*** empty log message ***

1 files changed, 171 insertions, 117 deletions

diff --git a/src/liblzf/lzf_c.c b/src/liblzf/lzf_c.c
index b9b9ef9..0b5d816 100644
--- a/src/liblzf/lzf_c.c
+++ b/src/liblzf/lzf_c.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2005 Marc Alexander Lehmann <schmorp@schmorp.de>
+ * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
  * 
  * Redistribution and use in source and binary forms, with or without modifica-
  * tion, are permitted provided that the following conditions are met:
@@ -11,9 +11,6 @@
  *       notice, this list of conditions and the following disclaimer in the
  *       documentation and/or other materials provided with the distribution.
  * 
- *   3.  The name of the author may not be used to endorse or promote products
- *       derived from this software without specific prior written permission.
- * 
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
@@ -26,14 +23,15 @@
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Alternatively, the contents of this file may be used under the terms of
- * the GNU General Public License version 2 (the "GPL"), in which case the
- * provisions of the GPL are applicable instead of the above. If you wish to
- * allow the use of your version of this file only under the terms of the
- * GPL and not to allow others to use your version of this file under the
- * BSD license, indicate your decision by deleting the provisions above and
- * replace them with the notice and other provisions required by the GPL. If
- * you do not delete the provisions above, a recipient may use your version
- * of this file under either the BSD or the GPL.
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
  */
 
 #include "lzfP.h"
@@ -49,12 +47,18 @@
 #ifndef FRST
 # define FRST(p) (((p[0]) << 8) | p[1])
 # define NEXT(v,p) (((v) << 8) | p[2])
-# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
+# if ULTRA_FAST
+#  define IDX(h) ((( h             >> (3*8 - HLOG)) - h  ) & (HSIZE - 1))
+# elif VERY_FAST
+#  define IDX(h) ((( h             >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
+# else
+#  define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
+# endif
 #endif
 /*
  * IDX works because it is very similar to a multiplicative hash, e.g.
  * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
- * the latter is also quite fast on newer CPUs, and sligthly better
+ * the latter is also quite fast on newer CPUs, and compresses similarly.
  *
  * the next one is also quite good, albeit slow ;)
  * (int)(cos(h & 0xffffff) * 1e6)
@@ -69,7 +73,18 @@
 
 #define        MAX_LIT        (1 <<  5)
 #define        MAX_OFF        (1 << 13)
-#define        MAX_REF        ((1 <<  8) + (1 << 3))
+#define        MAX_REF        ((1 << 8) + (1 << 3))
+
+#if __GNUC__ >= 3
+# define expect(expr,value)         __builtin_expect ((expr),(value))
+# define inline                     inline
+#else
+# define expect(expr,value)         (expr)
+# define inline                     static
+#endif
+
+#define expect_false(expr) expect ((expr) != 0, 0)
+#define expect_true(expr)  expect ((expr) != 0, 1)
 
 /*
  * compressed format
@@ -84,7 +99,7 @@ unsigned int
 lzf_compress (const void *const in_data, unsigned int in_len,
 	      void *out_data, unsigned int out_len
 #if LZF_STATE_ARG
-              , LZF_STATE *htab
+              , LZF_STATE htab
 #endif
               )
 {
@@ -98,145 +113,184 @@ lzf_compress (const void *const in_data, unsigned int in_len,
         u8 *out_end = op + out_len;
   const u8 *ref;
 
-  unsigned int hval = FRST (ip);
+  /* off requires a type wide enough to hold a general pointer difference.
+   * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
+   * works for differences within a single object). We also assume that no
+   * no bit pattern traps. Since the only platform that is both non-POSIX
+   * and fails to support both assumptions is windows 64 bit, we make a
+   * special workaround for it.
+   */
+#if defined (WIN32) && defined (_M_X64)
+  unsigned _int64 off; /* workaround for missing POSIX compliance */
+#else
   unsigned long off;
-           int lit = 0;
+#endif
+  unsigned int hval;
+  int lit;
+
+  if (!in_len || !out_len)
+    return 0;
 
 #if INIT_HTAB
-# if USE_MEMCPY
-    memset (htab, 0, sizeof (htab));
-# else
-    for (hslot = htab; hslot < htab + HSIZE; hslot++)
-      *hslot++ = ip;
+  memset (htab, 0, sizeof (htab));
+# if 0
+  for (hslot = htab; hslot < htab + HSIZE; hslot++)
+    *hslot++ = ip;
 # endif
 #endif
 
-  for (;;)
+  lit = 0; op++; /* start run */
+
+  hval = FRST (ip);
+  while (ip < in_end - 2)
     {
-      if (ip < in_end - 2)
-        {
-          hval = NEXT (hval, ip);
-          hslot = htab + IDX (hval);
-          ref = *hslot; *hslot = ip;
+      hval = NEXT (hval, ip);
+      hslot = htab + IDX (hval);
+      ref = *hslot; *hslot = ip;
 
