integrate lzma

[zpackage] / lzma / check / crc64_small.c

diff --git a/lzma/check/crc64_small.c b/lzma/check/crc64_small.c
new file mode 100644 (file)
index 0000000..55d7231
--- /dev/null
+++ b/lzma/check/crc64_small.c
@@ -0,0 +1,53 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       crc64_small.c
+/// \brief      CRC64 calculation (size-optimized)
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "check.h"
+
+
+static uint64_t crc64_table[256];
+
+
+static void
+crc64_init(void)
+{
+       static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);
+
+       for (size_t b = 0; b < 256; ++b) {
+               uint64_t r = b;
+               for (size_t i = 0; i < 8; ++i) {
+                       if (r & 1)
+                               r = (r >> 1) ^ poly64;
+                       else
+                               r >>= 1;
+               }
+
+               crc64_table[b] = r;
+       }
+
+       return;
+}
+
+
+extern LZMA_API(uint64_t)
+lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc)
+{
+       mythread_once(crc64_init);
+
+       crc = ~crc;
+
+       while (size != 0) {
+               crc = crc64_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
+               --size;
+       }
+
+       return ~crc;
+}