diff options
Diffstat (limited to 'lz4.c')
| -rw-r--r-- | lz4.c | 785 |
1 files changed, 241 insertions, 544 deletions
@@ -31,6 +31,10 @@ - LZ4 source repository : http://code.google.com/p/lz4/
*/
+/*
+Note : this source file requires "lz4_encoder.h" and "lz4_decoder.h"
+*/
+
//**************************************
// Tuning parameters
//**************************************
@@ -41,6 +45,12 @@ // Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
#define MEMORY_USAGE 14
+// HEAPMODE :
+// Select if compression algorithm will allocate space for its tables
+// in memory stack (0:default, fastest), or in memory heap (1:requires memory allocation (malloc)).
+// Default allocation strategy is to use stack (HEAPMODE 0)
+#define HEAPMODE 0
+
// BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE :
// This will provide a small boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU.
// You can set this option to 1 in situations where data will remain within closed environment
@@ -175,21 +185,18 @@ typedef struct _U64_S { U64 v; } U64_S; //**************************************
// Constants
//**************************************
-#define MINMATCH 4
+#define HASHTABLESIZE (1 << MEMORY_USAGE)
-#define HASH_LOG (MEMORY_USAGE-2)
-#define HASHTABLESIZE (1 << HASH_LOG)
-#define HASH_MASK (HASHTABLESIZE - 1)
+#define MINMATCH 4
-#define NOTCOMPRESSIBLE_DETECTIONLEVEL 6 // Increasing this value will make the algorithm slower on incompressible data
-#define SKIPSTRENGTH (NOTCOMPRESSIBLE_DETECTIONLEVEL>2?NOTCOMPRESSIBLE_DETECTIONLEVEL:2)
-#define STACKLIMIT 13
-#define HEAPMODE (HASH_LOG>STACKLIMIT) // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()).
#define COPYLENGTH 8
#define LASTLITERALS 5
#define MFLIMIT (COPYLENGTH+MINMATCH)
#define MINLENGTH (MFLIMIT+1)
+#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT-1))
+#define SKIPSTRENGTH 6 // Increasing this value will make the compression run slower on incompressible data
+
#define MAXD_LOG 16
#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
@@ -232,19 +239,8 @@ typedef struct _U64_S { U64 v; } U64_S; //**************************************
-// Local structures
-//**************************************
-struct refTables
-{
- HTYPE hashTable[HASHTABLESIZE];
-};
-
-
-//**************************************
// Macros
//**************************************
-#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
-#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p))
#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=(d)+l; LZ4_WILDCOPY(s,d,e); d=e; }
@@ -289,29 +285,29 @@ static inline int LZ4_NbCommonBytes (register U64 val) static inline int LZ4_NbCommonBytes (register U32 val)
{
#if defined(LZ4_BIG_ENDIAN)
- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+# if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
unsigned long r = 0;
_BitScanReverse( &r, val );
return (int)(r>>3);
- #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+# elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (__builtin_clz(val) >> 3);
- #else
+# else
int r;
if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
r += (!val);
return r;
- #endif
+# endif
#else
- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
+# if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
unsigned long r;
_BitScanForward( &r, val );
return (int)(r>>3);
- #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
+# elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)
return (__builtin_ctz(val) >> 3);
- #else
+# else
static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
- #endif
+# endif
#endif
}
@@ -323,581 +319,282 @@ static inline int LZ4_NbCommonBytes (register U32 val) // Compression functions
//******************************
-// LZ4_compressCtx :
-// -----------------
-// Compress 'isize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
-// If it cannot achieve it, compression will stop, and result of the function will be zero.
-// return : the number of bytes written in buffer 'dest', or 0 if the compression fails
-
-static inline int LZ4_compressCtx(void** ctx,
+/*
+int LZ4_compress_stack(
const char* source,
char* dest,
- int inputSize,
- int maxOutputSize)
-{
-#if HEAPMODE
- struct refTables *srt = (struct refTables *) (*ctx);
- HTYPE* HashTable;
-#else
- HTYPE HashTable[HASHTABLESIZE] = {0};
-#endif
+ int inputSize)
- const BYTE* ip = (BYTE*) source;
- INITBASE(base);
- const BYTE* anchor = ip;
- const BYTE* const iend = ip + inputSize;
- const BYTE* const mflimit = iend - MFLIMIT;
-#define matchlimit (iend - LASTLITERALS)
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
+Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
+return : the number of bytes written in buffer 'dest'
+*/
+#define FUNCTION_NAME LZ4_compress_stack
+#include "lz4_encoder.h"
- BYTE* op = (BYTE*) dest;
- BYTE* const oend = op + maxOutputSize;
- int length;
- const int skipStrength = SKIPSTRENGTH;
- U32 forwardH;
+/*
+int LZ4_compress_stack_limitedOutput(
+ const char* source,
+ char* dest,
+ int inputSize,
+ int maxOutputSize)
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
+If it cannot achieve it, compression will stop, and result of the function will be zero.
