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-rw-r--r--lib/lz4/lz4_compress.c443
1 files changed, 443 insertions, 0 deletions
diff --git a/lib/lz4/lz4_compress.c b/lib/lz4/lz4_compress.c
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+++ b/lib/lz4/lz4_compress.c
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+/*
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <asm/unaligned.h>
+#include "lz4defs.h"
+
+/*
+ * 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(void *ctx,
+ const char *source,
+ char *dest,
+ int isize,
+ int maxoutputsize)
+{
+ HTYPE *hashtable = (HTYPE *)ctx;
+ const u8 *ip = (u8 *)source;
+#if LZ4_ARCH64
+ const BYTE * const base = ip;
+#else
+ const int base = 0;
+#endif
+ const u8 *anchor = ip;
+ const u8 *const iend = ip + isize;
+ const u8 *const mflimit = iend - MFLIMIT;
+ #define MATCHLIMIT (iend - LASTLITERALS)
+
+ u8 *op = (u8 *) dest;
+ u8 *const oend = op + maxoutputsize;
+ int length;
+ const int skipstrength = SKIPSTRENGTH;
+ u32 forwardh;
+ int lastrun;
+
+ /* Init */
+ if (isize < MINLENGTH)
+ goto _last_literals;
+
+ memset((void *)hashtable, 0, LZ4_MEM_COMPRESS);
+
+ /* First Byte */
+ hashtable[LZ4_HASH_VALUE(ip)] = ip - base;
+ ip++;
+ forwardh = LZ4_HASH_VALUE(ip);
+
+ /* Main Loop */
+ for (;;) {
+ int findmatchattempts = (1U << skipstrength) + 3;
+ const u8 *forwardip = ip;
+ const u8 *ref;
+ u8 *token;
+
+ /* Find a match */
+ do {
+ u32 h = forwardh;
+ int step = findmatchattempts++ >> skipstrength;
+ ip = forwardip;
+ forwardip = ip + step;
+
+ if (unlikely(forwardip > mflimit))
+ goto _last_literals;
+
+ forwardh = LZ4_HASH_VALUE(forwardip);
+ ref = base + hashtable[h];
+ hashtable[h] = ip - base;
+ } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));
+
+ /* Catch up */
+ while ((ip > anchor) && (ref > (u8 *)source) &&
+ unlikely(ip[-1] == ref[-1])) {
+ ip--;
+ ref--;
+ }
+
+ /* Encode Literal length */
+ length = (int)(ip - anchor);
+ token = op++;
+ /* check output limit */
+ if (unlikely(op + length + (2 + 1 + LASTLITERALS) +
+ (length >> 8) > oend))
+ return 0;
+
+ if (length >= (int)RUN_MASK) {
+ int len;
+ *token = (RUN_MASK << ML_BITS);
+ len = length - RUN_MASK;
+ for (; len > 254 ; len -= 255)
+ *op++ = 255;
+ *op++ = (u8)len;
+ } else
+ *token = (length << ML_BITS);
+
+ /* Copy Literals */
+ LZ4_BLINDCOPY(anchor, op, length);
+_next_match:
+ /* Encode Offset */
+ LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref));
+
+ /* Start Counting */
+ ip += MINMATCH;
+ /* MinMatch verified */
+ ref += MINMATCH;
+ anchor = ip;
+ while (likely(ip < MATCHLIMIT - (STEPSIZE - 1))) {
+ #if LZ4_ARCH64
+ u64 diff = A64(ref) ^ A64(ip);
+ #else
+ u32 diff = A32(ref) ^ A32(ip);
+ #endif
+ if (!diff) {
+ ip += STEPSIZE;
+ ref += STEPSIZE;
+ continue;
+ }
+ ip += LZ4_NBCOMMONBYTES(diff);
+ goto _endcount;
+ }
+ #if LZ4_ARCH64
+ if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) {
+ ip += 4;
+ ref += 4;
+ }
+ #endif
+ if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) {
