* Local (static) routines in this file.
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*/
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local void tr_static_init OF((void));
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local void init_block OF((deflate_state *s));
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local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
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local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
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local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
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local void build_tree OF((deflate_state *s, tree_desc *desc));
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local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
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local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
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local int build_bl_tree OF((deflate_state *s));
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local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
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int blcodes));
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local void compress_block OF((deflate_state *s, ct_data *ltree,
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ct_data *dtree));
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local void set_data_type OF((deflate_state *s));
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local unsigned bi_reverse OF((unsigned value, int length));
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local void bi_windup OF((deflate_state *s));
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local void bi_flush OF((deflate_state *s));
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local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
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int header));
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#ifdef GEN_TREES_H
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local void gen_trees_header OF((void));
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#endif
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#ifndef DEBUG
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# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
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/* Send a code of the given tree. c and tree must not have side effects */
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#else /* DEBUG */
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# define send_code(s, c, tree) \
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{ if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
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send_bits(s, tree[c].Code, tree[c].Len); }
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#endif
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/* ===========================================================================
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* Output a short LSB first on the stream.
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* IN assertion: there is enough room in pendingBuf.
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*/
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#define put_short(s, w) { \
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put_byte(s, (uch)((w) & 0xff)); \
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put_byte(s, (uch)((ush)(w) >> 8)); \
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}
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/* ===========================================================================
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* Send a value on a given number of bits.
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* IN assertion: length <= 16 and value fits in length bits.
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*/
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#ifdef DEBUG
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local void send_bits OF((deflate_state *s, int value, int length));
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local void send_bits(s, value, length)
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deflate_state *s;
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int value; /* value to send */
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int length; /* number of bits */
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{
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Tracevv((stderr," l %2d v %4x ", length, value));
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Assert(length > 0 && length <= 15, "invalid length");
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s->bits_sent += (ulg)length;
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201 |
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/* If not enough room in bi_buf, use (valid) bits from bi_buf and
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* (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
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* unused bits in value.
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*/
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if (s->bi_valid > (int)Buf_size - length) {
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s->bi_buf |= (value << s->bi_valid);
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put_short(s, s->bi_buf);
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s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
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s->bi_valid += length - Buf_size;
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} else {
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s->bi_buf |= value << s->bi_valid;
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s->bi_valid += length;
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}
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}
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#else /* !DEBUG */
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217 |
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#define send_bits(s, value, length) \
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{ int len = length;\
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if (s->bi_valid > (int)Buf_size - len) {\
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int val = value;\
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s->bi_buf |= (val << s->bi_valid);\
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put_short(s, s->bi_buf);\
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s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
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s->bi_valid += len - Buf_size;\
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} else {\
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s->bi_buf |= (value) << s->bi_valid;\
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s->bi_valid += len;\
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}\
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}
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#endif /* DEBUG */
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231 |
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232 |
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233 |
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/* the arguments must not have side effects */
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234 |
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235 |
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/* ===========================================================================
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236 |
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* Initialize the various 'constant' tables.
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237 |
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*/
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238 |
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local void tr_static_init()
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{
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240 |
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#if defined(GEN_TREES_H) || !defined(STDC)
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static int static_init_done = 0;
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int n; /* iterates over tree elements */
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int bits; /* bit counter */
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int length; /* length value */
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245 |
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int code; /* code value */
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246 |
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int dist; /* distance index */
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247 |
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ush bl_count[MAX_BITS+1];
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248 |
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/* number of codes at each bit length for an optimal tree */
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249 |
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250 |
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if (static_init_done) return;
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251 |
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252 |
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/* For some embedded targets, global variables are not initialized: */
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253 |
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static_l_desc.static_tree = static_ltree;
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254 |
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static_l_desc.extra_bits = extra_lbits;
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255 |
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static_d_desc.static_tree = static_dtree;
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256 |
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static_d_desc.extra_bits = extra_dbits;
|
257 |
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static_bl_desc.extra_bits = extra_blbits;
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258 |
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|
259 |
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/* Initialize the mapping length (0..255) -> length code (0..28) */
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260 |
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length = 0;
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261 |
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for (code = 0; code < LENGTH_CODES-1; code++) {
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262 |
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base_length[code] = length;
|
263 |
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for (n = 0; n < (1<<extra_lbits[code]); n++) {
|
264 |
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_length_code[length++] = (uch)code;
|
265 |
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}
|
266 |
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}
|
267 |
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Assert (length == 256, "tr_static_init: length != 256");
|
268 |
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/* Note that the length 255 (match length 258) can be represented
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269 |
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* in two different ways: code 284 + 5 bits or code 285, so we
|
270 |
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* overwrite length_code[255] to use the best encoding:
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271 |
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*/
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272 |
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_length_code[length-1] = (uch)code;
|
273 |
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|
274 |
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/* Initialize the mapping dist (0..32K) -> dist code (0..29) */
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275 |
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dist = 0;
|
276 |
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for (code = 0 ; code < 16; code++) {
|
277 |
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base_dist[code] = dist;
|
278 |
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for (n = 0; n < (1<<extra_dbits[code]); n++) {
|
279 |
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_dist_code[dist++] = (uch)code;
|
280 |
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}
|
281 |
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}
|
282 |
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Assert (dist == 256, "tr_static_init: dist != 256");
|
283 |
|
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dist >>= 7; /* from now on, all distances are divided by 128 */
|
284 |
|
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for ( ; code < D_CODES; code++) {
|
285 |
|
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base_dist[code] = dist << 7;
|
286 |
|
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for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
|
287 |
|
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_dist_code[256 + dist++] = (uch)code;
|
288 |
|
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}
|
289 |
|
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}
|
290 |
|
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Assert (dist == 256, "tr_static_init: 256+dist != 512");
|
291 |
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|
292 |
|
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/* Construct the codes of the static literal tree */
|
293 |
|
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for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
|
294 |
|
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n = 0;
|
295 |
|
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while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
|
296 |
|
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while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
|
297 |
|
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while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
|
298 |
|
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while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
|
299 |
|
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/* Codes 286 and 287 do not exist, but we must include them in the
|
300 |
|
|
* tree construction to get a canonical Huffman tree (longest code
|
301 |
|
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* all ones)
|
302 |
|
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*/
|
303 |
|
|
gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
|
304 |
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|
305 |
|
|
/* The static distance tree is trivial: */
|
306 |
|
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for (n = 0; n < D_CODES; n++) {
|
307 |
|
|
static_dtree[n].Len = 5;
|
308 |
|
|
static_dtree[n].Code = bi_reverse((unsigned)n, 5);
|
309 |
|
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}
|
310 |
|
|
static_init_done = 1;
|
311 |
|
|
|
312 |
|
|
# ifdef GEN_TREES_H
|
313 |
|
|
gen_trees_header();
|
314 |
|
|
# endif
|
315 |
|
|
#endif /* defined(GEN_TREES_H) || !defined(STDC) */
|
316 |
|
|
}
|
317 |
|
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|
318 |
|
|
/* ===========================================================================
|
319 |
|
|
* Genererate the file trees.h describing the static trees.
|
320 |
|
|
*/
|
321 |
|
|
#ifdef GEN_TREES_H
|
322 |
|
|
# ifndef DEBUG
|
323 |
|
|
# include <stdio.h>
|
324 |
|
|
# endif
|
325 |
|
|
|
326 |
|
|
# define SEPARATOR(i, last, width) \
|
327 |
|
|
((i) == (last)? "\n};\n\n" : \
|
328 |
|
|
((i) % (width) == (width)-1 ? ",\n" : ", "))
|
329 |
|
|
|
330 |
|
|
void gen_trees_header()
|
331 |
|
|
{
|
332 |
|
|
FILE *header = fopen("trees.h", "w");
|
333 |
|
|
int i;
|
334 |
|
|
|
335 |
|
|
Assert (header != NULL, "Can't open trees.h");
|
336 |
|
|
fprintf(header,
|
337 |
|
|
"/* header created automatically with -DGEN_TREES_H */\n\n");
|
338 |
|
|
|
339 |
|
|
fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
|
340 |
|
|
for (i = 0; i < L_CODES+2; i++) {
|
341 |
|
|
fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
|
342 |
|
|
static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
|
343 |
|
|
}
|
344 |
|
|
|
345 |
|
|
fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
|
346 |
|
|
for (i = 0; i < D_CODES; i++) {
|
347 |
|
|
fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
|
348 |
|
|
static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
|
349 |
|
|
}
|
350 |
|
|
|
351 |
|
|
fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n");
|
352 |
|
|
for (i = 0; i < DIST_CODE_LEN; i++) {
|
353 |
|
|
fprintf(header, "%2u%s", _dist_code[i],
|
354 |
|
|
SEPARATOR(i, DIST_CODE_LEN-1, 20));
|
355 |
|
|
}
|
356 |
|
|
|
357 |
|
|
fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
|
358 |
|
|
for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
|
359 |
|
|
fprintf(header, "%2u%s", _length_code[i],
|
360 |
|
|
SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
|
361 |
|
|
}
|
362 |
|
|
|
363 |
|
|
fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
|
364 |
|
|
for (i = 0; i < LENGTH_CODES; i++) {
|
365 |
|
|
fprintf(header, "%1u%s", base_length[i],
|
366 |
|
|
SEPARATOR(i, LENGTH_CODES-1, 20));
|
367 |
|
|
}
|
368 |
|
|
|
369 |
|
|
fprintf(header, "local const int base_dist[D_CODES] = {\n");
|
370 |
|
|
for (i = 0; i < D_CODES; i++) {
|
371 |
|
|
fprintf(header, "%5u%s", base_dist[i],
|
372 |
|
|
SEPARATOR(i, D_CODES-1, 10));
|
373 |
|
|
}
|
374 |
|
|
|
375 |
|
|
fclose(header);
|
376 |
|
|
}
|
377 |
|
|
#endif /* GEN_TREES_H */
|
378 |
|
|
|
379 |
|
|
/* ===========================================================================
|
380 |
|
|
* Initialize the tree data structures for a new zlib stream.
|
381 |
|
|
*/
|
382 |
|
|
void _tr_init(s)
|
383 |
|
|
deflate_state *s;
|
384 |
|
|
{
|
385 |
|
|
tr_static_init();
|
386 |
|
|
|
387 |
|
|
s->l_desc.dyn_tree = s->dyn_ltree;
|
388 |
|
|
s->l_desc.stat_desc = &static_l_desc;
|
389 |
|
|
|
390 |
|
|
s->d_desc.dyn_tree = s->dyn_dtree;
|
391 |
|
|
s->d_desc.stat_desc = &static_d_desc;
|
392 |
|
|
|
393 |
|
|
s->bl_desc.dyn_tree = s->bl_tree;
|
394 |
|
|
s->bl_desc.stat_desc = &static_bl_desc;
|
395 |
|
|
|
396 |
|
|
s->bi_buf = 0;
|
397 |
|
|
s->bi_valid = 0;
|
398 |
|
|
s->last_eob_len = 8; /* enough lookahead for inflate */
|
399 |
|
|
#ifdef DEBUG
|
400 |
|
|
s->compressed_len = 0L;
|
401 |
|
|
s->bits_sent = 0L;
|
402 |
|
|
#endif
|
403 |
|
|
|
404 |
|
|
/* Initialize the first block of the first file: */
|
405 |
|
|
init_block(s);
|
406 |
|
|
}
|
407 |
|
|
|
408 |
|
|
/* ===========================================================================
|
409 |
|
|
* Initialize a new block.
|
410 |
|
|
*/
|
411 |
|
|
local void init_block(s)
|
412 |
|
|
deflate_state *s;
|
413 |
|
|
{
|
414 |
|
|
int n; /* iterates over tree elements */
|
415 |
|
|
|
416 |
|
|
/* Initialize the trees. */
|
417 |
|
|
for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
|
418 |
|
|
for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
|
419 |
|
|
for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
|
420 |
|
|
|
421 |
|
|
s->dyn_ltree[END_BLOCK].Freq = 1;
|
422 |
|
|
s->opt_len = s->static_len = 0L;
|
423 |
|
|
s->last_lit = s->matches = 0;
|
424 |
|
|
}
|
425 |
|
|
|
426 |
|
|
#define SMALLEST 1
|
427 |
|
|
/* Index within the heap array of least frequent node in the Huffman tree */
|
428 |
|
|
|
429 |
|
|
|
430 |
|
|
/* ===========================================================================
|
431 |
|
|
* Remove the smallest element from the heap and recreate the heap with
|
432 |
|
|
* one less element. Updates heap and heap_len.
|
433 |
|
|
*/
|
434 |
|
|
#define pqremove(s, tree, top) \
|
435 |
|
|
{\
|
436 |
|
|
top = s->heap[SMALLEST]; \
|
437 |
|
|
s->heap[SMALLEST] = s->heap[s->heap_len--]; \
|
438 |
|
|
pqdownheap(s, tree, SMALLEST); \
|
439 |
|
|
}
|
440 |
|
|
|
441 |
|
|
/* ===========================================================================
|
442 |
|
|
* Compares to subtrees, using the tree depth as tie breaker when
|
443 |
|
|
* the subtrees have equal frequency. This minimizes the worst case length.
|
444 |
|
|
*/
|
445 |
|
|
#define smaller(tree, n, m, depth) \
|
446 |
|
|
(tree[n].Freq < tree[m].Freq || \
|
447 |
|
|
(tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
|
448 |
|
|
|
449 |
|
|
/* ===========================================================================
|
450 |
|
|
* Restore the heap property by moving down the tree starting at node k,
|
451 |
|
|
* exchanging a node with the smallest of its two sons if necessary, stopping
|
452 |
|
|
* when the heap property is re-established (each father smaller than its
|
453 |
|
|
* two sons).
