ZSTDds_decompressLastBlock
if (!(dctx->stage == ZSTDds_decompressBlock || dctx->stage == ZSTDds_decompressLastBlock))
case ZSTDds_decompressLastBlock:
dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock;
case ZSTDds_decompressLastBlock:
if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */