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GEEKING
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watrabi
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/*
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LZ4 Decoder - Part of LZ4 compression algorithm
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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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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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* 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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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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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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/* lz4_decoder.h must be included into lz4.c
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The objective of this file is to create a single LZ4 decoder function source
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which will be instanciated multiple times with minor variations
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depending on a set of #define.
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*/
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//****************************
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// Check required defines
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//****************************
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#ifndef FUNCTION_NAME
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# error "FUNTION_NAME is not defined"
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#endif
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//****************************
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// Control tests
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//****************************
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#ifdef EXITCONDITION_INPUTSIZE
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# define INPUTBUFFER_CONTROL(ip,iend) likely(ip<iend)
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#else
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# define INPUTBUFFER_CONTROL(ip,iend) (1)
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#endif
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#ifdef PARTIAL_DECODING
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# define OUTPUTTARGET(cpy,oexit) (cpy >= oexit)
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#else
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# define OUTPUTTARGET(cpy,oexit) (0)
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#endif
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//****************************
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// Function code
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//****************************
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int FUNCTION_NAME(const char* source,
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char* dest,
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#ifdef EXITCONDITION_INPUTSIZE
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int inputSize,
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#endif
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#ifdef PARTIAL_DECODING
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int targetOutputSize,
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#endif
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int outputSize
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)
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{
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// Local Variables
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const BYTE* restrict ip = (const BYTE*) source;
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const BYTE* ref;
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#ifdef EXITCONDITION_INPUTSIZE
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const BYTE* const iend = ip + inputSize;
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#endif
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BYTE* op = (BYTE*) dest;
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BYTE* const oend = op + outputSize;
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BYTE* cpy;
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#ifdef PARTIAL_DECODING
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BYTE* const oexit = op + targetOutputSize;
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#endif
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size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
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#if LZ4_ARCH64
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size_t dec64table[] = {0, 0, 0, (size_t)-1, 0, 1, 2, 3};
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#endif
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#ifdef EXITCONDITION_INPUTSIZE
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// Special case
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if unlikely(!inputSize) goto _output_error; // A correctly formed null-compressed LZ4 must have at least one byte (token=0)
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#endif
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// Main Loop
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while (1)
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{
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unsigned token;
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size_t length;
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// get runlength
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token = *ip++;
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if ((length=(token>>ML_BITS)) == RUN_MASK)
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{
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unsigned s=255;
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while (INPUTBUFFER_CONTROL(ip,iend) && (s==255))
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{
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s=*ip++;
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length += s;
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}
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}
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// copy literals
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cpy = op+length;
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#ifdef EXITCONDITION_INPUTSIZE
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if ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS)) || OUTPUTTARGET(cpy,oexit))
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{
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if (cpy > oend) goto _output_error; // Error : write attempt beyond end of output buffer
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if ((!OUTPUTTARGET(cpy,oexit)) && (ip+length != iend)) goto _output_error; // Error : Must consume all input at this stage, except if reaching TargetOutputSize
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#else
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if (cpy>oend-COPYLENGTH)
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{
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if (cpy != oend) goto _output_error; // Error : not enough place for another match (min 4) + 5 literals
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#endif
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memcpy(op, ip, length);
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ip += length;
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op += length;
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break; // Necessarily EOF, due to parsing restrictions
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}
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LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
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// get offset
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LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
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#ifndef PREFIX_64K
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if unlikely(ref < (BYTE* const)dest) goto _output_error; // Error : offset outside destination buffer
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#endif
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// get matchlength
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if ((length=(token&ML_MASK)) == ML_MASK)
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{
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while INPUTBUFFER_CONTROL(ip,iend-(LASTLITERALS+1)) // A minimum nb of input bytes must remain for LASTLITERALS + token
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{
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unsigned s = *ip++;
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length += s;
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if (s==255) continue;
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break;
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}
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}
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// copy repeated sequence
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if unlikely((op-ref)<STEPSIZE)
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{
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#if LZ4_ARCH64
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size_t dec64 = dec64table[op-ref];
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#else
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const size_t dec64 = 0;
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#endif
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op[0] = ref[0];
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op[1] = ref[1];
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op[2] = ref[2];
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op[3] = ref[3];
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op += 4, ref += 4; ref -= dec32table[op-ref];
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A32(op) = A32(ref);
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op += STEPSIZE-4; ref -= dec64;
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} else { LZ4_COPYSTEP(ref,op); }
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cpy = op + length - (STEPSIZE-4);
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if unlikely(cpy>oend-(COPYLENGTH)-(STEPSIZE-4))
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{
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if (cpy > oend-LASTLITERALS) goto _output_error; // Error : last 5 bytes must be literals
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LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
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while(op<cpy) *op++=*ref++;
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op=cpy;
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continue;
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}
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LZ4_WILDCOPY(ref, op, cpy);
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op=cpy; // correction
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}
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// end of decoding
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#ifdef EXITCONDITION_INPUTSIZE
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return (int) (((char*)op)-dest); // Nb of output bytes decoded
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#else
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return (int) (((char*)ip)-source); // Nb of input bytes read
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#endif
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// Overflow error detected
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_output_error:
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return (int) (-(((char*)ip)-source))-1;
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}
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//****************************
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// Clean defines
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//****************************
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// Required defines
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#undef FUNCTION_NAME
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// Locally Generated
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#undef INPUTBUFFER_CONTROL
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#undef OUTPUTTARGET
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// Optional defines
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#ifdef EXITCONDITION_INPUTSIZE
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#undef EXITCONDITION_INPUTSIZE
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#endif
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#ifdef PREFIX_64K
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#undef PREFIX_64K
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#endif
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#ifdef PARTIAL_DECODING
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#undef PARTIAL_DECODING
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#endif
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