static size_t ZSTD_decompressSequences_body()

in csharp/src/ZStdDecompress.cs [1555:1608]

• 45 lines of code
• 10 McCabe index (conditional complexity)

		static size_t ZSTD_decompressSequences_body(ZSTD_DCtx dctx,
									   void* dst, size_t maxDstSize,
								 void* seqStart, size_t seqSize, int nbSeq,
								 ZSTD_longOffset_e isLongOffset)
		{
			BYTE* ip = (BYTE*)seqStart;
			BYTE* iend = ip + seqSize;
			BYTE* ostart = (BYTE*)dst;
			BYTE* oend = ostart + maxDstSize;
			BYTE* op = ostart;
			BYTE* litPtr = dctx.litPtr;
			BYTE* litEnd = litPtr + dctx.litSize;
			BYTE* baseField = (BYTE*)(dctx.baseField);
			BYTE* vBase = (BYTE*)(dctx.vBase);
			BYTE* dictEnd = (BYTE*)(dctx.dictEnd);

			/* Regen sequences */
			if (nbSeq != 0)
			{
				seqState_t seqState = new seqState_t();
				dctx.fseEntropy = 1;
				{ U32 i; for (i = 0; i < ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx.entropy.rep[i]; }
				{ size_t errcod = InitDStream(seqState.DStream, ip, (size_t)(iend - ip)); if (IsError(errcod)) return ERROR(Error.corruption_detected); }
				InitFseState(ref seqState.stateLL, seqState.DStream, dctx.LLTptr);
				InitFseState(ref seqState.stateOffb, seqState.DStream, dctx.OFTptr);
				InitFseState(ref seqState.stateML, seqState.DStream, dctx.MLTptr);

				for (; (ReloadDStream(seqState.DStream) <= BIT_DStream_status.BIT_DStream_completed) && nbSeq != 0;)
				{
					nbSeq--;
					{
						seq_t sequence = DecodeSequence(seqState, isLongOffset);
						size_t oneSeqSize = ExecSequence(op, oend, sequence, &litPtr, litEnd, baseField, vBase, dictEnd);
						if (IsError(oneSeqSize)) return oneSeqSize;
						op += oneSeqSize;
					}
				}

				/* check if reached exact end */
				if (nbSeq != 0) return ERROR(Error.corruption_detected);
				/* save reps for next block */
				{ U32 i; for (i = 0; i < ZSTD_REP_NUM; i++) dctx.entropy.rep[i] = (U32)(seqState.prevOffset[i]); }
			}

			/* last literal segment */
			{
				size_t lastLLSize = (size_t)(litEnd - litPtr);
				if (lastLLSize > (size_t)(oend - op)) return ERROR(Error.dstSize_tooSmall);
				memcpy(op, litPtr, lastLLSize);
				op += lastLLSize;
			}

			return (size_t)(op - ostart);
		}