|
454 |
|
|
*/
|
455 |
|
|
local void pqdownheap(s, tree, k)
|
456 |
|
|
deflate_state *s;
|
457 |
|
|
ct_data *tree; /* the tree to restore */
|
458 |
|
|
int k; /* node to move down */
|
459 |
|
|
{
|
460 |
|
|
int v = s->heap[k];
|
461 |
|
|
int j = k << 1; /* left son of k */
|
462 |
|
|
while (j <= s->heap_len) {
|
463 |
|
|
/* Set j to the smallest of the two sons: */
|
464 |
|
|
if (j < s->heap_len &&
|
465 |
|
|
smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
|
466 |
|
|
j++;
|
467 |
|
|
}
|
468 |
|
|
/* Exit if v is smaller than both sons */
|
469 |
|
|
if (smaller(tree, v, s->heap[j], s->depth)) break;
|
470 |
|
|
|
471 |
|
|
/* Exchange v with the smallest son */
|
472 |
|
|
s->heap[k] = s->heap[j]; k = j;
|
473 |
|
|
|
474 |
|
|
/* And continue down the tree, setting j to the left son of k */
|
475 |
|
|
j <<= 1;
|
476 |
|
|
}
|
477 |
|
|
s->heap[k] = v;
|
478 |
|
|
}
|
479 |
|
|
|
480 |
|
|
/* ===========================================================================
|
481 |
|
|
* Compute the optimal bit lengths for a tree and update the total bit length
|
482 |
|
|
* for the current block.
|
483 |
|
|
* IN assertion: the fields freq and dad are set, heap[heap_max] and
|
484 |
|
|
* above are the tree nodes sorted by increasing frequency.
|
485 |
|
|
* OUT assertions: the field len is set to the optimal bit length, the
|
486 |
|
|
* array bl_count contains the frequencies for each bit length.
|
487 |
|
|
* The length opt_len is updated; static_len is also updated if stree is
|
488 |
|
|
* not null.
|
489 |
|
|
*/
|
490 |
|
|
local void gen_bitlen(s, desc)
|
491 |
|
|
deflate_state *s;
|
492 |
|
|
tree_desc *desc; /* the tree descriptor */
|
493 |
|
|
{
|
494 |
|
|
ct_data *tree = desc->dyn_tree;
|
495 |
|
|
int max_code = desc->max_code;
|
496 |
|
|
const ct_data *stree = desc->stat_desc->static_tree;
|
497 |
|
|
const intf *extra = desc->stat_desc->extra_bits;
|
498 |
|
|
int base = desc->stat_desc->extra_base;
|
499 |
|
|
int max_length = desc->stat_desc->max_length;
|
500 |
|
|
int h; /* heap index */
|
501 |
|
|
int n, m; /* iterate over the tree elements */
|
502 |
|
|
int bits; /* bit length */
|
503 |
|
|
int xbits; /* extra bits */
|
504 |
|
|
ush f; /* frequency */
|
505 |
|
|
int overflow = 0; /* number of elements with bit length too large */
|
506 |
|
|
|
507 |
|
|
for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
|
508 |
|
|
|
509 |
|
|
/* In a first pass, compute the optimal bit lengths (which may
|
510 |
|
|
* overflow in the case of the bit length tree).
|
511 |
|
|
*/
|
512 |
|
|
tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
|
513 |
|
|
|
514 |
|
|
for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
|
515 |
|
|
n = s->heap[h];
|
516 |
|
|
bits = tree[tree[n].Dad].Len + 1;
|
517 |
|
|
if (bits > max_length) bits = max_length, overflow++;
|
518 |
|
|
tree[n].Len = (ush)bits;
|
519 |
|
|
/* We overwrite tree[n].Dad which is no longer needed */
|
520 |
|
|
|
521 |
|
|
if (n > max_code) continue; /* not a leaf node */
|
522 |
|
|
|
523 |
|
|
s->bl_count[bits]++;
|
524 |
|
|
xbits = 0;
|
525 |
|
|
if (n >= base) xbits = extra[n-base];
|
526 |
|
|
f = tree[n].Freq;
|
527 |
|
|
s->opt_len += (ulg)f * (bits + xbits);
|
528 |
|
|
if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
|
529 |
|
|
}
|
530 |
|
|
if (overflow == 0) return;
|
531 |
|
|
|
532 |
|
|
Trace((stderr,"\nbit length overflow\n"));
|
533 |
|
|
/* This happens for example on obj2 and pic of the Calgary corpus */
|
534 |
|
|
|
535 |
|
|
/* Find the first bit length which could increase: */
|
536 |
|
|
do {
|
537 |
|
|
bits = max_length-1;
|
538 |
|
|
while (s->bl_count[bits] == 0) bits--;
|
539 |
|
|
s->bl_count[bits]--; /* move one leaf down the tree */
|
540 |
|
|
s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
|
541 |
|
|
s->bl_count[max_length]--;
|
542 |
|
|
/* The brother of the overflow item also moves one step up,
|
543 |
|
|
* but this does not affect bl_count[max_length]
|
544 |
|
|
*/
|
545 |
|
|
overflow -= 2;
|
546 |
|
|
} while (overflow > 0);
|
547 |
|
|
|
548 |
|
|
/* Now recompute all bit lengths, scanning in increasing frequency.
|
549 |
|
|
* h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
|
550 |
|
|
* lengths instead of fixing only the wrong ones. This idea is taken
|
551 |
|
|
* from 'ar' written by Haruhiko Okumura.)
|
552 |
|
|
*/
|
553 |
|
|
for (bits = max_length; bits != 0; bits--) {
|
554 |
|
|
n = s->bl_count[bits];
|
555 |
|
|
while (n != 0) {
|
556 |
|
|
m = s->heap[--h];
|
557 |
|
|
if (m > max_code) continue;
|
558 |
|
|
if ((unsigned) tree[m].Len != (unsigned) bits) {
|
559 |
|
|
Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
|
560 |
|
|
s->opt_len += ((long)bits - (long)tree[m].Len)
|
561 |
|
|
*(long)tree[m].Freq;
|
562 |
|
|
tree[m].Len = (ush)bits;
|
563 |
|
|
}
|
564 |
|
|
n--;
|
565 |
|
|
}
|
566 |
|
|
}
|
567 |
|
|
}
|
568 |
|
|
|
569 |
|
|
/* ===========================================================================
|
570 |
|
|
* Generate the codes for a given tree and bit counts (which need not be
|
571 |
|
|
* optimal).
|
572 |
|
|
* IN assertion: the array bl_count contains the bit length statistics for
|
573 |
|
|
* the given tree and the field len is set for all tree elements.
|
574 |
|
|
* OUT assertion: the field code is set for all tree elements of non
|
575 |
|
|
* zero code length.
