1 files changed, 58 insertions, 19 deletions

diff --git a/C/7zCrc.c b/C/7zCrc.c
index 71962b2c..a9208496 100755
--- a/C/7zCrc.c
+++ b/C/7zCrc.c
@@ -1,35 +1,74 @@
 /* 7zCrc.c -- CRC32 calculation
-2008-08-05
-Igor Pavlov
-Public domain */
+2009-11-23 : Igor Pavlov : Public domain */
 
 #include "7zCrc.h"
+#include "CpuArch.h"
 
 #define kCrcPoly 0xEDB88320
-UInt32 g_CrcTable[256];
 
-void MY_FAST_CALL CrcGenerateTable(void)
+#ifdef MY_CPU_LE
+#define CRC_NUM_TABLES 8
+#else
+#define CRC_NUM_TABLES 1
+#endif
+
+typedef UInt32 (MY_FAST_CALL *CRC_FUNC)(UInt32 v, const void *data, size_t size, const UInt32 *table);
+
+static CRC_FUNC g_CrcUpdate;
+UInt32 g_CrcTable[256 * CRC_NUM_TABLES];
+
+#if CRC_NUM_TABLES == 1
+
+#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
+
+static UInt32 MY_FAST_CALL CrcUpdateT1(UInt32 v, const void *data, size_t size, const UInt32 *table)
 {
-  UInt32 i;
-  for (i = 0; i < 256; i++)
-  {
-    UInt32 r = i;
-    int j;
-    for (j = 0; j < 8; j++)
-      r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
-    g_CrcTable[i] = r;
-  }
+  const Byte *p = (const Byte *)data;
+  for (; size > 0; size--, p++)
+    v = CRC_UPDATE_BYTE_2(v, *p);
+  return v;
 }
 
+#else
+
+UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table);
+UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table);
+
+#endif
+
 UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size)
 {
-  const Byte *p = (const Byte *)data;
-  for (; size > 0 ; size--, p++)
-    v = CRC_UPDATE_BYTE(v, *p);
-  return v;
+  return g_CrcUpdate(v, data, size, g_CrcTable);
 }
 
 UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size)
 {
-  return CrcUpdate(CRC_INIT_VAL, data, size) ^ 0xFFFFFFFF;
+  return g_CrcUpdate(CRC_INIT_VAL, data, size, g_CrcTable) ^ CRC_INIT_VAL;
+}
+
+void MY_FAST_CALL CrcGenerateTable()
+{
+  UInt32 i;
+  for (i = 0; i < 256; i++)
+  {
+    UInt32 r = i;
+    unsigned j;
+    for (j = 0; j < 8; j++)
+      r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
+    g_CrcTable[i] = r;
+  }
+  #if CRC_NUM_TABLES == 1
+  g_CrcUpdate = CrcUpdateT1;
+  #else
+  for (; i < 256 * CRC_NUM_TABLES; i++)
+  {
+    UInt32 r = g_CrcTable[i - 256];
+    g_CrcTable[i] = g_CrcTable[r & 0xFF] ^ (r >> 8);
+  }
+  g_CrcUpdate = CrcUpdateT4;
+  #ifdef MY_CPU_X86_OR_AMD64
+  if (!CPU_Is_InOrder())
+    g_CrcUpdate = CrcUpdateT8;
+  #endif
+  #endif
 }