1 files changed, 68 insertions, 0 deletions
diff --git a/src/liblzma/check/crc32_small.c b/src/liblzma/check/crc32_small.c
new file mode 100644
index 0000000..186966e
--- /dev/null
+++ b/src/liblzma/check/crc32_small.c
@@ -0,0 +1,68 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       crc32_small.c
+/// \brief      CRC32 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"
+
+
+uint32_t lzma_crc32_table[1][256];
+
+
+#ifdef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
+__attribute__((__constructor__))
+#endif
+static void
+crc32_init(void)
+{
+	static const uint32_t poly32 = UINT32_C(0xEDB88320);
+
+	for (size_t b = 0; b < 256; ++b) {
+		uint32_t r = b;
+		for (size_t i = 0; i < 8; ++i) {
+			if (r & 1)
+				r = (r >> 1) ^ poly32;
+			else
+				r >>= 1;
+		}
+
+		lzma_crc32_table[0][b] = r;
+	}
+
+	return;
+}
+
+
+#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
+extern void
+lzma_crc32_init(void)
+{
+	mythread_once(crc32_init);
+	return;
+}
+#endif
+
+
+extern LZMA_API(uint32_t)
+lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc)
+{
+#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR
+	lzma_crc32_init();
+#endif
+
+	crc = ~crc;
+
+	while (size != 0) {
+		crc = lzma_crc32_table[0][*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
+		--size;
+	}
+
+	return ~crc;
+}