in cdk/extra/zstd/lib/compress/zstd_compress.c [5863:6046]
static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input,
ZSTD_EndDirective const flushMode)
{
const char* const istart = (assert(input != NULL), (const char*)input->src);
const char* const iend = (istart != NULL) ? istart + input->size : istart;
const char* ip = (istart != NULL) ? istart + input->pos : istart;
char* const ostart = (assert(output != NULL), (char*)output->dst);
char* const oend = (ostart != NULL) ? ostart + output->size : ostart;
char* op = (ostart != NULL) ? ostart + output->pos : ostart;
U32 someMoreWork = 1;
/* check expectations */
DEBUGLOG(5, "ZSTD_compressStream_generic, flush=%i, srcSize = %zu", (int)flushMode, input->size - input->pos);
assert(zcs != NULL);
if (zcs->appliedParams.inBufferMode == ZSTD_bm_stable) {
assert(input->pos >= zcs->stableIn_notConsumed);
input->pos -= zcs->stableIn_notConsumed;
ip -= zcs->stableIn_notConsumed;
zcs->stableIn_notConsumed = 0;
}
if (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered) {
assert(zcs->inBuff != NULL);
assert(zcs->inBuffSize > 0);
}
if (zcs->appliedParams.outBufferMode == ZSTD_bm_buffered) {
assert(zcs->outBuff != NULL);
assert(zcs->outBuffSize > 0);
}
if (input->src == NULL) assert(input->size == 0);
assert(input->pos <= input->size);
if (output->dst == NULL) assert(output->size == 0);
assert(output->pos <= output->size);
assert((U32)flushMode <= (U32)ZSTD_e_end);
while (someMoreWork) {
switch(zcs->streamStage)
{
case zcss_init:
RETURN_ERROR(init_missing, "call ZSTD_initCStream() first!");
case zcss_load:
if ( (flushMode == ZSTD_e_end)
&& ( (size_t)(oend-op) >= ZSTD_compressBound(iend-ip) /* Enough output space */
|| zcs->appliedParams.outBufferMode == ZSTD_bm_stable) /* OR we are allowed to return dstSizeTooSmall */
&& (zcs->inBuffPos == 0) ) {
/* shortcut to compression pass directly into output buffer */
size_t const cSize = ZSTD_compressEnd_public(zcs,
op, oend-op, ip, iend-ip);
DEBUGLOG(4, "ZSTD_compressEnd : cSize=%u", (unsigned)cSize);
FORWARD_IF_ERROR(cSize, "ZSTD_compressEnd failed");
ip = iend;
op += cSize;
zcs->frameEnded = 1;
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
someMoreWork = 0; break;
}
/* complete loading into inBuffer in buffered mode */
if (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered) {
size_t const toLoad = zcs->inBuffTarget - zcs->inBuffPos;
size_t const loaded = ZSTD_limitCopy(
zcs->inBuff + zcs->inBuffPos, toLoad,
ip, iend-ip);
zcs->inBuffPos += loaded;
if (ip) ip += loaded;
if ( (flushMode == ZSTD_e_continue)
&& (zcs->inBuffPos < zcs->inBuffTarget) ) {
/* not enough input to fill full block : stop here */
someMoreWork = 0; break;
}
if ( (flushMode == ZSTD_e_flush)
&& (zcs->inBuffPos == zcs->inToCompress) ) {
/* empty */
someMoreWork = 0; break;
}
} else {
assert(zcs->appliedParams.inBufferMode == ZSTD_bm_stable);
if ( (flushMode == ZSTD_e_continue)
&& ( (size_t)(iend - ip) < zcs->blockSize) ) {
/* can't compress a full block : stop here */
zcs->stableIn_notConsumed = (size_t)(iend - ip);
ip = iend; /* pretend to have consumed input */
someMoreWork = 0; break;
}
if ( (flushMode == ZSTD_e_flush)
&& (ip == iend) ) {
/* empty */
someMoreWork = 0; break;
}
}
/* compress current block (note : this stage cannot be stopped in the middle) */
DEBUGLOG(5, "stream compression stage (flushMode==%u)", flushMode);
{ int const inputBuffered = (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered);
void* cDst;
size_t cSize;
size_t oSize = oend-op;
size_t const iSize = inputBuffered ? zcs->inBuffPos - zcs->inToCompress
: MIN((size_t)(iend - ip), zcs->blockSize);
if (oSize >= ZSTD_compressBound(iSize) || zcs->appliedParams.outBufferMode == ZSTD_bm_stable)
cDst = op; /* compress into output buffer, to skip flush stage */
else
cDst = zcs->outBuff, oSize = zcs->outBuffSize;
if (inputBuffered) {
unsigned const lastBlock = (flushMode == ZSTD_e_end) && (ip==iend);
cSize = lastBlock ?
