1031 lines
26 KiB
C
1031 lines
26 KiB
C
/*
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* LZ4 - Fast LZ compression algorithm
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* Header File
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* Copyright (C) 2011-2013, Yann Collet.
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* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* You can contact the author at :
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* - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
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* - LZ4 source repository : http://code.google.com/p/lz4/
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*/
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#include <sys/zfs_context.h>
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#include <sys/zio_compress.h>
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static int real_LZ4_compress(const char *source, char *dest, int isize,
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int osize);
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static int LZ4_uncompress_unknownOutputSize(const char *source, char *dest,
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int isize, int maxOutputSize);
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static int LZ4_compressCtx(void *ctx, const char *source, char *dest,
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int isize, int osize);
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static int LZ4_compress64kCtx(void *ctx, const char *source, char *dest,
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int isize, int osize);
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static kmem_cache_t *lz4_cache;
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/*ARGSUSED*/
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size_t
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lz4_compress_zfs(void *s_start, void *d_start, size_t s_len,
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size_t d_len, int n)
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{
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uint32_t bufsiz;
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char *dest = d_start;
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ASSERT(d_len >= sizeof (bufsiz));
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bufsiz = real_LZ4_compress(s_start, &dest[sizeof (bufsiz)], s_len,
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d_len - sizeof (bufsiz));
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/* Signal an error if the compression routine returned zero. */
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if (bufsiz == 0)
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return (s_len);
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/*
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* The exact compressed size is needed by the decompression routine,
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* so it is stored at the start of the buffer. Note that this may be
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* less than the compressed block size, which is rounded up to a
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* multiple of 1<<ashift.
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*/
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*(uint32_t *)dest = BE_32(bufsiz);
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return (bufsiz + sizeof (bufsiz));
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}
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/*ARGSUSED*/
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int
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lz4_decompress_zfs(void *s_start, void *d_start, size_t s_len,
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size_t d_len, int n)
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{
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const char *src = s_start;
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uint32_t bufsiz = BE_IN32(src);
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/* invalid compressed buffer size encoded at start */
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if (bufsiz + sizeof (bufsiz) > s_len)
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return (1);
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/*
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* Returns 0 on success (decompression function returned non-negative)
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* and non-zero on failure (decompression function returned negative).
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*/
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return (LZ4_uncompress_unknownOutputSize(&src[sizeof (bufsiz)],
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d_start, bufsiz, d_len) < 0);
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}
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/*
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* LZ4 API Description:
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*
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* Simple Functions:
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* real_LZ4_compress() :
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* isize : is the input size. Max supported value is ~1.9GB
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* return : the number of bytes written in buffer dest
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* or 0 if the compression fails (if LZ4_COMPRESSMIN is set).
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* note : destination buffer must be already allocated.
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* destination buffer must be sized to handle worst cases
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* situations (input data not compressible) worst case size
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* evaluation is provided by function LZ4_compressBound().
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*
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* real_LZ4_uncompress() :
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* osize : is the output size, therefore the original size
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* return : the number of bytes read in the source buffer.
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* If the source stream is malformed, the function will stop
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* decoding and return a negative result, indicating the byte
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* position of the faulty instruction. This function never
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* writes beyond dest + osize, and is therefore protected
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* against malicious data packets.
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* note : destination buffer must be already allocated
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* note : real_LZ4_uncompress() is not used in ZFS so its code
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* is not present here.
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*
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* Advanced Functions
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*
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* LZ4_compressBound() :
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* Provides the maximum size that LZ4 may output in a "worst case"
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* scenario (input data not compressible) primarily useful for memory
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* allocation of output buffer.
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*
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* isize : is the input size. Max supported value is ~1.9GB
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* return : maximum output size in a "worst case" scenario
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* note : this function is limited by "int" range (2^31-1)
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*
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* LZ4_uncompress_unknownOutputSize() :
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* isize : is the input size, therefore the compressed size
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* maxOutputSize : is the size of the destination buffer (which must be
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* already allocated)
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* return : the number of bytes decoded in the destination buffer
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* (necessarily <= maxOutputSize). If the source stream is
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* malformed, the function will stop decoding and return a
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* negative result, indicating the byte position of the faulty
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* instruction. This function never writes beyond dest +
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* maxOutputSize, and is therefore protected against malicious
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* data packets.
