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1848 lines
70 KiB
C#
1848 lines
70 KiB
C#
//! \file Lossless.cs
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//! \date Wed May 18 20:10:59 2016
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//! \brief Google WEBP lossless compression decoder.
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/*
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Copyright (c) 2010, Google Inc. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of Google nor the names of its contributors may
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be used to endorse or promote products derived from this software
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without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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//
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// C# port by morkt (C) 2016
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//
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using System;
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using System.IO;
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using GameRes.Utility;
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namespace GameRes.Formats.Google
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{
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enum VP8StatusCode
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{
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Ok = 0,
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OutOfMemory,
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InvalidParam,
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BitstreamError,
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UnsupportedFeature,
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Suspended,
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UserAbort,
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NotEnoughData
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}
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enum VP8DecodeState
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{
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ReadData = 0,
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ReadHdr = 1,
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ReadDim = 2
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}
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enum VP8LImageTransformType
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{
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Predictor,
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CrossColor,
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SubtractGreen,
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ColorIndexing
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}
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internal struct VP8LMultipliers
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{
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public byte green_to_red_;
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public byte green_to_blue_;
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public byte red_to_blue_;
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public void Reset ()
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{
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green_to_red_ = 0;
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green_to_blue_ = 0;
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red_to_blue_ = 0;
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}
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public void ColorCodeToMultipliers (uint color_code)
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{
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green_to_red_ = (byte)color_code;
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green_to_blue_ = (byte)(color_code >> 8);
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red_to_blue_ = (byte)(color_code >> 16);
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}
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static uint ColorTransformDelta (sbyte color_pred, sbyte color)
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{
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return (uint)((int)color_pred * color) >> 5;
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}
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public void TransformColorInverse (uint[] data, int offset, int num_pixels)
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{
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for (int i = 0; i < num_pixels; ++i)
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{
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uint argb = data[offset+i];
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uint green = argb >> 8;
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uint red = argb >> 16;
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uint new_red = red;
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uint new_blue = argb;
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new_red += ColorTransformDelta ((sbyte)green_to_red_, (sbyte)green);
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new_red &= 0xFF;
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new_blue += ColorTransformDelta ((sbyte)green_to_blue_, (sbyte)green);
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new_blue += ColorTransformDelta ((sbyte)red_to_blue_, (sbyte)new_red);
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new_blue &= 0xFF;
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data[offset+i] = (argb & 0xFF00FF00u) | (new_red << 16) | (new_blue);
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}
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}
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}
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internal class VP8LTransform
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{
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public VP8LImageTransformType type_; // transform type.
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public int bits_; // subsampling bits defining transform window.
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public int xsize_; // transform window X index.
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public int ysize_; // transform window Y index.
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public uint[] data_; // transform data.
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public void InverseTransform (int row_start, int row_end,
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uint[] input, int src, uint[] output, int dst)
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{
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int width = xsize_;
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switch (type_)
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{
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case VP8LImageTransformType.SubtractGreen:
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AddGreenToBlueAndRed (output, dst, (row_end - row_start) * width);
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break;
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case VP8LImageTransformType.Predictor:
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PredictorInverseTransform (row_start, row_end, output, dst);
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if (row_end != ysize_)
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{
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// The last predicted row in this iteration will be the top-pred row
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// for the first row in next iteration.
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Buffer.BlockCopy (output, dst + (row_end - row_start - 1) * width,
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output, dst - width, width * sizeof(uint));
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}
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break;
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case VP8LImageTransformType.CrossColor:
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ColorSpaceInverseTransform (row_start, row_end, output, dst);
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break;
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case VP8LImageTransformType.ColorIndexing:
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if (input == output && src == dst && bits_ > 0)
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{
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// Move packed pixels to the end of unpacked region, so that unpacking
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// can occur seamlessly.
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// Also, note that this is the only transform that applies on
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// the effective width of VP8LSubSampleSize(xsize_, bits_). All other
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// transforms work on effective width of xsize_.
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int out_stride = (row_end - row_start) * width;
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int in_stride = (row_end - row_start) * LosslessDecoder.SubSampleSize (xsize_, bits_);
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src += out_stride - in_stride;
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Buffer.BlockCopy (output, dst, input, src, in_stride * sizeof(uint));
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// memmove(src, out, in_stride * sizeof(*src));
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ColorIndexInverseTransform (row_start, row_end, input, src, output, dst);
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}
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else
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{
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ColorIndexInverseTransform (row_start, row_end, input, src, output, dst);
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}
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break;
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}
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}
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static byte GetAlphaValue (uint val)
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{
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return (byte)(val >> 8);
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}
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static void MapARGB (uint[] input, int src, uint[] color_map,
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uint[] output, int dst, int y_start, int y_end, int width)
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{
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for (int y = y_start; y < y_end; ++y)
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for (int x = 0; x < width; ++x)
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output[dst++] = color_map[(input[src++] >> 8) & 0xFF];
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}
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static void MapAlpha (byte[] input, int src, uint[] color_map,
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byte[] output, int dst, int y_start, int y_end, int width)
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{
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for (int y = y_start; y < y_end; ++y)
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for (int x = 0; x < width; ++x)
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output[dst++] = GetAlphaValue (color_map[input[src++]]);
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}
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void ColorIndexInverseTransform (int y_start, int y_end, uint[] input, int src,
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uint[] output, int dst)
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{
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int bits_per_pixel = 8 >> bits_;
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int width = xsize_;
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if (bits_per_pixel < 8)
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{
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int pixels_per_byte = 1 << bits_;
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int count_mask = pixels_per_byte - 1;
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uint bit_mask = (1u << bits_per_pixel) - 1u;
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for (int y = y_start; y < y_end; ++y)
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{
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uint packed_pixels = 0;
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for (int x = 0; x < width; ++x)
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{
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// We need to load fresh 'packed_pixels' once every
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// 'pixels_per_byte' increments of x. Fortunately, pixels_per_byte
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// is a power of 2, so can just use a mask for that, instead of
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// decrementing a counter.
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if ((x & count_mask) == 0)
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packed_pixels = (input[src++] >> 8) & 0xFF; // GetARGBIndex
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output[dst++] = data_[packed_pixels & bit_mask]; // GetARGBValue
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packed_pixels >>= bits_per_pixel;
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}
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}
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}
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else
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{
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MapARGB (input, src, data_, output, dst, y_start, y_end, width);
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}
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}
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public void ColorIndexInverseTransformAlpha (int y_start, int y_end, byte[] input, int src, byte[] output, int dst)
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{
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int bits_per_pixel = 8 >> bits_;
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int width = xsize_;
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var color_map = data_;
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if (bits_per_pixel < 8)
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{
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int pixels_per_byte = 1 << bits_;
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int count_mask = pixels_per_byte - 1;
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uint bit_mask = (1u << bits_per_pixel) - 1u;
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for (int y = y_start; y < y_end; ++y)
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{
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uint packed_pixels = 0;
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for (int x = 0; x < width; ++x)
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{
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if ((x & count_mask) == 0)
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packed_pixels = input[src++];
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output[dst++] = GetAlphaValue (color_map[packed_pixels & bit_mask]);
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packed_pixels >>= bits_per_pixel;
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}
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}
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}
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else
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{
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MapAlpha (input, src, color_map, output, dst, y_start, y_end, width);
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}
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}
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void AddGreenToBlueAndRed (uint[] data, int offset, int num_pixels)
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{
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for (int i = 0; i < num_pixels; ++i)
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{
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uint argb = data[i];
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uint green = (argb >> 8) & 0xFFu;
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uint red_blue = argb & 0x00FF00FFu;
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red_blue += (green << 16) | green;
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red_blue &= 0x00FF00FFu;
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data[i] = (argb & 0xFF00FF00u) | red_blue;
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}
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}
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void PredictorInverseTransform (int y_start, int y_end, uint[] data, int offset)
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{
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int width = xsize_;
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if (y_start == 0) // First Row follows the L (mode=1) mode.
