internal static byte[] CompressBytes(byte[] ori, int offset, int len, bool compress) { try { MemoryStream inb = new MemoryStream(ori, offset, len); Stream inx = inb; if (!compress) { inx = ZlibStreamFactory.CreateZlibInputStream(inb); } MemoryStream outb = new MemoryStream(); Stream outx = outb; if (compress) { outx = ZlibStreamFactory.CreateZlibOutputStream(outb); } ShovelInToOut(inx, outx); inx.Close(); outx.Close(); byte[] res = outb.ToArray(); return(res); } catch (Exception e) { throw new PngjException(e); } }
/// <summary> /// Reads chunks before first IDAT. Position before: after IDHR (crc included) /// Position after: just after the first IDAT chunk id Returns length of first /// IDAT chunk , -1 if not found /// </summary> /// private void ReadFirstChunks() { if (!FirstChunksNotYetRead()) { return; } int clen = 0; bool found = false; byte[] chunkid = new byte[4]; // it's important to reallocate in each this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_1_AFTERIDHR; while (!found) { clen = PngHelperInternal.ReadInt4(inputStream); offset += 4; if (clen < 0) { break; } PngHelperInternal.ReadBytes(inputStream, chunkid, 0, 4); offset += 4; if (PngCsUtils.arraysEqual4(chunkid, Hjg.Pngcs.Chunks.ChunkHelper.b_IDAT)) { found = true; this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_4_IDAT; // add dummy idat chunk to list chunksList.AppendReadChunk(new PngChunkIDAT(ImgInfo, clen, offset - 8), CurrentChunkGroup); break; } else if (PngCsUtils.arraysEqual4(chunkid, Hjg.Pngcs.Chunks.ChunkHelper.b_IEND)) { throw new PngjInputException("END chunk found before image data (IDAT) at offset=" + offset); } String chunkids = ChunkHelper.ToString(chunkid); if (chunkids.Equals(ChunkHelper.PLTE)) { this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_2_PLTE; } ReadChunk(chunkid, clen, false); if (chunkids.Equals(ChunkHelper.PLTE)) { this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_3_AFTERPLTE; } } int idatLen = found ? clen : -1; if (idatLen < 0) { throw new PngjInputException("first idat chunk not found!"); } iIdatCstream = new PngIDatChunkInputStream(inputStream, idatLen, offset); idatIstream = ZlibStreamFactory.CreateZlibInputStream(iIdatCstream, true); if (!crcEnabled) { iIdatCstream.DisableCrcCheck(); } }