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* note : Destination buffer must be already allocated.
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* This version is slightly slower than real_LZ4_uncompress()
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*
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* LZ4_compressCtx() :
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* This function explicitly handles the CTX memory structure.
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*
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* ILLUMOS CHANGES: the CTX memory structure must be explicitly allocated
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* by the caller (either on the stack or using kmem_cache_alloc). Passing
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* NULL isn't valid.
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*
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* LZ4_compress64kCtx() :
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* Same as LZ4_compressCtx(), but specific to small inputs (<64KB).
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* isize *Must* be <64KB, otherwise the output will be corrupted.
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*
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* ILLUMOS CHANGES: the CTX memory structure must be explicitly allocated
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* by the caller (either on the stack or using kmem_cache_alloc). Passing
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* NULL isn't valid.
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*/
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/*
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* Tuning parameters
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*/
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/*
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* COMPRESSIONLEVEL: Increasing this value improves compression ratio
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* Lowering this value reduces memory usage. Reduced memory usage
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* typically improves speed, due to cache effect (ex: L1 32KB for Intel,
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* L1 64KB for AMD). Memory usage formula : N->2^(N+2) Bytes
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* (examples : 12 -> 16KB ; 17 -> 512KB)
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*/
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#define COMPRESSIONLEVEL 12
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/*
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* NOTCOMPRESSIBLE_CONFIRMATION: Decreasing this value will make the
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* algorithm skip faster data segments considered "incompressible".
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* This may decrease compression ratio dramatically, but will be
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* faster on incompressible data. Increasing this value will make
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* the algorithm search more before declaring a segment "incompressible".
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* This could improve compression a bit, but will be slower on
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* incompressible data. The default value (6) is recommended.
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*/
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#define NOTCOMPRESSIBLE_CONFIRMATION 6
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/*
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* BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE: This will provide a boost to
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* performance for big endian cpu, but the resulting compressed stream
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* will be incompatible with little-endian CPU. You can set this option
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* to 1 in situations where data will stay within closed environment.
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* This option is useless on Little_Endian CPU (such as x86).
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*/
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/* #define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1 */
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/*
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* CPU Feature Detection
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*/
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/* 32 or 64 bits ? */
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#if defined(_LP64)
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#define LZ4_ARCH64 1
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#else
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#define LZ4_ARCH64 0
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#endif
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/*
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* Little Endian or Big Endian?
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* Note: overwrite the below #define if you know your architecture endianness.
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*/
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#if defined(_ZFS_BIG_ENDIAN)
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#define LZ4_BIG_ENDIAN 1
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#else
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/*
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* Little Endian assumed. PDP Endian and other very rare endian format
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* are unsupported.
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*/
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#undef LZ4_BIG_ENDIAN
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#endif
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/*
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* Unaligned memory access is automatically enabled for "common" CPU,
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* such as x86. For others CPU, the compiler will be more cautious, and
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* insert extra code to ensure aligned access is respected. If you know
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* your target CPU supports unaligned memory access, you may want to
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* force this option manually to improve performance
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*/
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#if defined(__ARM_FEATURE_UNALIGNED)
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#define LZ4_FORCE_UNALIGNED_ACCESS 1
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#endif
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/*
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* Illumos : we can't use GCC's __builtin_ctz family of builtins in the
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* kernel
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* Linux : we can use GCC's __builtin_ctz family of builtins in the
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* kernel
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*/
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#undef LZ4_FORCE_SW_BITCOUNT
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#if defined(__sparc)
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#define LZ4_FORCE_SW_BITCOUNT
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#endif
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/*
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* Compiler Options
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*/
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/* Disable restrict */
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#define restrict
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/*
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* Linux : GCC_VERSION is defined as of 3.9-rc1, so undefine it.
