/* inftrees.c -- generate Huffman trees for efficient decoding
- * Copyright (C) 1995-2005 Mark Adler
+ * Copyright (C) 1995-2010 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#define MAXBITS 15
const char inflate_copyright[] =
- " inflate 1.2.3 Copyright 1995-2005 Mark Adler ";
+ " inflate 1.2.5 Copyright 1995-2010 Mark Adler ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
unsigned fill; /* index for replicating entries */
unsigned low; /* low bits for current root entry */
unsigned mask; /* mask for low root bits */
- code this; /* table entry for duplication */
+ code here; /* table entry for duplication */
code FAR *next; /* next available space in table */
const unsigned short FAR *base; /* base value table to use */
const unsigned short FAR *extra; /* extra bits table to use */
35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
static const unsigned short lext[31] = { /* Length codes 257..285 extra */
16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
- 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 201, 196};
+ 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 73, 195};
static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
if (count[max] != 0) break;
if (root > max) root = max;
if (max == 0) { /* no symbols to code at all */
- this.op = (unsigned char)64; /* invalid code marker */
- this.bits = (unsigned char)1;
- this.val = (unsigned short)0;
- *(*table)++ = this; /* make a table to force an error */
- *(*table)++ = this;
+ here.op = (unsigned char)64; /* invalid code marker */
+ here.bits = (unsigned char)1;
+ here.val = (unsigned short)0;
+ *(*table)++ = here; /* make a table to force an error */
+ *(*table)++ = here;
*bits = 1;
return 0; /* no symbols, but wait for decoding to report error */
}
- for (min = 1; min <= MAXBITS; min++)
+ for (min = 1; min < max; min++)
if (count[min] != 0) break;
if (root < min) root = min;
entered in the tables.
used keeps track of how many table entries have been allocated from the
- provided *table space. It is checked when a LENS table is being made
- against the space in *table, ENOUGH, minus the maximum space needed by
- the worst case distance code, MAXD. This should never happen, but the
- sufficiency of ENOUGH has not been proven exhaustively, hence the check.
- This assumes that when type == LENS, bits == 9.
+ provided *table space. It is checked for LENS and DIST tables against
+ the constants ENOUGH_LENS and ENOUGH_DISTS to guard against changes in
+ the initial root table size constants. See the comments in inftrees.h
+ for more information.
sym increments through all symbols, and the loop terminates when
all codes of length max, i.e. all codes, have been processed. This
mask = used - 1; /* mask for comparing low */
/* check available table space */
- if (type == LENS && used >= ENOUGH - MAXD)
+ if ((type == LENS && used >= ENOUGH_LENS) ||
+ (type == DISTS && used >= ENOUGH_DISTS))
return 1;
/* process all codes and make table entries */
for (;;) {
/* create table entry */
- this.bits = (unsigned char)(len - drop);
+ here.bits = (unsigned char)(len - drop);
if ((int)(work[sym]) < end) {
- this.op = (unsigned char)0;
- this.val = work[sym];
+ here.op = (unsigned char)0;
+ here.val = work[sym];
}
else if ((int)(work[sym]) > end) {
- this.op = (unsigned char)(extra[work[sym]]);
- this.val = base[work[sym]];
+ here.op = (unsigned char)(extra[work[sym]]);
+ here.val = base[work[sym]];
}
else {
- this.op = (unsigned char)(32 + 64); /* end of block */
- this.val = 0;
+ here.op = (unsigned char)(32 + 64); /* end of block */
+ here.val = 0;
}
/* replicate for those indices with low len bits equal to huff */
min = fill; /* save offset to next table */
do {
fill -= incr;
- next[(huff >> drop) + fill] = this;
+ next[(huff >> drop) + fill] = here;
} while (fill != 0);
/* backwards increment the len-bit code huff */
/* check for enough space */
used += 1U << curr;
- if (type == LENS && used >= ENOUGH - MAXD)
+ if ((type == LENS && used >= ENOUGH_LENS) ||
+ (type == DISTS && used >= ENOUGH_DISTS))
return 1;
/* point entry in root table to sub-table */
through high index bits. When the current sub-table is filled, the loop
drops back to the root table to fill in any remaining entries there.
*/
- this.op = (unsigned char)64; /* invalid code marker */
- this.bits = (unsigned char)(len - drop);
- this.val = (unsigned short)0;
+ here.op = (unsigned char)64; /* invalid code marker */
+ here.bits = (unsigned char)(len - drop);
+ here.val = (unsigned short)0;
while (huff != 0) {
/* when done with sub-table, drop back to root table */
if (drop != 0 && (huff & mask) != low) {
drop = 0;
len = root;
next = *table;
- this.bits = (unsigned char)len;
+ here.bits = (unsigned char)len;
}
/* put invalid code marker in table */
- next[huff >> drop] = this;
+ next[huff >> drop] = here;
/* backwards increment the len-bit code huff */
incr = 1U << (len - 1);
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