Issue #18527: Upgrade internal copy of zlib to 1.2.8
diff --git a/Modules/zlib/trees.c b/Modules/zlib/trees.c
index 56e9bb1..1fd7759 100644
--- a/Modules/zlib/trees.c
+++ b/Modules/zlib/trees.c
@@ -1,5 +1,5 @@
/* trees.c -- output deflated data using Huffman coding
- * Copyright (C) 1995-2010 Jean-loup Gailly
+ * Copyright (C) 1995-2012 Jean-loup Gailly
* detect_data_type() function provided freely by Cosmin Truta, 2006
* For conditions of distribution and use, see copyright notice in zlib.h
*/
@@ -74,11 +74,6 @@
* probability, to avoid transmitting the lengths for unused bit length codes.
*/
-#define Buf_size (8 * 2*sizeof(char))
-/* Number of bits used within bi_buf. (bi_buf might be implemented on
- * more than 16 bits on some systems.)
- */
-
/* ===========================================================================
* Local data. These are initialized only once.
*/
@@ -151,8 +146,8 @@
local int build_bl_tree OF((deflate_state *s));
local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
int blcodes));
-local void compress_block OF((deflate_state *s, ct_data *ltree,
- ct_data *dtree));
+local void compress_block OF((deflate_state *s, const ct_data *ltree,
+ const ct_data *dtree));
local int detect_data_type OF((deflate_state *s));
local unsigned bi_reverse OF((unsigned value, int length));
local void bi_windup OF((deflate_state *s));
@@ -399,7 +394,6 @@
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;
@@ -883,15 +877,17 @@
}
/* ===========================================================================
+ * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
+ */
+void ZLIB_INTERNAL _tr_flush_bits(s)
+ deflate_state *s;
+{
+ bi_flush(s);
+}
+
+/* ===========================================================================
* Send one empty static block to give enough lookahead for inflate.
* This takes 10 bits, of which 7 may remain in the bit buffer.
- * The current inflate code requires 9 bits of lookahead. If the
- * last two codes for the previous block (real code plus EOB) were coded
- * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
- * the last real code. In this case we send two empty static blocks instead
- * of one. (There are no problems if the previous block is stored or fixed.)
- * To simplify the code, we assume the worst case of last real code encoded
- * on one bit only.
*/
void ZLIB_INTERNAL _tr_align(s)
deflate_state *s;
@@ -902,20 +898,6 @@
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;
}
/* ===========================================================================
@@ -990,7 +972,8 @@
} else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
#endif
send_bits(s, (STATIC_TREES<<1)+last, 3);
- compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
+ compress_block(s, (const ct_data *)static_ltree,
+ (const ct_data *)static_dtree);
#ifdef DEBUG
s->compressed_len += 3 + s->static_len;
#endif
@@ -998,7 +981,8 @@
send_bits(s, (DYN_TREES<<1)+last, 3);
send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
max_blindex+1);
- compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
+ compress_block(s, (const ct_data *)s->dyn_ltree,
+ (const ct_data *)s->dyn_dtree);
#ifdef DEBUG
s->compressed_len += 3 + s->opt_len;
#endif
@@ -1075,8 +1059,8 @@
*/
local void compress_block(s, ltree, dtree)
deflate_state *s;
- ct_data *ltree; /* literal tree */
- ct_data *dtree; /* distance tree */
+ const ct_data *ltree; /* literal tree */
+ const ct_data *dtree; /* distance tree */
{
unsigned dist; /* distance of matched string */
int lc; /* match length or unmatched char (if dist == 0) */
@@ -1118,7 +1102,6 @@
} while (lx < s->last_lit);
send_code(s, END_BLOCK, ltree);
- s->last_eob_len = ltree[END_BLOCK].Len;
}
/* ===========================================================================
@@ -1226,7 +1209,6 @@
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);