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Diffstat (limited to 'lz4_decoder.h')
| -rw-r--r-- | lz4_decoder.h | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/lz4_decoder.h b/lz4_decoder.h new file mode 100644 index 0000000..e7c04a0 --- /dev/null +++ b/lz4_decoder.h @@ -0,0 +1,233 @@ +/*
+ LZ4 Decoder - Part of LZ4 compression algorithm
+ Copyright (C) 2011-2013, 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/
+*/
+
+/* lz4_decoder.h must be included into lz4.c
+ The objective of this file is to create a single LZ4 decoder function source
+ which will be instanciated multiple times with minor variations
+ depending on a set of #define.
+*/
+
+
+
+//****************************
+// Check required defines
+//****************************
+
+#ifndef FUNCTION_NAME
+# error "FUNTION_NAME is not defined"
+#endif
+
+
+//****************************
+// Control tests
+//****************************
+
+#ifdef EXITCONDITION_INPUTSIZE
+# define INPUTBUFFER_CONTROL(ip,iend) likely(ip<iend)
+#else
+# define INPUTBUFFER_CONTROL(ip,iend) (1)
+#endif
+
+#ifdef PARTIAL_DECODING
+# define OUTPUTTARGET(cpy,oexit) (cpy >= oexit)
+#else
+# define OUTPUTTARGET(cpy,oexit) (0)
+#endif
+
+
+
+
+//****************************
+// Function code
+//****************************
+
+int FUNCTION_NAME(const char* source,
+ char* dest,
+#ifdef EXITCONDITION_INPUTSIZE
+ int inputSize,
+#endif
+#ifdef PARTIAL_DECODING
+ int targetOutputSize,
+#endif
+ int outputSize
+ )
+{
+ // Local Variables
+ const BYTE* restrict ip = (const BYTE*) source;
+ const BYTE* ref;
+#ifdef EXITCONDITION_INPUTSIZE
+ const BYTE* const iend = ip + inputSize;
+#endif
+
+ BYTE* op = (BYTE*) dest;
+ BYTE* const oend = op + outputSize;
+ BYTE* cpy;
+#ifdef PARTIAL_DECODING
+ BYTE* const oexit = op + targetOutputSize;
+#endif
+
+ size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
+#if LZ4_ARCH64
+ size_t dec64table[] = {0, 0, 0, (size_t)-1, 0, 1, 2, 3};
+#endif
+
+
+#ifdef EXITCONDITION_INPUTSIZE
+ // Special case
+ if unlikely(!inputSize) goto _output_error; // A correctly formed null-compressed LZ4 must have at least one byte (token=0)
+#endif
+
+ // Main Loop
+ while (1)
+ {
+ unsigned token;
+ size_t length;
+
+ // get runlength
+ token = *ip++;
+ if ((length=(token>>ML_BITS)) == RUN_MASK)
+ {
+ unsigned s=255;
+ while (INPUTBUFFER_CONTROL(ip,iend) && (s==255))
+ {
+ s=*ip++;
+ length += s;
+ }
+ }
+
+ // copy literals
+ cpy = op+length;
+#ifdef EXITCONDITION_INPUTSIZE
+ if ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS)) || OUTPUTTARGET(cpy,oexit))
+ {
+ if (cpy > oend) goto _output_error; // Error : write attempt beyond end of output buffer
+ if ((!OUTPUTTARGET(cpy,oexit)) && (ip+length != iend)) goto _output_error; // Error : Must consume all input at this stage, except if reaching TargetOutputSize
+#else
+ if (cpy>oend-COPYLENGTH)
+ {
+ if (cpy != oend) goto _output_error; // Error : not enough place for another match (min 4) + 5 literals
+#endif
+ memcpy(op, ip, length);
+ ip += length;
+ op += length;
+ break; // Necessarily EOF, due to parsing restrictions
+ }
+ LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
+
+ // get offset
+ LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
+#ifndef PREFIX_64K
+ if unlikely(ref < (BYTE* const)dest) goto _output_error; // Error : offset outside destination buffer
+#endif
+
+ // get matchlength
+ if ((length=(token&ML_MASK)) == ML_MASK)
+ {
+ while INPUTBUFFER_CONTROL(ip,iend-(LASTLITERALS+1)) // A minimum nb of input bytes must remain for LASTLITERALS + token
+ {
+ unsigned s = *ip++;
+ length += s;
+ if (s==255) continue;
+ break;
+ }
+ }
+
+ // copy repeated sequence
+ if unlikely((op-ref)<STEPSIZE)
+ {
+#if LZ4_ARCH64
+ size_t dec64 = dec64table[op-ref];
+#else
+ const size_t 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 unlikely(cpy>oend-(COPYLENGTH)-(STEPSIZE-4))
+ {
+ if (cpy > oend-LASTLITERALS) goto _output_error; // Error : last 5 bytes must be literals
+ LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
+ while(op<cpy) *op++=*ref++;
+ op=cpy;
+ continue;
+ }
+
+ LZ4_WILDCOPY(ref, op, cpy);
+ op=cpy; // correction
+ }
+
+ // end of decoding
+#ifdef EXITCONDITION_INPUTSIZE
+ return (int) (((char*)op)-dest); // Nb of output bytes decoded
+#else
+ return (int) (((char*)ip)-source); // Nb of input bytes read
+#endif
+
+ // Overflow error detected
+_output_error:
+ return (int) (-(((char*)ip)-source))-1;
+}
+
+
+
+//****************************
+// Clean defines
+//****************************
+
+// Required defines
+#undef FUNCTION_NAME
+
+// Locally Generated
+#undef INPUTBUFFER_CONTROL
+#undef OUTPUTTARGET
+
+// Optional defines
+#ifdef EXITCONDITION_INPUTSIZE
+#undef EXITCONDITION_INPUTSIZE
+#endif
+
+#ifdef PREFIX_64K
+#undef PREFIX_64K
+#endif
+
+#ifdef PARTIAL_DECODING
+#undef PARTIAL_DECODING
+#endif
+
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