+return : the number of bytes written in buffer 'dest', or 0 if the compression fails
+*/
+#define FUNCTION_NAME LZ4_compress_stack_limitedOutput
+#define LIMITED_OUTPUT
+#include "lz4_encoder.h"
- // Init
- if (inputSize<MINLENGTH) goto _last_literals;
-#if HEAPMODE
- if (*ctx == NULL)
- {
- srt = (struct refTables *) malloc ( sizeof(struct refTables) );
- *ctx = (void*) srt;
- }
- HashTable = (HTYPE*)(srt->hashTable);
- memset((void*)HashTable, 0, sizeof(srt->hashTable));
-#else
- (void) ctx;
-#endif
+/*
+int LZ4_compress64k_stack(
+ const char* source,
+ char* dest,
+ int inputSize)
- // First Byte
- HashTable[LZ4_HASH_VALUE(ip)] = (HTYPE)(ip - base);
- ip++; forwardH = LZ4_HASH_VALUE(ip);
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
+This function compresses better than LZ4_compress_stack(), on the condition that
+'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.
+Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
+return : the number of bytes written in buffer 'dest', or 0 if compression fails
+*/
+#define FUNCTION_NAME LZ4_compress64k_stack
+#define COMPRESS_64K
+#include "lz4_encoder.h"
- // 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;
+/*
+int LZ4_compress64k_stack_limitedOutput(
+ const char* source,
+ char* dest,
+ int inputSize,
+ int maxOutputSize)
- if unlikely(forwardIp > mflimit) { goto _last_literals; }
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
+This function compresses better than LZ4_compress_stack_limitedOutput(), on the condition that
+'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.
+If it cannot achieve it, compression will stop, and result of the function will be zero.
+return : the number of bytes written in buffer 'dest', or 0 if the compression fails
+*/
+#define FUNCTION_NAME LZ4_compress64k_stack_limitedOutput
+#define COMPRESS_64K
+#define LIMITED_OUTPUT
+#include "lz4_encoder.h"
- forwardH = LZ4_HASH_VALUE(forwardIp);
- ref = base + HashTable[h];
- HashTable[h] = (HTYPE)(ip - base);
- } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));
+/*
+void* LZ4_createHeapMemory();
+int LZ4_freeHeapMemory(void* ctx);
- // Catch up
- while ((ip>anchor) && (ref>(BYTE*)source) && unlikely(ip[-1]==ref[-1])) { ip--; ref--; }
+Used to allocate and free hashTable memory
+to be used by the LZ4_compress_heap* family of functions.
+LZ4_createHeapMemory() returns NULL is memory allocation fails.
+*/
+void* LZ4_create() { return malloc(HASHTABLESIZE); }
+int LZ4_free(void* ctx) { free(ctx); return 0; }
- // Encode Literal length
- length = (int)(ip - anchor);
- token = op++;
- if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
-#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);
- if unlikely(op + (1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
- 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_HASH_VALUE(ip-2)] = (HTYPE)(ip - 2 - base);
-
- // Test next position
- ref = base + HashTable[LZ4_HASH_VALUE(ip)];
- HashTable[LZ4_HASH_VALUE(ip)] = (HTYPE)(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 = (int)(iend - anchor);
- if (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize) return 0; // Check output limit
- 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);
-}
+/*
+int LZ4_compress_heap(
+ void* ctx,
+ const char* source,
+ char* dest,
+ int inputSize)
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
+The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.
+Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
+return : the number of bytes written in buffer 'dest'
+*/
+#define FUNCTION_NAME LZ4_compress_heap
+#define USE_HEAPMEMORY
+#include "lz4_encoder.h"
-// 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))
-static inline int LZ4_compress64kCtx(void** ctx,
+/*
+int LZ4_compress_heap_limitedOutput(
+ void* ctx,
const char* source,
char* dest,
- int isize,
+ int inputSize,
int maxOutputSize)
-{
-#if HEAPMODE
- struct refTables *srt = (struct refTables *) (*ctx);
- U16* HashTable;
-#else
- U16 HashTable[HASH64KTABLESIZE] = {0};
-#endif
-
- const BYTE* ip = (BYTE*) source;
- const BYTE* anchor = ip;
- const BYTE* const base = ip;
- const BYTE* const iend = ip + isize;
- const BYTE* const mflimit = iend - MFLIMIT;
-#define matchlimit (iend - LASTLITERALS)
-
- BYTE* op = (BYTE*) dest;
- BYTE* const oend = op + maxOutputSize;
-
- int len, length;
- const int skipStrength = SKIPSTRENGTH;
- U32 forwardH;
-
-
- // Init
- if (isize<MINLENGTH) goto _last_literals;
-#if HEAPMODE
- if (*ctx == NULL)
- {
- srt = (struct refTables *) malloc ( sizeof(struct refTables) );
- *ctx = (void*) srt;
- }
- HashTable = (U16*)(srt->hashTable);
- memset((void*)HashTable, 0, sizeof(srt->hashTable));
-#else
- (void) ctx;
-#endif
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
+If it cannot achieve it, compression will stop, and result of the function will be zero.
+The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.
+return : the number of bytes written in buffer 'dest', or 0 if the compression fails
+*/
+#define FUNCTION_NAME LZ4_compress_heap_limitedOutput
+#define LIMITED_OUTPUT
+#define USE_HEAPMEMORY
+#include "lz4_encoder.h"
- // 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;
+/*
+int LZ4_compress64k_heap(
+ void* ctx,
+ const char* source,
+ char* dest,
+ int inputSize)
- // Find a match
- do {
- U32 h = forwardH;
- int step = findMatchAttempts++ >> skipStrength;
- ip = forwardIp;
- forwardIp = ip + step;
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
+The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.
+'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.
+Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
+return : the number of bytes written in buffer 'dest'
+*/
+#define FUNCTION_NAME LZ4_compress64k_heap
+#define COMPRESS_64K
+#define USE_HEAPMEMORY
+#include "lz4_encoder.h"
- if (forwardIp > mflimit) { goto _last_literals; }
- forwardH = LZ4_HASH64K_VALUE(forwardIp);
- ref = base + HashTable[h];
- HashTable[h] = (U16)(ip - base);
+/*
+int LZ4_compress64k_heap_limitedOutput(
+ void* ctx,
+ const char* source,
+ char* dest,
+ int inputSize,
+ int maxOutputSize)
- } while (A32(ref) != A32(ip));
+Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.
+If it cannot achieve it, compression will stop, and result of the function will be zero.
+The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.
+'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.
+return : the number of bytes written in buffer 'dest', or 0 if the compression fails
+*/
+#define FUNCTION_NAME LZ4_compress64k_heap_limitedOutput
+#define COMPRESS_64K
+#define LIMITED_OUTPUT
+#define USE_HEAPMEMORY
+#include "lz4_encoder.h"
- // Catch up
- while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; }
- // Encode Literal length
- length = (int)(ip - anchor);
- token = op++;
- if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
-#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);
+int LZ4_compress(const char* source, char* dest, int inputSize)
+{
+#if HEAPMODE
+ void* ctx = LZ4_create();
+ int result;
+ if (ctx == NULL) return 0; // Failed allocation => compression not done
+ if (inputSize < LZ4_64KLIMIT)
+ result = LZ4_compress64k_heap(ctx, source, dest, inputSize);
+ else result = LZ4_compress_heap(ctx, source, dest, inputSize);
+ LZ4_free(ctx);
+ return result;
#else
- 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);
+ if (inputSize < (int)LZ4_64KLIMIT) return LZ4_compress64k_stack(source, dest, inputSize);