|
576 |
|
|
*/
|
577 |
|
|
local void gen_codes (tree, max_code, bl_count)
|
578 |
|
|
ct_data *tree; /* the tree to decorate */
|
579 |
|
|
int max_code; /* largest code with non zero frequency */
|
580 |
|
|
ushf *bl_count; /* number of codes at each bit length */
|
581 |
|
|
{
|
582 |
|
|
ush next_code[MAX_BITS+1]; /* next code value for each bit length */
|
583 |
|
|
ush code = 0; /* running code value */
|
584 |
|
|
int bits; /* bit index */
|
585 |
|
|
int n; /* code index */
|
586 |
|
|
|
587 |
|
|
/* The distribution counts are first used to generate the code values
|
588 |
|
|
* without bit reversal.
|
589 |
|
|
*/
|
590 |
|
|
for (bits = 1; bits <= MAX_BITS; bits++) {
|
591 |
|
|
next_code[bits] = code = (code + bl_count[bits-1]) << 1;
|
592 |
|
|
}
|
593 |
|
|
/* Check that the bit counts in bl_count are consistent. The last code
|
594 |
|
|
* must be all ones.
|
595 |
|
|
*/
|
596 |
|
|
Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
|
597 |
|
|
"inconsistent bit counts");
|
598 |
|
|
Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
|
599 |
|
|
|
600 |
|
|
for (n = 0; n <= max_code; n++) {
|
601 |
|
|
int len = tree[n].Len;
|
602 |
|
|
if (len == 0) continue;
|
603 |
|
|
/* Now reverse the bits */
|
604 |
|
|
tree[n].Code = bi_reverse(next_code[len]++, len);
|
605 |
|
|
|
606 |
|
|
Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
|
607 |
|
|
n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
|
608 |
|
|
}
|
609 |
|
|
}
|
610 |
|
|
|
611 |
|
|
/* ===========================================================================
|
612 |
|
|
* Construct one Huffman tree and assigns the code bit strings and lengths.
|
613 |
|
|
* Update the total bit length for the current block.
|
614 |
|
|
* IN assertion: the field freq is set for all tree elements.
|
615 |
|
|
* OUT assertions: the fields len and code are set to the optimal bit length
|
616 |
|
|
* and corresponding code. The length opt_len is updated; static_len is
|
617 |
|
|
* also updated if stree is not null. The field max_code is set.
|
618 |
|
|
*/
|
619 |
|
|
local void build_tree(s, desc)
|
620 |
|
|
deflate_state *s;
|
621 |
|
|
tree_desc *desc; /* the tree descriptor */
|
622 |
|
|
{
|
623 |
|
|
ct_data *tree = desc->dyn_tree;
|
624 |
|
|
const ct_data *stree = desc->stat_desc->static_tree;
|
625 |
|
|
int elems = desc->stat_desc->elems;
|
626 |
|
|
int n, m; /* iterate over heap elements */
|
627 |
|
|
int max_code = -1; /* largest code with non zero frequency */
|
628 |
|
|
int node; /* new node being created */
|
629 |
|
|
|
630 |
|
|
/* Construct the initial heap, with least frequent element in
|
631 |
|
|
* heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
|
632 |
|
|
* heap[0] is not used.
|
633 |
|
|
*/
|
634 |
|
|
s->heap_len = 0, s->heap_max = HEAP_SIZE;
|
635 |
|
|
|
636 |
|
|
for (n = 0; n < elems; n++) {
|
637 |
|
|
if (tree[n].Freq != 0) {
|
638 |
|
|
s->heap[++(s->heap_len)] = max_code = n;
|
639 |
|
|
s->depth[n] = 0;
|
640 |
|
|
} else {
|
641 |
|
|
tree[n].Len = 0;
|
642 |
|
|
}
|
643 |
|
|
}
|
644 |
|
|
|
645 |
|
|
/* The pkzip format requires that at least one distance code exists,
|
646 |
|
|
* and that at least one bit should be sent even if there is only one
|
647 |
|
|
* possible code. So to avoid special checks later on we force at least
|
648 |
|
|
* two codes of non zero frequency.
|
649 |
|
|
*/
|
650 |
|
|
while (s->heap_len < 2) {
|
651 |
|
|
node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
|
652 |
|
|
tree[node].Freq = 1;
|
653 |
|
|
s->depth[node] = 0;
|
654 |
|
|
s->opt_len--; if (stree) s->static_len -= stree[node].Len;
|
655 |
|
|
/* node is 0 or 1 so it does not have extra bits */
|
656 |
|
|
}
|
657 |
|
|
desc->max_code = max_code;
|
658 |
|
|
|
659 |
|
|
/* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
|
660 |
|
|
* establish sub-heaps of increasing lengths:
|
661 |
|
|
*/
|
662 |
|
|
for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
|
663 |
|
|
|
664 |
|
|
/* Construct the Huffman tree by repeatedly combining the least two
|
665 |
|
|
* frequent nodes.
|
666 |
|
|
*/
|
667 |
|
|
node = elems; /* next internal node of the tree */
|
668 |
|
|
do {
|
669 |
|
|
pqremove(s, tree, n); /* n = node of least frequency */
|
670 |
|
|
m = s->heap[SMALLEST]; /* m = node of next least frequency */
|
671 |
|
|
|
672 |
|
|
s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
|
673 |
|
|
s->heap[--(s->heap_max)] = m;
|
674 |
|
|
|
675 |
|
|
/* Create a new node father of n and m */
|
676 |
|
|
tree[node].Freq = tree[n].Freq + tree[m].Freq;
|
677 |
|
|
s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
|
678 |
|
|
s->depth[n] : s->depth[m]) + 1);
|
679 |
|
|
tree[n].Dad = tree[m].Dad = (ush)node;
|
680 |
|
|
#ifdef DUMP_BL_TREE
|
681 |
|
|
if (tree == s->bl_tree) {
|
682 |
|
|
fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
|
683 |
|
|
node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
|
684 |
|
|
}
|
685 |
|
|
#endif
|
686 |
|
|
/* and insert the new node in the heap */
|
687 |
|
|
s->heap[SMALLEST] = node++;
|
688 |
|
|
pqdownheap(s, tree, SMALLEST);
|
689 |
|
|
|
690 |
|
|
} while (s->heap_len >= 2);
|
691 |
|
|
|
692 |
|
|
s->heap[--(s->heap_max)] = s->heap[SMALLEST];
|
693 |
|
|
|
694 |
|
|
/* At this point, the fields freq and dad are set. We can now
|
695 |
|
|
* generate the bit lengths.
|
696 |
|
|
*/
|
697 |
|
|
gen_bitlen(s, (tree_desc *)desc);
|
698 |
|
|
|
699 |
|
|
/* The field len is now set, we can generate the bit codes */
|
700 |
|
|
gen_codes ((ct_data *)tree, max_code, s->bl_count);
|
701 |
|
|
}
|
702 |
|
|
|
703 |
|
|
/* ===========================================================================
|
704 |
|
|
* Scan a literal or distance tree to determine the frequencies of the codes
|
705 |
|
|
* in the bit length tree.
