Revert of Update Zlib to version 1.2.8

third_party/zlib/trees.c

Index: third_party/zlib/trees.c
diff --git a/third_party/zlib/trees.c b/third_party/zlib/trees.c
index 1fd7759ef004c66fd920873efb030eda5d1eafe0..56e9bb1c115e81082f58a89b003b766760e12a12 100644
--- a/third_party/zlib/trees.c
+++ b/third_party/zlib/trees.c
@@ -1,5 +1,5 @@
 /* trees.c -- output deflated data using Huffman coding
- * Copyright (C) 1995-2012 Jean-loup Gailly
+ * Copyright (C) 1995-2010 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
  */
@@ -74,6 +74,11 @@
  * 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.
  */
@@ -146,8 +151,8 @@
 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, const ct_data *ltree,
-                              const ct_data *dtree));
+local void compress_block OF((deflate_state *s, ct_data *ltree,
+                              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));
@@ -394,6 +399,7 @@
 
     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;
@@ -877,17 +883,15 @@
 }
 
 /* ===========================================================================
- * 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;
@@ -898,6 +902,20 @@
     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;
 }
 
 /* ===========================================================================
@@ -972,8 +990,7 @@
     } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
 #endif
         send_bits(s, (STATIC_TREES<<1)+last, 3);
-        compress_block(s, (const ct_data *)static_ltree,
-                       (const ct_data *)static_dtree);
+        compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
 #ifdef DEBUG
         s->compressed_len += 3 + s->static_len;
 #endif
@@ -981,8 +998,7 @@
         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, (const ct_data *)s->dyn_ltree,
-                       (const ct_data *)s->dyn_dtree);
+        compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
 #ifdef DEBUG
         s->compressed_len += 3 + s->opt_len;
 #endif
@@ -1059,8 +1075,8 @@
  */
 local void compress_block(s, ltree, dtree)
     deflate_state *s;
-    const ct_data *ltree; /* literal tree */
-    const ct_data *dtree; /* distance tree */
+    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) */
@@ -1102,6 +1118,7 @@
     } while (lx < s->last_lit);
 
     send_code(s, END_BLOCK, ltree);
+    s->last_eob_len = ltree[END_BLOCK].Len;
 }
 
 /* ===========================================================================
@@ -1209,6 +1226,7 @@
     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);