decompressor: Add LZ4 decompressor module

This patch adds support for LZ4 decompression in the Linux Kernel.
LZ4 Decompression APIs for kernel are based on LZ4 implementation
by Yann Collet.

LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
LZ4 source repository : http://code.google.com/p/lz4/

Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 87 insertions, 0 deletions

diff --git a/include/linux/lz4.h b/include/linux/lz4.h
new file mode 100644
index 0000000000..d21c13f10a
--- /dev/null
+++ b/include/linux/lz4.h
@@ -0,0 +1,87 @@
+#ifndef __LZ4_H__
+#define __LZ4_H__
+/*
+ * LZ4 Kernel Interface
+ *
+ * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define LZ4_MEM_COMPRESS	(4096 * sizeof(unsigned char *))
+#define LZ4HC_MEM_COMPRESS	(65538 * sizeof(unsigned char *))
+
+/*
+ * lz4_compressbound()
+ * Provides the maximum size that LZ4 may output in a "worst case" scenario
+ * (input data not compressible)
+ */
+static inline size_t lz4_compressbound(size_t isize)
+{
+	return isize + (isize / 255) + 16;
+}
+
+/*
+ * lz4_compress()
+ *	src     : source address of the original data
+ *	src_len : size of the original data
+ *	dst	: output buffer address of the compressed data
+ *		This requires 'dst' of size LZ4_COMPRESSBOUND.
+ *	dst_len : is the output size, which is returned after compress done
+ *	workmem : address of the working memory.
+ *		This requires 'workmem' of size LZ4_MEM_COMPRESS.
+ *	return  : Success if return 0
+ *		  Error if return (< 0)
+ *	note :  Destination buffer and workmem must be already allocated with
+ *		the defined size.
+ */
+int lz4_compress(const unsigned char *src, size_t src_len,
+		unsigned char *dst, size_t *dst_len, void *wrkmem);
+
+ /*
+  * lz4hc_compress()
+  *	 src	 : source address of the original data
+  *	 src_len : size of the original data
+  *	 dst	 : output buffer address of the compressed data
+  *		This requires 'dst' of size LZ4_COMPRESSBOUND.
+  *	 dst_len : is the output size, which is returned after compress done
+  *	 workmem : address of the working memory.
+  *		This requires 'workmem' of size LZ4HC_MEM_COMPRESS.
+  *	 return  : Success if return 0
+  *		   Error if return (< 0)
+  *	 note :  Destination buffer and workmem must be already allocated with
+  *		 the defined size.
+  */
+int lz4hc_compress(const unsigned char *src, size_t src_len,
+		unsigned char *dst, size_t *dst_len, void *wrkmem);
+
+/*
+ * lz4_decompress()
+ *	src     : source address of the compressed data
+ *	src_len : is the input size, whcih is returned after decompress done
+ *	dest	: output buffer address of the decompressed data
+ *	actual_dest_len: is the size of uncompressed data, supposing it's known
+ *	return  : Success if return 0
+ *		  Error if return (< 0)
+ *	note :  Destination buffer must be already allocated.
+ *		slightly faster than lz4_decompress_unknownoutputsize()
+ */
+int lz4_decompress(const char *src, size_t *src_len, char *dest,
+		size_t actual_dest_len);
+
+/*
+ * lz4_decompress_unknownoutputsize()
+ *	src     : source address of the compressed data
+ *	src_len : is the input size, therefore the compressed size
+ *	dest	: output buffer address of the decompressed data
+ *	dest_len: is the max size of the destination buffer, which is
+ *			returned with actual size of decompressed data after
+ *			decompress done
+ *	return  : Success if return 0
+ *		  Error if return (< 0)
+ *	note :  Destination buffer must be already allocated.
+ */
+int lz4_decompress_unknownoutputsize(const char *src, size_t src_len,
+		char *dest, size_t *dest_len);
+#endif