ZSTD_compressEnd_public(zcs, cDst, oSize,
zcs->inBuff + zcs->inToCompress, iSize) :
ZSTD_compressContinue_public(zcs, cDst, oSize,
zcs->inBuff + zcs->inToCompress, iSize);
FORWARD_IF_ERROR(cSize, "%s", lastBlock ? "ZSTD_compressEnd failed" : "ZSTD_compressContinue failed");
zcs->frameEnded = lastBlock;
/* prepare next block */
zcs->inBuffTarget = zcs->inBuffPos + zcs->blockSize;
if (zcs->inBuffTarget > zcs->inBuffSize)
zcs->inBuffPos = 0, zcs->inBuffTarget = zcs->blockSize;
DEBUGLOG(5, "inBuffTarget:%u / inBuffSize:%u",
(unsigned)zcs->inBuffTarget, (unsigned)zcs->inBuffSize);
if (!lastBlock)
assert(zcs->inBuffTarget <= zcs->inBuffSize);
zcs->inToCompress = zcs->inBuffPos;
} else { /* !inputBuffered, hence ZSTD_bm_stable */
unsigned const lastBlock = (flushMode == ZSTD_e_end) && (ip + iSize == iend);
cSize = lastBlock ?
ZSTD_compressEnd_public(zcs, cDst, oSize, ip, iSize) :
ZSTD_compressContinue_public(zcs, cDst, oSize, ip, iSize);
/* Consume the input prior to error checking to mirror buffered mode. */
if (ip) ip += iSize;
FORWARD_IF_ERROR(cSize, "%s", lastBlock ? "ZSTD_compressEnd failed" : "ZSTD_compressContinue failed");
zcs->frameEnded = lastBlock;
if (lastBlock) assert(ip == iend);
}
if (cDst == op) { /* no need to flush */
op += cSize;
if (zcs->frameEnded) {
DEBUGLOG(5, "Frame completed directly in outBuffer");
someMoreWork = 0;
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
}
break;
}
zcs->outBuffContentSize = cSize;
zcs->outBuffFlushedSize = 0;
zcs->streamStage = zcss_flush; /* pass-through to flush stage */
}
ZSTD_FALLTHROUGH;
case zcss_flush:
DEBUGLOG(5, "flush stage");
assert(zcs->appliedParams.outBufferMode == ZSTD_bm_buffered);
{ size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
size_t const flushed = ZSTD_limitCopy(op, (size_t)(oend-op),
zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
DEBUGLOG(5, "toFlush: %u into %u ==> flushed: %u",
(unsigned)toFlush, (unsigned)(oend-op), (unsigned)flushed);
if (flushed)
op += flushed;
zcs->outBuffFlushedSize += flushed;
if (toFlush!=flushed) {
/* flush not fully completed, presumably because dst is too small */
assert(op==oend);
someMoreWork = 0;
break;
}
zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
if (zcs->frameEnded) {
DEBUGLOG(5, "Frame completed on flush");
someMoreWork = 0;
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
break;
}
zcs->streamStage = zcss_load;
break;
}
default: /* impossible */
assert(0);
}
}
input->pos = ip - istart;
output->pos = op - ostart;
if (zcs->frameEnded) return 0;
return ZSTD_nextInputSizeHint(zcs);
}