|
706 |
|
|
*/
|
707 |
|
|
local void scan_tree (s, tree, max_code)
|
708 |
|
|
deflate_state *s;
|
709 |
|
|
ct_data *tree; /* the tree to be scanned */
|
710 |
|
|
int max_code; /* and its largest code of non zero frequency */
|
711 |
|
|
{
|
712 |
|
|
int n; /* iterates over all tree elements */
|
713 |
|
|
int prevlen = -1; /* last emitted length */
|
714 |
|
|
int curlen; /* length of current code */
|
715 |
|
|
int nextlen = tree[0].Len; /* length of next code */
|
716 |
|
|
int count = 0; /* repeat count of the current code */
|
717 |
|
|
int max_count = 7; /* max repeat count */
|
718 |
|
|
int min_count = 4; /* min repeat count */
|
719 |
|
|
|
720 |
|
|
if (nextlen == 0) max_count = 138, min_count = 3;
|
721 |
|
|
tree[max_code+1].Len = (ush)0xffff; /* guard */
|
722 |
|
|
|
723 |
|
|
for (n = 0; n <= max_code; n++) {
|
724 |
|
|
curlen = nextlen; nextlen = tree[n+1].Len;
|
725 |
|
|
if (++count < max_count && curlen == nextlen) {
|
726 |
|
|
continue;
|
727 |
|
|
} else if (count < min_count) {
|
728 |
|
|
s->bl_tree[curlen].Freq += count;
|
729 |
|
|
} else if (curlen != 0) {
|
730 |
|
|
if (curlen != prevlen) s->bl_tree[curlen].Freq++;
|
731 |
|
|
s->bl_tree[REP_3_6].Freq++;
|
732 |
|
|
} else if (count <= 10) {
|
733 |
|
|
s->bl_tree[REPZ_3_10].Freq++;
|
734 |
|
|
} else {
|
735 |
|
|
s->bl_tree[REPZ_11_138].Freq++;
|
736 |
|
|
}
|
737 |
|
|
count = 0; prevlen = curlen;
|
738 |
|
|
if (nextlen == 0) {
|
739 |
|
|
max_count = 138, min_count = 3;
|
740 |
|
|
} else if (curlen == nextlen) {
|
741 |
|
|
max_count = 6, min_count = 3;
|
742 |
|
|
} else {
|
743 |
|
|
max_count = 7, min_count = 4;
|
744 |
|
|
}
|
745 |
|
|
}
|
746 |
|
|
}
|
747 |
|
|
|
748 |
|
|
/* ===========================================================================
|
749 |
|
|
* Send a literal or distance tree in compressed form, using the codes in
|
750 |
|
|
* bl_tree.
|
751 |
|
|
*/
|
752 |
|
|
local void send_tree (s, tree, max_code)
|
753 |
|
|
deflate_state *s;
|
754 |
|
|
ct_data *tree; /* the tree to be scanned */
|
755 |
|
|
int max_code; /* and its largest code of non zero frequency */
|
756 |
|
|
{
|
757 |
|
|
int n; /* iterates over all tree elements */
|
758 |
|
|
int prevlen = -1; /* last emitted length */
|
759 |
|
|
int curlen; /* length of current code */
|
760 |
|
|
int nextlen = tree[0].Len; /* length of next code */
|
761 |
|
|
int count = 0; /* repeat count of the current code */
|
762 |
|
|
int max_count = 7; /* max repeat count */
|
763 |
|
|
int min_count = 4; /* min repeat count */
|
764 |
|
|
|
765 |
|
|
/* tree[max_code+1].Len = -1; */ /* guard already set */
|
766 |
|
|
if (nextlen == 0) max_count = 138, min_count = 3;
|
767 |
|
|
|
768 |
|
|
for (n = 0; n <= max_code; n++) {
|
769 |
|
|
curlen = nextlen; nextlen = tree[n+1].Len;
|
770 |
|
|
if (++count < max_count && curlen == nextlen) {
|
771 |
|
|
continue;
|
772 |
|
|
} else if (count < min_count) {
|
773 |
|
|
do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
|
774 |
|
|
|
775 |
|
|
} else if (curlen != 0) {
|
776 |
|
|
if (curlen != prevlen) {
|
777 |
|
|
send_code(s, curlen, s->bl_tree); count--;
|
778 |
|
|
}
|
779 |
|
|
Assert(count >= 3 && count <= 6, " 3_6?");
|
780 |
|
|
send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
|
781 |
|
|
|
782 |
|
|
} else if (count <= 10) {
|
783 |
|
|
send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
|
784 |
|
|
|
785 |
|
|
} else {
|
786 |
|
|
send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
|
787 |
|
|
}
|
788 |
|
|
count = 0; prevlen = curlen;
|
789 |
|
|
if (nextlen == 0) {
|
790 |
|
|
max_count = 138, min_count = 3;
|
791 |
|
|
} else if (curlen == nextlen) {
|
792 |
|
|
max_count = 6, min_count = 3;
|
793 |
|
|
} else {
|
794 |
|
|
max_count = 7, min_count = 4;
|
795 |
|
|
}
|
796 |
|
|
}
|
797 |
|
|
}
|
798 |
|
|
|
799 |
|
|
/* ===========================================================================
|
800 |
|
|
* Construct the Huffman tree for the bit lengths and return the index in
|
801 |
|
|
* bl_order of the last bit length code to send.
|
802 |
|
|
*/
|
803 |
|
|
local int build_bl_tree(s)
|
804 |
|
|
deflate_state *s;
|
805 |
|
|
{
|
806 |
|
|
int max_blindex; /* index of last bit length code of non zero freq */
|
807 |
|
|
|
808 |
|
|
/* Determine the bit length frequencies for literal and distance trees */
|
809 |
|
|
scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
|
810 |
|
|
scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
|
811 |
|
|
|
812 |
|
|
/* Build the bit length tree: */
|
813 |
|
|
build_tree(s, (tree_desc *)(&(s->bl_desc)));
|
814 |
|
|
/* opt_len now includes the length of the tree representations, except
|
815 |
|
|
* the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
|
816 |
|
|
*/
|
817 |
|
|
|
818 |
|
|
/* Determine the number of bit length codes to send. The pkzip format
|
819 |
|
|
* requires that at least 4 bit length codes be sent. (appnote.txt says
|
820 |
|
|
* 3 but the actual value used is 4.)
|
821 |
|
|
*/
|
822 |
|
|
for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
|
823 |
|
|
if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
|
824 |
|
|
}
|
825 |
|
|
/* Update opt_len to include the bit length tree and counts */
|
826 |
|
|
s->opt_len += 3*(max_blindex+1) + 5+5+4;
|
827 |
|
|
Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
|
828 |
|
|
s->opt_len, s->static_len));
|
829 |
|
|
|
830 |
|
|
return max_blindex;
|
831 |
|
|
}
|
832 |
|
|
|
833 |
|
|
/* ===========================================================================
|
834 |
|
|
* Send the header for a block using dynamic Huffman trees: the counts, the
|
835 |
|
|
* lengths of the bit length codes, the literal tree and the distance tree.
