zlib: import zlib-1.3.1

This is vanilla zlib-1.3.1 imported over the existing zlib/ dir with:
* README adjusted to add the GCC note at the top;
* GCC's ChangeLog merged with the upstream one, as before;
* Deleted upstream Makefile as has been done before (we use an autoconf-
  generated one)

1 files changed, 52 insertions, 24 deletions

diff --git a/zlib/deflate.h b/zlib/deflate.h
index 360ca23ff34..300c6ada62b 100644
--- a/zlib/deflate.h
+++ b/zlib/deflate.h
@@ -1,5 +1,5 @@
 /* deflate.h -- internal compression state
- * Copyright (C) 1995-2016 Jean-loup Gailly
+ * Copyright (C) 1995-2024 Jean-loup Gailly
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -8,7 +8,7 @@
    subject to change. Applications should only use zlib.h.
  */
 
-/* @(#) $Id: deflate.h,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */
+/* @(#) $Id$ */
 
 #ifndef DEFLATE_H
 #define DEFLATE_H
@@ -23,6 +23,10 @@
 #  define GZIP
 #endif
 
+/* define LIT_MEM to slightly increase the speed of deflate (order 1% to 2%) at
+   the cost of a larger memory footprint */
+/* #define LIT_MEM */
+
 /* ===========================================================================
  * Internal compression state.
  */
@@ -217,7 +221,14 @@ typedef struct internal_state {
     /* Depth of each subtree used as tie breaker for trees of equal frequency
      */
 
-    uchf *l_buf;          /* buffer for literals or lengths */
+#ifdef LIT_MEM
+#   define LIT_BUFS 5
+    ushf *d_buf;          /* buffer for distances */
+    uchf *l_buf;          /* buffer for literals/lengths */
+#else
+#   define LIT_BUFS 4
+    uchf *sym_buf;        /* buffer for distances and literals/lengths */
+#endif
 
     uInt  lit_bufsize;
     /* Size of match buffer for literals/lengths.  There are 4 reasons for
@@ -239,13 +250,8 @@ typedef struct internal_state {
      *   - I can't count above 4
      */
 
-    uInt last_lit;      /* running index in l_buf */
-
-    ushf *d_buf;
-    /* Buffer for distances. To simplify the code, d_buf and l_buf have
-     * the same number of elements. To use different lengths, an extra flag
-     * array would be necessary.
-     */
+    uInt sym_next;      /* running index in symbol buffer */
+    uInt sym_end;       /* symbol table full when sym_next reaches this */
 
     ulg opt_len;        /* bit length of current block with optimal trees */
     ulg static_len;     /* bit length of current block with static trees */
@@ -296,14 +302,14 @@ typedef struct internal_state {
    memory checker errors from longest match routines */
 
         /* in trees.c */
-void ZLIB_INTERNAL _tr_init OF((deflate_state *s));
-int ZLIB_INTERNAL _tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
-void ZLIB_INTERNAL _tr_flush_block OF((deflate_state *s, charf *buf,
-                        ulg stored_len, int last));
-void ZLIB_INTERNAL _tr_flush_bits OF((deflate_state *s));
-void ZLIB_INTERNAL _tr_align OF((deflate_state *s));
-void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
-                        ulg stored_len, int last));
+void ZLIB_INTERNAL _tr_init(deflate_state *s);
+int ZLIB_INTERNAL _tr_tally(deflate_state *s, unsigned dist, unsigned lc);
+void ZLIB_INTERNAL _tr_flush_block(deflate_state *s, charf *buf,
+                                   ulg stored_len, int last);
+void ZLIB_INTERNAL _tr_flush_bits(deflate_state *s);
+void ZLIB_INTERNAL _tr_align(deflate_state *s);
+void ZLIB_INTERNAL _tr_stored_block(deflate_state *s, charf *buf,
+                                    ulg stored_len, int last);
 
 #define d_code(dist) \
    ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
@@ -323,23 +329,45 @@ void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
   extern const uch ZLIB_INTERNAL _dist_code[];
 #endif
 
+#ifdef LIT_MEM
+# define _tr_tally_lit(s, c, flush) \
+  { uch cc = (c); \
+    s->d_buf[s->sym_next] = 0; \
+    s->l_buf[s->sym_next++] = cc; \
+    s->dyn_ltree[cc].Freq++; \
+    flush = (s->sym_next == s->sym_end); \
+   }
+# define _tr_tally_dist(s, distance, length, flush) \
+  { uch len = (uch)(length); \
+    ush dist = (ush)(distance); \
+    s->d_buf[s->sym_next] = dist; \
+    s->l_buf[s->sym_next++] = len; \
+    dist--; \
+    s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
+    s->dyn_dtree[d_code(dist)].Freq++; \
+    flush = (s->sym_next == s->sym_end); \
+  }
+#else
 # define _tr_tally_lit(s, c, flush) \
   { uch cc = (c); \
-    s->d_buf[s->last_lit] = 0; \
-    s->l_buf[s->last_lit++] = cc; \
+    s->sym_buf[s->sym_next++] = 0; \
+    s->sym_buf[s->sym_next++] = 0; \
+    s->sym_buf[s->sym_next++] = cc; \
     s->dyn_ltree[cc].Freq++; \
-    flush = (s->last_lit == s->lit_bufsize-1); \
+    flush = (s->sym_next == s->sym_end); \
    }
 # define _tr_tally_dist(s, distance, length, flush) \
   { uch len = (uch)(length); \
     ush dist = (ush)(distance); \
-    s->d_buf[s->last_lit] = dist; \
-    s->l_buf[s->last_lit++] = len; \
+    s->sym_buf[s->sym_next++] = (uch)dist; \
+    s->sym_buf[s->sym_next++] = (uch)(dist >> 8); \
+    s->sym_buf[s->sym_next++] = len; \
     dist--; \
     s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
     s->dyn_dtree[d_code(dist)].Freq++; \
-    flush = (s->last_lit == s->lit_bufsize-1); \
+    flush = (s->sym_next == s->sym_end); \
   }
+#endif
 #else
 # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
 # define _tr_tally_dist(s, distance, length, flush) \