+ return LZ4_compress_stack(source, dest, inputSize);
#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 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; }
- if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
- if ((ip<matchlimit) && (*ref == *ip)) ip++;
-_endCount:
-
- // Encode MatchLength
- len = (int)(ip - anchor);
- if unlikely(op + (1 + LASTLITERALS) + (len>>8) > oend) return 0; // Check output limit
- 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 += (BYTE)len;
-
- // Test end of chunk
- if (ip > mflimit) { anchor = ip; break; }
-
- // Fill table
- HashTable[LZ4_HASH64K_VALUE(ip-2)] = (U16)(ip - 2 - base);
-
- // Test next position
- ref = base + HashTable[LZ4_HASH64K_VALUE(ip)];
- HashTable[LZ4_HASH64K_VALUE(ip)] = (U16)(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 = (int)(iend - anchor);
- if (op + lastRun + 1 + (lastRun-RUN_MASK+255)/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++ = (BYTE)(lastRun<<ML_BITS);
- memcpy(op, anchor, iend - anchor);
- op += iend-anchor;
- }
-
- // End
- return (int) (((char*)op)-dest);
}
-int LZ4_compress_limitedOutput(const char* source,
- char* dest,
- int isize,
- int maxOutputSize)
+int LZ4_compress_limitedOutput(const char* source, char* dest, int inputSize, int maxOutputSize)
{
#if HEAPMODE
- void* ctx = malloc(sizeof(struct refTables));
+ void* ctx = LZ4_create();
int result;
if (ctx == NULL) return 0; // Failed allocation => compression not done
- if (isize < LZ4_64KLIMIT)
- result = LZ4_compress64kCtx(&ctx, source, dest, isize, maxOutputSize);
- else result = LZ4_compressCtx(&ctx, source, dest, isize, maxOutputSize);
- free(ctx);
+ if (inputSize < LZ4_64KLIMIT)
+ result = LZ4_compress64k_heap_limitedOutput(ctx, source, dest, inputSize, maxOutputSize);
+ else result = LZ4_compress_heap_limitedOutput(ctx, source, dest, inputSize, maxOutputSize);
+ LZ4_free(ctx);
return result;
#else
- if (isize < (int)LZ4_64KLIMIT) return LZ4_compress64kCtx(NULL, source, dest, isize, maxOutputSize);
- return LZ4_compressCtx(NULL, source, dest, isize, maxOutputSize);
+ if (inputSize < (int)LZ4_64KLIMIT) return LZ4_compress64k_stack_limitedOutput(source, dest, inputSize, maxOutputSize);
+ return LZ4_compress_stack_limitedOutput(source, dest, inputSize, maxOutputSize);
#endif
}
-int LZ4_compress(const char* source,
- char* dest,
- int isize)
-{
- return LZ4_compress_limitedOutput(source, dest, isize, LZ4_compressBound(isize));
-}
-
-
-
-
//****************************
// Decompression functions
//****************************
-// Note : The decoding functions 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.
-// LZ4_uncompress() guarantees that it will never read before source, nor beyond source + LZ4_compressBound(osize)
-// A corrupted input will produce an error result, a negative int, indicating the position of the error within input stream.
-
-int LZ4_uncompress(const char* source,
- char* dest,
- int osize)
-{
- // Local Variables
- const BYTE* restrict ip = (const BYTE*) source;
- const BYTE* ref;
-
- BYTE* op = (BYTE*) dest;
- BYTE* const oend = op + osize;
- BYTE* cpy;
-
- unsigned token;
+/*
+int LZ4_decompress_safe(const char* source,
+ char* dest,
+ int inputSize,
+ int maxOutputSize);
+
+LZ4_decompress_safe() guarantees it will never write nor read outside of the provided output buffers.
+This function is safe against "buffer overflow" attacks.
+A corrupted input will produce an error result, a negative int.
+*/
+#define FUNCTION_NAME LZ4_decompress_safe
+#define EXITCONDITION_INPUTSIZE
+#include "lz4_decoder.h"
- 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
+/*
+int LZ4_decompress_safe_withPrefix64k(
+ const char* source,
+ char* dest,
+ int inputSize,
+ int maxOutputSize);
+
+Same as LZ4_decompress_safe(), but will also use 64K of memory before the beginning of input buffer.
+Typically used to decode streams of inter-dependant blocks.
+Note : the 64K of memory before pointer 'source' must be allocated and read-allowed.
