[PATCH 1/1] lz4: Implement lz4 with dynamic offset length.

From: Maninder Singh
Date: Wed Mar 21 2018 - 00:42:03 EST

LZ4 specification defines 2 byte offset length for 64 KB data.
But in case of ZRAM we compress data per page and in most of
architecture PAGE_SIZE is 4KB. So we can decide offset length based
on actual offset value. For this we can reserve 1 bit to decide offset
length (1 byte or 2 byte). 2 byte required only if ofsset is greater than 127,
else 1 byte is enough.

With this new implementation new offset value can be at MAX 32 KB.

Thus we can save more memory for compressed data.

results checked with new implementation:-
LZO
=======
orig_data_size: 78917632
compr_data_size: 15894668
mem_used_total: 17117184

LZ4
========
orig_data_size: 78917632
compr_data_size: 16310717
mem_used_total: 17592320

LZ4_DYN
=======
orig_data_size: 78917632
compr_data_size: 15520506
mem_used_total: 16748544

Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>
Signed-off-by: Vaneet Narang <v.narang@xxxxxxxxxxx>
---
crypto/lz4.c | 64 ++++++++++++++++++++++++++++++++-
drivers/block/zram/zcomp.c | 4 ++
fs/pstore/platform.c | 2 +-
include/linux/lz4.h | 15 ++++++--
lib/decompress_unlz4.c | 2 +-
lib/lz4/lz4_compress.c | 84 +++++++++++++++++++++++++++++++++++--------
lib/lz4/lz4_decompress.c | 56 ++++++++++++++++++++---------
lib/lz4/lz4defs.h | 11 ++++++
8 files changed, 197 insertions(+), 41 deletions(-)

diff --git a/crypto/lz4.c b/crypto/lz4.c
index 2ce2660..f1a8a20 100644
--- a/crypto/lz4.c
+++ b/crypto/lz4.c
@@ -67,7 +67,20 @@ static int __lz4_compress_crypto(const u8 *src, unsigned int slen,
u8 *dst, unsigned int *dlen, void *ctx)
{
int out_len = LZ4_compress_default(src, dst,
- slen, *dlen, ctx);
+ slen, *dlen, ctx, false);
+
+ if (!out_len)
+ return -EINVAL;
+
+ *dlen = out_len;
+ return 0;
+}
+
+static int __lz4_compress_crypto_dynamic(const u8 *src, unsigned int slen,
+ u8 *dst, unsigned int *dlen, void *ctx)
+{
+ int out_len = LZ4_compress_default(src, dst,
+ slen, *dlen, ctx, true);

if (!out_len)
return -EINVAL;
@@ -91,10 +104,30 @@ static int lz4_compress_crypto(struct crypto_tfm *tfm, const u8 *src,
return __lz4_compress_crypto(src, slen, dst, dlen, ctx->lz4_comp_mem);
}

+static int lz4_compress_crypto_dynamic(struct crypto_tfm *tfm, const u8 *src,
+ unsigned int slen, u8 *dst, unsigned int *dlen)
+{
+ struct lz4_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ return __lz4_compress_crypto_dynamic(src, slen, dst, dlen, ctx->lz4_comp_mem);
+}
+
static int __lz4_decompress_crypto(const u8 *src, unsigned int slen,
u8 *dst, unsigned int *dlen, void *ctx)
{
- int out_len = LZ4_decompress_safe(src, dst, slen, *dlen);
+ int out_len = LZ4_decompress_safe(src, dst, slen, *dlen, false);
+
+ if (out_len < 0)
+ return -EINVAL;
+
+ *dlen = out_len;
+ return 0;
+}
+
+static int __lz4_decompress_crypto_dynamic(const u8 *src, unsigned int slen,
+ u8 *dst, unsigned int *dlen, void *ctx)
+{
+ int out_len = LZ4_decompress_safe(src, dst, slen, *dlen, true);

if (out_len < 0)
return -EINVAL;
@@ -117,6 +150,13 @@ static int lz4_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
return __lz4_decompress_crypto(src, slen, dst, dlen, NULL);
}

