/* trees.c -- output deflated data using Huffman coding+
−
 * 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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/*+
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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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 *  REFERENCES+
−
 *+
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 *      Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".+
−
 *      Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc+
−
 *+
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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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/* @(#) $Id$ */+
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+
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/* #define GEN_TREES_H */+
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+
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#include "deflate.h"+
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+
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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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/* ===========================================================================+
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 * Constants+
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 */+
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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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+
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#define END_BLOCK 256+
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/* end of block literal code */+
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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/* ===========================================================================+
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 * Local data. These are initialized only once.+
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 */+
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+
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#define DIST_CODE_LEN  512 /* see definition of array dist_code below */+
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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#else+
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#  include "trees.h"+
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#endif /* GEN_TREES_H */+
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+
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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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+
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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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+
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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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+
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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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/* ===========================================================================+
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 * Local (static) routines in this file.+
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 */+
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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,+
−
                              int blcodes));+
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local void compress_block OF((deflate_state *s, ct_data *ltree,+
−
                              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,+
−
                              int header));+
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+
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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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+
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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.+
−
 * 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)); \+
−
}+
−
+
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/* ===========================================================================+
−
 * 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;+
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    int value;  /* value to send */+
−
    int length; /* number of bits */+
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{+
−
    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 |= (value << s->bi_valid);+
−
        put_short(s, s->bi_buf);+
−
        s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);+
−
        s->bi_valid += length - Buf_size;+
−
    } else {+
−
        s->bi_buf |= value << s->bi_valid;+
−
        s->bi_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 |= (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;\+
−
    s->bi_valid += len;\+
−
  }\+
−
}+
−
#endif /* DEBUG */+
−
+
−
+
−
/* the arguments must not have side effects */+
−
+
−
/* ===========================================================================+
−
 * Initialize the various 'constant' tables.+
−
 */+
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local void tr_static_init()+
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{+
−
#if defined(GEN_TREES_H) || !defined(STDC)+
−
    static int static_init_done = 0;+
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    int n;        /* iterates over tree elements */+
−
    int bits;     /* bit counter */+
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    int length;   /* length value */+
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    int code;     /* code value */+
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    int dist;     /* distance index */+
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    ush bl_count[MAX_BITS+1];+
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    /* 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: */+
−
    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;+
−
+
−
    /* 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 _dist_code[DIST_CODE_LEN] = {\n");+
−
    for (i = 0; i < DIST_CODE_LEN; i++) {+
−
        fprintf(header, "%2u%s", _dist_code[i],+
−
                SEPARATOR(i, DIST_CODE_LEN-1, 20));+
−
    }+
−
+
−
    fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");+
−
    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 _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 _tr_stored_block(s, buf, stored_len, eof)+
−
    deflate_state *s;+
−
    charf *buf;       /* input block */+
−
    ulg stored_len;   /* length of input block */+
−
    int eof;          /* true if this is the last block for a file */+
−
{+
−
    send_bits(s, (STORED_BLOCK<<1)+eof, 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 _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 _tr_flush_block(s, buf, stored_len, eof)+
−
    deflate_state *s;+
−
    charf *buf;       /* input block, or NULL if too old */+
−
    ulg stored_len;   /* length of input block */+
−
    int eof;          /* true if this is the last block for a file */+
−
{+
−
    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 (stored_len > 0 && s->strm->data_type == Z_UNKNOWN)+
−
            set_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, eof);+
−
+
−
#ifdef FORCE_STATIC+
−
    } else if (static_lenb >= 0) { /* force static trees */+
−
#else+
−
    } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {+
−
#endif+
−
        send_bits(s, (STATIC_TREES<<1)+eof, 3);+
−
        compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);+
−
#ifdef DEBUG+
−
        s->compressed_len += 3 + s->static_len;+
−
#endif+
−
    } else {+
−
        send_bits(s, (DYN_TREES<<1)+eof, 3);+
−
        send_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 (eof) {+
−
        bi_windup(s);+
−
#ifdef DEBUG+
−
        s->compressed_len += 7;  /* align on byte boundary */+
−
#endif+
−
    }+
−
    Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,+
−
           s->compressed_len-7*eof));+
−
}+
−
+
−
/* ===========================================================================+
−
 * Save the match info and tally the frequency counts. Return true if+
−
 * the current block must be flushed.+
−
 */+
−
int _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;+
−
}+
−
+
−
/* ===========================================================================+
−
 * Set the data type to BINARY or TEXT, using a crude approximation:+
−
 * set it to Z_TEXT if all symbols are either printable characters (33 to 255)+
−
 * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise.+
−
 * IN assertion: the fields Freq of dyn_ltree are set.+
−
 */+
−
local void set_data_type(s)+
−
    deflate_state *s;+
−
{+
−
    int n;+
−
+
−
    for (n = 0; n < 9; n++)+
−
        if (s->dyn_ltree[n].Freq != 0)+
−
            break;+
−
    if (n == 9)+
−
        for (n = 14; n < 32; n++)+
−
            if (s->dyn_ltree[n].Freq != 0)+
−
                break;+
−
    s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY;+
−
}+
−
+
−
/* ===========================================================================+
−
 * 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++);+
−
    }+
−
}+
−