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* torvalds/linux@3f3f8d2f48acfd8ed3b8e6b7377935da57b27b16
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*/
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#ifdef GCC_VERSION
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#undef GCC_VERSION
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#endif
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#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
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#if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
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#define expect(expr, value) (__builtin_expect((expr), (value)))
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#else
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#define expect(expr, value) (expr)
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#endif
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#ifndef likely
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#define likely(expr) expect((expr) != 0, 1)
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#endif
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#ifndef unlikely
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#define unlikely(expr) expect((expr) != 0, 0)
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#endif
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#define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | \
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(((x) & 0xffu) << 8)))
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/* Basic types */
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#define BYTE uint8_t
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#define U16 uint16_t
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#define U32 uint32_t
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#define S32 int32_t
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#define U64 uint64_t
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#ifndef LZ4_FORCE_UNALIGNED_ACCESS
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#pragma pack(1)
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#endif
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typedef struct _U16_S {
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U16 v;
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} U16_S;
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typedef struct _U32_S {
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U32 v;
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} U32_S;
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typedef struct _U64_S {
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U64 v;
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} U64_S;
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#ifndef LZ4_FORCE_UNALIGNED_ACCESS
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#pragma pack()
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#endif
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#define A64(x) (((U64_S *)(x))->v)
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#define A32(x) (((U32_S *)(x))->v)
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#define A16(x) (((U16_S *)(x))->v)
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/*
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* Constants
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*/
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#define MINMATCH 4
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#define HASH_LOG COMPRESSIONLEVEL
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#define HASHTABLESIZE (1 << HASH_LOG)
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#define HASH_MASK (HASHTABLESIZE - 1)
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#define SKIPSTRENGTH (NOTCOMPRESSIBLE_CONFIRMATION > 2 ? \
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NOTCOMPRESSIBLE_CONFIRMATION : 2)
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#define COPYLENGTH 8
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#define LASTLITERALS 5
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#define MFLIMIT (COPYLENGTH + MINMATCH)
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#define MINLENGTH (MFLIMIT + 1)
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#define MAXD_LOG 16
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#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
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#define ML_BITS 4
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#define ML_MASK ((1U<<ML_BITS)-1)
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#define RUN_BITS (8-ML_BITS)
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#define RUN_MASK ((1U<<RUN_BITS)-1)
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/*
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* Architecture-specific macros
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*/
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#if LZ4_ARCH64