+static int lz4_decompress_crypto_dynamic(struct crypto_tfm *tfm, const u8 *src,
+ unsigned int slen, u8 *dst,
+ unsigned int *dlen)
+{
+ return __lz4_decompress_crypto_dynamic(src, slen, dst, dlen, NULL);
+}
+
static struct crypto_alg alg_lz4 = {
.cra_name = "lz4",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
@@ -130,6 +170,19 @@ static int lz4_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
.coa_decompress = lz4_decompress_crypto } }
};

+static struct crypto_alg alg_lz4_dyn = {
+ .cra_name = "lz4_dyn",
+ .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
+ .cra_ctxsize = sizeof(struct lz4_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg_lz4_dyn.cra_list),
+ .cra_init = lz4_init,
+ .cra_exit = lz4_exit,
+ .cra_u = { .compress = {
+ .coa_compress = lz4_compress_crypto_dynamic,
+ .coa_decompress = lz4_decompress_crypto_dynamic } }
+};
+
static struct scomp_alg scomp = {
.alloc_ctx = lz4_alloc_ctx,
.free_ctx = lz4_free_ctx,
@@ -150,9 +203,16 @@ static int __init lz4_mod_init(void)
if (ret)
return ret;

+ ret = crypto_register_alg(&alg_lz4_dyn);
+ if (ret) {
+ crypto_unregister_alg(&alg_lz4);
+ return ret;
+ }
+
ret = crypto_register_scomp(&scomp);
if (ret) {
crypto_unregister_alg(&alg_lz4);
+ crypto_unregister_alg(&alg_lz4_dyn);
return ret;
}

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 4ed0a78..5bc5aab 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -17,11 +17,15 @@
#include <linux/crypto.h>

#include "zcomp.h"
+#define KB (1 << 10)

static const char * const backends[] = {
"lzo",
#if IS_ENABLED(CONFIG_CRYPTO_LZ4)
"lz4",
+#if (PAGE_SIZE < (32 * KB))
+ "lz4_dyn",
+#endif
#endif
#if IS_ENABLED(CONFIG_CRYPTO_LZ4HC)
"lz4hc",
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 6910321..2b03449 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -342,7 +342,7 @@ static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
{
int ret;

- ret = LZ4_compress_default(in, out, inlen, outlen, workspace);
+ ret = LZ4_compress_default(in, out, inlen, outlen, workspace, false);
if (!ret) {
pr_err("LZ4_compress_default error; compression failed!\n");
return -EIO;
diff --git a/include/linux/lz4.h b/include/linux/lz4.h
index 394e3d9..08bb95d 100644
--- a/include/linux/lz4.h
+++ b/include/linux/lz4.h
@@ -181,6 +181,9 @@ static inline int LZ4_compressBound(size_t isize)
* which must be already allocated
* @wrkmem: address of the working memory.
* This requires 'workmem' of LZ4_MEM_COMPRESS.
+ * @dynoffset: 1 or 0.
+ * 1 specifies dynamic offset. (1 byte or 2 byte based on offset value),
+ * 0 specifies normal offset. (2 bytes for each offset value).
*
* Compresses 'sourceSize' bytes from buffer 'source'
* into already allocated 'dest' buffer of size 'maxOutputSize'.
@@ -195,7 +198,7 @@ static inline int LZ4_compressBound(size_t isize)
* (necessarily <= maxOutputSize) or 0 if compression fails
*/
int LZ4_compress_default(const char *source, char *dest, int inputSize,
- int maxOutputSize, void *wrkmem);
+ int maxOutputSize, void *wrkmem, bool dynOffset);

/**
* LZ4_compress_fast() - As LZ4_compress_default providing an acceleration param
@@ -207,6 +210,9 @@ int LZ4_compress_default(const char *source, char *dest, int inputSize,
* @acceleration: acceleration factor
* @wrkmem: address of the working memory.
* This requires 'workmem' of LZ4_MEM_COMPRESS.
+ * @dynoffset: 1 or 0.
+ * 1 specifies dynamic offset. (1 byte or 2 byte based on offset value),
+ * 0 specifies normal offset. (2 bytes for each offset value).
*
* Same as LZ4_compress_default(), but allows to select an "acceleration"
* factor. The larger the acceleration value, the faster the algorithm,
@@ -219,7 +225,7 @@ int LZ4_compress_default(const char *source, char *dest, int inputSize,
* (necessarily <= maxOutputSize) or 0 if compression fails
*/
int LZ4_compress_fast(const char *source, char *dest, int inputSize,
- int maxOutputSize, int acceleration, void *wrkmem);
+ int maxOutputSize, int acceleration, void *wrkmem, bool dynOffset);