-          if (1
-#if INIT_HTAB && !USE_MEMCPY
-              && ref < ip /* the next test will actually take care of this, but this is faster */
+      if (1
+#if INIT_HTAB
+          && ref < ip /* the next test will actually take care of this, but this is faster */
 #endif
-              && (off = ip - ref - 1) < MAX_OFF
-              && ip + 4 < in_end
-              && ref > (u8 *)in_data
+          && (off = ip - ref - 1) < MAX_OFF
+          && ip + 4 < in_end
+          && ref > (u8 *)in_data
 #if STRICT_ALIGN
-              && ref[0] == ip[0]
-              && ref[1] == ip[1]
-              && ref[2] == ip[2]
+          && ref[0] == ip[0]
+          && ref[1] == ip[1]
+          && ref[2] == ip[2]
 #else
-              && *(u16 *)ref == *(u16 *)ip
-              && ref[2] == ip[2]
+          && *(u16 *)ref == *(u16 *)ip
+          && ref[2] == ip[2]
 #endif
-            )
+        )
+        {
+          /* match found at *ref++ */
+          unsigned int len = 2;
+          unsigned int maxlen = in_end - ip - len;
+          maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
+
+          if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
+            if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
+              return 0;
+
+          op [- lit - 1] = lit - 1; /* stop run */
+          op -= !lit; /* undo run if length is zero */
+
+          for (;;)
             {
-              /* match found at *ref++ */
-              unsigned int len = 2;
-              unsigned int maxlen = in_end - ip - len;
-              maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
+              if (expect_true (maxlen > 16))
+                {
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
 
-              if (op + lit + 1 + 3 >= out_end)
-                return 0;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                  len++; if (ref [len] != ip [len]) break;
+                }
 
               do
                 len++;
               while (len < maxlen && ref[len] == ip[len]);
 
-              if (lit)
-                {
-                  *op++ = lit - 1;
-                  lit = -lit;
-                  do
-                    *op++ = ip[lit];
-                  while (++lit);
-                }
+              break;
+            }
 
-              len -= 2;
-              ip++;
+          len -= 2; /* len is now #octets - 1 */
+          ip++;
 
-              if (len < 7)
-                {
-                  *op++ = (off >> 8) + (len << 5);
-                }
-              else
-                {
-                  *op++ = (off >> 8) + (  7 << 5);
-                  *op++ = len - 7;
-                }
+          if (len < 7)
+            {
+              *op++ = (off >> 8) + (len << 5);
+            }
+          else
+            {
+              *op++ = (off >> 8) + (  7 << 5);
+              *op++ = len - 7;
+            }
 
-              *op++ = off;
+          *op++ = off;
+          lit = 0; op++; /* start run */
+
+          ip += len + 1;
+
+          if (expect_false (ip >= in_end - 2))
+            break;
 
 #if ULTRA_FAST || VERY_FAST
-              ip += len;
-#if VERY_FAST && !ULTRA_FAST
-              --ip;
-#endif
-              hval = FRST (ip);
+          --ip;
+# if VERY_FAST && !ULTRA_FAST
+          --ip;
+# endif
+          hval = FRST (ip);
 
-              hval = NEXT (hval, ip);
-              htab[IDX (hval)] = ip;
-              ip++;
+          hval = NEXT (hval, ip);
+          htab[IDX (hval)] = ip;
+          ip++;
+
+# if VERY_FAST && !ULTRA_FAST
+          hval = NEXT (hval, ip);
+          htab[IDX (hval)] = ip;
+          ip++;
+# endif
+#else
+          ip -= len + 1;
 
-#if VERY_FAST && !ULTRA_FAST
+          do
+            {
               hval = NEXT (hval, ip);
               htab[IDX (hval)] = ip;
               ip++;
-#endif
-#else
-              do
-                {
-                  hval = NEXT (hval, ip);
-                  htab[IDX (hval)] = ip;
-                  ip++;
-                }
-              while (len--);
-#endif
-              continue;
             }
+          while (len--);
+#endif
         }
-      else if (ip == in_end)
-        break;
-
-      /* one more literal byte we must copy */
-      lit++;
-      ip++;
-
-      if (lit == MAX_LIT)
+      else
         {
-          if (op + 1 + MAX_LIT >= out_end)
+          /* one more literal byte we must copy */
+          if (expect_false (op >= out_end))
             return 0;
 
-          *op++ = MAX_LIT - 1;
-#if USE_MEMCPY
-          memcpy (op, ip - MAX_LIT, MAX_LIT);
-          op += MAX_LIT;
-          lit = 0;
-#else
-          lit = -lit;
-          do
-            *op++ = ip[lit];
-          while (++lit);
-#endif
+          lit++; *op++ = *ip++;
+
+          if (expect_false (lit == MAX_LIT))
+            {
+              op [- lit - 1] = lit - 1; /* stop run */
+              lit = 0; op++; /* start run */
+            }
         }
     }
 
-  if (lit)
+  if (op + 3 > out_end) /* at most 3 bytes can be missing here */
+    return 0;
+
+  while (ip < in_end)
     {
-      if (op + lit + 1 >= out_end)
-	return 0;
-
-      *op++ = lit - 1;
-      lit = -lit;
-      do
-	*op++ = ip[lit];
-      while (++lit);
+      lit++; *op++ = *ip++;
+
+      if (expect_false (lit == MAX_LIT))
+        {
+          op [- lit - 1] = lit - 1; /* stop run */
+          lit = 0; op++; /* start run */
+        }
     }
 
-  return op - (u8 *) out_data;
+  op [- lit - 1] = lit - 1; /* end run */
+  op -= !lit; /* undo run if length is zero */
+
+  return op - (u8 *)out_data;
 }
+