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#define STEPSIZE 8
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#define UARCH U64
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#define AARCH A64
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#define LZ4_COPYSTEP(s, d) A64(d) = A64(s); d += 8; s += 8;
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#define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d)
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#define LZ4_SECURECOPY(s, d, e) if (d < e) LZ4_WILDCOPY(s, d, e)
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#define HTYPE U32
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#define INITBASE(base) const BYTE* const base = ip
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#else /* !LZ4_ARCH64 */
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#define STEPSIZE 4
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#define UARCH U32
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#define AARCH A32
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#define LZ4_COPYSTEP(s, d) A32(d) = A32(s); d += 4; s += 4;
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#define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d); LZ4_COPYSTEP(s, d);
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#define LZ4_SECURECOPY LZ4_WILDCOPY
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#define HTYPE const BYTE *
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#define INITBASE(base) const int base = 0
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#endif /* !LZ4_ARCH64 */
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#if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
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#define LZ4_READ_LITTLEENDIAN_16(d, s, p) \
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{ U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
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#define LZ4_WRITE_LITTLEENDIAN_16(p, i) \
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{ U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p += 2; }
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#else
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#define LZ4_READ_LITTLEENDIAN_16(d, s, p) { d = (s) - A16(p); }
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#define LZ4_WRITE_LITTLEENDIAN_16(p, v) { A16(p) = v; p += 2; }
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#endif
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/* Local structures */
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struct refTables {
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HTYPE hashTable[HASHTABLESIZE];
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};
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/* Macros */
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#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH * 8) - \
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HASH_LOG))
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#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p))
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#define LZ4_WILDCOPY(s, d, e) do { LZ4_COPYPACKET(s, d) } while (d < e);
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#define LZ4_BLINDCOPY(s, d, l) { BYTE* e = (d) + l; LZ4_WILDCOPY(s, d, e); \
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d = e; }
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/* Private functions */
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#if LZ4_ARCH64
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static inline int
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LZ4_NbCommonBytes(register U64 val)
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{
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#if defined(LZ4_BIG_ENDIAN)
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#if ((defined(__GNUC__) && (GCC_VERSION >= 304)) || defined(__clang__)) && \
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!defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_clzll(val) >> 3);
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#else
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int r;
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if (!(val >> 32)) {
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r = 4;
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} else {
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r = 0;
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val >>= 32;
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}
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if (!(val >> 16)) {
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r += 2;
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val >>= 8;
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} else {
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val >>= 24;
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}