/**
* LZ4_compress_destSize() - Compress as much data as possible
@@ -277,6 +283,9 @@ int LZ4_compress_destSize(const char *source, char *dest, int *sourceSizePtr,
* which must be already allocated
* @compressedSize: is the precise full size of the compressed block
* @maxDecompressedSize: is the size of 'dest' buffer
+ * @dynoffset: 1 or 0.
+ * 1 specifies dynamic offset. (1 byte or 2 byte based on offset value),
+ * 0 specifies normal offset. (2 bytes for each offset value).
*
* Decompresses data fom 'source' into 'dest'.
* If the source stream is detected malformed, the function will
@@ -290,7 +299,7 @@ int LZ4_compress_destSize(const char *source, char *dest, int *sourceSizePtr,
* or a negative result in case of error
*/
int LZ4_decompress_safe(const char *source, char *dest, int compressedSize,
- int maxDecompressedSize);
+ int maxDecompressedSize, bool dynOffset);

/**
* LZ4_decompress_safe_partial() - Decompress a block of size 'compressedSize'
diff --git a/lib/decompress_unlz4.c b/lib/decompress_unlz4.c
index 1b0baf3..8be2faa 100644
--- a/lib/decompress_unlz4.c
+++ b/lib/decompress_unlz4.c
@@ -158,7 +158,7 @@ STATIC inline int INIT unlz4(u8 *input, long in_len,
#else
dest_len = uncomp_chunksize;

- ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len);
+ ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len, false);
dest_len = ret;
#endif
if (ret < 0) {
diff --git a/lib/lz4/lz4_compress.c b/lib/lz4/lz4_compress.c
index cc7b6d4..185c358 100644
--- a/lib/lz4/lz4_compress.c
+++ b/lib/lz4/lz4_compress.c
@@ -183,7 +183,8 @@ static FORCE_INLINE int LZ4_compress_generic(
const tableType_t tableType,
const dict_directive dict,
const dictIssue_directive dictIssue,
- const U32 acceleration)
+ const U32 acceleration,
+ const Dynamic_Offset dynOffset)
{
const BYTE *ip = (const BYTE *) source;
const BYTE *base;
@@ -199,6 +200,7 @@ static FORCE_INLINE int LZ4_compress_generic(

BYTE *op = (BYTE *) dest;
BYTE * const olimit = op + maxOutputSize;
+ int max_distance = dynOffset ? MAX_DISTANCE_DYN : MAX_DISTANCE;

U32 forwardH;
size_t refDelta = 0;
@@ -245,6 +247,7 @@ static FORCE_INLINE int LZ4_compress_generic(
for ( ; ; ) {
const BYTE *match;
BYTE *token;
+ int curr_offset;

/* Find a match */
{
@@ -285,7 +288,7 @@ static FORCE_INLINE int LZ4_compress_generic(
: 0)
|| ((tableType == byU16)
? 0
- : (match + MAX_DISTANCE < ip))
+ : (match + max_distance < ip))
|| (LZ4_read32(match + refDelta)
!= LZ4_read32(ip)));
}
@@ -328,8 +331,26 @@ static FORCE_INLINE int LZ4_compress_generic(

_next_match:
/* Encode Offset */
- LZ4_writeLE16(op, (U16)(ip - match));
- op += 2;
+ if (dynOffset) {
+ curr_offset = (U16)(ip - match);
+
+ /*
+ * If Ofsset is greater than 127, we need 2 bytes
+ * to store it. Otherwise 1 byte is enough.
+ */
+ if (curr_offset > 127) {
+ curr_offset = (curr_offset << 1) | DYN_BIT;
+ LZ4_writeLE16(op, (U16)curr_offset);
+ op += 2;
+ } else {
+ curr_offset = curr_offset << 1;
+ *op = (BYTE)curr_offset;
+ op++;
+ }
+ } else {
+ LZ4_writeLE16(op, (U16)(ip - match));
+ op += 2;
+ }

