diff options
-rw-r--r-- | lib/lz4.c | 367 |
1 files changed, 233 insertions, 134 deletions
@@ -1716,7 +1716,7 @@ int LZ4_saveDict (LZ4_stream_t* LZ4_dict, char* safeBuffer, int dictSize) if (dictSize > 0) { const BYTE* const previousDictEnd = dict->dictionary + dict->dictSize; assert(dict->dictionary); - LZ4_memmove(safeBuffer, previousDictEnd - dictSize, dictSize); + LZ4_memmove(safeBuffer, previousDictEnd - dictSize, (size_t)dictSize); } dict->dictionary = (const BYTE*)safeBuffer; @@ -1731,39 +1731,163 @@ int LZ4_saveDict (LZ4_stream_t* LZ4_dict, char* safeBuffer, int dictSize) * Decompression functions ********************************/ -typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive; typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive; #undef MIN #define MIN(a,b) ( (a) < (b) ? (a) : (b) ) + +/* variant for decompress_unsafe() + * does not know end of input + * presumes input is well formed + * note : will consume at least one byte */ +size_t read_long_length_no_check(const BYTE** pp) +{ + size_t b, l = 0; + do { b = **pp; (*pp)++; l += b; } while (b==255); + DEBUGLOG(6, "read_long_length_no_check: +length=%zu using %zu input bytes", l, l/255 + 1) + return l; +} + +/* core decoder variant for LZ4_decompress_fast*() + * for legacy support only : these entry points are deprecated. + * - Presumes input is correctly formed (no defense vs malformed inputs) + * - Does not know input size (presume input buffer is "large enough") + * - Decompress a full block (only) + * @return : nb of bytes read from input. + * Note : this variant is not optimized for speed, just for maintenance. + * the goal is to remove support of decompress_fast*() variants by v2.0 +**/ +LZ4_FORCE_INLINE int +LZ4_decompress_unsafe_generic( + const BYTE* const istart, + BYTE* const ostart, + int decompressedSize, + + size_t prefixSize, + const BYTE* const dictStart, /* only if dict==usingExtDict */ + const size_t dictSize /* note: =0 if dictStart==NULL */ + ) +{ + const BYTE* ip = istart; + BYTE* op = (BYTE*)ostart; + BYTE* const oend = ostart + decompressedSize; + const BYTE* const prefixStart = ostart - prefixSize; + + DEBUGLOG(5, "LZ4_decompress_unsafe_generic"); + if (dictStart == NULL) assert(dictSize == 0); + + while (1) { + /* start new sequence */ + unsigned token = *ip++; + + /* literals */ + { size_t ll = token >> ML_BITS; + if (ll==15) { + /* long literal length */ + ll += read_long_length_no_check(&ip); + } + if ((size_t)(oend-op) < ll) return -1; /* output buffer overflow */ + LZ4_memmove(op, ip, ll); /* support in-place decompression */ + op += ll; + ip += ll; + if ((size_t)(oend-op) < MFLIMIT) { + if (op==oend) break; /* end of block */ + DEBUGLOG(5, "invalid: literals end at distance %zi from end of block", oend-op); + /* incorrect end of block : + * last match must start at least MFLIMIT==12 bytes before end of output block */ + return -1; + } } + + /* match */ + { size_t ml = token & 15; + size_t const offset = LZ4_readLE16(ip); + ip+=2; + + if (ml==15) { + /* long literal length */ + ml += read_long_length_no_check(&ip); + } + ml += MINMATCH; + + if ((size_t)(oend-op) < ml) return -1; /* output buffer overflow */ + + { const BYTE* match = op - offset; + + /* out of range */ + if (offset > (size_t)(op - prefixStart) + dictSize) { + DEBUGLOG(6, "offset out of range"); + return -1; + } + + /* check special case : extDict */ + if (offset > (size_t)(op - prefixStart)) { + /* extDict scenario */ + const BYTE* const dictEnd = dictStart + dictSize; + const BYTE* extMatch = dictEnd - (offset - (size_t)(op-prefixStart)); + size_t const extml = (size_t)(dictEnd - extMatch); + if (extml > ml) { + /* match