Upgrade LZF to 3.6 (2011) from 3.5 (2009)

This is lzf_c and lzf_d from
http://dist.schmorp.de/liblzf/liblzf-3.6.tar.gz

1 files changed, 19 insertions, 23 deletions

diff --git a/src/lzf_c.c b/src/lzf_c.c
index 9e031ad0b..e9c69a0b8 100644
--- a/src/lzf_c.c
+++ b/src/lzf_c.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
+ * Copyright (c) 2000-2010 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:
@@ -40,8 +40,8 @@
 
 /*
  * don't play with this unless you benchmark!
- * decompression is not dependent on the hash function
- * the hashing function might seem strange, just believe me
+ * the data format is not dependent on the hash function.
+ * the hash function might seem strange, just believe me,
  * it works ;)
  */
 #ifndef FRST
@@ -89,9 +89,9 @@
 /*
  * compressed format
  *
- * 000LLLLL <L+1>    ; literal
- * LLLooooo oooooooo ; backref L
- * 111ooooo LLLLLLLL oooooooo ; backref L+7
+ * 000LLLLL <L+1>    ; literal, L+1=1..33 octets
+ * LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset
+ * 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset
  *
  */
 
@@ -106,7 +106,6 @@ lzf_compress (const void *const in_data, unsigned int in_len,
 #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;
@@ -133,10 +132,6 @@ lzf_compress (const void *const in_data, unsigned int in_len,
 
 #if INIT_HTAB
   memset (htab, 0, sizeof (htab));
-# if 0
-  for (hslot = htab; hslot < htab + HSIZE; hslot++)
-    *hslot++ = ip;
-# endif
 #endif
 
   lit = 0; op++; /* start run */
@@ -144,24 +139,23 @@ lzf_compress (const void *const in_data, unsigned int in_len,
   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
-          && ip + 4 < in_end
           && ref > (u8 *)in_data
-#if STRICT_ALIGN
-          && ref[0] == ip[0]
-          && ref[1] == ip[1]
           && ref[2] == ip[2]
+#if STRICT_ALIGN
+          && ((ref[1] << 8) | ref[0]) == ((ip[1] << 8) | ip[0])
 #else
           && *(u16 *)ref == *(u16 *)ip
-          && ref[2] == ip[2]
 #endif
         )
         {
@@ -170,12 +164,13 @@ lzf_compress (const void *const in_data, unsigned int in_len,
           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 */
 
-          if (expect_false (op + 3 + 1 >= out_end))
-            return 0;
-
           for (;;)
             {
               if (expect_true (maxlen > 16))
@@ -222,6 +217,7 @@ lzf_compress (const void *const in_data, unsigned int in_len,
             }
 
           *op++ = off;
+
           lit = 0; op++; /* start run */
 
           ip += len + 1;
@@ -237,12 +233,12 @@ lzf_compress (const void *const in_data, unsigned int in_len,
           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
@@ -251,7 +247,7 @@ lzf_compress (const void *const in_data, unsigned int in_len,
           do
             {
               hval = NEXT (hval, ip);
-              htab[IDX (hval)] = ip;
+              htab[IDX (hval)] = ip - LZF_HSLOT_BIAS;
               ip++;
             }
           while (len--);