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{
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uint pred0 = Predictor0 (data[offset-1], data, offset-1);
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AddPixelsEq (data, offset, pred0);
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for (int x = 1; x < width; ++x)
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{
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uint pred1 = Predictor1 (data[offset + x - 1], data, offset-1);
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AddPixelsEq (data, offset + x, pred1);
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}
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offset += width;
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++y_start;
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}
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int y = y_start;
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int tile_width = 1 << bits_;
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int mask = tile_width - 1;
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int safe_width = width & ~mask;
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int tiles_per_row = LosslessDecoder.SubSampleSize (width, bits_);
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int pred_mode_base = (y >> bits_) * tiles_per_row; // within data_
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while (y < y_end)
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{
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uint pred2 = Predictor2 (data[offset-1], data, offset - width);
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int pred_mode_src = pred_mode_base;
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int x = 1;
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int t = 1;
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// First pixel follows the T (mode=2) mode.
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AddPixelsEq (data, offset, pred2);
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// .. the rest:
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while (x < safe_width)
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{
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var pred_func = kPredictors[(data_[pred_mode_src++] >> 8) & 0xF];
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for (; t < tile_width; ++t, ++x)
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{
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uint pred = pred_func (data[offset + x - 1], data, offset + x - width);
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AddPixelsEq (data, offset + x, pred);
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}
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t = 0;
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}
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if (x < width)
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{
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var pred_func = kPredictors[(data_[pred_mode_src++] >> 8) & 0xF];
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for (; x < width; ++x)
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{
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uint pred = pred_func (data[offset + x - 1], data, offset + x - width);
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AddPixelsEq (data, offset + x, pred);
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}
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}
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offset += width;
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++y;
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if ((y & mask) == 0) // Use the same mask, since tiles are squares.
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pred_mode_base += tiles_per_row;
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}
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}
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void ColorSpaceInverseTransform (int y_start, int y_end, uint[] data, int offset)
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{
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int width = xsize_;
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int tile_width = 1 << bits_;
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int mask = tile_width - 1;
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int safe_width = width & ~mask;
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int remaining_width = width - safe_width;
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int tiles_per_row = LosslessDecoder.SubSampleSize (width, bits_);
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int y = y_start;
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int pred_row = (y >> bits_) * tiles_per_row; // within data_
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var m = new VP8LMultipliers();
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while (y < y_end)
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{
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m.Reset();
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int pred = pred_row;
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int data_safe_end = offset + safe_width;
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int data_end = offset + width;
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while (offset < data_safe_end)
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{
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m.ColorCodeToMultipliers (data_[pred++]);
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m.TransformColorInverse (data, offset, tile_width);
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offset += tile_width;
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}
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if (offset < data_end)
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{
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m.ColorCodeToMultipliers (data_[pred++]);
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m.TransformColorInverse (data, offset, remaining_width);
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offset += remaining_width;
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}
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++y;
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if ((y & mask) == 0)
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pred_row += tiles_per_row;
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}
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}
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//------------------------------------------------------------------------------
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// Predictors
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static uint Predictor0 (uint left, uint[] data, int top)
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{
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return 0xFF000000u; // ARGB_BLACK
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}
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static uint Predictor1 (uint left, uint[] data, int top)
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{
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return left;
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}
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static uint Predictor2 (uint left, uint[] data, int top)
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{
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return data[top];
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}
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static uint Predictor3 (uint left, uint[] data, int top)
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{
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return data[top+1];
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}
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static uint Predictor4 (uint left, uint[] data, int top)
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{
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return data[top-1];
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}
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static uint Predictor5 (uint left, uint[] data, int top)
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{
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return Average3 (left, data[top], data[top+1]);
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}
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static uint Predictor6 (uint left, uint[] data, int top)
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{
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return Average2 (left, data[top-1]);
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}
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static uint Predictor7 (uint left, uint[] data, int top)
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{
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return Average2 (left, data[top]);
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}
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static uint Predictor8 (uint left, uint[] data, int top)
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{
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return Average2 (data[top-1], data[top]);
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}
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static uint Predictor9 (uint left, uint[] data, int top)
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{
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return Average2 (data[top], data[top+1]);
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}
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static uint Predictor10 (uint left, uint[] data, int top)
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{
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return Average4 (left, data[top-1], data[top], data[top+1]);
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}
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static uint Predictor11(uint left, uint[] data, int top)
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{
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return Select (data[top], left, data[top-1]);
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}
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static uint Predictor12 (uint left, uint[] data, int top)
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{
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return ClampedAddSubtractFull (left, data[top], data[top-1]);
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}
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static uint Predictor13 (uint left, uint[] data, int top)
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{
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return ClampedAddSubtractHalf (left, data[top], data[top-1]);
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}
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delegate uint PredictorFunc (uint left, uint[] data, int top);
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static readonly PredictorFunc[] kPredictors = new PredictorFunc[16]
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{
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Predictor0, Predictor1, Predictor2, Predictor3,
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Predictor4, Predictor5, Predictor6, Predictor7,
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Predictor8, Predictor9, Predictor10, Predictor11,
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Predictor12, Predictor13, Predictor0, Predictor0,
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};
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//------------------------------------------------------------------------------
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// Image transforms.
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// In-place sum of each component with mod 256.
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static void AddPixelsEq (uint[] data, int a, uint b)
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{
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data[a] = MMX.PAddB (data[a], b);
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}
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static uint Average2 (uint a0, uint a1)
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{
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return (((a0 ^ a1) & 0xFEFEFEFEu) >> 1) + (a0 & a1);
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}
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static uint Average3 (uint a0, uint a1, uint a2)
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{
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return Average2 (Average2 (a0, a2), a1);
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}
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static uint Average4 (uint a0, uint a1, uint a2, uint a3)
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{
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return Average2 (Average2 (a0, a1), Average2 (a2, a3));
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}
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static int Sub3 (int a, int b, int c)
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{
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return Math.Abs (b - c) - Math.Abs(a - c);
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}
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static uint Select (uint a, uint b, uint c)
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{
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int pa_minus_pb =
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Sub3 ((int)(a >> 24) , (int)(b >> 24) , (int)(c >> 24) ) +
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Sub3 ((int)(a >> 16) & 0xFF, (int)(b >> 16) & 0xFF, (int)(c >> 16) & 0xFF) +
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Sub3 ((int)(a >> 8) & 0xFF, (int)(b >> 8) & 0xFF, (int)(c >> 8) & 0xFF) +
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Sub3 ((int)(a ) & 0xFF, (int)(b ) & 0xFF, (int)(c ) & 0xFF);
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return (pa_minus_pb <= 0) ? a : b;
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}
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static uint Clip255 (uint a)
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{
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if (a < 256)
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return a;
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// return 0, when a is a negative integer.
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// return 255, when a is positive.