entirely within extDict */ + LZ4_memmove(op, extMatch, ml); + op += ml; + ml = 0; + } else { + /* match split between extDict & prefix */ + LZ4_memmove(op, extMatch, extml); + op += extml; + ml -= extml; + } + match = prefixStart; + } + + /* match copy - slow variant, supporting overlap copy */ + { size_t u; + for (u=0; u<ml; u++) { + op[u] = match[u]; + } } } + op += ml; + if ((size_t)(oend-op) < LASTLITERALS) { + DEBUGLOG(5, "invalid: match ends at distance %zi from end of block", oend-op); + /* incorrect end of block : + * last match must stop at least LASTLITERALS==5 bytes before end of output block */ + return -1; + } + } /* match */ + } /* main loop */ + return (int)(ip - istart); +} + + /* Read the variable-length literal or match length. * - * ip - pointer to use as input. - * lencheck - end ip. Return an error if ip advances >= lencheck. - * loop_check - check ip >= lencheck in body of loop. Returns loop_error if so. - * initial_check - check ip >= lencheck before start of loop. Returns initial_error if so. - * error (output) - error code. Should be set to 0 before call. - */ -typedef enum { loop_error = -2, initial_error = -1, ok = 0 } variable_length_error; -LZ4_FORCE_INLINE unsigned -read_variable_length(const BYTE**ip, const BYTE* lencheck, - int loop_check, int initial_check, - variable_length_error* error) -{ - U32 length = 0; - U32 s; - if (initial_check && unlikely((*ip) >= lencheck)) { /* overflow detection */ - *error = initial_error; - return length; + * @ip : input pointer + * @ilimit : position after which if length is not decoded, the input is necessarily corrupted. + * @initial_check - check ip >= ipmax before start of loop. Returns initial_error if so. + * @error (output) - error code. Must be set to 0 before call. +**/ +typedef size_t Rvl_t; +static const Rvl_t rvl_error = (Rvl_t)(-1); +LZ4_FORCE_INLINE Rvl_t +read_variable_length(const BYTE** ip, const BYTE* ilimit, + int initial_check) +{ + Rvl_t s, length = 0; + assert(ip != NULL); + assert(*ip != NULL); + assert(ilimit != NULL); + if (initial_check && unlikely((*ip) >= ilimit)) { /* read limit reached */ + return rvl_error; } do { s = **ip; (*ip)++; length += s; - if (loop_check && unlikely((*ip) >= lencheck)) { /* overflow detection */ - *error = loop_error; - return length; + if (unlikely((*ip) > ilimit)) { /* read limit reached */ + return rvl_error; + } + /* accumulator overflow detection (32-bit mode only) */ + if ((sizeof(length)<8) && unlikely(length > ((Rvl_t)(-1)/2)) ) { + return rvl_error; } } while (s==255); @@ -1783,7 +1907,6 @@ LZ4_decompress_generic( int srcSize, int outputSize, /* If endOnInput==endOnInputSize, this value is `dstCapacity` */ - endCondition_directive endOnInput, /* endOnOutputSize, endOnInputSize */ earlyEnd_directive partialDecoding, /* full, partial */ dict_directive dict, /* noDict, withPrefix64k, usingExtDict */ const BYTE* const lowPrefix, /* always <= dst, == dst when no prefix */ @@ -1802,13 +1925,12 @@ LZ4_decompress_generic( const BYTE* const dictEnd = (dictStart == NULL) ? NULL : dictStart + dictSize; - const int safeDecode = (endOnInput==endOnInputSize); - const int checkOffset = ((safeDecode) && (dictSize < (int)(64 KB))); + const int checkOffset = (dictSize < (int)(64 KB)); /* Set up the "end" pointers for the shortcut. */ - const BYTE* const shortiend = iend - (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/; - const BYTE* const shortoend = oend - (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/; + const BYTE* const shortiend = iend - 14 /*maxLL*/ - 2 /*offset*/; + const BYTE* const shortoend = oend - 14 /*maxLL*/ - 18 /*maxML*/; const BYTE* match; size_t offset; @@ -1820,83 +1942,70 @@ LZ4_decompress_generic( /* Special cases */ assert(lowPrefix <= op); - if ((endOnInput) && (unlikely(outputSize==0))) { + if (unlikely(outputSize==0)) { /* Empty output buffer */ if (partialDecoding) return 0; return ((srcSize==1) && (*ip==0)) ? 