List collectTriangles()

in pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/shading/PDShadingType4.java [92:207]
113 lines of code
19 McCabe index (conditional complexity)

    List<ShadedTriangle> collectTriangles(AffineTransform xform, Matrix matrix)
            throws IOException
    {
        int bitsPerFlag = getBitsPerFlag();
        COSDictionary dict = getCOSObject();
        if (!(dict instanceof COSStream))
        {
            return Collections.emptyList();
        }
        PDRange rangeX = getDecodeForParameter(0);
        PDRange rangeY = getDecodeForParameter(1);
        if (rangeX == null || rangeY == null ||
            Float.compare(rangeX.getMin(), rangeX.getMax()) == 0 ||
            Float.compare(rangeY.getMin(), rangeY.getMax()) == 0)
        {
            return Collections.emptyList();
        }
        PDRange[] colRange = new PDRange[getNumberOfColorComponents()];
        for (int i = 0; i < colRange.length; ++i)
        {
            colRange[i] = getDecodeForParameter(2 + i);
            if (colRange[i] == null)
            {
                throw new IOException("Range missing in shading /Decode entry");
            }
        }
        List<ShadedTriangle> list = new ArrayList<>();
        long maxSrcCoord = (long) Math.pow(2, getBitsPerCoordinate()) - 1;
        long maxSrcColor = (long) Math.pow(2, getBitsPerComponent()) - 1;

        // MemoryCacheImageInputStream doesn't close the wrapped stream
        try (InputStream imageStream = ((COSStream) dict).createInputStream())
        {
            try (ImageInputStream mciis = new MemoryCacheImageInputStream(imageStream))
            {
                byte flag = (byte) 0;
                try
                {
                    flag = (byte) (mciis.readBits(bitsPerFlag) & 3);
                }
                catch (EOFException ex)
                {
                    LOG.error(ex);
                }

                boolean eof = false;
                while (!eof)
                {
                    Vertex p0;
                    Vertex p1;
                    Vertex p2;
                    Point2D[] ps;
                    float[][] cs;
                    int lastIndex;
                    try
                    {
                        switch (flag)
                        {
                        case 0:
                            p0 = readVertex(mciis, maxSrcCoord, maxSrcColor, rangeX, rangeY,
                                    colRange, matrix, xform);
                            flag = (byte) (mciis.readBits(bitsPerFlag) & 3);
                            if (flag != 0)
                            {
                                LOG.error("bad triangle: {}", flag);
                            }
                            p1 = readVertex(mciis, maxSrcCoord, maxSrcColor, rangeX, rangeY,
                                    colRange, matrix, xform);
                            mciis.readBits(bitsPerFlag);
                            if (flag != 0)
                            {
                                LOG.error("bad triangle: {}", flag);
                            }
                            p2 = readVertex(mciis, maxSrcCoord, maxSrcColor, rangeX, rangeY,
                                    colRange, matrix, xform);
                            ps = new Point2D[] { p0.point, p1.point, p2.point };
                            cs = new float[][] { p0.color, p1.color, p2.color };
                                list.add(new ShadedTriangle(ps, cs));
                                flag = (byte) (mciis.readBits(bitsPerFlag) & 3);
                                break;
                            case 1:
                            case 2:
                                lastIndex = list.size() - 1;
                                if (lastIndex < 0)
                                {
                                    LOG.error("broken data stream: {}", list.size());
                                }
                                else
                                {
                                    ShadedTriangle preTri = list.get(lastIndex);
                                    p2 = readVertex(mciis, maxSrcCoord, maxSrcColor, rangeX, rangeY,
                                            colRange, matrix, xform);
                                    ps = new Point2D[] {
                                            flag == 1 ? preTri.corner[1] : preTri.corner[0],
                                            preTri.corner[2], p2.point };
                                    cs = new float[][] {
                                            flag == 1 ? preTri.color[1] : preTri.color[0],
                                            preTri.color[2], p2.color };
                                    list.add(new ShadedTriangle(ps, cs));
                                    flag = (byte) (mciis.readBits(bitsPerFlag) & 3);
                                }
                                break;
                            default:
                                LOG.warn("bad flag: {}", flag);
                                break;
                            }
                        }
                        catch (EOFException ex)
                        {
                            eof = true;
                    }
                }
            }
        }
        return list;
    }