[lib] Set ZSTD_c_stable{In,Out}Buffer in ZSTD_compress2()

Sets these parameters in ZSTD_compress2() then resets them to their
orignal values after the compression call.

An alternative design could be to add a flush mode `ZSTD_e_singlePass`
which implies `ZSTD_c_stable{In,Out}Buffer` but only for a single
compression call, by directly setting the applied parameters. I've opted
for the smaller change, but this is open for discussion.
This commit is contained in:
Nick Terrell 2020-10-12 13:51:35 -07:00
parent c74be3f6de
commit 809b2f2071

View File

@ -4364,14 +4364,22 @@ size_t ZSTD_compress2(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize)
{
ZSTD_bufferMode_e const originalInBufferMode = cctx->requestedParams.inBufferMode;
ZSTD_bufferMode_e const originalOutBufferMode = cctx->requestedParams.outBufferMode;
DEBUGLOG(4, "ZSTD_compress2 (srcSize=%u)", (unsigned)srcSize);
ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
/* Enable stable input/output buffers. */
cctx->requestedParams.inBufferMode = ZSTD_bm_stable;
cctx->requestedParams.outBufferMode = ZSTD_bm_stable;
{ size_t oPos = 0;
size_t iPos = 0;
size_t const result = ZSTD_compressStream2_simpleArgs(cctx,
dst, dstCapacity, &oPos,
src, srcSize, &iPos,
ZSTD_e_end);
/* Reset to the original values. */
cctx->requestedParams.inBufferMode = originalInBufferMode;
cctx->requestedParams.outBufferMode = originalOutBufferMode;
FORWARD_IF_ERROR(result, "ZSTD_compressStream2_simpleArgs failed");
if (result != 0) { /* compression not completed, due to lack of output space */
assert(oPos == dstCapacity);