+*/
+#define FUNCTION_NAME LZ4_decompress_safe_withPrefix64k
+#define EXITCONDITION_INPUTSIZE
+#define PREFIX_64K
+#include "lz4_decoder.h"
- // Main Loop
- while (1)
- {
- size_t length;
-
- // get runlength
- token = *ip++;
- if ((length=(token>>ML_BITS)) == RUN_MASK) { size_t len; for (;(len=*ip++)==255;length+=255){} length += len; }
-
- // copy literals
- cpy = op+length;
- if (cpy>oend-COPYLENGTH)
- {
- if (cpy != oend) goto _output_error; // Error : not enough place for another match (min 4) + 5 literals
- memcpy(op, ip, length);
- ip += length;
- break; // EOF
- }
- LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
-
- // get offset
- LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
- if unlikely(ref < (BYTE* const)dest) goto _output_error; // Error : offset outside destination buffer
-
- // get matchlength
- if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; }
-
- // copy repeated sequence
- if unlikely((op-ref)<STEPSIZE)
- {
-#if LZ4_ARCH64
- size_t 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 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
- return (int) (((char*)ip)-source);
-
- // write overflow error detected
-_output_error:
- return (int) (-(((char*)ip)-source));
-}
+/*
+int LZ4_decompress_safe_partial(
+ const char* source,
+ char* dest,
+ int inputSize,
+ int targetOutputSize,
+ int maxOutputSize);
+
+LZ4_decompress_safe_partial() objective is to decompress only a part of the compressed input block provided.
+The decoding process stops as soon as 'targetOutputSize' bytes have been decoded, reducing decoding time.
+The result of the function is the number of bytes decoded.
+LZ4_decompress_safe_partial() may decode less than 'targetOutputSize' if input doesn't contain enough bytes to decode.
+Always verify how many bytes were decoded to ensure there are as many as wanted into the output buffer 'dest'.
+A corrupted input will produce an error result, a negative int.
+*/
+#define FUNCTION_NAME LZ4_decompress_safe_partial
+#define EXITCONDITION_INPUTSIZE
+#define PARTIAL_DECODING
+#include "lz4_decoder.h"
-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;
+/*
+int LZ4_decompress_fast(const char* source,
+ char* dest,
+ int outputSize);
+
+This function is faster than LZ4_decompress_safe().
+LZ4_decompress_fast() guarantees it will never write nor read outside of output buffer.
+Since LZ4_decompress_fast() doesn't know the size of input buffer.
+it can only guarantee that it will never write into the input buffer, and will never read before its beginning.
+To be used preferably in a controlled environment (when the compressed data to be decoded is from a trusted source).
+A detected corrupted input will produce an error result, a negative int.
+*/
+#define FUNCTION_NAME LZ4_decompress_fast
+#include "lz4_decoder.h"
- 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
+/*
+int LZ4_decompress_fast_withPrefix64k(
+ const char* source,
+ char* dest,
+ int inputSize
+ int maxOutputSize);
+
+Same as LZ4_decompress_fast(), but will use the 64K of memory before the beginning of input buffer.
+Typically used to decode streams of dependant inter-blocks.
+Note : the 64K of memory before pointer 'source' must be allocated and read-allowed.
+*/
+#define FUNCTION_NAME LZ4_decompress_fast_withPrefix64k
+#define PREFIX_64K
+#include "lz4_decoder.h"
- // Special case
- if unlikely(ip==iend) goto _output_error; // A correctly formed null-compressed LZ4 must have at least one byte (token=0)
-
- // Main Loop
- while (1)
- {
- unsigned token;
- size_t length;
-
- // get runlength
- token = *ip++;
- if ((length=(token>>ML_BITS)) == RUN_MASK)
- {
- int s=255;
- while (likely(ip<iend) && (s==255)) { s=*ip++; length += s; }
- }
-
- // copy literals
- cpy = op+length;
- if ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS)))
- {
- if (cpy > oend) goto _output_error; // Error : writes beyond output buffer
- if (ip+length != iend) goto _output_error; // Error : LZ4 format requires to consume all input at this stage (no match within the last 11 bytes, and at least 8 remaining input bytes for another match+literals)
- memcpy(op, 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;
- if unlikely(ref < (BYTE* const)dest) goto _output_error; // Error : offset outside of destination buffer
-
- // get matchlength
- if ((length=(token&ML_MASK)) == ML_MASK)
- {
- while likely(ip<iend-(LASTLITERALS+1)) // Error : a minimum input bytes must remain for LASTLITERALS + token
- {
- int 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 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 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
- return (int) (((char*)op)-dest);
-
- // write overflow error detected
-_output_error:
- return (int) (-(((char*)ip)-source));
-}
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