+ ip += 2;
+ ref += 2;
+ }
+ if ((ip < MATCHLIMIT) && (*ref == *ip))
+ ip++;
+_endcount:
+ /* Encode MatchLength */
+ length = (int)(ip - anchor);
+ /* Check output limit */
+ if (unlikely(op + (1 + LASTLITERALS) + (length >> 8) > oend))
+ return 0;
+ if (length >= (int)ML_MASK) {
+ *token += ML_MASK;
+ length -= ML_MASK;
+ for (; length > 509 ; length -= 510) {
+ *op++ = 255;
+ *op++ = 255;
+ }
+ if (length > 254) {
+ length -= 255;
+ *op++ = 255;
+ }
+ *op++ = (u8)length;
+ } else
+ *token += length;
+
+ /* Test end of chunk */
+ if (ip > mflimit) {
+ anchor = ip;
+ break;
+ }
+
+ /* Fill table */
+ hashtable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base;
+
+ /* Test next position */
+ ref = base + hashtable[LZ4_HASH_VALUE(ip)];
+ hashtable[LZ4_HASH_VALUE(ip)] = ip - base;
+ if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) {
+ token = op++;
+ *token = 0;
+ goto _next_match;
+ }
+
+ /* Prepare next loop */
+ anchor = ip++;
+ forwardh = LZ4_HASH_VALUE(ip);
+ }
+
+_last_literals:
+ /* Encode Last Literals */
+ lastrun = (int)(iend - anchor);
+ if (((char *)op - dest) + lastrun + 1
+ + ((lastrun + 255 - RUN_MASK) / 255) > (u32)maxoutputsize)
+ return 0;
+
+ if (lastrun >= (int)RUN_MASK) {
+ *op++ = (RUN_MASK << ML_BITS);
+ lastrun -= RUN_MASK;
+ for (; lastrun > 254 ; lastrun -= 255)
+ *op++ = 255;
+ *op++ = (u8)lastrun;
+ } else
+ *op++ = (lastrun << ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend - anchor;
+
+ /* End */
+ return (int)(((char *)op) - dest);
+}
+
+static inline int lz4_compress64kctx(void *ctx,
+ const char *source,
+ char *dest,
+ int isize,
+ int maxoutputsize)
+{
+ u16 *hashtable = (u16 *)ctx;
+ const u8 *ip = (u8 *) source;
+ const u8 *anchor = ip;
+ const u8 *const base = ip;
+ const u8 *const iend = ip + isize;
+ const u8 *const mflimit = iend - MFLIMIT;
+ #define MATCHLIMIT (iend - LASTLITERALS)
+
+ u8 *op = (u8 *) dest;
+ u8 *const oend = op + maxoutputsize;
+ int len, length;
+ const int skipstrength = SKIPSTRENGTH;
+ u32 forwardh;
+ int lastrun;
+
+ /* Init */
+ if (isize < MINLENGTH)
+ goto _last_literals;
+
+ memset((void *)hashtable, 0, LZ4_MEM_COMPRESS);
+
+ /* First Byte */
+ ip++;
+ forwardh = LZ4_HASH64K_VALUE(ip);
+
+ /* Main Loop */
+ for (;;) {
+ int findmatchattempts = (1U << skipstrength) + 3;
+ const u8 *forwardip = ip;
+ const u8 *ref;
+ u8 *token;
+
+ /* Find a match */
+ do {
+ u32 h = forwardh;
+ int step = findmatchattempts++ >> skipstrength;
+ ip = forwardip;
+ forwardip = ip + step;
+
+ if (forwardip > mflimit)
+ goto _last_literals;
+
+ forwardh = LZ4_HASH64K_VALUE(forwardip);
+ ref = base + hashtable[h];
+ hashtable[h] = (u16)(ip - base);
+ } while (A32(ref) != A32(ip));
+
+ /* Catch up */
+ while ((ip > anchor) && (ref > (u8 *)source)
+ && (ip[-1] == ref[-1])) {
+ ip--;
+ ref--;
+ }
+
+ /* Encode Literal length */
+ length = (int)(ip - anchor);
+ token = op++;
+ /* Check output limit */
+ if (unlikely(op + length + (2 + 1 + LASTLITERALS)