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return ~a >> 24;
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}
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static uint AddSubtractComponentFull (uint a, uint b, uint c)
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{
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return Clip255 ((uint)((int)a + (int)b - (int)c));
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}
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static uint ClampedAddSubtractFull (uint c0, uint c1, uint c2)
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{
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uint a = AddSubtractComponentFull (c0 >> 24, c1 >> 24, c2 >> 24);
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uint r = AddSubtractComponentFull ((c0 >> 16) & 0xFF,
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(c1 >> 16) & 0xFF,
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(c2 >> 16) & 0xFF);
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uint g = AddSubtractComponentFull ((c0 >> 8) & 0xFF,
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(c1 >> 8) & 0xFF,
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(c2 >> 8) & 0xFF);
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uint b = AddSubtractComponentFull (c0 & 0xFF, c1 & 0xFF, c2 & 0xFF);
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return (a << 24) | (r << 16) | (g << 8) | b;
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}
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static uint AddSubtractComponentHalf (uint a, uint b)
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{
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return Clip255 ((uint)((int)a + ((int)a - (int)b) / 2));
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}
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|
static uint ClampedAddSubtractHalf (uint c0, uint c1, uint c2)
|
|
{
|
|
uint ave = Average2 (c0, c1);
|
|
uint a = AddSubtractComponentHalf (ave >> 24, c2 >> 24);
|
|
uint r = AddSubtractComponentHalf ((ave >> 16) & 0xFF, (c2 >> 16) & 0xFF);
|
|
uint g = AddSubtractComponentHalf ((ave >> 8) & 0xFF, (c2 >> 8) & 0xFF);
|
|
uint b = AddSubtractComponentHalf ((ave >> 0) & 0xFF, (c2 >> 0) & 0xFF);
|
|
return (a << 24) | (r << 16) | (g << 8) | b;
|
|
}
|
|
}
|
|
|
|
internal static class HuffIndex
|
|
{
|
|
public const int Green = 0;
|
|
public const int Red = 1;
|
|
public const int Blue = 2;
|
|
public const int Alpha = 3;
|
|
public const int Dist = 4;
|
|
}
|
|
|
|
internal class LosslessDecoder
|
|
{
|
|
const uint kHashMul = 0x1E35A7BDu;
|
|
const int NumARGBCacheRows = 16;
|
|
const int MaxCacheBits = 11;
|
|
const int NumTransforms = 4;
|
|
const int SyncEveryNRows = 8; // minimum number of rows between check-points
|
|
const int BitsSpecialMarker = 0x100; // something large enough (and a bit-mask)
|
|
const int PackedNonLiteralCode = 0; // must be < NUM_LITERAL_CODES
|
|
|
|
const int kCodeLengthLiterals = 16;
|
|
const int kCodeLengthRepeatCode = 16;
|
|
static readonly int[] kCodeLengthExtraBits = { 2, 3, 7 };
|
|
static readonly int[] kCodeLengthRepeatOffsets = { 3, 3, 11 };
|
|
|
|
public delegate void ProcessRowsFunc (LosslessDecoder dec, int row);
|
|
|
|
VP8StatusCode status_;
|
|
VP8DecodeState state_;
|
|
public VP8Io io_;
|
|
|
|
byte[] pixels8_;
|
|
uint[] pixels32_; // Internal data: either uint8_t* for alpha
|
|
// or uint32_t* for BGRA.
|
|
int argb_cache_; // Scratch buffer for temporary BGRA storage.
|
|
|
|
LBitReader br_ = new LBitReader();
|
|
bool incremental_ = false; // if true, incremental decoding is expected
|
|
LBitReader saved_br_ = new LBitReader(); // note: could be local variables too
|
|
int saved_last_pixel_;
|
|
|
|
int width_;
|
|
int height_;
|
|
public int last_row_; // last input row decoded so far.
|
|
public int last_pixel_; // last pixel decoded so far. However, it may
|
|
// not be transformed, scaled and
|
|
// color-converted yet.
|
|
int last_out_row_; // last row output so far.
|
|
|
|
public uint[] Pixels { get { return pixels32_; } }
|
|
public int Width
|
|
{
|
|
get { return width_; }
|
|
set { width_ = value; }
|
|
}
|
|
public int Height
|
|
{
|
|
get { return height_; }
|
|
set { height_ = value; }
|
|
}
|
|
|
|
LMetadata hdr_ = new LMetadata();
|
|
|
|
public int next_transform_;
|
|
public VP8LTransform[] transforms_ = new VP8LTransform[NumTransforms];
|
|
// or'd bitset storing the transforms types.
|
|
uint transforms_seen_;
|
|
|
|
public LosslessDecoder ()
|
|
{
|
|
status_ = VP8StatusCode.Ok;
|
|
state_ = VP8DecodeState.ReadDim;
|
|
|
|
for (int i = 0; i < transforms_.Length; ++i)
|
|
transforms_[i] = new VP8LTransform();
|
|
}
|
|
|
|
public void Init (int width, int height, VP8Io io,
|
|
byte[] data, int data_i, int data_size, byte[] output)
|
|
{
|
|
width_ = width;
|
|
height_ = height;
|
|
status_ = VP8StatusCode.Ok;
|
|
io_ = io;
|
|
|
|
io_.opaque = output;
|
|
io_.width = width_;
|
|
io_.height = height_;
|
|
|
|
br_.Init (data, data_i, (uint)data_size);
|
|
}
|
|
|
|
public void Init (BinaryReader input, int length, VP8Io io)
|
|
{
|
|
io_ = io;
|
|
br_.Init (input, (uint)length);
|
|
DecodeHeader();
|
|
}
|
|
|
|
public bool Is8bOptimizable ()
|
|
{
|
|
if (hdr_.color_cache_size_ > 0)
|
|
return false;
|
|
// When the Huffman tree contains only one symbol, we can skip the
|
|
// call to ReadSymbol() for red/blue/alpha channels.
|
|
for (int i = 0; i < hdr_.num_htree_groups_; ++i)
|
|
{
|
|
var htree_group = hdr_.htree_groups_[i];
|
|
if (htree_group.GetCode (HuffIndex.Red, 0).bits > 0) return false;
|
|
if (htree_group.GetCode (HuffIndex.Blue, 0).bits > 0) return false;
|
|
if (htree_group.GetCode (HuffIndex.Alpha, 0).bits > 0) return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
|
|
void DecodeHeader ()
|
|
{
|
|
status_ = VP8StatusCode.Ok;
|
|
|
|
ReadImageInfo();
|
|
state_ = VP8DecodeState.ReadDim;
|
|
uint[] data = null;
|
|
if (!DecodeImageStream (io_.width, io_.height, true, ref data, false))
|
|
throw new InvalidFormatException();
|
|
}
|
|
|
|
void ReadImageInfo ()
|
|
{
|
|
if (0x2F != br_.ReadBits (8))
|
|
throw new InvalidFormatException();
|
|
width_ = (int)br_.ReadBits (14) + 1;
|
|
height_ = (int)br_.ReadBits (14) + 1;
|
|
io_.width = width_;
|
|
io_.height = height_;
|
|
bool has_alpha = 0 != br_.ReadBits (1);
|
|
if (br_.ReadBits (3) != 0)
|
|
throw new InvalidFormatException();
|
|
}
|
|
|
|
public bool DecodeImage ()
|
|
{
|
|
// Initialization.
|
|
if (state_ != VP8DecodeState.ReadData)
|
|
{
|
|
AllocateInternalBuffers32b (io_.width);
|
|
if (incremental_)
|
|
{
|
|
if (hdr_.color_cache_size_ > 0
|
|
&& hdr_.saved_color_cache_.colors_ == null)
|
|
{
|
|
hdr_.saved_color_cache_.Init (hdr_.color_cache_.hash_bits_);
|
|
}
|
|
}
|
|
state_ = VP8DecodeState.ReadData;
|
|
}
|
|
|
|
// Decode.
|
|
return DecodeImageData (pixels32_, width_, height_, height_, (dec, row) => dec.ProcessRows (row));
|
|
}
|
|
|
|
// Processes (transforms, scales & color-converts) the rows decoded after the
|
|
// last call.
|
|
void ProcessRows (int row)
|
|
{
|
|
int rows = width_ * last_row_;
|
|
int num_rows = row - last_row_;
|
|
|
|
if (num_rows <= 0) return; // Nothing to be done.
|
|
ApplyInverseTransforms (num_rows, pixels32_, rows);
|
|
|
|
// Emit output.
|
|
int rows_data = argb_cache_;
|
|
int in_stride = io_.width * sizeof(uint); // in unit of RGBA
|
|
int out_stride = in_stride;
|
|
if (SetCropWindow (last_row_, row))
|
|
{
|
|
int rgba = last_out_row_ * out_stride;
|
|
int num_rows_out = EmitRows (pixels32_, rows_data, in_stride,
|
|
io_.mb_w, io_.mb_h, io_.opaque, rgba, out_stride);
|
|
// Update 'last_out_row_'.
|
|
last_out_row_ += num_rows_out;
|
|
}
|
|
|
|
// Update 'last_row_'.
|
|
last_row_ = row;
|
|
}
|
|
|
|
int EmitRows (uint[] input, int row_in, int in_stride, int mb_w, int mb_h, byte[] output, int row_out, int out_stride)
|
|
{
|
|
int lines = mb_h;
|
|
while (lines --> 0)
|
|
{
|
|
Buffer.BlockCopy (input, row_in, output, row_out, mb_w * 4);
|
|
row_in += in_stride;
|
|
row_out += out_stride;
|
|
}
|
|
return mb_h; // Num rows out == num rows in.
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Cropping.
|
|
|
|
// Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and
|
|
// crop options. Also updates the input data pointer, so that it points to the
|
|
// start of the cropped window.
|
|
// Returns true if the crop window is not empty.
|
|
bool SetCropWindow (int y_start, int y_end)
|
|
{
|
|
if (y_end > io_.height)
|
|
{
|
|
y_end = io_.height; // make sure we don't overflow on last row.
|
|
}
|
|
if (y_start >= y_end) return false; // Crop window is empty.
|
|
|
|
io_.mb_y = y_start;
|
|
io_.mb_w = io_.width;
|
|
io_.mb_h = y_end - y_start;
|
|
return true; // Non-empty crop window.
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Allocate internal buffers dec->pixels_ and dec->argb_cache_.
|
|
|
|
public void AllocateInternalBuffers32b (int final_width)
|
|
{
|
|
int num_pixels = width_ * height_;
|
|
// Scratch buffer corresponding to top-prediction row for transforming the
|
|
// first row in the row-blocks. Not needed for paletted alpha.
|
|
int cache_top_pixels = (ushort)final_width;
|
|
// Scratch buffer for temporary BGRA storage. Not needed for paletted alpha.
|
|
int cache_pixels = final_width * NumARGBCacheRows;
|
|
int total_num_pixels = num_pixels + cache_top_pixels + cache_pixels;
|
|
|
|
pixels32_ = new uint[total_num_pixels];
|
|
argb_cache_ = num_pixels + cache_top_pixels;
|
|
}
|
|
|
|
public void AllocateInternalBuffers8b ()
|
|
{
|
|
int total_num_pixels = width_ * height_;
|
|
pixels8_ = new byte[total_num_pixels];
|
|
argb_cache_ = 0;
|
|
}
|
|
|
|
public bool DecodeImageStream (int xsize, int ysize, bool is_level0, ref uint[] decoded_data, bool set_data)
|
|
{
|
|
bool ok = true;
|
|
int transform_xsize = xsize;
|
|
int transform_ysize = ysize;
|
|
int color_cache_bits = 0;
|
|
uint[] data = null;
|
|
|
|
// Read the transforms (may recurse).
|
|
if (is_level0)
|
|
{
|
|
while (ok && 0 != br_.ReadBits (1))
|
|
ok = ReadTransform (ref transform_xsize, ref transform_ysize);
|
|
}
|
|
|
|
// Color cache
|
|
if (ok && 0 != br_.ReadBits (1))
|
|
{
|
|
color_cache_bits = (int)br_.ReadBits (4);
|
|
ok = (color_cache_bits >= 1 && color_cache_bits <= MaxCacheBits);
|
|
if (!ok)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Read the Huffman codes (may recurse).
|
|
ok = ok && ReadHuffmanCodes (transform_xsize, transform_ysize, color_cache_bits, is_level0);
|
|
if (!ok)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
|
|
// Finish setting up the color-cache
|
|
if (color_cache_bits > 0)
|
|
{
|
|
hdr_.color_cache_size_ = 1 << color_cache_bits;
|
|
hdr_.color_cache_.Init (color_cache_bits);
|
|
}
|
|
else
|
|
{
|
|
hdr_.color_cache_size_ = 0;
|
|
}
|
|
UpdateDecoder (transform_xsize, transform_ysize);
|
|
|
|
if (is_level0) // level 0 complete
|
|
{
|
|
state_ = VP8DecodeState.ReadHdr;
|
|
}
|
|
else
|
|
{
|
|
var total_size = transform_xsize * transform_ysize;
|
|
data = new uint[total_size];
|
|
|
|
// Use the Huffman trees to decode the LZ77 encoded data.
|
|
ok = DecodeImageData (data, transform_xsize, transform_ysize, transform_ysize, null);
|
|
ok = ok && !br_.EoS;
|
|
}
|
|
if (ok)
|
|
{
|
|
if (set_data)
|
|
{
|
|
decoded_data = data;
|
|
}
|
|
last_pixel_ = 0; // Reset for future DECODE_DATA_FUNC() calls.
|
|
if (!is_level0)
|
|
hdr_.ClearMetadata();
|
|
}
|
|
return ok;
|
|
}
|
|
|
|
bool ReadTransform (ref int xsize, ref int ysize)
|
|
{
|
|
bool ok = true;
|
|
var transform = transforms_[next_transform_];
|
|
var type = (VP8LImageTransformType)br_.ReadBits (2);
|
|
|
|
// Each transform type can only be present once in the stream.
|
|
if (0 != (transforms_seen_ & (1U << (int)type)))
|
|
return false; // Already there, let's not accept the second same transform.
|
|
|
|
transforms_seen_ |= (1U << (int)type);
|
|
|
|
transform.type_ = type;
|
|
transform.xsize_ = xsize;
|
|
transform.ysize_ = ysize;
|
|
transform.data_ = null;
|
|
++next_transform_;
|
|
|
|
switch (type)
|
|
{
|
|
case VP8LImageTransformType.Predictor:
|
|
case VP8LImageTransformType.CrossColor:
|
|
transform.bits_ = (int)br_.ReadBits (3) + 2;
|
|
ok = DecodeImageStream (SubSampleSize (transform.xsize_, transform.bits_),
|
|
SubSampleSize (transform.ysize_, transform.bits_),
|
|
false, ref transform.data_, true);
|
|
break;
|
|
case VP8LImageTransformType.ColorIndexing:
|
|
int num_colors = (int)br_.ReadBits (8) + 1;
|
|
int bits = (num_colors > 16) ? 0
|
|
: (num_colors > 4) ? 1
|
|
: (num_colors > 2) ? 2
|
|
: 3;
|
|
xsize = SubSampleSize (transform.xsize_, bits);
|
|
transform.bits_ = bits;
|
|
ok = DecodeImageStream (num_colors, 1, false, ref transform.data_, true);
|
|
ok = ok && ExpandColorMap (num_colors, transform);
|
|
break;
|
|
case VP8LImageTransformType.SubtractGreen:
|
|
break;
|
|
default:
|
|
throw new InvalidFormatException();
|
|
}
|
|
return ok;
|
|
}
|
|
|
|
bool ExpandColorMap (int num_colors, VP8LTransform transform)
|
|
{
|
|
int final_num_colors = 1 << (8 >> transform.bits_);
|
|
uint[] new_color_map = new uint[final_num_colors];
|
|
new_color_map[0] = transform.data_[0];
|
|
for (int i = 1; i < num_colors; ++i)
|
|
new_color_map[i] = MMX.PAddB (transform.data_[i], new_color_map[i-1]);
|
|
transform.data_ = new_color_map;
|
|
return true;
|
|
}
|
|
|
|
bool ReadHuffmanCodes (int xsize, int ysize, int color_cache_bits, bool allow_recursion)
|
|
{
|
|
uint[] huffman_image = null;
|
|
int num_htree_groups = 1;
|
|
int max_alphabet_size = 0;
|
|
int table_size = kTableSize[color_cache_bits];
|
|
|
|
if (allow_recursion && 0 != br_.ReadBits (1))
|
|
{
|
|
// use meta Huffman codes.