0 : -1; } - if ((!endOnInput) && (unlikely(outputSize==0))) { return (*ip==0 ? 1 : -1); } - if ((endOnInput) && unlikely(srcSize==0)) { return -1; } + if (unlikely(srcSize==0)) { return -1; } - /* Currently the fast loop shows a regression on qualcomm arm chips. */ + /* LZ4_FAST_DEC_LOOP: + * designed for modern OoO performance cpus, + * where copying reliably 32-bytes is preferable to an unpredictable branch. + * note : fast loop may show a regression for some client arm chips. */ #if LZ4_FAST_DEC_LOOP if ((oend - op) < FASTLOOP_SAFE_DISTANCE) { DEBUGLOG(6, "skip fast decode loop"); goto safe_decode; } - /* Fast loop : decode sequences as long as output < iend-FASTLOOP_SAFE_DISTANCE */ + /* Fast loop : decode sequences as long as output < oend-FASTLOOP_SAFE_DISTANCE */ while (1) { /* Main fastloop assertion: We can always wildcopy FASTLOOP_SAFE_DISTANCE */ assert(oend - op >= FASTLOOP_SAFE_DISTANCE); - if (endOnInput) { assert(ip < iend); } + assert(ip < iend); token = *ip++; length = token >> ML_BITS; /* literal length */ - assert(!endOnInput || ip <= iend); /* ip < iend before the increment */ - /* decode literal length */ if (length == RUN_MASK) { - variable_length_error error = ok; - length += read_variable_length(&ip, iend-RUN_MASK, (int)endOnInput, (int)endOnInput, &error); - if (error == initial_error) { goto _output_error; } - if ((safeDecode) && unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */ - if ((safeDecode) && unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */ + size_t const addl = read_variable_length(&ip, iend-RUN_MASK, 1); + if (addl == rvl_error) { goto _output_error; } + length += addl; + if (unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */ + if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */ /* copy literals */ cpy = op+length; LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); - if (endOnInput) { /* LZ4_decompress_safe() */ - if ((cpy>oend-32) || (ip+length>iend-32)) { goto safe_literal_copy; } - LZ4_wildCopy32(op, ip, cpy); - } else { /* LZ4_decompress_fast() */ - if (cpy>oend-8) { goto safe_literal_copy; } - LZ4_wildCopy8(op, ip, cpy); /* LZ4_decompress_fast() cannot copy more than 8 bytes at a time : - * it doesn't know input length, and only relies on end-of-block properties */ - } + if ((cpy>oend-32) || (ip+length>iend-32)) { goto safe_literal_copy; } + LZ4_wildCopy32(op, ip, cpy); ip += length; op = cpy; } else { cpy = op+length; - if (endOnInput) { /* LZ4_decompress_safe() */ - DEBUGLOG(7, "copy %u bytes in a 16-bytes stripe", (unsigned)length); - /* We don't need to check oend, since we check it once for each loop below */ - if (ip > iend-(16 + 1/*max lit + offset + nextToken*/)) { goto safe_literal_copy; } - /* Literals can only be 14, but hope compilers optimize if we copy by a register size */ - LZ4_memcpy(op, ip, 16); - } else { /* LZ4_decompress_fast() */ - /* LZ4_decompress_fast() cannot copy more than 8 bytes at a time : - * it doesn't know input length, and relies on end-of-block properties */ - LZ4_memcpy(op, ip, 8); - if (length > 8) { LZ4_memcpy(op+8, ip+8, 8); } - } + DEBUGLOG(7, "copy %u bytes in a 16-bytes stripe", (unsigned)length); + /* We don't need to check oend, since we check it once for each loop below */ + if (ip > iend-(16 + 1/*max lit + offset + nextToken*/)) { goto safe_literal_copy; } + /* Literals can only be <= 14, but hope compilers optimize