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Diffstat (limited to 'lz4_encoder.h')
| -rw-r--r-- | lz4_encoder.h | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/lz4_encoder.h b/lz4_encoder.h new file mode 100644 index 0000000..d285848 --- /dev/null +++ b/lz4_encoder.h @@ -0,0 +1,278 @@ +/*
+ LZ4 Encoder - 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_encoder.h must be included into lz4.c
+ The objective of this file is to create a single LZ4 compression 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
+
+
+//****************************
+// Local definitions
+//****************************
+
+#ifdef COMPRESS_64K
+# define HASHLOG (MEMORY_USAGE-1)
+# define CURRENT_H_TYPE U16
+# define CURRENTBASE(base) const BYTE* const base = ip
+#else
+# define HASHLOG (MEMORY_USAGE-2)
+# define CURRENT_H_TYPE HTYPE
+# define CURRENTBASE(base) INITBASE(base)
+#endif
+
+#define HASHTABLE_NBCELLS (1U<<HASHLOG)
+#define LZ4_HASH(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASHLOG))
+#define LZ4_HASHVALUE(p) LZ4_HASH(A32(p))
+
+
+
+//****************************
+// Function code
+//****************************
+
+int FUNCTION_NAME(
+#ifdef USE_HEAPMEMORY
+ void* ctx,
+#endif
+ const char* source,
+ char* dest,
+ int inputSize
+#ifdef LIMITED_OUTPUT
+ ,int maxOutputSize
+#endif
+ )
+{
+#ifdef USE_HEAPMEMORY
+ CURRENT_H_TYPE* HashTable = (CURRENT_H_TYPE*)ctx;
+#else
+ CURRENT_H_TYPE HashTable[HASHTABLE_NBCELLS] = {0};
+#endif
+
+ const BYTE* ip = (BYTE*) source;
+ CURRENTBASE(base);
+ const BYTE* anchor = ip;
+ const BYTE* const iend = ip + inputSize;
+ const BYTE* const mflimit = iend - MFLIMIT;
+#define matchlimit (iend - LASTLITERALS)
+
+ BYTE* op = (BYTE*) dest;
+#ifdef LIMITED_OUTPUT
+ BYTE* const oend = op + maxOutputSize;
+#endif
+
+ int length;
+ const int skipStrength = SKIPSTRENGTH;
+ U32 forwardH;
+
+
+ // Init
+ if (inputSize<MINLENGTH) goto _last_literals;
+#ifdef COMPRESS_64K
+ if (inputSize>LZ4_64KLIMIT) return 0; // Size too large (not within 64K limit)
+#endif
+#ifdef USE_HEAPMEMORY
+ memset((void*)HashTable, 0, HASHTABLESIZE);
+#endif
+
+ // First Byte
+ HashTable[LZ4_HASHVALUE(ip)] = (CURRENT_H_TYPE)(ip - base);
+ ip++; forwardH = LZ4_HASHVALUE(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_HASHVALUE(forwardIp);
+ ref = base + HashTable[h];
+ HashTable[h] = (CURRENT_H_TYPE)(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 = (int)(ip - anchor);
+ token = op++;
+#ifdef LIMITED_OUTPUT
+ if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
+#endif
+#ifdef _MSC_VER
+ if (length>=(int)RUN_MASK)
+ {
+ int len = length-RUN_MASK;
+ *token=(RUN_MASK<<ML_BITS);
+ if (len>254)
+ {
+ do { *op++ = 255; len -= 255; } while (len>254);
+ *op++ = (BYTE)len;
+ memcpy(op, anchor, length);
+ op += length;
+ goto _next_match;
+ }
+ else
+ *op++ = (BYTE)len;
+ }
+ else *token = (BYTE)(length<<ML_BITS);
+#else
+ if (length>=(int)RUN_MASK)
+ {
+ int len;
+ *token=(RUN_MASK<<ML_BITS);
+ len = length-RUN_MASK;
+ for(; len > 254 ; len-=255) *op++ = 255;
+ *op++ = (BYTE)len;
+ }
+ else *token = (length<<ML_BITS);
+#endif
+
+ // Copy Literals
+ LZ4_BLINDCOPY(anchor, op, length);
+
+_next_match:
+ // Encode Offset
+ LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref));
+
+ // Start Counting
+ ip+=MINMATCH; ref+=MINMATCH; // MinMatch already 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; }
+ if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
+ if ((ip<matchlimit) && (*ref == *ip)) ip++;
+_endCount:
+
+ // Encode MatchLength
+ length = (int)(ip - anchor);
+#ifdef LIMITED_OUTPUT
+ if unlikely(op + (1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
+#endif
+ if (length>=(int)ML_MASK)
+ {
+ *token += ML_MASK;
+ length -= ML_MASK;
+ for (; length > 509 ; length-=510) { *op++ = 255; *op++ = 255; }
+ if (length > 254) { length-=255; *op++ = 255; }
+ *op++ = (BYTE)length;
+ }
+ else *token += (BYTE)length;
+
+ // Test end of chunk
+ if (ip > mflimit) { anchor = ip; break; }
+
+ // Fill table
+ HashTable[LZ4_HASHVALUE(ip-2)] = (CURRENT_H_TYPE)(ip - 2 - base);
+
+ // Test next position
+ ref = base + HashTable[LZ4_HASHVALUE(ip)];
+ HashTable[LZ4_HASHVALUE(ip)] = (CURRENT_H_TYPE)(ip - base);
+ if ((ref >= ip - MAX_DISTANCE) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; }
+
+ // Prepare next loop
+ anchor = ip++;
+ forwardH = LZ4_HASHVALUE(ip);
+ }
+
+_last_literals:
+ // Encode Last Literals
+ {
+ int lastRun = (int)(iend - anchor);
+#ifdef LIMITED_OUTPUT
+ if (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize) return 0; // Check output limit
+#endif
+ 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++ = (BYTE)(lastRun<<ML_BITS);
+ memcpy(op, anchor, iend - anchor);
+ op += iend-anchor;
+ }
+
+ // End
+ return (int) (((char*)op)-dest);
+}
+
+
+
+//****************************
+// Clean defines
+//****************************
+
+// Required defines
+#undef FUNCTION_NAME
+
+// Locally Generated
+#undef HASHLOG
+#undef HASHTABLE_NBCELLS
+#undef LZ4_HASH
+#undef LZ4_HASHVALUE
+#undef CURRENT_H_TYPE
+#undef CURRENTBASE
+
+// Optional defines
+#ifdef LIMITED_OUTPUT
+#undef LIMITED_OUTPUT
+#endif
+
+#ifdef USE_HEAPMEMORY
+#undef USE_HEAPMEMORY
+#endif
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