/* Encode MatchLength */
{
@@ -480,39 +501,70 @@ static int LZ4_compress_fast_extState(
return LZ4_compress_generic(ctx, source,
dest, inputSize, 0,
noLimit, byU16, noDict,
- noDictIssue, acceleration);
+ noDictIssue, acceleration, NoDynOffset);
else
return LZ4_compress_generic(ctx, source,
dest, inputSize, 0,
noLimit, tableType, noDict,
- noDictIssue, acceleration);
+ noDictIssue, acceleration, NoDynOffset);
} else {
if (inputSize < LZ4_64Klimit)
return LZ4_compress_generic(ctx, source,
dest, inputSize,
maxOutputSize, limitedOutput, byU16, noDict,
- noDictIssue, acceleration);
+ noDictIssue, acceleration, NoDynOffset);
else
return LZ4_compress_generic(ctx, source,
dest, inputSize,
maxOutputSize, limitedOutput, tableType, noDict,
- noDictIssue, acceleration);
+ noDictIssue, acceleration, NoDynOffset);
}
}

+static int LZ4_compress_fast_extState_dynamic(
+ void *state,
+ const char *source,
+ char *dest,
+ int inputSize,
+ int maxOutputSize,
+ int acceleration)
+{
+ LZ4_stream_t_internal *ctx = &((LZ4_stream_t *)state)->internal_donotuse;
+
+ LZ4_resetStream((LZ4_stream_t *)state);
+
+ if (acceleration < 1)
+ acceleration = LZ4_ACCELERATION_DEFAULT;
+
+ if (maxOutputSize >= LZ4_COMPRESSBOUND(inputSize))
+ return LZ4_compress_generic(ctx, source,
+ dest, inputSize, 0,
+ noLimit, byU16, noDict,
+ noDictIssue, acceleration, DynOffset);
+ else
+ return LZ4_compress_generic(ctx, source,
+ dest, inputSize,
+ maxOutputSize, limitedOutput, byU16, noDict,
+ noDictIssue, acceleration, DynOffset);
+}
+
int LZ4_compress_fast(const char *source, char *dest, int inputSize,
- int maxOutputSize, int acceleration, void *wrkmem)
+ int maxOutputSize, int acceleration, void *wrkmem, bool dynOffset)
{
- return LZ4_compress_fast_extState(wrkmem, source, dest, inputSize,
+ if (!dynOffset)
+ return LZ4_compress_fast_extState(wrkmem, source, dest, inputSize,
+ maxOutputSize, acceleration);
+
+ return LZ4_compress_fast_extState_dynamic(wrkmem, source, dest, inputSize,
maxOutputSize, acceleration);
}
EXPORT_SYMBOL(LZ4_compress_fast);

int LZ4_compress_default(const char *source, char *dest, int inputSize,
- int maxOutputSize, void *wrkmem)
+ int maxOutputSize, void *wrkmem, bool dynOffset)
{
return LZ4_compress_fast(source, dest, inputSize,
- maxOutputSize, LZ4_ACCELERATION_DEFAULT, wrkmem);
+ maxOutputSize, LZ4_ACCELERATION_DEFAULT, wrkmem, dynOffset);
}
EXPORT_SYMBOL(LZ4_compress_default);