better when copy by a register size */ + LZ4_memcpy(op, ip, 16); ip += length; op = cpy; } /* get offset */ offset = LZ4_readLE16(ip); ip+=2; match = op - offset; - assert(match <= op); + assert(match <= op); /* overflow check */ /* get matchlength */ length = token & ML_MASK; if (length == ML_MASK) { - variable_length_error error = ok; - if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { goto _output_error; } /* Error : offset outside buffers */ - length += read_variable_length(&ip, iend - LASTLITERALS + 1, (int)endOnInput, 0, &error); - if (error != ok) { goto _output_error; } - if ((safeDecode) && unlikely((uptrval)(op)+length<(uptrval)op)) { goto _output_error; } /* overflow detection */ + size_t const addl = read_variable_length(&ip, iend - LASTLITERALS + 1, 0); + if (addl == rvl_error) { goto _output_error; } + length += addl; length += MINMATCH; + if (unlikely((uptrval)(op)+length<(uptrval)op)) { goto _output_error; } /* overflow detection */ + if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { goto _output_error; } /* Error : offset outside buffers */ if (op + length >= oend - FASTLOOP_SAFE_DISTANCE) { goto safe_match_copy; } @@ -1906,7 +2015,7 @@ LZ4_decompress_generic( goto safe_match_copy; } - /* Fastpath check: Avoids a branch in LZ4_wildCopy32 if true */ + /* Fastpath check: skip LZ4_wildCopy32 when true */ if ((dict == withPrefix64k) || (match >= lowPrefix)) { if (offset >= 8) { assert(match >= lowPrefix); @@ -1923,6 +2032,7 @@ LZ4_decompress_generic( if (checkOffset && (unlikely(match + dictSize < lowPrefix))) { goto _output_error; } /* Error : offset outside buffers */ /* match starting within external dictionary */ if ((dict==usingExtDict) && (match < lowPrefix)) { + assert(dictEnd != NULL); if (unlikely(op+length > oend-LASTLITERALS)) { if (partialDecoding) { DEBUGLOG(7, "partialDecoding: dictionary match, close to dstEnd"); @@ -1969,11 +2079,10 @@ LZ4_decompress_generic( /* Main Loop : decode remaining sequences where output < FASTLOOP_SAFE_DISTANCE */ while (1) { + assert(ip < iend); token = *ip++; length = token >> ML_BITS; /* literal length */ - assert(!endOnInput || ip <= iend); /* ip < iend before the increment */ - /* A two-stage shortcut for the most common case: * 1) If the literal length is 0..14, and there is enough space, * enter the shortcut and copy 16 bytes on behalf of the literals @@ -1983,11 +2092,11 @@ LZ4_decompress_generic( * those 18 bytes earlier, upon entering the shortcut (in other words, * there is a combined check for both stages). */ - if ( (endOnInput ? length != RUN_MASK : length <= 8) + if ( (length != RUN_MASK) /* strictly "less than" on input, to re-enter the loop with at least one byte */ - && likely((endOnInput ? ip < shortiend : 1) & (op <= shortoend)) ) { + && likely((ip < shortiend) & (op <= shortoend)) ) { /* Copy the literals */ - LZ4_memcpy(op, ip, endOnInput ? 16 : 8); + LZ4_memcpy(op, ip, 16); op += length; ip += length; /* The second stage: prepare for match copying, decode full info. @@ -2017,11 +2126,11 @@ LZ4_decompress_generic( /* decode literal length */ if (length == RUN_MASK) { - variable_length_error error = ok; - length += read_variable_length(&ip, iend-RUN_MASK, (int)endOnInput, (int)endOnInput, &error); - if (error == initial_error) { goto _output_error; } - if ((safeDecode) && unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */ - if ((safeDecode) && unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */ + size_t const addl = read_variable_length(&ip, iend-RUN_MASK, 1); + if (addl == rvl_error) { goto _output_error; } + length += addl; + if (unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */ + if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */ } /* copy literals */ @@ -2030,9 +2139,7 @@ LZ4_decompress_generic( safe_literal_copy: #endif LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH); - if ( ((endOnInput) && ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS))) ) - || ((!endOnInput) && (cpy>oend-WILDCOPYLENGTH)) ) - { + if ((cpy>oend-MFLIMIT) || (ip+length>iend-(2+1+LASTLITERALS))) { /* We've either hit the input parsing restriction or the output parsing restriction. * In the normal scenario, decoding a full block, it must be the last sequence, * otherwise it's an error (invalid input or dimensions). @@ -2042,7 +2149,6 @@ LZ4_decompress_generic( /* Since we are partial decoding we may be in this block because of the output parsing * restriction, which is not valid since the output buffer is allowed to be undersized. */ - assert(endOnInput); DEBUGLOG(7, "partialDecoding: copying literals, close to input or output end") DEBUGLOG(7, "partialDecoding: literal length = %u", (unsigned)length); DEBUGLOG(7, "partialDecoding: remaining space in dstBuffer : %i", (int)(oend - op)); @@ -2063,21 +2169,17 @@ LZ4_decompress_generic( length = (size_t)(oend-op); } } else { - /* We must be on the last sequence because of the parsing limitations so check - * that we exactly regenerate the original size (must be exact when !endOnInput). - */ - if ((!endOnInput) && (cpy != oend)) { goto _output_error; } /* We must be on the last sequence (or invalid) because of the parsing limitations * so check that we exactly consume the input and don't overrun the output buffer. */ - if ((endOnInput) && ((ip+length != iend) || (cpy > oend))) { + if ((ip+length != iend) || (cpy > oend)) { DEBUGLOG(6, "should have been last run of literals") DEBUGLOG(6, "ip(%p) + length(%i) = %p != iend (%p)", ip, (int)length, ip+length, iend); DEBUGLOG(6, "or cpy(%p) > oend(%p)", cpy, oend); goto _output_error; } } - LZ4_memmove(op, ip, length); /* supports overlapping memory regions; only matters for in-place decompression scenarios */ + LZ4_memmove(op, ip, length); /* supports overlapping memory regions, for in-place decompression scenarios */ ip += length; op += length; /* Necessarily EOF when !partialDecoding. @@ -2089,7 +2191,7 @@ LZ4_decompress_generic( break; } } else { - LZ4_wildCopy8(op, ip, cpy); /* may overwrite up to WILDCOPYLENGTH beyond cpy */ + LZ4_wildCopy8(op, ip, cpy); /* can overwrite up to 8 bytes beyond cpy */ ip += length; op = cpy; } @@ -2102,10 +2204,10 @@ LZ4_decompress_generic( _copy_match: if (length == ML_MASK) { - variable_length_error error = ok; - length += read_variable_length(&ip, iend - LASTLITERALS + 1, (int)endOnInput, 0, &error); - if (error != ok) goto _output_error; - if ((safeDecode) && unlikely((uptrval)(op)+length<(uptrval)op)) goto _output_error; /* overflow detection */ + size_t const addl = read_variable_length(&ip, iend - LASTLITERALS + 1, 0); + if (addl == rvl_error) { goto _output_error; } + length += addl; + if (unlikely((uptrval)(op)+length<(uptrval)op)) goto _output_error; /* overflow detection */ } length += MINMATCH; @@ -2115,6 +2217,7 @@ LZ4_decompress_generic( if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) goto _output_error; /* Error : offset outside buffers */ /* match starting within external dictionary */ if ((dict==usingExtDict) && (match < lowPrefix)) { + assert(dictEnd != NULL); if (unlikely(op+length > oend-LASTLITERALS)) { if (partialDecoding) length = MIN(length, (size_t)(oend-op)); else goto _output_error; /* doesn't respect parsing restriction */ @@ -2193,12 +2296,8 @@ LZ4_decompress_generic( } /* end of decoding */ - if (endOnInput) { - DEBUGLOG(5, "decoded %i bytes", (int) (((char*)op)-dst)); - return (int) (((char*)op)-dst); /* Nb of output bytes decoded */ - } else { - return (int) (((const char*)ip)-src); /* Nb of input bytes read */ - } + DEBUGLOG(5, "decoded %i bytes", (int) (((char*)op)-dst)); + return (int) (((char*)op)-dst); /* Nb of output bytes decoded */ /* Overflow error detected */ _output_error: @@ -2213,7 +2312,7 @@ LZ4_FORCE_O2 int LZ4_decompress_safe(const char* source, char* dest, int compressedSize, int maxDecompressedSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxDecompressedSize, - endOnInputSize, decode_full_block, noDict, + decode_full_block, noDict, (BYTE*)dest, NULL, 0); } @@ -2222,16 +2321,17 @@ int LZ4_decompress_safe_partial(const char* src, char* dst, int compressedSize, { dstCapacity = MIN(targetOutputSize, dstCapacity); return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity, - endOnInputSize, partial_decode, + partial_decode, noDict, (BYTE*)dst, NULL, 0); } LZ4_FORCE_O2 int LZ4_decompress_fast(const char* source, char* dest, int originalSize) { - return LZ4_decompress_generic(source, dest, 0, originalSize, - endOnOutputSize, decode_full_block, withPrefix64k, - (BYTE*)dest - 64 KB, NULL, 0); + DEBUGLOG(5, "LZ4_decompress_fast"); + return LZ4_decompress_unsafe_generic( + (const BYTE*)source, (BYTE*)dest, originalSize, + 0, NULL, 0); } /*===== Instantiate a few more decoding cases, used more than once. =====*/ @@ -2240,7 +2340,7 @@ LZ4_FORCE_O2 /* Exported, an obsolete API function. */ int LZ4_decompress_safe_withPrefix64k(const char* source, char* dest, int compressedSize, int maxOutputSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, decode_full_block, withPrefix64k, + decode_full_block, withPrefix64k, (BYTE*)dest - 64 KB, NULL, 0); } @@ -2249,16 +2349,16 @@ static int LZ4_decompress_safe_partial_withPrefix64k(const char* source, char* d { dstCapacity = MIN(targetOutputSize, dstCapacity); return LZ4_decompress_generic(source, dest, compressedSize, dstCapacity, - endOnInputSize, partial_decode, withPrefix64k, + partial_decode, withPrefix64k, (BYTE*)dest - 64 KB, NULL, 0); } /* Another obsolete API function, paired with the previous one. */ int LZ4_decompress_fast_withPrefix64k(const char* source, char* dest, int originalSize) { - /* LZ4_decompress_fast doesn't validate match offsets, - * and thus serves well with any prefixed dictionary. */ - return LZ4_decompress_fast(source, dest, originalSize); + return LZ4_decompress_unsafe_generic( + (const BYTE*)source, (BYTE*)dest, originalSize, + 64 KB, NULL, 0); } LZ4_FORCE_O2 @@ -2266,7 +2366,7 @@ static int LZ4_decompress_safe_withSmallPrefix(const char* source, char* dest, i size_t prefixSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, decode_full_block, noDict, + decode_full_block, noDict, (BYTE*)dest-prefixSize, NULL, 0); } @@ -2276,7 +2376,7 @@ static int LZ4_decompress_safe_partial_withSmallPrefix(const char* source, char* { dstCapacity = MIN(targetOutputSize, dstCapacity); return LZ4_decompress_generic(source, dest, compressedSize, dstCapacity, - endOnInputSize, partial_decode, noDict, + partial_decode, noDict, (BYTE*)dest-prefixSize, NULL, 0); } @@ -2286,7 +2386,7 @@ int LZ4_decompress_safe_forceExtDict(const char* source, char* dest, const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, decode_full_block, usingExtDict, + decode_full_block, usingExtDict, (BYTE*)dest, (const BYTE*)dictStart, dictSize); } @@ -2297,7 +2397,7 @@ int LZ4_decompress_safe_partial_forceExtDict(const char* source, char* dest, { dstCapacity = MIN(targetOutputSize, dstCapacity); return