/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */
static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
{
BYTE* d = dstPtr;
const BYTE* s = srcPtr;
BYTE* e = dstEnd;
do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
}
/* customized variant of memcpy, which can overwrite up to 8 bytes beyond dstEnd */
static inline void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
{
BYTE* d = (BYTE*)dstPtr;
const BYTE* s = (const BYTE*)srcPtr;
BYTE* const e = (BYTE*)dstEnd;
do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
}
/*
* no public solution to solve our requirement yet.
* see: <required buffer size for LZ4_decompress_safe_partial>
* https://groups.google.com/forum/#!topic/lz4c/_3kkz5N6n00
*/
static FORCE_INLINE int customized_lz4_decompress_safe_partial(
const void * const source,
void * const dest,
int inputSize,
int outputSize)
{
/* Local Variables */
const BYTE *ip = (const BYTE *) source;
const BYTE * const iend = ip + inputSize;
BYTE *op = (BYTE *) dest;
BYTE * const oend = op + outputSize;
BYTE *cpy;
static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
/* Empty output buffer */
if (unlikely(outputSize == 0))
return ((inputSize == 1) && (*ip == 0)) ? 0 : -1;
/* Main Loop : decode sequences */
while (1) {
size_t length;
const BYTE *match;
size_t offset;
/* get literal length */
unsigned int const token = *ip++;
length = token>>ML_BITS;
if (length == RUN_MASK) {
unsigned int s;
do {
s = *ip++;
length += s;
} while ((ip < iend - RUN_MASK) & (s == 255));
if (unlikely((size_t)(op + length) < (size_t)(op))) {
/* overflow detection */
goto _output_error;
}
if (unlikely((size_t)(ip + length) < (size_t)(ip))) {
/* overflow detection */
goto _output_error;
}
}
/* copy literals */
cpy = op + length;
if ((cpy > oend - WILDCOPYLENGTH) ||
(ip + length > iend - (2 + 1 + LASTLITERALS))) {
if (cpy > oend) {
memcpy(op, ip, length = oend - op);
op += length;
break;
}
if (unlikely(ip + length > iend)) {
/*
* Error :
* read attempt beyond
* end of input buffer
*/
goto _output_error;
}
memcpy(op, ip, length);
ip += length;
op += length;
if (ip > iend - 2)
break;
/* Necessarily EOF, due to parsing restrictions */
/* break; */
} else {
LZ4_wildCopy(op, ip, cpy);
ip += length;
op = cpy;
}
/* get offset */
offset = LZ4_readLE16(ip);
ip += 2;
match = op - offset;
if (unlikely(match < (const BYTE *)dest)) {
/* Error : offset outside buffers */
goto _output_error;
}
/* get matchlength */
length = token & ML_MASK;
if (length == ML_MASK) {
unsigned int s;
do {
s = *ip++;
if (ip > iend - LASTLITERALS)
goto _output_error;
length += s;
} while (s == 255);
if (unlikely((size_t)(op + length) < (size_t)op)) {
/* overflow detection */
goto _output_error;
}
}
length += MINMATCH;
/* copy match within block */
cpy = op + length;
if (unlikely(cpy >= oend - WILDCOPYLENGTH)) {
if (cpy >= oend) {
while (op < oend)
*op++ = *match++;
break;
}
goto __match;
}
/* costs ~1%; silence an msan warning when offset == 0 */
LZ4_write32(op, (U32)offset);
if (unlikely(offset < 8)) {
const int dec64 = dec64table[offset];
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += dec32table[offset];
memcpy(op + 4, match, 4);
match -= dec64;
} else {
LZ4_copy8(op, match);
match += 8;
}
op += 8;
if (unlikely(cpy > oend - 12)) {
BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
if (op < oCopyLimit) {
LZ4_wildCopy(op, match, oCopyLimit);
match += oCopyLimit - op;
op = oCopyLimit;
}
__match:
while (op < cpy)
*op++ = *match++;
} else {
LZ4_copy8(op, match);
if (length > 16)
LZ4_wildCopy(op + 8, match + 8, cpy);
}
op = cpy; /* correction */
}
DBG_BUGON((void *)ip - source > inputSize);
DBG_BUGON((void *)op - dest > outputSize);
/* Nb of output bytes decoded */
return (int) ((void *)op - dest);
/* Overflow error detected */
_output_error:
return -ERANGE;
}