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r += (!val);
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return (r);
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#endif
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#else
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#if ((defined(__GNUC__) && (GCC_VERSION >= 304)) || defined(__clang__)) && \
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!defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_ctzll(val) >> 3);
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#else
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static const int DeBruijnBytePos[64] =
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{ 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5,
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3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5,
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5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4,
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4, 5, 7, 2, 6, 5, 7, 6, 7, 7
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};
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return DeBruijnBytePos[((U64) ((val & -val) * 0x0218A392CDABBD3F)) >>
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58];
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#endif
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#endif
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}
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#else
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static inline int
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LZ4_NbCommonBytes(register U32 val)
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{
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#if defined(LZ4_BIG_ENDIAN)
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#if ((defined(__GNUC__) && (GCC_VERSION >= 304)) || defined(__clang__)) && \
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!defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_clz(val) >> 3);
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#else
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int r;
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if (!(val >> 16)) {
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r = 2;
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val >>= 8;
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} else {
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r = 0;
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val >>= 24;
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}
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r += (!val);
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return (r);
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#endif
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#else
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#if defined(__GNUC__) && (GCC_VERSION >= 304) && \
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!defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_ctz(val) >> 3);
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#else
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static const int DeBruijnBytePos[32] = {
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0, 0, 3, 0, 3, 1, 3, 0,
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3, 2, 2, 1, 3, 2, 0, 1,
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3, 3, 1, 2, 2, 2, 2, 0,
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3, 1, 2, 0, 1, 0, 1, 1
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};
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return DeBruijnBytePos[((U32) ((val & -(S32) val) * 0x077CB531U)) >>
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27];
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#endif
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#endif
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}
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#endif
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|
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/* Compression functions */
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/*ARGSUSED*/
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static int
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LZ4_compressCtx(void *ctx, const char *source, char *dest, int isize,
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int osize)
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{
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struct refTables *srt = (struct refTables *)ctx;
|
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HTYPE *HashTable = (HTYPE *) (srt->hashTable);
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const BYTE *ip = (BYTE *) source;
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INITBASE(base);
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const BYTE *anchor = ip;
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const BYTE *const iend = ip + isize;