|
|
int huffman_precision = (int)br_.ReadBits (3) + 2;
|
|
int huffman_xsize = SubSampleSize (xsize, huffman_precision);
|
|
int huffman_ysize = SubSampleSize (ysize, huffman_precision);
|
|
int huffman_pixs = huffman_xsize * huffman_ysize;
|
|
if (!DecodeImageStream (huffman_xsize, huffman_ysize, false, ref huffman_image, true))
|
|
return false;
|
|
hdr_.huffman_subsample_bits_ = huffman_precision;
|
|
for (int i = 0; i < huffman_pixs; ++i)
|
|
{
|
|
// The huffman data is stored in red and green bytes.
|
|
int group = (int)(huffman_image[i] >> 8) & 0xffff;
|
|
huffman_image[i] = (uint)group;
|
|
if (group >= num_htree_groups)
|
|
num_htree_groups = group + 1;
|
|
}
|
|
}
|
|
|
|
if (br_.EoS) return false;
|
|
|
|
// Find maximum alphabet size for the htree group.
|
|
for (int j = 0; j < Huffman.CodesPerMetaCode; ++j)
|
|
{
|
|
int alphabet_size = kAlphabetSize[j];
|
|
if (j == 0 && color_cache_bits > 0)
|
|
alphabet_size += 1 << color_cache_bits;
|
|
if (max_alphabet_size < alphabet_size)
|
|
max_alphabet_size = alphabet_size;
|
|
}
|
|
|
|
var htree_groups = HTreeGroup.New (num_htree_groups, table_size);
|
|
var huffman_tables = htree_groups[0].Tables;
|
|
var code_lengths = new int[max_alphabet_size];
|
|
|
|
int next = 0;
|
|
for (int i = 0; i < num_htree_groups; ++i)
|
|
{
|
|
var htree_group = htree_groups[i];
|
|
int size;
|
|
int total_size = 0;
|
|
bool is_trivial_literal = true;
|
|
int max_bits = 0;
|
|
for (int j = 0; j < Huffman.CodesPerMetaCode; ++j)
|
|
{
|
|
int alphabet_size = kAlphabetSize[j];
|
|
htree_group.SetMeta (j, next);
|
|
if (j == 0 && color_cache_bits > 0)
|
|
alphabet_size += 1 << color_cache_bits;
|
|
|
|
size = ReadHuffmanCode (alphabet_size, code_lengths, huffman_tables, next);
|
|
if (0 == size)
|
|
return false;
|
|
|
|
if (is_trivial_literal && kLiteralMap[j] == 1)
|
|
is_trivial_literal = (huffman_tables[next].bits == 0);
|
|
|
|
total_size += huffman_tables[next].bits;
|
|
next += size;
|
|
if (j <= HuffIndex.Alpha)
|
|
{
|
|
int local_max_bits = code_lengths[0];
|
|
for (int k = 1; k < alphabet_size; ++k)
|
|
{
|
|
if (code_lengths[k] > local_max_bits)
|
|
local_max_bits = code_lengths[k];
|
|
}
|
|
max_bits += local_max_bits;
|
|
}
|
|
}
|
|
htree_group.is_trivial_literal = is_trivial_literal;
|
|
htree_group.is_trivial_code = false;
|
|
if (is_trivial_literal)
|
|
{
|
|
uint red = htree_group.GetCode (HuffIndex.Red, 0).value;
|
|
uint blue = htree_group.GetCode (HuffIndex.Blue, 0).value;
|
|
uint alpha = htree_group.GetCode (HuffIndex.Alpha, 0).value;
|
|
htree_group.literal_arb = (alpha << 24) | (red << 16) | blue;
|
|
if (total_size == 0 && htree_group.GetCode (HuffIndex.Green, 0).value < Huffman.NumLiteralCodes)
|
|
{
|
|
htree_group.is_trivial_code = true;
|
|
htree_group.literal_arb |= (uint)htree_group.GetCode (HuffIndex.Green, 0).value << 8;
|
|
}
|
|
}
|
|
htree_group.use_packed_table = !htree_group.is_trivial_code && (max_bits < Huffman.PackedBits);
|
|
if (htree_group.use_packed_table)
|
|
BuildPackedTable (htree_group);
|
|
}
|
|
|
|
// All OK. Finalize pointers and return.
|
|
hdr_.huffman_image_ = huffman_image;
|
|
hdr_.num_htree_groups_ = num_htree_groups;
|
|
hdr_.htree_groups_ = htree_groups;
|
|
return true;
|
|
}
|
|
|
|
int ReadHuffmanCode (int alphabet_size, int[] code_lengths, HuffmanCode[] table, int index)
|
|
{
|
|
bool ok = false;
|
|
int size = 0;
|
|
bool simple_code = br_.ReadBits (1) != 0;
|
|
|
|
for (int i = 0; i < alphabet_size; ++i)
|
|
code_lengths[i] = 0;
|
|
|
|
if (simple_code) // Read symbols, codes & code lengths directly.
|
|
{
|
|
int num_symbols = (int)br_.ReadBits (1) + 1;
|
|
int first_symbol_len_code = (int)br_.ReadBits (1);
|
|
// The first code is either 1 bit or 8 bit code.
|
|
int symbol = (int)br_.ReadBits ((first_symbol_len_code == 0) ? 1 : 8);
|
|
code_lengths[symbol] = 1;
|
|
// The second code (if present), is always 8 bit long.
|
|
if (2 == num_symbols)
|
|
{
|
|
symbol = (int)br_.ReadBits (8);
|
|
code_lengths[symbol] = 1;
|
|
}
|
|
ok = true;
|
|
}
|
|
else // Decode Huffman-coded code lengths.