@@ -900,12 +952,12 @@ int LZ4_compress_fast_continue(LZ4_stream_t *LZ4_stream, const char *source,
result = LZ4_compress_generic(
streamPtr, source, dest, inputSize,
maxOutputSize, limitedOutput, byU32,
- withPrefix64k, dictSmall, acceleration);
+ withPrefix64k, dictSmall, acceleration, NoDynOffset);
} else {
result = LZ4_compress_generic(
streamPtr, source, dest, inputSize,
maxOutputSize, limitedOutput, byU32,
- withPrefix64k, noDictIssue, acceleration);
+ withPrefix64k, noDictIssue, acceleration, NoDynOffset);
}
streamPtr->dictSize += (U32)inputSize;
streamPtr->currentOffset += (U32)inputSize;
@@ -921,12 +973,12 @@ int LZ4_compress_fast_continue(LZ4_stream_t *LZ4_stream, const char *source,
result = LZ4_compress_generic(
streamPtr, source, dest, inputSize,
maxOutputSize, limitedOutput, byU32,
- usingExtDict, dictSmall, acceleration);
+ usingExtDict, dictSmall, acceleration, NoDynOffset);
} else {
result = LZ4_compress_generic(
streamPtr, source, dest, inputSize,
maxOutputSize, limitedOutput, byU32,
- usingExtDict, noDictIssue, acceleration);
+ usingExtDict, noDictIssue, acceleration, NoDynOffset);
}
streamPtr->dictionary = (const BYTE *)source;
streamPtr->dictSize = (U32)inputSize;
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index 141734d..337a828 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -71,7 +71,9 @@ static FORCE_INLINE int LZ4_decompress_generic(
/* only if dict == usingExtDict */
const BYTE * const dictStart,
/* note : = 0 if noDict */
- const size_t dictSize
+ const size_t dictSize,
+ /* offset == 1; dynamic offset */
+ const Dynamic_Offset dynOffset
)
{
/* Local Variables */
@@ -141,8 +143,8 @@ static FORCE_INLINE int LZ4_decompress_generic(
/* copy literals */
cpy = op + length;
if (((endOnInput) && ((cpy > (partialDecoding ? oexit : oend - MFLIMIT))
- || (ip + length > iend - (2 + 1 + LASTLITERALS))))
- || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
+ || (ip + length > iend - (2 + LASTLITERALS))))
+ || ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH - 1))) {
if (partialDecoding) {
if (cpy > oend) {
/*
@@ -188,13 +190,31 @@ static FORCE_INLINE int LZ4_decompress_generic(
break;
}

- LZ4_wildCopy(op, ip, cpy);
+ if (dynOffset && length < 4)
+ LZ4_copy4(op, ip);
+ else
+ LZ4_wildCopy(op, ip, cpy);
+
ip += length;
op = cpy;

/* get offset */
- offset = LZ4_readLE16(ip);
- ip += 2;
+ if (dynOffset) {
+ /*
+ * Check if DYN_BIT is set, means 2 Byte Offset,
+ * else 1 Byte Offset.
+ */
+ if (*ip & DYN_BIT) {
+ offset = LZ4_readLE16(ip) >> 1;
+ ip += 2;
+ } else {
+ offset = *ip >> 1;
+ ip += 1;
+ }
+ } else {
+ offset = LZ4_readLE16(ip);
+ ip += 2;
+ }
match = op - offset;

if ((checkOffset) && (unlikely(match < lowLimit))) {
@@ -335,11 +355,11 @@ static FORCE_INLINE int LZ4_decompress_generic(
}

int LZ4_decompress_safe(const char *source, char *dest,
- int compressedSize, int maxDecompressedSize)
+ int compressedSize, int maxDecompressedSize, bool dynOffset)
{
return LZ4_decompress_generic(source, dest, compressedSize,
maxDecompressedSize, endOnInputSize, full, 0,
- noDict, (BYTE *)dest, NULL, 0);
+ noDict, (BYTE *)dest, NULL, 0, dynOffset);
}

int LZ4_decompress_safe_partial(const char *source, char *dest,
@@ -347,14 +367,14 @@ int LZ4_decompress_safe_partial(const char *source, char *dest,
{
return LZ4_decompress_generic(source, dest, compressedSize,
maxDecompressedSize, endOnInputSize, partial,
- targetOutputSize, noDict, (BYTE *)dest, NULL, 0);
+ targetOutputSize, noDict, (BYTE *)dest, NULL, 0, NoDynOffset);
}

int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
{
return LZ4_decompress_generic(source, dest, 0, originalSize,
endOnOutputSize, full, 0, withPrefix64k,
- (BYTE *)(dest - 64 * KB), NULL, 64 * KB);
+ (BYTE *)(dest - 64 * KB), NULL, 64 * KB, NoDynOffset);
}

int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
@@ -392,7 +412,7 @@ int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
endOnInputSize, full, 0,
usingExtDict, lz4sd->prefixEnd - lz4sd->prefixSize,
lz4sd->externalDict,
- lz4sd->extDictSize);
+ lz4sd->extDictSize, NoDynOffset);