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const BYTE *const oend = (BYTE *) dest + osize;
|
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const BYTE *const mflimit = iend - MFLIMIT;
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#define matchlimit (iend - LASTLITERALS)
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|
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BYTE *op = (BYTE *) dest;
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|
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int len, length;
|
|
const int skipStrength = SKIPSTRENGTH;
|
|
U32 forwardH;
|
|
|
|
|
|
/* Init */
|
|
if (isize < MINLENGTH)
|
|
goto _last_literals;
|
|
|
|
/* First Byte */
|
|
HashTable[LZ4_HASH_VALUE(ip)] = ip - base;
|
|
ip++;
|
|
forwardH = LZ4_HASH_VALUE(ip);
|
|
|
|
/* Main Loop */
|
|
for (;;) {
|
|
int findMatchAttempts = (1U << skipStrength) + 3;
|
|
const BYTE *forwardIp = ip;
|
|
const BYTE *ref;
|
|
BYTE *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 > (BYTE *) source) &&
|
|
unlikely(ip[-1] == ref[-1])) {
|
|
ip--;
|
|
ref--;
|
|
}
|
|
|
|
/* Encode Literal length */
|
|
length = 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++ = (BYTE)len;
|
|
} else
|
|
*token = (length << ML_BITS);
|
|
|
|
/* Copy Literals */
|
|
LZ4_BLINDCOPY(anchor, op, length);
|
|
|
|
_next_match:
|
|
/* Encode Offset */
|
|
LZ4_WRITE_LITTLEENDIAN_16(op, ip - ref);
|
|
|
|
/* Start Counting */
|
|
ip += MINMATCH;
|
|
ref += MINMATCH; /* MinMatch verified */
|
|
anchor = ip;
|
|
while (likely(ip < matchlimit - (STEPSIZE - 1))) {
|
|
UARCH diff = AARCH(ref) ^ AARCH(ip);
|
|
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 = (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++ = (BYTE)len;
|
|
} else
|
|
*token += len;
|
|
|
|
/* 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 */
|
|
{
|
|
int lastRun = iend - anchor;
|
|
if (op + lastRun + 1 + ((lastRun + 255 - RUN_MASK) / 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++ = (BYTE)lastRun;
|
|
} else
|
|
*op++ = (lastRun << ML_BITS);
|
|
(void) memcpy(op, anchor, iend - anchor);
|
|
op += iend - anchor;
|
|
}
|
|
|
|
/* End */
|
|
return (int)(((char *)op) - dest);
|
|
}
|
|
|
|
|
|
|
|
/* Note : this function is valid only if isize < LZ4_64KLIMIT */
|
|
#define LZ4_64KLIMIT ((1 << 16) + (MFLIMIT - 1))
|
|
#define HASHLOG64K (HASH_LOG + 1)
|
|
#define HASH64KTABLESIZE (1U << HASHLOG64K)
|
|
#define LZ4_HASH64K_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8) - \
|
|
HASHLOG64K))
|
|
#define LZ4_HASH64K_VALUE(p) LZ4_HASH64K_FUNCTION(A32(p))
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
LZ4_compress64kCtx(void *ctx, const char *source, char *dest, int isize,
|
|
int osize)
|
|
{
|
|
struct refTables *srt = (struct refTables *)ctx;
|
|
U16 *HashTable = (U16 *) (srt->hashTable);
|
|
|
|
const BYTE *ip = (BYTE *) source;
|
|
const BYTE *anchor = ip;
|
|
const BYTE *const base = ip;
|
|
const BYTE *const iend = ip + isize;
|
|
const BYTE *const oend = (BYTE *) dest + osize;
|
|
const BYTE *const mflimit = iend - MFLIMIT;
|
|
#define matchlimit (iend - LASTLITERALS)
|
|
|
|
BYTE *op = (BYTE *) dest;
|
|
|
|
int len, length;
|
|
const int skipStrength = SKIPSTRENGTH;
|
|
U32 forwardH;
|
|
|
|
/* Init */
|
|
if (isize < MINLENGTH)
|
|
goto _last_literals;
|
|
|
|
/* First Byte */
|
|
ip++;
|
|
forwardH = LZ4_HASH64K_VALUE(ip);
|
|
|
|
/* Main Loop */
|
|
for (;;) {
|
|
int findMatchAttempts = (1U << skipStrength) + 3;
|
|
const BYTE *forwardIp = ip;
|
|
const BYTE *ref;
|
|
BYTE *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] = ip - base;
|
|
|
|
} while (A32(ref) != A32(ip));
|
|
|
|
/* Catch up */
|
|
while ((ip > anchor) && (ref > (BYTE *) source) &&
|
|
(ip[-1] == ref[-1])) {
|
|
ip--;
|
|
ref--;
|
|
}
|
|
|
|
/* Encode Literal length */
|
|
length = 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++ = (BYTE)len;
|
|
} else
|
|
*token = (length << ML_BITS);
|
|
|
|
/* Copy Literals */
|
|
LZ4_BLINDCOPY(anchor, op, length);
|
|
|
|
_next_match:
|
|
/* Encode Offset */
|
|
LZ4_WRITE_LITTLEENDIAN_16(op, ip - ref);
|
|
|
|
/* Start Counting */
|
|
ip += MINMATCH;
|
|
ref += MINMATCH; /* MinMatch verified */
|
|
anchor = ip;
|
|
while (ip < matchlimit - (STEPSIZE - 1)) {
|
|
UARCH diff = AARCH(ref) ^ AARCH(ip);
|
|
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 = (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++ = (BYTE)len;
|
|
} else
|
|
*token += len;
|
|
|
|
/* Test end of chunk */
|
|
if (ip > mflimit) {
|
|
anchor = ip;
|
|
break;
|
|
}
|
|
/* Fill table */
|
|
HashTable[LZ4_HASH64K_VALUE(ip - 2)] = ip - 2 - base;
|
|
|
|
/* Test next position */
|
|
ref = base + HashTable[LZ4_HASH64K_VALUE(ip)];
|
|
HashTable[LZ4_HASH64K_VALUE(ip)] = 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 */
|
|
{
|
|
int lastRun = iend - anchor;
|
|
if (op + lastRun + 1 + ((lastRun + 255 - RUN_MASK) / 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++ = (BYTE)lastRun;
|
|
} else
|
|
*op++ = (lastRun << ML_BITS);
|
|
(void) memcpy(op, anchor, iend - anchor);
