[ViewVC] Diff of: cvs/liblzf/lzf

Comparing liblzf/lzf_c.c (file contents):
Revision 1.40 by root, Tue Jun 1 01:50:24 2010 UTC vs.
Revision 1.51 by root, Wed May 24 18:37:18 2017 UTC

 /*
- * Copyright (c) 2000-2010 Marc Alexander Lehmann <schmorp@schmorp.de>
+ * Copyright (c) 2000-2010,2012 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:
  *
  *   1.  Redistributions of source code must retain the above copyright notice,
  *       this list of conditions and the following disclaimer.
  *
  *   2.  Redistributions in binary form must reproduce the above copyright
  *       notice, this list of conditions and the following disclaimer in the
  *       documentation and/or other materials provided with the distribution.
  *
  * 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
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 #define HSIZE (1 << (HLOG))
 /*
  * don't play with this unless you benchmark!
- * decompression is not dependent on the hash function
+ * the data format is not dependent on the hash function.
- * the hashing function might seem strange, just believe me
+ * the hash function might seem strange, just believe me,
  * it works ;)
  */
 #ifndef FRST
 # define FRST(p) (((p[0]) << 8) | p[1])
 # define NEXT(v,p) (((v) << 8) | p[2])
+# if MULTIPLICATION_IS_SLOW
-# if ULTRA_FAST
+#  if ULTRA_FAST
-#  define IDX(h) ((( h             >> (3*8 - HLOG)) - h  ) & (HSIZE - 1))
+#   define IDX(h) ((( h             >> (3*8 - HLOG)) - h  ) & (HSIZE - 1))
-# elif VERY_FAST
+#  elif VERY_FAST
-#  define IDX(h) ((( h             >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
+#   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
 # else
+/* this one was developed with sesse,
+ * and is very similar to the one in snappy.
+ * it does need a modern enough cpu with a fast multiplication.
+ */
-#  define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
+#  define IDX(h) (((h * 0x1e35a7bdU) >> (32 - HLOG - 8)) & (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 compresses similarly.
- *
- * the next one is also quite good, albeit slow ;)
- * (int)(cos(h & 0xffffff) * 1e6)
- */
 #if 0
 /* original lzv-like hash function, much worse and thus slower */
 # define FRST(p) (p[0] << 5) ^ p[1]
 # define NEXT(v,p) ((v) << 5) ^ p[2]
 # define IDX(h) ((h) & (HSIZE - 1))
 #endif
-#define        MAX_LIT        (1 <<  5)
-#define        MAX_OFF        (1 << 13)
-#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)
               )
 {
 #if !LZF_STATE_ARG
   LZF_STATE htab;
 #endif
-  const u8 **hslot;
   const u8 *ip = (const u8 *)in_data;
         u8 *op = (u8 *)out_data;
   const u8 *in_end  = ip + in_len;
         u8 *out_end = op + out_len;
   const u8 *ref;
   /* 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
+   * works for differences within a single object). We also assume that
    * 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)
+#if defined (_WIN32) && defined (_M_X64)
-  unsigned _int64 off; /* workaround for missing POSIX compliance */
+  /* workaround for missing POSIX compliance */
+  #if __GNUC__
+    unsigned long long off;
+  #else
+    unsigned __int64 off;
+  #endif
 #else
   unsigned long off;
 #endif
   unsigned int hval;
   int lit;
   if (!in_len || !out_len)
     return 0;
 #if INIT_HTAB
-  memset (htab, 0, sizeof (htab));
+  memset (htab, 0, sizeof (LZF_STATE));
-# if 0
-  for (hslot = htab; hslot < htab + HSIZE; hslot++)
-    *hslot++ = ip;
-# endif
 #endif
   lit = 0; op++; /* start run */
   hval = FRST (ip);
   while (ip < in_end - 2)
     {
+      LZF_HSLOT *hslot;
       hval = NEXT (hval, ip);
       hslot = htab + IDX (hval);
-      ref = *hslot; *hslot = ip;
+      ref = *hslot + LZF_HSLOT_BIAS; *hslot = ip - LZF_HSLOT_BIAS;
       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
+          && (off = ip - ref - 1) < LZF_MAX_OFF
-          && ip + 4 < in_end
           && ref > (u8 *)in_data
           && ref[2] == ip[2]
 #if STRICT_ALIGN
-          && (ref[1] << 8) | ref[0] == (ip[1] << 8) | ip[0]
+          && ((ref[1] << 8) | ref[0]) == ((ip[1] << 8) | ip[0])
 #else
           && *(u16 *)ref == *(u16 *)ip
 #endif
         )
         {
           /* match found at *ref++ */
           unsigned int len = 2;
           unsigned int maxlen = in_end - ip - len;
-          maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
+          maxlen = maxlen > LZF_MAX_REF ? LZF_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++ = (off >> 8) + (  7 << 5);
               *op++ = len - 7;
             }
           *op++ = off;
           lit = 0; op++; /* start run */
           ip += len + 1;
           if (expect_false (ip >= in_end - 2))
           --ip;
 # endif
           hval = FRST (ip);
           hval = NEXT (hval, ip);
-          htab[IDX (hval)] = ip;
+          htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
           ip++;
 # if VERY_FAST && !ULTRA_FAST
           hval = NEXT (hval, ip);
-          htab[IDX (hval)] = ip;
+          htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
           ip++;
 # endif
 #else
           ip -= len + 1;
           do
             {
               hval = NEXT (hval, ip);
-              htab[IDX (hval)] = ip;
+              htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
               ip++;
             }
           while (len--);
 #endif
         }
           if (expect_false (op >= out_end))
             return 0;
           lit++; *op++ = *ip++;
-          if (expect_false (lit == MAX_LIT))
+          if (expect_false (lit == LZF_MAX_LIT))
             {
               op [- lit - 1] = lit - 1; /* stop run */
               lit = 0; op++; /* start run */
             }
         }
   while (ip < in_end)
     {
       lit++; *op++ = *ip++;
-      if (expect_false (lit == MAX_LIT))
+      if (expect_false (lit == LZF_MAX_LIT))
         {
           op [- lit - 1] = lit - 1; /* stop run */
           lit = 0; op++; /* start run */
         }
     }

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Comparing liblzf/lzf_c.c (file contents): Revision 1.40 by root, Tue Jun 1 01:50:24 2010 UTC vs. Revision 1.51 by root, Wed May 24 18:37:18 2017 UTC

Diff Legend

Comparing liblzf/lzf_c.c (file contents):
Revision 1.40 by root, Tue Jun 1 01:50:24 2010 UTC vs.
Revision 1.51 by root, Wed May 24 18:37:18 2017 UTC