|
836 |
|
|
* IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
|
837 |
|
|
*/
|
838 |
|
|
local void send_all_trees(s, lcodes, dcodes, blcodes)
|
839 |
|
|
deflate_state *s;
|
840 |
|
|
int lcodes, dcodes, blcodes; /* number of codes for each tree */
|
841 |
|
|
{
|
842 |
|
|
int rank; /* index in bl_order */
|
843 |
|
|
|
844 |
|
|
Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
|
845 |
|
|
Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
|
846 |
|
|
"too many codes");
|
847 |
|
|
Tracev((stderr, "\nbl counts: "));
|
848 |
|
|
send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
|
849 |
|
|
send_bits(s, dcodes-1, 5);
|
850 |
|
|
send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
|
851 |
|
|
for (rank = 0; rank < blcodes; rank++) {
|
852 |
|
|
Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
|
853 |
|
|
send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
|
854 |
|
|
}
|
855 |
|
|
Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
|
856 |
|
|
|
857 |
|
|
send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
|
858 |
|
|
Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
|
859 |
|
|
|
860 |
|
|
send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
|
861 |
|
|
Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
|
862 |
|
|
}
|
863 |
|
|
|
864 |
|
|
/* ===========================================================================
|
865 |
|
|
* Send a stored block
|
866 |
|
|
*/
|
867 |
|
|
void _tr_stored_block(s, buf, stored_len, eof)
|
868 |
|
|
deflate_state *s;
|
869 |
|
|
charf *buf; /* input block */
|
870 |
|
|
ulg stored_len; /* length of input block */
|
871 |
|
|
int eof; /* true if this is the last block for a file */
|
872 |
|
|
{
|
873 |
|
|
send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */
|
874 |
|
|
#ifdef DEBUG
|
875 |
|
|
s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
|
876 |
|
|
s->compressed_len += (stored_len + 4) << 3;
|
877 |
|
|
#endif
|
878 |
|
|
copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
|
879 |
|
|
}
|
880 |
|
|
|
881 |
|
|
/* ===========================================================================
|
882 |
|
|
* Send one empty static block to give enough lookahead for inflate.
|
883 |
|
|
* This takes 10 bits, of which 7 may remain in the bit buffer.
|
884 |
|
|
* The current inflate code requires 9 bits of lookahead. If the
|
885 |
|
|
* last two codes for the previous block (real code plus EOB) were coded
|
886 |
|
|
* on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
|
887 |
|
|
* the last real code. In this case we send two empty static blocks instead
|
888 |
|
|
* of one. (There are no problems if the previous block is stored or fixed.)
|
889 |
|
|
* To simplify the code, we assume the worst case of last real code encoded
|
890 |
|
|
* on one bit only.
|
891 |
|
|
*/
|
892 |
|
|
void _tr_align(s)
|
893 |
|
|
deflate_state *s;
|
894 |
|
|
{
|
895 |
|
|
send_bits(s, STATIC_TREES<<1, 3);
|
896 |
|
|
send_code(s, END_BLOCK, static_ltree);
|
897 |
|
|
#ifdef DEBUG
|
898 |
|
|
s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
|
899 |
|
|
#endif
|
900 |
|
|
bi_flush(s);
|
901 |
|
|
/* Of the 10 bits for the empty block, we have already sent
|
902 |
|
|
* (10 - bi_valid) bits. The lookahead for the last real code (before
|
903 |
|
|
* the EOB of the previous block) was thus at least one plus the length
|
904 |
|
|
* of the EOB plus what we have just sent of the empty static block.
|
905 |
|
|
*/
|
906 |
|
|
if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
|
907 |
|
|
send_bits(s, STATIC_TREES<<1, 3);
|
908 |
|
|
send_code(s, END_BLOCK, static_ltree);
|
909 |
|
|
#ifdef DEBUG
|
910 |
|
|
s->compressed_len += 10L;
|
911 |
|
|
#endif
|
912 |
|
|
bi_flush(s);
|
913 |
|
|
}
|
914 |
|
|
s->last_eob_len = 7;
|
915 |
|
|
}
|
916 |
|
|
|
917 |
|
|
/* ===========================================================================
|
918 |
|
|
* Determine the best encoding for the current block: dynamic trees, static
|
919 |
|
|
* trees or store, and output the encoded block to the zip file.
|
920 |
|
|
*/
|
921 |
|
|
void _tr_flush_block(s, buf, stored_len, eof)
|
922 |
|
|
deflate_state *s;
|
923 |
|
|
charf *buf; /* input block, or NULL if too old */
|
924 |
|
|
ulg stored_len; /* length of input block */
|
925 |
|
|
int eof; /* true if this is the last block for a file */
|
926 |
|
|
{
|
927 |
|
|
ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
|
928 |
|
|
int max_blindex = 0; /* index of last bit length code of non zero freq */
|
929 |
|
|
|
930 |
|
|
/* Build the Huffman trees unless a stored block is forced */
|
931 |
|
|
if (s->level > 0) {
|
932 |
|
|
|
933 |
|
|
/* Check if the file is binary or text */
|
934 |
|
|
if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN)
|
935 |
|
|
set_data_type(s);
|
936 |
|
|
|
937 |
|
|
/* Construct the literal and distance trees */
|
938 |
|
|
build_tree(s, (tree_desc *)(&(s->l_desc)));
|
939 |
|
|
Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
|
940 |
|
|
s->static_len));
|
941 |
|
|
|
942 |
|
|
build_tree(s, (tree_desc *)(&(s->d_desc)));
|
943 |
|
|
Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
|
944 |
|
|
s->static_len));
|
945 |
|
|
/* At this point, opt_len and static_len are the total bit lengths of
|
946 |
|
|
* the compressed block data, excluding the tree representations.
|
947 |
|
|
*/
|
948 |
|
|
|
949 |
|
|
/* Build the bit length tree for the above two trees, and get the index
|
950 |
|
|
* in bl_order of the last bit length code to send.
|
951 |
|
|
*/
|
952 |
|
|
max_blindex = build_bl_tree(s);
|
953 |
|
|
|
954 |
|
|
/* Determine the best encoding. Compute the block lengths in bytes. */
|
955 |
|
|
opt_lenb = (s->opt_len+3+7)>>3;
|
956 |
|
|
static_lenb = (s->static_len+3+7)>>3;
|
957 |
|
|
|
958 |
|
|
Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
|
959 |
|
|
opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
|
960 |
|
|
s->last_lit));
|
961 |
|
|
|
962 |
|
|
if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
|
963 |
|
|
|
964 |
|
|
} else {
|
965 |
|
|
Assert(buf != (char*)0, "lost buf");
|
966 |
|
|
opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
|
967 |
|
|
}
|
968 |
|
|
|
969 |
|
|
#ifdef FORCE_STORED
|
970 |
|
|
if (buf != (char*)0) { /* force stored block */
|
971 |
|
|
#else
|
972 |
|
|
if (stored_len+4 <= opt_lenb && buf != (char*)0) {
|
973 |
|
|
/* 4: two words for the lengths */
|
974 |
|
|
#endif
|
975 |
|
|
/* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
|
976 |
|
|
* Otherwise we can't have processed more than WSIZE input bytes since
|
977 |
|
|
* the last block flush, because compression would have been
|
978 |
|
|
* successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
|
979 |
|
|
* transform a block into a stored block.