if (result <= 0)
return result;
@@ -406,7 +426,7 @@ int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
compressedSize, maxOutputSize,
endOnInputSize, full, 0,
usingExtDict, (BYTE *)dest,
- lz4sd->externalDict, lz4sd->extDictSize);
+ lz4sd->externalDict, lz4sd->extDictSize, NoDynOffset);
if (result <= 0)
return result;
lz4sd->prefixSize = result;
@@ -427,7 +447,7 @@ int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
endOnOutputSize, full, 0,
usingExtDict,
lz4sd->prefixEnd - lz4sd->prefixSize,
- lz4sd->externalDict, lz4sd->extDictSize);
+ lz4sd->externalDict, lz4sd->extDictSize, NoDynOffset);

if (result <= 0)
return result;
@@ -440,7 +460,7 @@ int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
result = LZ4_decompress_generic(source, dest, 0, originalSize,
endOnOutputSize, full, 0,
usingExtDict, (BYTE *)dest,
- lz4sd->externalDict, lz4sd->extDictSize);
+ lz4sd->externalDict, lz4sd->extDictSize, NoDynOffset);
if (result <= 0)
return result;
lz4sd->prefixSize = originalSize;
@@ -463,19 +483,19 @@ static FORCE_INLINE int LZ4_decompress_usingDict_generic(const char *source,
if (dictSize == 0)
return LZ4_decompress_generic(source, dest,
compressedSize, maxOutputSize, safe, full, 0,
- noDict, (BYTE *)dest, NULL, 0);
+ noDict, (BYTE *)dest, NULL, 0, NoDynOffset);
if (dictStart + dictSize == dest) {
if (dictSize >= (int)(64 * KB - 1))
return LZ4_decompress_generic(source, dest,
compressedSize, maxOutputSize, safe, full, 0,
- withPrefix64k, (BYTE *)dest - 64 * KB, NULL, 0);
+ withPrefix64k, (BYTE *)dest - 64 * KB, NULL, 0, NoDynOffset);
return LZ4_decompress_generic(source, dest, compressedSize,
maxOutputSize, safe, full, 0, noDict,
- (BYTE *)dest - dictSize, NULL, 0);
+ (BYTE *)dest - dictSize, NULL, 0, NoDynOffset);
}
return LZ4_decompress_generic(source, dest, compressedSize,
maxOutputSize, safe, full, 0, usingExtDict,
- (BYTE *)dest, (const BYTE *)dictStart, dictSize);
+ (BYTE *)dest, (const BYTE *)dictStart, dictSize, NoDynOffset);
}

int LZ4_decompress_safe_usingDict(const char *source, char *dest,
diff --git a/lib/lz4/lz4defs.h b/lib/lz4/lz4defs.h
index 00a0b58..9451a73 100644
--- a/lib/lz4/lz4defs.h
+++ b/lib/lz4/lz4defs.h
@@ -75,6 +75,7 @@
#define WILDCOPYLENGTH 8
#define LASTLITERALS 5
#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
+#define DYN_BIT 0x1

/* Increase this value ==> compression run slower on incompressible data */
#define LZ4_SKIPTRIGGER 6
@@ -87,6 +88,7 @@

#define MAXD_LOG 16
#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+#define MAX_DISTANCE_DYN ((1 << (MAXD_LOG - 1)) - 1)
#define STEPSIZE sizeof(size_t)

#define ML_BITS 4
@@ -147,6 +149,13 @@ static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
#endif
}

+static FORCE_INLINE void LZ4_copy4(void *dst, const void *src)
+{
+ U32 a = get_unaligned((const U32 *)src);
+
+ put_unaligned(a, (U32 *)dst);
+}
+
/*
* customized variant of memcpy,
* which can overwrite up to 7 bytes beyond dstEnd
@@ -224,4 +233,6 @@ static FORCE_INLINE unsigned int LZ4_count(
typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
typedef enum { full = 0, partial = 1 } earlyEnd_directive;

+typedef enum { NoDynOffset = 0, DynOffset = 1 } Dynamic_Offset;
+
#endif
--
1.7.1