integrate lzma

[zpackage] / lzma / check / crc64_fast.c

diff --git a/lzma/check/crc64_fast.c b/lzma/check/crc64_fast.c
new file mode 100644 (file)
index 0000000..52af29e
--- /dev/null
+++ b/lzma/check/crc64_fast.c
@@ -0,0 +1,72 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       crc64.c
+/// \brief      CRC64 calculation
+///
+/// Calculate the CRC64 using the slice-by-four algorithm. This is the same
+/// idea that is used in crc32_fast.c, but for CRC64 we use only four tables
+/// instead of eight to avoid increasing CPU cache usage.
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "check.h"
+#include "crc_macros.h"
+
+
+#ifdef WORDS_BIGENDIAN
+#      define A1(x) ((x) >> 56)
+#else
+#      define A1 A
+#endif
+
+
+// See the comments in crc32_fast.c. They aren't duplicated here.
+extern LZMA_API(uint64_t)
+lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc)
+{
+       crc = ~crc;
+
+#ifdef WORDS_BIGENDIAN
+       crc = bswap64(crc);
+#endif
+
+       if (size > 4) {
+               while ((uintptr_t)(buf) & 3) {
+                       crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
+                       --size;
+               }
+
+               const uint8_t *const limit = buf + (size & ~(size_t)(3));
+               size &= (size_t)(3);
+
+               while (buf < limit) {
+#ifdef WORDS_BIGENDIAN
+                       const uint32_t tmp = (crc >> 32)
+                                       ^ *(const uint32_t *)(buf);
+#else
+                       const uint32_t tmp = crc ^ *(const uint32_t *)(buf);
+#endif
+                       buf += 4;
+
+                       crc = lzma_crc64_table[3][A(tmp)]
+                           ^ lzma_crc64_table[2][B(tmp)]
+                           ^ S32(crc)
+                           ^ lzma_crc64_table[1][C(tmp)]
+                           ^ lzma_crc64_table[0][D(tmp)];
+               }
+       }
+
+       while (size-- != 0)
+               crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
+
+#ifdef WORDS_BIGENDIAN
+       crc = bswap64(crc);
+#endif
+
+       return ~crc;
+}