|
980 |
|
|
*/
|
981 |
|
|
_tr_stored_block(s, buf, stored_len, eof);
|
982 |
|
|
|
983 |
|
|
#ifdef FORCE_STATIC
|
984 |
|
|
} else if (static_lenb >= 0) { /* force static trees */
|
985 |
|
|
#else
|
986 |
|
|
} else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
|
987 |
|
|
#endif
|
988 |
|
|
send_bits(s, (STATIC_TREES<<1)+eof, 3);
|
989 |
|
|
compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
|
990 |
|
|
#ifdef DEBUG
|
991 |
|
|
s->compressed_len += 3 + s->static_len;
|
992 |
|
|
#endif
|
993 |
|
|
} else {
|
994 |
|
|
send_bits(s, (DYN_TREES<<1)+eof, 3);
|
995 |
|
|
send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
|
996 |
|
|
max_blindex+1);
|
997 |
|
|
compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
|
998 |
|
|
#ifdef DEBUG
|
999 |
|
|
s->compressed_len += 3 + s->opt_len;
|
1000 |
|
|
#endif
|
1001 |
|
|
}
|
1002 |
|
|
Assert (s->compressed_len == s->bits_sent, "bad compressed size");
|
1003 |
|
|
/* The above check is made mod 2^32, for files larger than 512 MB
|
1004 |
|
|
* and uLong implemented on 32 bits.
|
1005 |
|
|
*/
|
1006 |
|
|
init_block(s);
|
1007 |
|
|
|
1008 |
|
|
if (eof) {
|
1009 |
|
|
bi_windup(s);
|
1010 |
|
|
#ifdef DEBUG
|
1011 |
|
|
s->compressed_len += 7; /* align on byte boundary */
|
1012 |
|
|
#endif
|
1013 |
|
|
}
|
1014 |
|
|
Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
|
1015 |
|
|
s->compressed_len-7*eof));
|
1016 |
|
|
}
|
1017 |
|
|
|
1018 |
|
|
/* ===========================================================================
|
1019 |
|
|
* Save the match info and tally the frequency counts. Return true if
|
1020 |
|
|
* the current block must be flushed.
|
1021 |
|
|
*/
|
1022 |
|
|
int _tr_tally (s, dist, lc)
|
1023 |
|
|
deflate_state *s;
|
1024 |
|
|
unsigned dist; /* distance of matched string */
|
1025 |
|
|
unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
|
1026 |
|
|
{
|
1027 |
|
|
s->d_buf[s->last_lit] = (ush)dist;
|
1028 |
|
|
s->l_buf[s->last_lit++] = (uch)lc;
|
1029 |
|
|
if (dist == 0) {
|
1030 |
|
|
/* lc is the unmatched char */
|
1031 |
|
|
s->dyn_ltree[lc].Freq++;
|
1032 |
|
|
} else {
|
1033 |
|
|
s->matches++;
|
1034 |
|
|
/* Here, lc is the match length - MIN_MATCH */
|
1035 |
|
|
dist--; /* dist = match distance - 1 */
|
1036 |
|
|
Assert((ush)dist < (ush)MAX_DIST(s) &&
|
1037 |
|
|
(ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
|
1038 |
|
|
(ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
|
1039 |
|
|
|
1040 |
|
|
s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
|
1041 |
|
|
s->dyn_dtree[d_code(dist)].Freq++;
|
1042 |
|
|
}
|
1043 |
|
|
|
1044 |
|
|
#ifdef TRUNCATE_BLOCK
|
1045 |
|
|
/* Try to guess if it is profitable to stop the current block here */
|
1046 |
|
|
if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
|
1047 |
|
|
/* Compute an upper bound for the compressed length */
|
1048 |
|
|
ulg out_length = (ulg)s->last_lit*8L;
|
1049 |
|
|
ulg in_length = (ulg)((long)s->strstart - s->block_start);
|
1050 |
|
|
int dcode;
|
1051 |
|
|
for (dcode = 0; dcode < D_CODES; dcode++) {
|
1052 |
|
|
out_length += (ulg)s->dyn_dtree[dcode].Freq *
|
1053 |
|
|
(5L+extra_dbits[dcode]);
|
1054 |
|
|
}
|
1055 |
|
|
out_length >>= 3;
|
1056 |
|
|
Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
|
1057 |
|
|
s->last_lit, in_length, out_length,
|
1058 |
|
|
100L - out_length*100L/in_length));
|
1059 |
|
|
if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
|
1060 |
|
|
}
|
1061 |
|
|
#endif
|
1062 |
|
|
return (s->last_lit == s->lit_bufsize-1);
|
1063 |
|
|
/* We avoid equality with lit_bufsize because of wraparound at 64K
|
1064 |
|
|
* on 16 bit machines and because stored blocks are restricted to
|
1065 |
|
|
* 64K-1 bytes.
