1 files changed, 258 insertions, 0 deletions
diff --git a/linux/lz4_compress.c b/linux/lz4_compress.c
new file mode 100644
index 0000000..65243c7
--- /dev/null
+++ b/linux/lz4_compress.c
@@ -0,0 +1,258 @@
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011-2012, Yann Collet.
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * You can contact the author at :
+ * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
+ * - LZ4 source repository : http://code.google.com/p/lz4/
+ *
+ *  Changed for kernel use by:
+ *  Chanho Min <chanho.min@lge.com>
+ */
+
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <asm/unaligned.h>
+#include "lz4defs.h"
+
+#define LZ4_HASH_VALUE(p, _table)				\
+	__HASH_VALUE(p, MEMORY_USAGE - ilog2(sizeof(_table[0])))
+
+struct lz4_hash_table {
+	const u8	*(*add)(const struct lz4_hash_table, const u8 *);
+	void		*ctx;
+	const u8	*base;
+};
+
+#if __SIZEOF_POINTER__ == 4
+static inline const u8 *hash_table_add32(const struct lz4_hash_table hash,
+					 const u8 *ip)
+{
+	const u8 **table = hash.ctx;
+
+	swap(table[LZ4_HASH_VALUE(ip, table)], ip);
+	return ip;
+}
+#else
+static inline const u8 *hash_table_add32(const struct lz4_hash_table hash,
+					 const u8 *ip)
+{
+	u32 *table = hash.ctx;
+	size_t offset = ip - hash.base;
+
+	swap(table[LZ4_HASH_VALUE(ip, table)], offset);
+	return hash.base + offset;
+}
+#endif
+
+static inline const u8 *hash_table_add16(const struct lz4_hash_table hash,
+					 const u8 *ip)
+{
+	u16 *table = hash.ctx;
+	size_t offset = ip - hash.base;
+
+	swap(table[LZ4_HASH_VALUE(ip, table)], offset);
+	return hash.base + offset;
+}
+
+static inline const u8 *try_match(const struct lz4_hash_table hash,
+				  const u8 *ip)
+{
+	const u8 *ref = hash.add(hash, ip);
+
+	return ref >= ip - MAX_DISTANCE &&
+		A32(ref) == A32(ip) ? ref : NULL;
+}
+
+static inline const u8 *find_match(const struct lz4_hash_table hash,
+				   const u8 **ip, const u8 *anchor,
+				   const u8 *start, const u8 *end)
+{
+
+	int findmatchattempts = (1U << SKIPSTRENGTH) + 3;
+	const u8 *next_ip = *ip, *ref;
+
+	do {
+		*ip = next_ip;
+		next_ip += findmatchattempts++ >> SKIPSTRENGTH;
+
+		if (unlikely(next_ip > end))
+			return NULL;
+	} while (!(ref = try_match(hash, *ip)));
+
+	/* Catch up */
+	while (*ip > anchor &&
+	       ref > start &&
+	       unlikely((*ip)[-1] == ref[-1])) {
+		(*ip)--;
+		ref--;
+	}
+
+	return ref;
+}
+
+/*
+ * LZ4_compressCtx :
+ * -----------------
+ * Compress 'isize' bytes from 'source' into an output buffer 'dest' of
+ * maximum size 'maxOutputSize'.  * If it cannot achieve it, compression
+ * will stop, and result of the function will be zero.
+ * return : the number of bytes written in buffer 'dest', or 0 if the
+ * compression fails
+ */
+static inline int lz4_compressctx(const struct lz4_hash_table hash,
+				  const u8 *src, size_t src_len,
+				  u8 *dst, size_t *dst_len)
+{
+	const u8 *ip = src;
+	const u8 *anchor = ip, *ref;
+	const u8 *const iend = ip + src_len;
+	const u8 *const mflimit = iend - MFLIMIT;
+	const u8 *const matchlimit = iend - LASTLITERALS;
+	size_t maxoutputsize = *dst_len;
+	u8 *op = dst;
+	u8 *const oend = op + maxoutputsize;
+	int length;
+	u8 *token;
+
+	/* Init */
+	if (src_len < MINLENGTH)
+		goto _last_literals;
+
+	memset(hash.ctx, 0, LZ4_MEM_COMPRESS);
+	hash.add(hash, ip);
+
+	/* Main Loop */
+	while (1) {
+		/* Starting a literal: */
+		anchor = ip++;
+		ref = find_match(hash, &ip, anchor, src, mflimit);
+		if (!ref)
+			goto _last_literals;
+
+		/*
+		 * We found a match; @ip now points to the match and @ref points
+		 * to the prior part of the input we matched with. Everything up
+		 * to @anchor has been encoded; the range from @anchor to @ip
+		 * didn't match and now has to be encoded as a literal:
+		 */
+		length = ip - anchor;
+		token = op++;
+
+		/* check output limit */
+		if (unlikely(op + length + (2 + 1 + LASTLITERALS) +
+			     (length >> 8) > oend))
+			return -(ip - src);
+
+		*token = encode_length(&op, length) << ML_BITS;
+
+		/* Copy Literals */
+		MEMCPY_ADVANCE_CHUNKED(op, anchor, length);
+
+		/* Encode matches: */
+		while (1) {
+			/* Match offset: */
+			PUT_LE16_ADVANCE(op, ip - ref);
+
+			/* MINMATCH bytes already matched from find_match(): */
+			ip += MINMATCH;
+			ref += MINMATCH;
+
+			length = common_length(ip, ref, matchlimit);
+
+			/* Check output limit */
+			if (unlikely(op + (1 + LASTLITERALS) +
+				     (length >> 8) > oend))
+				return -(ip - src);
+
+			ip += length;
+
+			*token += encode_length(&op, length);
+
+			/* Test end of chunk */
+			if (ip > mflimit) {
+				anchor = ip;
+				break;
+			}
+
+			/* Fill table */
+			hash.add(hash, ip - 2);
+
+			/* Test next position */
+			ref = try_match(hash, ip);
+			if (!ref)
+				break;
+
+			token = op++;
+			*token = 0;
+		}
+	}
+
+_last_literals:
+	/* Encode Last Literals */
+	length = iend - anchor;
+	if ((op - dst) + length + 1 +
+	    ((length + 255 - RUN_MASK) / 255) > (u32)maxoutputsize)
+		return -(ip - src);
+
+	token = op++;
+	*token = encode_length(&op, length) << ML_BITS;
+	MEMCPY_ADVANCE(op, anchor, iend - anchor);
+
+	/* End */
+	*dst_len = op - dst;
+	return 0;
+}
+
+__attribute__((flatten))
+int lz4_compress(const unsigned char *src, size_t src_len,
+		 unsigned char *dst, size_t *dst_len, void *wrkmem)
+{
+	if (src_len < LZ4_64KLIMIT) {
+		const struct lz4_hash_table hash = {
+			.add	= hash_table_add16,
+			.ctx	= wrkmem,
+			.base	= src,
+		};
+
+		return lz4_compressctx(hash, src, src_len, dst, dst_len);
+	} else {
+		const struct lz4_hash_table hash = {
+			.add	= hash_table_add32,
+			.ctx	= wrkmem,
+			.base	= src,
+		};
+
+		return lz4_compressctx(hash, src, src_len, dst, dst_len);
+	}
+}
+EXPORT_SYMBOL(lz4_compress);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("LZ4 compressor");