|
|
op += iend - anchor;
|
|
}
|
|
|
|
/* End */
|
|
return (int)(((char *)op) - dest);
|
|
}
|
|
|
|
static int
|
|
real_LZ4_compress(const char *source, char *dest, int isize, int osize)
|
|
{
|
|
void *ctx;
|
|
int result;
|
|
|
|
ASSERT(lz4_cache != NULL);
|
|
ctx = kmem_cache_alloc(lz4_cache, KM_SLEEP);
|
|
|
|
/*
|
|
* out of kernel memory, gently fall through - this will disable
|
|
* compression in zio_compress_data
|
|
*/
|
|
if (ctx == NULL)
|
|
return (0);
|
|
|
|
memset(ctx, 0, sizeof (struct refTables));
|
|
|
|
if (isize < LZ4_64KLIMIT)
|
|
result = LZ4_compress64kCtx(ctx, source, dest, isize, osize);
|
|
else
|
|
result = LZ4_compressCtx(ctx, source, dest, isize, osize);
|
|
|
|
kmem_cache_free(lz4_cache, ctx);
|
|
return (result);
|
|
}
|
|
|
|
/* Decompression functions */
|
|
|
|
/*
|
|
* Note: The decoding functions real_LZ4_uncompress() and
|
|
* LZ4_uncompress_unknownOutputSize() are safe against "buffer overflow"
|
|
* attack type. They will never write nor read outside of the provided
|
|
* output buffers. LZ4_uncompress_unknownOutputSize() also insures that
|
|
* it will never read outside of the input buffer. A corrupted input
|
|
* will produce an error result, a negative int, indicating the position
|
|
* of the error within input stream.
|
|
*
|
|
* Note[2]: real_LZ4_uncompress(), referred to above, is not used in ZFS so
|
|
* its code is not present here.
|
|
*/
|
|
|
|
static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
|
|
#if LZ4_ARCH64
|
|
static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
|
|
#endif
|
|
|
|
static int
|
|
LZ4_uncompress_unknownOutputSize(const char *source, char *dest, int isize,
|
|
int maxOutputSize)
|
|
{
|
|
/* Local Variables */
|
|
const BYTE *restrict ip = (const BYTE *) source;
|
|
const BYTE *const iend = ip + isize;
|
|
const BYTE *ref;
|
|
|
|
BYTE *op = (BYTE *) dest;
|
|
BYTE *const oend = op + maxOutputSize;
|
|
BYTE *cpy;
|
|
|
|
/* Main Loop */
|
|
while (ip < iend) {
|
|
unsigned token;
|
|
size_t length;
|
|
|
|
/* get runlength */
|
|
token = *ip++;
|
|
if ((length = (token >> ML_BITS)) == RUN_MASK) {
|
|
int s = 255;
|
|
while ((ip < iend) && (s == 255)) {
|
|
s = *ip++;
|
|
if (unlikely(length > (size_t)(length + s)))
|
|
goto _output_error;
|
|
length += s;
|
|
}
|
|
}
|
|
/* copy literals */
|
|
cpy = op + length;
|
|
/* CORNER-CASE: cpy might overflow. */
|
|
if (cpy < op)
|
|
goto _output_error; /* cpy was overflowed, bail! */
|
|
if ((cpy > oend - COPYLENGTH) ||
|
|
(ip + length > iend - COPYLENGTH)) {
|
|
if (cpy > oend)
|
|
/* Error: writes beyond output buffer */
|
|
goto _output_error;
|
|
if (ip + length != iend)
|
|
/*
|
|
* Error: LZ4 format requires to consume all
|
|
* input at this stage
|
|
*/
|
|
goto _output_error;
|
|
(void) memcpy(op, ip, length);
|
|
op += length;
|
|
/* Necessarily EOF, due to parsing restrictions */
|
|
break;
|
|
}
|
|
LZ4_WILDCOPY(ip, op, cpy);
|
|
ip -= (op - cpy);
|
|
op = cpy;
|
|
|
|
/* get offset */
|
|
LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
|
|
ip += 2;
|
|
if (ref < (BYTE * const) dest)
|
|
/*
|
|
* Error: offset creates reference outside of
|
|
* destination buffer
|
|
*/
|
|
goto _output_error;
|
|
|
|
/* get matchlength */
|
|
if ((length = (token & ML_MASK)) == ML_MASK) {
|
|
while (ip < iend) {
|
|
int s = *ip++;
|
|
if (unlikely(length > (size_t)(length + s)))
|
|
goto _output_error;
|
|
length += s;
|
|
if (s == 255)
|
|
continue;
|
|
break;
|
|
}
|
|
}
|
|
/* copy repeated sequence */
|
|
if (unlikely(op - ref < STEPSIZE)) {
|
|
#if LZ4_ARCH64
|
|
int dec64 = dec64table[op - ref];
|
|
#else
|
|
const int dec64 = 0;
|
|
#endif
|
|
op[0] = ref[0];
|
|
op[1] = ref[1];
|
|
op[2] = ref[2];
|
|
op[3] = ref[3];
|
|
op += 4;
|
|
ref += 4;
|
|
ref -= dec32table[op - ref];
|
|
A32(op) = A32(ref);
|
|
op += STEPSIZE - 4;
|
|
ref -= dec64;
|
|
} else {
|
|
LZ4_COPYSTEP(ref, op);
|
|
}
|
|
cpy = op + length - (STEPSIZE - 4);
|
|
if (cpy > oend - COPYLENGTH) {
|
|
if (cpy > oend)
|
|
/*
|
|
* Error: request to write outside of
|
|
* destination buffer
|
|
*/
|
|
goto _output_error;
|
|
#if LZ4_ARCH64
|
|
if ((ref + COPYLENGTH) > oend)
|
|
#else
|
|
if ((ref + COPYLENGTH) > oend ||
|
|
(op + COPYLENGTH) > oend)
|
|
#endif
|
|
goto _output_error;
|
|
LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
|
|
while (op < cpy)
|
|
*op++ = *ref++;
|
|
op = cpy;
|
|
if (op == oend)
|
|
/*
|
|
* Check EOF (should never happen, since
|
|
* last 5 bytes are supposed to be literals)
|
|
*/
|
|
goto _output_error;
|
|
continue;
|
|
}
|
|
LZ4_SECURECOPY(ref, op, cpy);
|
|
op = cpy; /* correction */
|
|
}
|
|
|
|
/* end of decoding */
|
|
return (int)(((char *)op) - dest);
|
|
|
|
/* write overflow error detected */
|
|
_output_error:
|
|
return (-1);
|
|
}
|
|
|
|
void
|
|
lz4_init(void)
|
|
{
|
|
lz4_cache = kmem_cache_create("lz4_cache",
|
|
sizeof (struct refTables), 0, NULL, NULL, NULL, NULL, NULL, 0);
|
|
}
|
|
|
|
void
|
|
lz4_fini(void)
|
|
{
|
|
if (lz4_cache) {
|
|
kmem_cache_destroy(lz4_cache);
|
|
lz4_cache = NULL;
|
|
}
|
|
}
|