Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/check/crc64_small.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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;
+}