Revert of Update Zlib to version 1.2.8

third_party/zlib/trees.c

 /* 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
  */
 
 /*
  *  ALGORITHM
  *
  *      The "deflation" process uses several Huffman trees. The more
  *      common source values are represented by shorter bit sequences.
  *
@@ skipping 54 matching lines @@
 
 local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
    = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
 
 local const uch bl_order[BL_CODES]
    = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
 /* The lengths of the bit length codes are sent in order of decreasing
  * 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.
  */
 
 #define DIST_CODE_LEN  512 /* see definition of array dist_code below */
 
 #if defined(GEN_TREES_H) || !defined(STDC)
 /* non ANSI compilers may not accept trees.h */
 
 local ct_data static_ltree[L_CODES+2];
@@ skipping 52 matching lines @@
 local void init_block     OF((deflate_state *s));
 local void pqdownheap     OF((deflate_state *s, ct_data *tree, int k));
 local void gen_bitlen     OF((deflate_state *s, tree_desc *desc));
 local void gen_codes      OF((ct_data *tree, int max_code, ushf *bl_count));
 local void build_tree     OF((deflate_state *s, tree_desc *desc));
 local void scan_tree      OF((deflate_state *s, ct_data *tree, int max_code));
 local void send_tree      OF((deflate_state *s, ct_data *tree, int max_code));
 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));
 local void bi_flush       OF((deflate_state *s));
 local void copy_block     OF((deflate_state *s, charf *buf, unsigned len,
                               int header));
 
 #ifdef GEN_TREES_H
 local void gen_trees_header OF((void));
 #endif
@@ skipping 226 matching lines @@
     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);
 }
 
 /* ===========================================================================
@@ skipping 463 matching lines @@
 {
     send_bits(s, (STORED_BLOCK<<1)+last, 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 */
 }
 
 /* ===========================================================================
- * 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;
 {
     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 ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
     deflate_state *s;
     charf *buf;       /* input block, or NULL if too old */
     ulg stored_len;   /* length of input block */
@@ skipping 54 matching lines @@
          * transform a block into a stored block.
          */
         _tr_stored_block(s, buf, stored_len, last);
 
 #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)+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
     } else {
         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
     }
     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);
 
@@ skipping 56 matching lines @@
      * 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;
-    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) */
     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++];
@@ skipping 21 matching lines @@
             }
         } /* 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;
 }
 
 /* ===========================================================================
  * Check if the data type is TEXT or BINARY, using the following algorithm:
  * - TEXT if the two conditions below are satisfied:
  *    a) There are no non-portable control characters belonging to the
  *       "black list" (0..6, 14..25, 28..31).
  *    b) There is at least one printable character belonging to the
  *       "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
  * - BINARY otherwise.
@@ skipping 87 matching lines @@
  * 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++);
     }
 }