LZ4_decompress_generic(source, dest, compressedSize, dstCapacity, - endOnInputSize, partial_decode, usingExtDict, + partial_decode, usingExtDict, (BYTE*)dest, (const BYTE*)dictStart, dictSize); } @@ -2305,9 +2405,9 @@ LZ4_FORCE_O2 static int LZ4_decompress_fast_extDict(const char* source, char* dest, int originalSize, const void* dictStart, size_t dictSize) { - return LZ4_decompress_generic(source, dest, 0, originalSize, - endOnOutputSize, decode_full_block, usingExtDict, - (BYTE*)dest, (const BYTE*)dictStart, dictSize); + return LZ4_decompress_unsafe_generic( + (const BYTE*)source, (BYTE*)dest, originalSize, + 0, (const BYTE*)dictStart, dictSize); } /* The "double dictionary" mode, for use with e.g. ring buffers: the first part @@ -2319,16 +2419,7 @@ int LZ4_decompress_safe_doubleDict(const char* source, char* dest, int compresse size_t prefixSize, const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, - endOnInputSize, decode_full_block, usingExtDict, - (BYTE*)dest-prefixSize, (const BYTE*)dictStart, dictSize); -} - -LZ4_FORCE_INLINE -int LZ4_decompress_fast_doubleDict(const char* source, char* dest, int originalSize, - size_t prefixSize, const void* dictStart, size_t dictSize) -{ - return LZ4_decompress_generic(source, dest, 0, originalSize, - endOnOutputSize, decode_full_block, usingExtDict, + decode_full_block, usingExtDict, (BYTE*)dest-prefixSize, (const BYTE*)dictStart, dictSize); } @@ -2434,29 +2525,35 @@ int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const ch return result; } -LZ4_FORCE_O2 -int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize) +LZ4_FORCE_O2 int +LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, + const char* source, char* dest, int originalSize) { - LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse; + LZ4_streamDecode_t_internal* const lz4sd = + (assert(LZ4_streamDecode!=NULL), &LZ4_streamDecode->internal_donotuse); int result; + + DEBUGLOG(5, "LZ4_decompress_fast_continue (toDecodeSize=%i)", originalSize); assert(originalSize >= 0); if (lz4sd->prefixSize == 0) { + DEBUGLOG(5, "first invocation : no prefix nor extDict"); assert(lz4sd->extDictSize == 0); result = LZ4_decompress_fast(source, dest, originalSize); if (result <= 0) return result; lz4sd->prefixSize = (size_t)originalSize; lz4sd->prefixEnd = (BYTE*)dest + originalSize; } else if (lz4sd->prefixEnd == (BYTE*)dest) { - if (lz4sd->prefixSize >= 64 KB - 1 || lz4sd->extDictSize == 0) - result = LZ4_decompress_fast(source, dest, originalSize); - else - result = LZ4_decompress_fast_doubleDict(source, dest, originalSize, - lz4sd->prefixSize, lz4sd->externalDict, lz4sd->extDictSize); + DEBUGLOG(5, "continue using existing prefix"); + result = LZ4_decompress_unsafe_generic( + (const BYTE*)source, (BYTE*)dest, originalSize, + lz4sd->prefixSize, + lz4sd->externalDict, lz4sd->extDictSize); if (result <= 0) return result; lz4sd->prefixSize += (size_t)originalSize; lz4sd->prefixEnd += originalSize; } else { + DEBUGLOG(5, "prefix becomes extDict"); lz4sd->extDictSize = lz4sd->prefixSize; lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; result = LZ4_decompress_fast_extDict(source, dest, originalSize, @@ -2510,7 +2607,9 @@ int LZ4_decompress_safe_partial_usingDict(const char* source, char* dest, int co int LZ4_decompress_fast_usingDict(const char* source, char* dest, int originalSize, const char* dictStart, int dictSize) { if (dictSize==0 || dictStart+dictSize == dest) - return LZ4_decompress_fast(source, dest, originalSize); + return LZ4_decompress_unsafe_generic( + (const BYTE*)source, (BYTE*)dest, originalSize, + (size_t)dictSize, NULL, 0); assert(dictSize >= 0); return LZ4_decompress_fast_extDict(source, dest, originalSize, dictStart, (size_t)dictSize); } |