static size_t HUF_decompress4X4_usingDTable_internal_body()

in csharp/src/HufDecompress.cs [455:542]

• 72 lines of code
• 12 McCabe index (conditional complexity)

		static size_t HUF_decompress4X4_usingDTable_internal_body(void* dst, size_t dstSize, void* cSrc, size_t cSrcSize, HUF_DTable* DTable)
		{
			if (cSrcSize < 10) return ERROR(Error.corruption_detected);   /* strict minimum : jump table + 1 byte per stream */

			{
				BYTE* istart = (BYTE*)cSrc;
				BYTE* ostart = (BYTE*)dst;
				BYTE* oend = ostart + dstSize;
				void* dtPtr = DTable + 1;
				HUF_DEltX4* dt = (HUF_DEltX4*)dtPtr;

				/* Init */
				BIT_DStream_t bitD1 = new BIT_DStream_t();
				BIT_DStream_t bitD2 = new BIT_DStream_t();
				BIT_DStream_t bitD3 = new BIT_DStream_t();
				BIT_DStream_t bitD4 = new BIT_DStream_t();
				size_t length1 = MEM_readLE16(istart);
				size_t length2 = MEM_readLE16(istart + 2);
				size_t length3 = MEM_readLE16(istart + 4);
				size_t length4 = cSrcSize - (length1 + length2 + length3 + 6);
				BYTE* istart1 = istart + 6;  /* jumpTable */
				BYTE* istart2 = istart1 + length1;
				BYTE* istart3 = istart2 + length2;
				BYTE* istart4 = istart3 + length3;
				size_t segmentSize = (dstSize + 3) / 4;
				BYTE* opStart2 = ostart + segmentSize;
				BYTE* opStart3 = opStart2 + segmentSize;
				BYTE* opStart4 = opStart3 + segmentSize;
				BYTE* op1 = ostart;
				BYTE* op2 = opStart2;
				BYTE* op3 = opStart3;
				BYTE* op4 = opStart4;
				U32 endSignal;
				DTableDesc dtd = GetDTableDesc(DTable);
				U32 dtLog = dtd.tableLog;

				if (length4 > cSrcSize) return ERROR(Error.corruption_detected);   /* overflow */
				{ size_t errcod = InitDStream(bitD1, istart1, length1); if (IsError(errcod)) return errcod; }
				{ size_t errcod = InitDStream(bitD2, istart2, length2); if (IsError(errcod)) return errcod; }
				{ size_t errcod = InitDStream(bitD3, istart3, length3); if (IsError(errcod)) return errcod; }
				{ size_t errcod = InitDStream(bitD4, istart4, length4); if (IsError(errcod)) return errcod; }

				/* 16-32 symbols per loop (4-8 symbols per stream) */
				endSignal = (U32)ReloadDStream(bitD1) | (U32)ReloadDStream(bitD2) | (U32)ReloadDStream(bitD3) | (U32)ReloadDStream(bitD4);
				for (; (endSignal == (U32)BIT_DStream_status.BIT_DStream_unfinished) & (op4 < (oend - (sizeOfBitContainer - 1)));)
				{
					HUF_DECODE_SYMBOLX4_2(ref op1, bitD1, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op2, bitD2, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op3, bitD3, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op4, bitD4, dt, dtLog);
					HUF_DECODE_SYMBOLX4_1(ref op1, bitD1, dt, dtLog);
					HUF_DECODE_SYMBOLX4_1(ref op2, bitD2, dt, dtLog);
					HUF_DECODE_SYMBOLX4_1(ref op3, bitD3, dt, dtLog);
					HUF_DECODE_SYMBOLX4_1(ref op4, bitD4, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op1, bitD1, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op2, bitD2, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op3, bitD3, dt, dtLog);
					HUF_DECODE_SYMBOLX4_2(ref op4, bitD4, dt, dtLog);
					HUF_DECODE_SYMBOLX4_0(ref op1, bitD1, dt, dtLog);
					HUF_DECODE_SYMBOLX4_0(ref op2, bitD2, dt, dtLog);
					HUF_DECODE_SYMBOLX4_0(ref op3, bitD3, dt, dtLog);
					HUF_DECODE_SYMBOLX4_0(ref op4, bitD4, dt, dtLog);

					endSignal = (U32)ReloadDStream(bitD1) | (U32)ReloadDStream(bitD2) | (U32)ReloadDStream(bitD3) | (U32)ReloadDStream(bitD4);
				}

				/* check corruption */
				if (op1 > opStart2) return ERROR(Error.corruption_detected);
				if (op2 > opStart3) return ERROR(Error.corruption_detected);
				if (op3 > opStart4) return ERROR(Error.corruption_detected);
				/* note : op4 already verified within main loop */

				/* finish bitStreams one by one */
				HUF_decodeStreamX4(op1, bitD1, opStart2, dt, dtLog);
				HUF_decodeStreamX4(op2, bitD2, opStart3, dt, dtLog);
				HUF_decodeStreamX4(op3, bitD3, opStart4, dt, dtLog);
				HUF_decodeStreamX4(op4, bitD4, oend, dt, dtLog);

				/* check */
				{
					U32 endCheck = (U32)EndOfDStream(bitD1) & (U32)EndOfDStream(bitD2) & (U32)EndOfDStream(bitD3) & (U32)EndOfDStream(bitD4);
					if (endCheck == 0) return ERROR(Error.corruption_detected);
				}

				/* decoded size */
				return dstSize;
			}
		}