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authorLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
committerLasse Collin <lasse.collin@tukaani.org>2007-12-09 00:42:33 +0200
commit5d018dc03549c1ee4958364712fb0c94e1bf2741 (patch)
tree1b211911fb33fddb3f04b77f99e81df23623ffc4 /src/liblzma/check/crc64_init.c
downloadxz-5d018dc03549c1ee4958364712fb0c94e1bf2741.tar.xz
Imported to git.
Diffstat (limited to 'src/liblzma/check/crc64_init.c')
-rw-r--r--src/liblzma/check/crc64_init.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/src/liblzma/check/crc64_init.c b/src/liblzma/check/crc64_init.c
new file mode 100644
index 00000000..49c59e93
--- /dev/null
+++ b/src/liblzma/check/crc64_init.c
@@ -0,0 +1,58 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file crc64_init.c
+/// \brief CRC64 table initialization
+//
+// This code is based on various public domain sources.
+// This code has been put into the public domain.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <sys/types.h>
+#include <inttypes.h>
+
+#ifdef WORDS_BIGENDIAN
+# include "check_byteswap.h"
+#endif
+
+
+uint64_t lzma_crc64_table[4][256];
+
+
+extern void
+lzma_crc64_init(void)
+{
+ static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);
+
+ for (size_t s = 0; s < 4; ++s) {
+ for (size_t b = 0; b < 256; ++b) {
+ uint64_t r = s == 0 ? b : lzma_crc64_table[s - 1][b];
+
+ for (size_t i = 0; i < 8; ++i) {
+ if (r & 1)
+ r = (r >> 1) ^ poly64;
+ else
+ r >>= 1;
+ }
+
+ lzma_crc64_table[s][b] = r;
+ }
+ }
+
+#ifdef WORDS_BIGENDIAN
+ for (size_t s = 0; s < 4; ++s)
+ for (size_t b = 0; b < 256; ++b)
+ lzma_crc64_table[s][b]
+ = bswap_64(lzma_crc64_table[s][b]);
+#endif
+
+ return;
+}