'21.07'21.07

1 files changed, 86 insertions, 0 deletions

diff --git a/C/XzCrc64.c b/C/XzCrc64.c
new file mode 100644
index 0000000..b6d02cb
--- /dev/null
+++ b/C/XzCrc64.c
@@ -0,0 +1,86 @@
+/* XzCrc64.c -- CRC64 calculation
+2017-05-23 : Igor Pavlov : Public domain */
+
+#include "Precomp.h"
+
+#include "XzCrc64.h"
+#include "CpuArch.h"
+
+#define kCrc64Poly UINT64_CONST(0xC96C5795D7870F42)
+
+#ifdef MY_CPU_LE
+  #define CRC64_NUM_TABLES 4
+#else
+  #define CRC64_NUM_TABLES 5
+  #define CRC_UINT64_SWAP(v) \
+      ((v >> 56) \
+    | ((v >> 40) & ((UInt64)0xFF <<  8)) \
+    | ((v >> 24) & ((UInt64)0xFF << 16)) \
+    | ((v >>  8) & ((UInt64)0xFF << 24)) \
+    | ((v <<  8) & ((UInt64)0xFF << 32)) \
+    | ((v << 24) & ((UInt64)0xFF << 40)) \
+    | ((v << 40) & ((UInt64)0xFF << 48)) \
+    | ((v << 56)))
+
+  UInt64 MY_FAST_CALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
+#endif
+
+#ifndef MY_CPU_BE
+  UInt64 MY_FAST_CALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
+#endif
+
+typedef UInt64 (MY_FAST_CALL *CRC64_FUNC)(UInt64 v, const void *data, size_t size, const UInt64 *table);
+
+static CRC64_FUNC g_Crc64Update;
+UInt64 g_Crc64Table[256 * CRC64_NUM_TABLES];
+
+UInt64 MY_FAST_CALL Crc64Update(UInt64 v, const void *data, size_t size)
+{
+  return g_Crc64Update(v, data, size, g_Crc64Table);
+}
+
+UInt64 MY_FAST_CALL Crc64Calc(const void *data, size_t size)
+{
+  return g_Crc64Update(CRC64_INIT_VAL, data, size, g_Crc64Table) ^ CRC64_INIT_VAL;
+}
+
+void MY_FAST_CALL Crc64GenerateTable()
+{
+  UInt32 i;
+  for (i = 0; i < 256; i++)
+  {
+    UInt64 r = i;
+    unsigned j;
+    for (j = 0; j < 8; j++)
+      r = (r >> 1) ^ (kCrc64Poly & ((UInt64)0 - (r & 1)));
+    g_Crc64Table[i] = r;
+  }
+  for (i = 256; i < 256 * CRC64_NUM_TABLES; i++)
+  {
+    UInt64 r = g_Crc64Table[(size_t)i - 256];
+    g_Crc64Table[i] = g_Crc64Table[r & 0xFF] ^ (r >> 8);
+  }
+  
+  #ifdef MY_CPU_LE
+
+  g_Crc64Update = XzCrc64UpdateT4;
+
+  #else
+  {
+    #ifndef MY_CPU_BE
+    UInt32 k = 1;
+    if (*(const Byte *)&k == 1)
+      g_Crc64Update = XzCrc64UpdateT4;
+    else
+    #endif
+    {
+      for (i = 256 * CRC64_NUM_TABLES - 1; i >= 256; i--)
+      {
+        UInt64 x = g_Crc64Table[(size_t)i - 256];
+        g_Crc64Table[i] = CRC_UINT64_SWAP(x);
+      }
+      g_Crc64Update = XzCrc64UpdateT1_BeT4;
+    }
+  }
+  #endif
+}