Hjg.Pngcs.PngReader.ReadChunk C# (CSharp) Method

        private PngChunk ReadChunk(byte[] chunkid, int clen, bool skipforced)
        {
            if (clen < 0) throw new PngjInputException("invalid chunk lenght: " + clen);
            // skipChunksByIdSet is created lazyly, if fist IHDR has already been read
            if (skipChunkIdsSet == null && CurrentChunkGroup > ChunksList.CHUNK_GROUP_0_IDHR) {
                skipChunkIdsSet = new Dictionary<string, int>();
                if (SkipChunkIds != null)
                    foreach (string id in SkipChunkIds) skipChunkIdsSet.Add(id, 1);
            }

            String chunkidstr = ChunkHelper.ToString(chunkid);
            PngChunk pngChunk = null;
            bool critical = ChunkHelper.IsCritical(chunkidstr);
            bool skip = skipforced;
            if (MaxTotalBytesRead > 0 && clen + offset > MaxTotalBytesRead)
                throw new PngjInputException("Maximum total bytes to read exceeeded: " + MaxTotalBytesRead + " offset:"
                        + offset + " clen=" + clen);
            // an ancillary chunks can be skipped because of several reasons:
            if (CurrentChunkGroup > ChunksList.CHUNK_GROUP_0_IDHR && !ChunkHelper.IsCritical(chunkidstr))
                skip = skip || (SkipChunkMaxSize > 0 && clen >= SkipChunkMaxSize) || skipChunkIdsSet.ContainsKey(chunkidstr)
                        || (MaxBytesMetadata > 0 && clen > MaxBytesMetadata - bytesChunksLoaded)
                        || !ChunkHelper.ShouldLoad(chunkidstr, ChunkLoadBehaviour);

            if (skip) {
                PngHelperInternal.SkipBytes(inputStream, clen);
                PngHelperInternal.ReadInt4(inputStream); // skip - we dont call PngHelperInternal.skipBytes(inputStream, clen + 4) for risk of overflow
                pngChunk = new PngChunkSkipped(chunkidstr, ImgInfo, clen);
            } else {
                ChunkRaw chunk = new ChunkRaw(clen, chunkid, true);
                chunk.ReadChunkData(inputStream, crcEnabled || critical);
                pngChunk = PngChunk.Factory(chunk, ImgInfo);
                if (!pngChunk.Crit) {
                    bytesChunksLoaded += chunk.Len;
                }

            }
            pngChunk.Offset = offset - 8L;
            chunksList.AppendReadChunk(pngChunk, CurrentChunkGroup);
            offset += clen + 4L;
            return pngChunk;
        }