|
|
{
|
|
var code_length_code_lengths = new int[NumCodeLengthCodes];
|
|
int num_codes = (int)br_.ReadBits (4) + 4;
|
|
if (num_codes > NumCodeLengthCodes)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return 0;
|
|
}
|
|
for (int i = 0; i < num_codes; ++i)
|
|
{
|
|
code_length_code_lengths[kCodeLengthCodeOrder[i]] = (int)br_.ReadBits (3);
|
|
}
|
|
ok = ReadHuffmanCodeLengths (code_length_code_lengths, alphabet_size, code_lengths);
|
|
}
|
|
|
|
ok = ok && !br_.EoS;
|
|
if (ok)
|
|
size = Huffman.BuildTable (table, index, Huffman.TableBits, code_lengths, alphabet_size);
|
|
if (!ok || size == 0)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return 0;
|
|
}
|
|
return size;
|
|
}
|
|
|
|
bool ReadHuffmanCodeLengths (int[] code_length_code_lengths, int num_symbols, int[] code_lengths)
|
|
{
|
|
int prev_code_len = Huffman.DefaultCodeLength;
|
|
var table = new HuffmanCode[1 << Huffman.LengthsTableBits];
|
|
|
|
if (0 == Huffman.BuildTable (table, 0, Huffman.LengthsTableBits, code_length_code_lengths, NumCodeLengthCodes))
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
|
|
int max_symbol;
|
|
if (0 != br_.ReadBits (1)) // use length
|
|
{
|
|
int length_nbits = 2 + 2 * (int)br_.ReadBits (3);
|
|
max_symbol = 2 + (int)br_.ReadBits (length_nbits);
|
|
if (max_symbol > num_symbols)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
max_symbol = num_symbols;
|
|
}
|
|
|
|
int symbol = 0;
|
|
while (symbol < num_symbols)
|
|
{
|
|
if (max_symbol-- == 0) break;
|
|
br_.FillBitWindow();
|
|
int p = (int)br_.PrefetchBits() & Huffman.LengthsTableMask;
|
|
br_.SkipBits (table[p].bits);
|
|
int code_len = table[p].value;
|
|
if (code_len < kCodeLengthLiterals)
|
|
{
|
|
code_lengths[symbol++] = code_len;
|
|
if (code_len != 0) prev_code_len = code_len;
|
|
}
|
|
else
|
|
{
|
|
bool use_prev = (code_len == kCodeLengthRepeatCode);
|
|
int slot = code_len - kCodeLengthLiterals;
|
|
int extra_bits = kCodeLengthExtraBits[slot];
|
|
int repeat_offset = kCodeLengthRepeatOffsets[slot];
|
|
int repeat = (int)br_.ReadBits(extra_bits) + repeat_offset;
|
|
if (symbol + repeat > num_symbols)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
else
|
|
{
|
|
int length = use_prev ? prev_code_len : 0;
|
|
while (repeat-- > 0)
|
|
code_lengths[symbol++] = length;
|
|
}
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
void BuildPackedTable (HTreeGroup htree_group)
|
|
{
|
|
var huff = htree_group.packed_table;
|
|
for (int code = 0; code < Huffman.PackedTableSize; ++code)
|
|
{
|
|
uint bits = (uint)code;
|
|
var hcode = htree_group.GetCode (HuffIndex.Green, code);
|
|
if (hcode.value >= Huffman.NumLiteralCodes)
|
|
{
|
|
huff[code].bits = hcode.bits + BitsSpecialMarker;
|
|
huff[code].value = hcode.value;
|
|
}
|
|
else
|
|
{
|
|
huff[code].bits = 0;
|
|
huff[code].value = 0;
|
|
bits >>= AccumulateHCode (hcode, 8, ref huff[code]);
|
|
bits >>= AccumulateHCode (htree_group.GetCode (HuffIndex.Red, (int)bits), 16, ref huff[code]);
|
|
bits >>= AccumulateHCode (htree_group.GetCode (HuffIndex.Blue, (int)bits), 0, ref huff[code]);
|
|
bits >>= AccumulateHCode (htree_group.GetCode (HuffIndex.Alpha, (int)bits), 24, ref huff[code]);
|
|
}
|
|
}
|
|
}
|
|
|
|
int AccumulateHCode (HuffmanCode hcode, int shift, ref HuffmanCode32 huff)
|
|
{
|
|
huff.bits += hcode.bits;
|
|
huff.value |= (uint)hcode.value << shift;
|
|
return hcode.bits;
|
|
}
|
|
|
|
void UpdateDecoder (int width, int height)
|
|
{
|
|
int num_bits = hdr_.huffman_subsample_bits_;
|
|
width_ = width;
|
|
height_ = height;
|
|
|
|
hdr_.huffman_xsize_ = SubSampleSize (width, num_bits);
|
|
hdr_.huffman_mask_ = (num_bits == 0) ? ~0 : (1 << num_bits) - 1;
|
|
}
|
|
|
|
public static int SubSampleSize (int size, int sampling_bits)
|
|
{
|
|
return (int)(((uint)size + (1u << sampling_bits) - 1u) >> sampling_bits);
|
|
}
|
|
|
|
public bool DecodeImageData (uint[] data, int width, int height, int last_row, ProcessRowsFunc process_func)
|
|
{
|
|
int row = last_pixel_ / width;
|
|
int col = last_pixel_ % width;
|
|
var htree_group = GetHtreeGroupForPos (col, row);
|
|
int src = last_pixel_;
|
|
int last_cached = src;
|
|
int src_end = width * height; // End of data
|
|
int src_last = width * last_row; // Last pixel to decode
|
|
int len_code_limit = Huffman.NumLiteralCodes + Huffman.NumLengthCodes;
|
|
int color_cache_limit = len_code_limit + hdr_.color_cache_size_;
|
|
int next_sync_row = incremental_ ? row : 1 << 24;
|
|
var color_cache = (hdr_.color_cache_size_ > 0) ? hdr_.color_cache_ : null;
|
|
int mask = hdr_.huffman_mask_;
|
|
|
|
while (src < src_last)
|
|
{
|
|
int code;
|
|
if (row >= next_sync_row)
|
|
{
|
|
SaveState (src);
|
|
next_sync_row = row + SyncEveryNRows;
|
|
}
|
|
// Only update when changing tile. Note we could use this test:
|
|
// if "((((prev_col ^ col) | prev_row ^ row)) > mask)" -> tile changed
|
|
// but that's actually slower and needs storing the previous col/row.
|
|
if ((col & mask) == 0)
|
|
htree_group = GetHtreeGroupForPos (col, row);
|
|
if (htree_group.is_trivial_code)
|
|
{
|
|
data[src] = htree_group.literal_arb;
|
|
goto AdvanceByOne;
|
|
}
|
|
br_.FillBitWindow();
|
|
if (htree_group.use_packed_table)
|
|
{
|
|
code = ReadPackedSymbols (htree_group, data, src);
|
|
if (code == PackedNonLiteralCode)
|
|
goto AdvanceByOne;
|
|
}
|
|
else
|
|
{
|
|
code = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Green));
|
|
}
|
|
if (br_.EoS) break; // early out
|
|
if (code < Huffman.NumLiteralCodes) // Literal
|
|
{
|
|
if (htree_group.is_trivial_literal)
|
|
{
|
|
data[src] = htree_group.literal_arb | (uint)(code << 8);
|
|
}
|
|
else
|
|
{
|
|
int red, blue, alpha;
|
|
red = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Red));
|
|
br_.FillBitWindow();
|
|
blue = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Blue));
|
|
alpha = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Alpha));
|
|
if (br_.EoS) break;
|
|
data[src] = ((uint)alpha << 24) | ((uint)red << 16) | ((uint)code << 8) | (uint)blue;
|
|
}
|
|
}
|
|
else if (code < len_code_limit) // Backward reference
|
|
{
|
|
int length_sym = code - Huffman.NumLiteralCodes;
|
|
int length = GetCopyLength (length_sym);
|
|
int dist_symbol = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Dist));
|
|
br_.FillBitWindow();
|
|
int dist_code = GetCopyDistance (dist_symbol);
|
|
int dist = PlaneCodeToDistance (width, dist_code);
|
|
if (br_.EoS) break;
|
|
if (src < dist || src_end - src < length)
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
else
|
|
{
|
|
int dst = src;
|
|
int s = dst - dist;
|
|
for (int i = 0; i < length; ++i)
|
|
data[dst+i] = data[s+i];
|
|
}
|
|
src += length;
|
|
col += length;
|
|
while (col >= width)
|
|
{
|
|
col -= width;
|
|
++row;
|
|
if ((row % NumARGBCacheRows == 0) && (process_func != null))
|
|
process_func (this, row);
|
|
}
|
|
if (0 != (col & mask)) htree_group = GetHtreeGroupForPos (col, row);
|
|
if (color_cache != null)
|
|
{
|
|
while (last_cached < src)
|
|
color_cache.Insert (data[last_cached++]);
|
|
}
|
|
continue;
|
|
}
|
|
else if (code < color_cache_limit) // Color cache
|
|
{
|
|
int key = code - len_code_limit;
|
|
while (last_cached < src)
|
|
color_cache.Insert (data[last_cached++]);
|
|
data[src] = color_cache.Lookup ((uint)key);
|
|
}
|
|
else // Not reached
|
|
{
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
|
|
AdvanceByOne:
|
|
++src;
|
|
++col;
|
|
if (col >= width)
|
|
{
|
|
col = 0;
|
|
++row;
|
|
if ((row % NumARGBCacheRows == 0) && (process_func != null))
|
|
{
|
|
process_func (this, row);
|
|
}
|
|
if (color_cache != null)
|
|
{
|
|
while (last_cached < src)
|
|
color_cache.Insert (data[last_cached++]);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (incremental_ && br_.EoS && src < src_end)
|
|
{
|
|
RestoreState();
|
|
}
|
|
else if (!br_.EoS)
|
|
{
|
|
// Process the remaining rows corresponding to last row-block.
