dist/zlib/trees.c

48 /* Bit length codes must not exceed MAX_BL_BITS bits */
54 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
57 /* repeat a zero length 3-10 times  (3 bits of repeat count) */
60 /* repeat a zero length 11-138 times  (7 bits of repeat count) */
62 local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
65 local const int extra_dbits[D_CODES] /* extra bits for each distance code */
68 local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
95  * 5 bits.)
100  * 3 .. 258, the last 256 values correspond to the top 8 bits of
119     const intf *extra_bits;      /* extra bits for each code or NULL */
180  * Send a value on a given number of bits.
181  * IN assertion: length <= 16 and value fits in length bits.
189     int length; /* number of bits */
195     /* If not enough room in bi_buf, use (valid) bits from bi_buf and
196      * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
197      * unused bits in value.
237     int bits;     /* bit counter */
265      * in two different ways: code 284 + 5 bits or code 285, so we
289     for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
498     int bits;           /* bit length */
499     int xbits;          /* extra bits */
503     for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
512         bits = tree[tree[n].Dad].Len + 1;
513         if (bits > max_length) bits = max_length, overflow++;
514         tree[n].Len = (ush)bits;
519         s->bl_count[bits]++;
523         s->opt_len += (ulg)f * (unsigned)(bits + xbits);
533         bits = max_length-1;
534         while (s->bl_count[bits] == 0) bits--;
535         s->bl_count[bits]--;      /* move one leaf down the tree */
536         s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
549     for (bits = max_length; bits != 0; bits--) {
550         n = s->bl_count[bits];
554             if ((unsigned) tree[m].Len != (unsigned) bits) {
555                 Tracev((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
556                 s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq;
557                 tree[m].Len = (ush)bits;
579     int bits;                  /* bit index */
585     for (bits = 1; bits <= MAX_BITS; bits++) {
586         code = (code + bl_count[bits-1]) << 1;
587         next_code[bits] = (ush)code;
599         /* Now reverse the bits */
651         /* node is 0 or 1 so it does not have extra bits */
811      * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
885  * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
895  * This takes 10 bits, of which 7 may remain in the bit buffer.
997      * and uLong implemented on 32 bits.
1052     int extra;          /* number of extra bits to send */
1068                 send_bits(s, lc, extra);       /* send the extra length bits */
1078                 send_bits(s, dist, extra);   /* send the extra distance bits */
1107      * set bits 0..6, 14..25, and 28..31
1133  * Reverse the first len bits of a code, using straightforward code (a faster
1150  * Flush the bit buffer, keeping at most 7 bits in it.