X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=ucw%2Fcrc.c;h=070a261642db4df11a994f0361165860c5af10b5;hb=e4c86af69014f1a129098c5edf8706e9d08dbb4e;hp=2f818840b3c1d29832eca1e3d6b0ef5ffde3ad53;hpb=ae7dfec55384883a72867d4877b5283a3c1c8aa1;p=libucw.git

diff --git a/ucw/crc.c b/ucw/crc.c
index 2f818840..070a2616 100644
--- a/ucw/crc.c
+++ b/ucw/crc.c
@@ -32,7 +32,12 @@ static void crc32_update_by4(crc32_context *ctx, const byte *buf, uint len)
 {
   uint init_bytes, words;
   u32 crc = ctx->state;
-  u32 term1, term2, *buf32;
+  u32 term1, term2;
+  const u32 *buf32;
+
+  // Special case
+  if (len < 4)
+    goto small;
 
   // Align start address to a multiple of 4 bytes
   init_bytes = ((uintptr_t) buf) & 3;
@@ -47,7 +52,7 @@ static void crc32_update_by4(crc32_context *ctx, const byte *buf, uint len)
   // Process 4 bytes at a time
   words = len/4;
   len -= 4*words;
-  buf32 = (u32 *) buf;
+  buf32 = (const u32 *) buf;
   while (words--)
     {
       crc ^= *buf32++;
@@ -59,7 +64,8 @@ static void crc32_update_by4(crc32_context *ctx, const byte *buf, uint len)
     }
 
   // Process remaining up to 7 bytes
-  buf = (byte *) buf32;
+  buf = (const byte *) buf32;
+small:
   while (len--)
     crc = crc_tableil8_o32[(crc ^ *buf++) & 0x000000FF] ^ (crc >> 8);
 
@@ -70,7 +76,12 @@ static void crc32_update_by8(crc32_context *ctx, const byte *buf, uint len)
 {
   uint init_bytes, quads;
   u32 crc = ctx->state;
-  u32 term1, term2, *buf32;
+  u32 term1, term2;
+  const u32 *buf32;
+
+  // Special case
+  if (len < 8)
+    goto small;
 
   // Align start address to a multiple of 8 bytes
   init_bytes = ((uintptr_t) buf) & 7;
@@ -85,7 +96,7 @@ static void crc32_update_by8(crc32_context *ctx, const byte *buf, uint len)
   // Process 8 bytes at a time
   quads = len/8;
   len -= 8*quads;
-  buf32 = (u32 *) buf;
+  buf32 = (const u32 *) buf;
   while (quads--)
     {
       crc ^= *buf32++;
@@ -107,7 +118,8 @@ static void crc32_update_by8(crc32_context *ctx, const byte *buf, uint len)
     }
 
   // Process remaining up to 7 bytes
-  buf = (byte *) buf32;
+  buf = (const byte *) buf32;
+small:
   while (len--)
     crc = crc_tableil8_o32[(crc ^ *buf++) & 0x000000FF] ^ (crc >> 8);