|
|
if (process_func != null)
|
|
process_func (this, row);
|
|
status_ = VP8StatusCode.Ok;
|
|
last_pixel_ = src; // end-of-scan marker
|
|
}
|
|
else
|
|
{
|
|
// if not incremental, and we are past the end of buffer (eos_=1), then this
|
|
// is a real bitstream error.
|
|
status_ = VP8StatusCode.BitstreamError;
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
HTreeGroup GetHtreeGroupForPos (int x, int y)
|
|
{
|
|
int meta_index = GetMetaIndex (hdr_.huffman_image_, hdr_.huffman_xsize_, hdr_.huffman_subsample_bits_, x, y);
|
|
return hdr_.htree_groups_[meta_index];
|
|
}
|
|
|
|
int GetMetaIndex (uint[] image, int xsize, int bits, int x, int y)
|
|
{
|
|
if (0 == bits) return 0;
|
|
return (int)image[xsize * (y >> bits) + (x >> bits)];
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Decodes the next Huffman code from bit-stream.
|
|
// FillBitWindow(br) needs to be called at minimum every second call
|
|
// to ReadSymbol, in order to pre-fetch enough bits.
|
|
int ReadSymbol (HuffmanCode[] table, int index)
|
|
{
|
|
int val = (int)br_.PrefetchBits();
|
|
index += val & Huffman.TableMask;
|
|
int nbits = table[index].bits - Huffman.TableBits;
|
|
if (nbits > 0)
|
|
{
|
|
br_.SkipBits (Huffman.TableBits);
|
|
val = (int)br_.PrefetchBits();
|
|
index += table[index].value;
|
|
index += val & ((1 << nbits) - 1);
|
|
}
|
|
br_.SkipBits (table[index].bits);
|
|
return table[index].value;
|
|
}
|
|
|
|
int ReadPackedSymbols (HTreeGroup group, uint[] data, int dst)
|
|
{
|
|
uint val = br_.PrefetchBits() & (Huffman.PackedTableSize - 1);
|
|
var code = group.packed_table[val];
|
|
if (code.bits < BitsSpecialMarker)
|
|
{
|
|
br_.SkipBits (code.bits);
|
|
data[dst] = code.value;
|
|
return PackedNonLiteralCode;
|
|
}
|
|
else
|
|
{
|
|
br_.SkipBits (code.bits - BitsSpecialMarker);
|
|
return (int)code.value;
|
|
}
|
|
}
|
|
|
|
int GetCopyLength (int length_symbol)
|
|
{
|
|
// Length and distance prefixes are encoded the same way.
|
|
return GetCopyDistance (length_symbol);
|
|
}
|
|
|
|
int GetCopyDistance (int distance_symbol)
|
|
{
|
|
if (distance_symbol < 4)
|
|
return distance_symbol + 1;
|
|
int extra_bits = (distance_symbol - 2) >> 1;
|
|
int offset = (2 + (distance_symbol & 1)) << extra_bits;
|
|
return offset + (int)br_.ReadBits (extra_bits) + 1;
|
|
}
|
|
|
|
int PlaneCodeToDistance (int xsize, int plane_code)
|
|
{
|
|
if (plane_code > CodeToPlaneCodes)
|
|
return plane_code - CodeToPlaneCodes;
|
|
int dist_code = kCodeToPlane[plane_code - 1];
|
|
int yoffset = dist_code >> 4;
|
|
int xoffset = 8 - (dist_code & 0xf);
|
|
int dist = yoffset * xsize + xoffset;
|
|
return (dist >= 1) ? dist : 1; // dist<1 can happen if xsize is very small
|
|
}
|
|
|
|
void SaveState (int last_pixel)
|
|
{
|
|
br_.CopyStateTo (saved_br_);
|
|
saved_last_pixel_ = last_pixel;
|
|
if (hdr_.color_cache_size_ > 0)
|
|
hdr_.color_cache_.Copy (hdr_.saved_color_cache_);
|
|
}
|
|
|
|
void RestoreState ()
|
|
{
|
|
status_ = VP8StatusCode.Suspended;
|
|
saved_br_.CopyStateTo (br_);
|
|
last_pixel_ = saved_last_pixel_;
|
|
if (hdr_.color_cache_size_ > 0)
|
|
hdr_.saved_color_cache_.Copy (hdr_.color_cache_);
|
|
}
|
|
|
|
public bool DecodeAlphaData (int width, int height, int last_row)
|
|
{
|
|
var data = pixels8_;
|
|
bool ok = true;
|
|
int row = last_pixel_ / width;
|
|
int col = last_pixel_ % width;
|
|
var htree_group = GetHtreeGroupForPos (col, row);
|
|
int pos = last_pixel_; // current position
|
|
int end = width * height; // End of data
|
|
int last = width * last_row; // Last pixel to decode
|
|
int len_code_limit = Huffman.NumLiteralCodes + Huffman.NumLengthCodes;
|
|
int mask = hdr_.huffman_mask_;
|
|
|
|
while (!br_.EoS && pos < last)
|
|
{
|
|
// Only update when changing tile.
|
|
if ((col & mask) == 0)
|
|
htree_group = GetHtreeGroupForPos (col, row);
|
|
|
|
br_.FillBitWindow();
|
|
int code = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Green));
|
|
if (code < Huffman.NumLiteralCodes) // Literal
|
|
{
|
|
data[pos] = (byte)code;
|
|
++pos;
|
|
++col;
|
|
if (col >= width)
|
|
{
|
|
col = 0;
|
|
++row;
|
|
if (row % NumARGBCacheRows == 0)
|
|
ExtractPalettedAlphaRows (row);
|
|
}
|
|
}
|
|
else if (code < len_code_limit) // Backward reference
|
|
{
|
|
int length_sym = code - Huffman.NumLiteralCodes;
|
|
int length = GetCopyLength (length_sym);
|
|
int dist_symbol = ReadSymbol (htree_group.Tables, htree_group.GetMeta (HuffIndex.Dist));
|
|
br_.FillBitWindow();
|
|
int dist_code = GetCopyDistance (dist_symbol);
|
|
int dist = PlaneCodeToDistance (width, dist_code);
|
|
if (pos >= dist && end - pos >= length)
|
|
{
|
|
Binary.CopyOverlapped (data, pos - dist, pos, length);
|
|
}
|
|
else
|
|
{
|
|
ok = false;
|
|
goto End;
|
|
}
|
|
pos += length;
|
|
col += length;
|
|
while (col >= width)
|
|
{
|
|
col -= width;
|
|
++row;
|
|
if (row % NumARGBCacheRows == 0)
|
|
ExtractPalettedAlphaRows (row);
|
|
}
|
|
if (pos < last && 0 != (col & mask))
|
|
htree_group = GetHtreeGroupForPos (col, row);
|
|
}
|
|
else // Not reached
|
|
{
|
|
ok = false;
|
|
goto End;
|
|
}
|
|
}
|
|
// Process the remaining rows corresponding to last row-block.