+ + (length >> 8) > oend))
+ return 0;
+ if (length >= (int)RUN_MASK) {
+ *token = (RUN_MASK << ML_BITS);
+ len = length - RUN_MASK;
+ for (; len > 254 ; len -= 255)
+ *op++ = 255;
+ *op++ = (u8)len;
+ } else
+ *token = (length << ML_BITS);
+
+ /* Copy Literals */
+ LZ4_BLINDCOPY(anchor, op, length);
+
+_next_match:
+ /* Encode Offset */
+ LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref));
+
+ /* Start Counting */
+ ip += MINMATCH;
+ /* MinMatch verified */
+ ref += MINMATCH;
+ anchor = ip;
+
+ while (ip < MATCHLIMIT - (STEPSIZE - 1)) {
+ #if LZ4_ARCH64
+ u64 diff = A64(ref) ^ A64(ip);
+ #else
+ u32 diff = A32(ref) ^ A32(ip);
+ #endif
+
+ if (!diff) {
+ ip += STEPSIZE;
+ ref += STEPSIZE;
+ continue;
+ }
+ ip += LZ4_NBCOMMONBYTES(diff);
+ goto _endcount;
+ }
+ #if LZ4_ARCH64
+ if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) {
+ ip += 4;
+ ref += 4;
+ }
+ #endif
+ if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) {
+ ip += 2;
+ ref += 2;
+ }
+ if ((ip < MATCHLIMIT) && (*ref == *ip))
+ ip++;
+_endcount:
+
+ /* Encode MatchLength */
+ len = (int)(ip - anchor);
+ /* Check output limit */
+ if (unlikely(op + (1 + LASTLITERALS) + (len >> 8) > oend))
+ return 0;
+ if (len >= (int)ML_MASK) {
+ *token += ML_MASK;
+ len -= ML_MASK;
+ for (; len > 509 ; len -= 510) {
+ *op++ = 255;
+ *op++ = 255;
+ }
+ if (len > 254) {
+ len -= 255;
+ *op++ = 255;
+ }
+ *op++ = (u8)len;
+ } else
+ *token += len;
+
+ /* Test end of chunk */
+ if (ip > mflimit) {
+ anchor = ip;
+ break;
+ }
+
+ /* Fill table */
+ hashtable[LZ4_HASH64K_VALUE(ip-2)] = (u16)(ip - 2 - base);
+
+ /* Test next position */
+ ref = base + hashtable[LZ4_HASH64K_VALUE(ip)];
+ hashtable[LZ4_HASH64K_VALUE(ip)] = (u16)(ip - base);
+ if (A32(ref) == A32(ip)) {
+ token = op++;
+ *token = 0;
+ goto _next_match;
+ }
+
+ /* Prepare next loop */
+ anchor = ip++;
+ forwardh = LZ4_HASH64K_VALUE(ip);
+ }
+
+_last_literals:
+ /* Encode Last Literals */
+ lastrun = (int)(iend - anchor);
+ if (op + lastrun + 1 + (lastrun - RUN_MASK + 255) / 255 > oend)
+ return 0;
+ if (lastrun >= (int)RUN_MASK) {
+ *op++ = (RUN_MASK << ML_BITS);
+ lastrun -= RUN_MASK;
+ for (; lastrun > 254 ; lastrun -= 255)
+ *op++ = 255;
+ *op++ = (u8)lastrun;
+ } else
+ *op++ = (lastrun << ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend - anchor;
+ /* End */
+ return (int)(((char *)op) - dest);
+}
+
+int lz4_compress(const unsigned char *src, size_t src_len,
+ unsigned char *dst, size_t *dst_len, void *wrkmem)
+{
+ int ret = -1;
+ int out_len = 0;
+
+ if (src_len < LZ4_64KLIMIT)
+ out_len = lz4_compress64kctx(wrkmem, src, dst, src_len,
+ lz4_compressbound(src_len));
+ else
+ out_len = lz4_compressctx(wrkmem, src, dst, src_len,
+ lz4_compressbound(src_len));
+
+ if (out_len < 0)
+ goto exit;
+
+ *dst_len = out_len;
+
+ return 0;
+exit:
+ return ret;
+}
+EXPORT_SYMBOL(lz4_compress);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("LZ4 compressor");
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