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-rwxr-xr-xC/7zCrcOpt.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/C/7zCrcOpt.c b/C/7zCrcOpt.c
new file mode 100755
index 0000000..6205d71
--- /dev/null
+++ b/C/7zCrcOpt.c
@@ -0,0 +1,34 @@
+/* 7zCrcOpt.c -- CRC32 calculation : optimized version
+2009-11-23 : Igor Pavlov : Public domain */
+
+#include "CpuArch.h"
+
+#ifdef MY_CPU_LE
+
+#define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
+
+UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
+{
+ const Byte *p = (const Byte *)data;
+ for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
+ v = CRC_UPDATE_BYTE_2(v, *p);
+ for (; size >= 4; size -= 4, p += 4)
+ {
+ v ^= *(const UInt32 *)p;
+ v =
+ table[0x300 + (v & 0xFF)] ^
+ table[0x200 + ((v >> 8) & 0xFF)] ^
+ table[0x100 + ((v >> 16) & 0xFF)] ^
+ table[0x000 + ((v >> 24))];
+ }
+ for (; size > 0; size--, p++)
+ v = CRC_UPDATE_BYTE_2(v, *p);
+ return v;
+}
+
+UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
+{
+ return CrcUpdateT4(v, data, size, table);
+}
+
+#endif