|
1066 |
|
|
*/
|
1067 |
|
|
}
|
1068 |
|
|
|
1069 |
|
|
/* ===========================================================================
|
1070 |
|
|
* Send the block data compressed using the given Huffman trees
|
1071 |
|
|
*/
|
1072 |
|
|
local void compress_block(s, ltree, dtree)
|
1073 |
|
|
deflate_state *s;
|
1074 |
|
|
ct_data *ltree; /* literal tree */
|
1075 |
|
|
ct_data *dtree; /* distance tree */
|
1076 |
|
|
{
|
1077 |
|
|
unsigned dist; /* distance of matched string */
|
1078 |
|
|
int lc; /* match length or unmatched char (if dist == 0) */
|
1079 |
|
|
unsigned lx = 0; /* running index in l_buf */
|
1080 |
|
|
unsigned code; /* the code to send */
|
1081 |
|
|
int extra; /* number of extra bits to send */
|
1082 |
|
|
|
1083 |
|
|
if (s->last_lit != 0) do {
|
1084 |
|
|
dist = s->d_buf[lx];
|
1085 |
|
|
lc = s->l_buf[lx++];
|
1086 |
|
|
if (dist == 0) {
|
1087 |
|
|
send_code(s, lc, ltree); /* send a literal byte */
|
1088 |
|
|
Tracecv(isgraph(lc), (stderr," '%c' ", lc));
|
1089 |
|
|
} else {
|
1090 |
|
|
/* Here, lc is the match length - MIN_MATCH */
|
1091 |
|
|
code = _length_code[lc];
|
1092 |
|
|
send_code(s, code+LITERALS+1, ltree); /* send the length code */
|
1093 |
|
|
extra = extra_lbits[code];
|
1094 |
|
|
if (extra != 0) {
|
1095 |
|
|
lc -= base_length[code];
|
1096 |
|
|
send_bits(s, lc, extra); /* send the extra length bits */
|
1097 |
|
|
}
|
1098 |
|
|
dist--; /* dist is now the match distance - 1 */
|
1099 |
|
|
code = d_code(dist);
|
1100 |
|
|
Assert (code < D_CODES, "bad d_code");
|
1101 |
|
|
|
1102 |
|
|
send_code(s, code, dtree); /* send the distance code */
|
1103 |
|
|
extra = extra_dbits[code];
|
1104 |
|
|
if (extra != 0) {
|
1105 |
|
|
dist -= base_dist[code];
|
1106 |
|
|
send_bits(s, dist, extra); /* send the extra distance bits */
|
1107 |
|
|
}
|
1108 |
|
|
} /* literal or match pair ? */
|
1109 |
|
|
|
1110 |
|
|
/* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
|
1111 |
|
|
Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
|
1112 |
|
|
"pendingBuf overflow");
|
1113 |
|
|
|
1114 |
|
|
} while (lx < s->last_lit);
|
1115 |
|
|
|
1116 |
|
|
send_code(s, END_BLOCK, ltree);
|
1117 |
|
|
s->last_eob_len = ltree[END_BLOCK].Len;
|
1118 |
|
|
}
|
1119 |
|
|
|
1120 |
|
|
/* ===========================================================================
|
1121 |
|
|
* Set the data type to BINARY or TEXT, using a crude approximation:
|
1122 |
|
|
* set it to Z_TEXT if all symbols are either printable characters (33 to 255)
|
1123 |
|
|
* or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise.
|
1124 |
|
|
* IN assertion: the fields Freq of dyn_ltree are set.
|
1125 |
|
|
*/
|
1126 |
|
|
local void set_data_type(s)
|
1127 |
|
|
deflate_state *s;
|
1128 |
|
|
{
|
1129 |
|
|
int n;
|
1130 |
|
|
|
1131 |
|
|
for (n = 0; n < 9; n++)
|
1132 |
|
|
if (s->dyn_ltree[n].Freq != 0)
|
1133 |
|
|
break;
|
1134 |
|
|
if (n == 9)
|
1135 |
|
|
for (n = 14; n < 32; n++)
|
1136 |
|
|
if (s->dyn_ltree[n].Freq != 0)
|
1137 |
|
|
break;
|
1138 |
|
|
s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY;
|
1139 |
|
|
}
|
1140 |
|
|
|
1141 |
|
|
/* ===========================================================================
|
1142 |
|
|
* Reverse the first len bits of a code, using straightforward code (a faster
|
1143 |
|
|
* method would use a table)
|
1144 |
|
|
* IN assertion: 1 <= len <= 15
|
1145 |
|
|
*/
|
1146 |
|
|
local unsigned bi_reverse(code, len)
|
1147 |
|
|
unsigned code; /* the value to invert */
|
1148 |
|
|
int len; /* its bit length */
|
1149 |
|
|
{
|
1150 |
|
|
register unsigned res = 0;
|
1151 |
|
|
do {
|
1152 |
|
|
res |= code & 1;
|
1153 |
|
|
code >>= 1, res <<= 1;
|
1154 |
|
|
} while (--len > 0);
|
1155 |
|
|
return res >> 1;
|
1156 |
|
|
}
|
1157 |
|
|
|
1158 |
|
|
/* ===========================================================================
|
1159 |
|
|
* Flush the bit buffer, keeping at most 7 bits in it.
|
1160 |
|
|
*/
|
1161 |
|
|
local void bi_flush(s)
|
1162 |
|
|
deflate_state *s;
|
1163 |
|
|
{
|
1164 |
|
|
if (s->bi_valid == 16) {
|
1165 |
|
|
put_short(s, s->bi_buf);
|
1166 |
|
|
s->bi_buf = 0;
|
1167 |
|
|
s->bi_valid = 0;
|
1168 |
|
|
} else if (s->bi_valid >= 8) {
|
1169 |
|
|
put_byte(s, (Byte)s->bi_buf);
|
1170 |
|
|
s->bi_buf >>= 8;
|
1171 |
|
|
s->bi_valid -= 8;
|
1172 |
|
|
}
|
1173 |
|
|
}
|
1174 |
|
|
|
1175 |
|
|
/* ===========================================================================
|
1176 |
|
|
* Flush the bit buffer and align the output on a byte boundary
|
1177 |
|
|
*/
|
1178 |
|
|
local void bi_windup(s)
|
1179 |
|
|
deflate_state *s;
|
1180 |
|
|
{
|
1181 |
|
|
if (s->bi_valid > 8) {
|
1182 |
|
|
put_short(s, s->bi_buf);
|
1183 |
|
|
} else if (s->bi_valid > 0) {
|
1184 |
|
|
put_byte(s, (Byte)s->bi_buf);
|
1185 |
|
|
}
|
1186 |
|
|
s->bi_buf = 0;
|
1187 |
|
|
s->bi_valid = 0;
|
1188 |
|
|
#ifdef DEBUG
|
1189 |
|
|
s->bits_sent = (s->bits_sent+7) & ~7;
|
1190 |
|
|
#endif
|
1191 |
|
|
}
|
1192 |
|
|
|
1193 |
|
|
/* ===========================================================================
|
1194 |
|
|
* Copy a stored block, storing first the length and its
|
1195 |
|
|
* one's complement if requested.
|
1196 |
|
|
*/
|
1197 |
|
|
local void copy_block(s, buf, len, header)
|
1198 |
|
|
deflate_state *s;
|
1199 |
|
|
charf *buf; /* the input data */
|
1200 |
|
|
unsigned len; /* its length */
|
1201 |
|
|
int header; /* true if block header must be written */
|
1202 |
|
|
{
|
1203 |
|
|
bi_windup(s); /* align on byte boundary */
|
1204 |
|
|
s->last_eob_len = 8; /* enough lookahead for inflate */
|
1205 |
|
|
|
1206 |
|
|
if (header) {
|
1207 |
|
|
put_short(s, (ush)len);
|
1208 |
|
|
put_short(s, (ush)~len);
|
1209 |
|
|
#ifdef DEBUG
|
1210 |
|
|
s->bits_sent += 2*16;
|
1211 |
|
|
#endif
|
1212 |
|
|
}
|
1213 |
|
|
#ifdef DEBUG
|
1214 |
|
|
s->bits_sent += (ulg)len<<3;
|
1215 |
|
|
#endif
|
1216 |
|
|
while (len--) {
|
1217 |
|
|
put_byte(s, *buf++);
|
1218 |
|
|
}
|
1219 |
|
|
}
|