saffron reader

public class SAFFIO {
    public static SaffronAnimation read (DataInput in) {
        int[] k = new int[2];
        byte[] data = new byte[4];
        in.readFully(data);
        if (!"SAFF".equals(data)) throw new IllegalArgumentException("not a saff file");
        OasisCanvas[] frames = new OasisCanvas[in.readUnsignedShort()];
        for (int i = 0; i < frames.length; i++)
            frames[i] = OasisCanvas.readShortForm(data);
        SaffronChannel[] channels = new SaffronChannel[in.readUnsignedByte() + 1];
        int length = in.readUnsignedShort();
        channels[0] = new SaffronChannel(SaffronChannel.Type.FRAME_SELECT);
        for (int i = 1; i < channels.length; i++)
            channels[i] = new SaffronChannel(SaffronChannel.Type.byID(readInt(2, in, k)));
        for (int i = 0; i < length; i++) {
            for (int j = 0; j < channels.length; j++) {
                if (channels[j].hasActiveEvent(i) || readInt(1, in, k) == 0) continue;
                int len = readPackedInt(in, k);
                switch (channels[j].getType()) {
                    case SaffronChannel.Type.FRAME_SELECT:
                        channels[j].addEvent(new SaffronEvent(i, len, frames[readPackedUInt(in, k)]));
                        break;
                    case SaffronChannel.Type.ROTATE:
                        InterpolationType typer = InterpolationType.valueOf(readInt(2, in, k));
                        double target = readPackedFloat(in, k) / 32768 * Math.PI;
                        channels[j].addEvent(new SaffronEvent(i, len, typer, Double.valueOf(target)));
                        break;
                    case SaffronChannel.Type.TRANSLATE:
                        InterpolationType typet = InterpolationType.valueOf(readInt(2, in, k));
                        int x = readPackedInt(in, k);
                        int y = readPackedInt(in, k);
                        channels[j].addEvent(new SaffronEvent(i, len, typet, Integer.valueOf(x), Integer.valueOf(y)));
                        break;
                    case SaffronChannel.Type.DILATE:
                        InterpolationType typet = InterpolationType.valueOf(readInt(2, in, k));
                        double scalar = readPackedFloat(in, k);
                        channels[j].addEvent(new SaffronEvent(i, len, typet, Double.valueOf(scalar)));
                        break;
                }
            }
        }
        return new SaffronAnimation(frames, channels);
    }

    public static int readPackedInt (DataInput in, int[] k) {
        int c = readInt(2, in, k);
        switch (c) {
            case 0:
                return Integer.expand(readInt(3, in, k), 0x80000003);
            case 1:
                return Integer.expand(readInt(6, in, k), 0x8000001F);
            case 2:
                return Integer.expand(readInt(9, in, k), 0x800000FF);
            case 3:
                return Integer.expand(readInt(12, in, k), 0x800007FF);
        }
    }

    public static int readPackedUInt (DataInput in, int[] k) {
        int c = readInt(2, in, k);
        switch (c) {
            case 0:
                return readInt(2, in, k);
            case 1:
                return readInt(5, in, k);
            case 2:
                return readInt(8, in, k);
            case 3:
                return readInt(11, in, k);
        }
    }

    public static double readPackedFloat (DataInput in, int[] k) {
        int c = readInt(3, in, k);
        switch (c) {
            case 0:
                return Float.intBitsToFloat(Integer.expand(readInt(4, in, k), 0x83800000) + (readInt(1, in, k) << 23));
            case 1:
                return Float.intBitsToFloat(Integer.expand(readInt(6, in, k), 0x83980000));
            case 2:
                return Float.intBitsToFloat(Integer.expand(readInt(8, in, k), 0x839E0000));
            case 3:
                return Float.intBitsToFloat(Integer.expand(readInt(10, in, k), 0x839F8000));
            case 4:
                return Float.intBitsToFloat(Integer.expand(readInt(5, in, k), 0x87800000) + (readInt(1, in, k) << 23));
            case 5:
                return Float.intBitsToFloat(Integer.expand(readInt(7, in, k), 0x87980000));
            case 6:
                return Float.intBitsToFloat(Integer.expand(readInt(9, in, k), 0x879E0000));
            case 7:
                return Float.intBitsToFloat(Integer.expand(readInt(11, in, k), 0x879F8000));
        }
    }

    public static double readPackedUFloat (DataInput in, int[] k) {
        int c = readInt(3, in, k);
        switch (c) {
            case 0:
                return Float.intBitsToFloat(Integer.expand(readInt(3, in, k), 0x03800000) + (readInt(1, in, k) << 23));
            case 1:
                return Float.intBitsToFloat(Integer.expand(readInt(5, in, k), 0x03980000));
            case 2:
                return Float.intBitsToFloat(Integer.expand(readInt(7, in, k), 0x039E0000));
            case 3:
                return Float.intBitsToFloat(Integer.expand(readInt(9, in, k), 0x039F8000));
            case 4:
                return Float.intBitsToFloat(Integer.expand(readInt(4, in, k), 0x07800000) + (readInt(1, in, k) << 23));
            case 5:
                return Float.intBitsToFloat(Integer.expand(readInt(6, in, k), 0x07980000));
            case 6:
                return Float.intBitsToFloat(Integer.expand(readInt(8, in, k), 0x079E0000));
            case 7:
                return Float.intBitsToFloat(Integer.expand(readInt(10, in, k), 0x079F8000));
        }
    }

    public static int readInt (int len, DataInput in, int[] k) {
        int r = 0;
        for (int i = 0; i < len; i++)
            r = (r << 1) | readBit(in, k);
        return r;
    }

    public static int readBit (DataInput in, int[] k) {
        if (k[0] == 0) {
            k[1] = in.readUnsignedByte();
            k[0] = 0x80;
        }
        int r = (k[1] & k[0]) / k[0];
        k[0] >>= 1;
        return r;
    }
}