public PNGRed()

in src/main/java/org/apache/xmlgraphics/image/codec/png/PNGRed.java [360:484]
111 lines of code
29 McCabe index (conditional complexity)

    public PNGRed(InputStream stream, PNGDecodeParam decodeParam)
        throws IOException {

        if (!stream.markSupported()) {
            stream = new BufferedInputStream(stream);
        }
        DataInputStream distream = new DataInputStream(stream);

        if (decodeParam == null) {
            decodeParam = new PNGDecodeParam();
        }
        this.decodeParam = decodeParam;

        // Get parameter values
        this.suppressAlpha = decodeParam.getSuppressAlpha();
        this.expandPalette = decodeParam.getExpandPalette();
        this.output8BitGray = decodeParam.getOutput8BitGray();
        this.expandGrayAlpha = decodeParam.getExpandGrayAlpha();
        if (decodeParam.getPerformGammaCorrection()) {
            this.userExponent = decodeParam.getUserExponent();
            this.displayExponent = decodeParam.getDisplayExponent();
            performGammaCorrection = true;
            output8BitGray = true;
        }
        this.generateEncodeParam = decodeParam.getGenerateEncodeParam();

        if (emitProperties) {
            properties.put("file_type", "PNG v. 1.0");
        }

        long magic = distream.readLong();
        if (magic != 0x89504e470d0a1a0aL) {
            String msg = PropertyUtil.getString("PNGImageDecoder0");
            throw new RuntimeException(msg);
        }

        do {
            PNGChunk chunk;

            String chunkType = getChunkType(distream);
            if (chunkType.equals("IHDR")) {
                chunk = readChunk(distream);
                parse_IHDR_chunk(chunk);
            } else if (chunkType.equals("PLTE")) {
                chunk = readChunk(distream);
                parse_PLTE_chunk(chunk);
            } else if (chunkType.equals("IDAT")) {
                chunk = readChunk(distream);
                streamVec.add(new ByteArrayInputStream(chunk.getData()));
            } else if (chunkType.equals("IEND")) {
                chunk = readChunk(distream);
                try {
                    parse_IEND_chunk(chunk);
                } catch (Exception e) {
                    e.printStackTrace();
                    String msg = PropertyUtil.getString("PNGImageDecoder2");
                    throw new RuntimeException(msg);
                }
                break; // fall through to the bottom
            } else if (chunkType.equals("bKGD")) {
                chunk = readChunk(distream);
                parse_bKGD_chunk(chunk);
            } else if (chunkType.equals("cHRM")) {
                chunk = readChunk(distream);
                parse_cHRM_chunk(chunk);
            } else if (chunkType.equals("gAMA")) {
                chunk = readChunk(distream);
                parse_gAMA_chunk(chunk);
            } else if (chunkType.equals("hIST")) {
                chunk = readChunk(distream);
                parse_hIST_chunk(chunk);
            } else if (chunkType.equals("iCCP")) {
                chunk = readChunk(distream);
            } else if (chunkType.equals("pHYs")) {
                chunk = readChunk(distream);
                parse_pHYs_chunk(chunk);
            } else if (chunkType.equals("sBIT")) {
                chunk = readChunk(distream);
                parse_sBIT_chunk(chunk);
            } else if (chunkType.equals("sRGB")) {
                chunk = readChunk(distream);
                parse_sRGB_chunk(chunk);
            } else if (chunkType.equals("tEXt")) {
                chunk = readChunk(distream);
                parse_tEXt_chunk(chunk);
            } else if (chunkType.equals("tIME")) {
                chunk = readChunk(distream);
                parse_tIME_chunk(chunk);
            } else if (chunkType.equals("tRNS")) {
                chunk = readChunk(distream);
                parse_tRNS_chunk(chunk);
            } else if (chunkType.equals("zTXt")) {
                chunk = readChunk(distream);
                parse_zTXt_chunk(chunk);
            } else {
                chunk = readChunk(distream);
                // Output the chunk data in raw form

                String type = chunk.getTypeString();
                byte[] data = chunk.getData();
                if (encodeParam != null) {
                    encodeParam.addPrivateChunk(type, data);
                }
                if (emitProperties) {
                    String key = "chunk_" + chunkIndex++ + ':' + type;
                    properties.put(key.toLowerCase(Locale.getDefault()), data);
                }
            }
        } while (true);

        // Final post-processing

        if (significantBits == null) {
            significantBits = new int[inputBands];
            for (int i = 0; i < inputBands; i++) {
                significantBits[i] = bitDepth;
            }

            if (emitProperties) {
                properties.put("significant_bits", significantBits);
            }
        }
        distream.close();
        stream.close();
    }