|
|
ExtractPalettedAlphaRows (row);
|
|
|
|
End:
|
|
if (!ok || (br_.EoS && pos < end))
|
|
{
|
|
ok = false;
|
|
status_ = br_.EoS ? VP8StatusCode.Suspended : VP8StatusCode.BitstreamError;
|
|
}
|
|
else
|
|
{
|
|
last_pixel_ = pos;
|
|
}
|
|
return ok;
|
|
}
|
|
|
|
void ExtractPalettedAlphaRows (int row)
|
|
{
|
|
int num_rows = row - last_row_;
|
|
int input = width_ * last_row_;
|
|
if (num_rows > 0)
|
|
ApplyInverseTransformsAlpha (num_rows, pixels8_, input);
|
|
|
|
last_row_ = last_out_row_ = row;
|
|
}
|
|
|
|
void ApplyInverseTransforms (int num_rows, uint[] rows, int rows_in)
|
|
{
|
|
int n = next_transform_;
|
|
int cache_pixs = width_ * num_rows;
|
|
int start_row = last_row_;
|
|
int end_row = start_row + num_rows;
|
|
int rows_out = argb_cache_;
|
|
|
|
// Inverse transforms.
|
|
// TODO: most transforms only need to operate on the cropped region only.
|
|
Buffer.BlockCopy (rows, rows_in, pixels32_, rows_out, cache_pixs * sizeof(uint));
|
|
while (n --> 0)
|
|
{
|
|
transforms_[n].InverseTransform (start_row, end_row, rows, rows_in, pixels32_, rows_out);
|
|
rows = pixels32_;
|
|
rows_in = rows_out;
|
|
}
|
|
}
|
|
|
|
void ApplyInverseTransformsAlpha (int num_rows, byte[] rows, int rows_in)
|
|
{
|
|
int start_row = last_row_;
|
|
int end_row = start_row + num_rows;
|
|
byte[] output = io_.opaque;
|
|
int rows_out = io_.width * start_row;
|
|
transforms_[0].ColorIndexInverseTransformAlpha (start_row, end_row, rows, rows_in, output, rows_out);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Special row-processing that only stores the alpha data.
|
|
/// </summary>
|
|
public static void ExtractAlphaRows (LosslessDecoder dec, int row)
|
|
{
|
|
int num_rows = row - dec.last_row_;
|
|
if (num_rows <= 0) return; // Nothing to be done.
|
|
|
|
dec.ApplyInverseTransforms (num_rows, dec.pixels32_, dec.width_ * dec.last_row_);
|
|
|
|
// Extract alpha (which is stored in the green plane).
|
|
|
|
int width = dec.io_.width; // the final width (!= dec->width_)
|
|
int cache_pixs = width * num_rows;
|
|
// uint8_t* const dst = (uint8_t*)dec->io_->opaque + width * dec->last_row_;
|
|
int dst = width * dec.last_row_;
|
|
int src = dec.argb_cache_;
|
|
for (int i = 0; i < cache_pixs; ++i)
|
|
dec.io_.opaque[dst+i] = (byte)(dec.pixels32_[src+i] >> 8);
|
|
dec.last_row_ = dec.last_out_row_ = row;
|
|
}
|
|
|
|
//------------------------------------------------------------------------------
|
|
|
|
internal class LMetadata
|
|
{
|
|
public int color_cache_size_;
|
|
public LColorCache color_cache_ = new LColorCache();
|
|
public LColorCache saved_color_cache_ = new LColorCache(); // for incremental
|
|
|
|
public int huffman_mask_;
|
|
public int huffman_subsample_bits_;
|
|
public int huffman_xsize_;
|
|
public uint[] huffman_image_;
|
|
public int num_htree_groups_;
|
|
public HTreeGroup[] htree_groups_;
|
|
|
|
public void ClearMetadata ()
|
|
{
|
|
color_cache_size_ = 0;
|
|
huffman_mask_ = 0;
|
|
huffman_subsample_bits_ = 0;
|
|
huffman_xsize_ = 0;
|
|
huffman_image_ = null;
|
|
num_htree_groups_ = 0;
|
|
htree_groups_ = null;
|
|
}
|
|
}
|
|
|
|
internal class LColorCache
|
|
{
|
|
public uint[] colors_; // color entries
|
|
public int hash_shift_; // Hash shift: 32 - hash_bits_.
|
|
public int hash_bits_;
|
|
|
|
public void Init (int hash_bits)
|
|
{
|
|
int hash_size = 1 << hash_bits;
|
|
colors_ = new uint[hash_size];
|
|
hash_shift_ = 32 - hash_bits;
|
|
hash_bits_ = hash_bits;
|
|
}
|
|
|
|
public void Copy (LColorCache dst)
|
|
{
|
|
Array.Copy (colors_, dst.colors_, 1u << dst.hash_bits_);
|
|
}
|
|
|
|
public uint Lookup (uint key)
|
|
{
|
|
return colors_[key];
|
|
}
|
|
|
|
public void Set (uint key, uint argb)
|
|
{
|
|
colors_[key] = argb;
|
|
}
|
|
|
|
public void Insert (uint argb)
|
|
{
|
|
uint key = (kHashMul * argb) >> hash_shift_;
|
|
colors_[key] = argb;
|
|
}
|
|
|
|
public int GetIndex (uint argb)
|
|
{
|
|
return (int)((kHashMul * argb) >> hash_shift_);
|
|
}
|
|
}
|
|
|
|
// -----------------------------------------------------------------------------
|
|
/// <summary>
|
|
/// Bitreader for lossless format
|
|
/// </summary>
|
|
internal class LBitReader
|
|
{
|
|
ulong val_; // pre-fetched bits
|
|
byte[] buf_; // input byte buffer
|
|
uint len_; // buffer length
|
|
uint pos_; // byte position in buf_
|
|
int bit_pos_; // current bit-reading position in val_
|
|
bool eos_; // true if a bit was read past the end of buffer
|
|
|
|
public const int MaxNumBitRead = 24;
|
|
|
|
public const int LBITS = 64; // Number of bits prefetched.
|
|
public const int WBITS = 32; // Minimum number of bytes ready after VP8LFillBitWindow.
|
|
|
|
const int LOG8_WBITS = 4; // Number of bytes needed to store WBITS bits.
|
|
|
|
public bool EoS { get { return eos_; } }
|
|
|
|
/// <summary>
|
|
/// Returns true if there was an attempt at reading bit past the end of
|
|
/// the buffer. Doesn't set br->eos_ flag.
|
|
/// </summary>
|
|
private bool IsEndOfStream { get { return eos_ || ((pos_ == len_) && (bit_pos_ > LBITS)); } }
|
|
|
|
public void Init (byte[] input, int start, uint length)
|
|
{
|
|
len_ = length;
|
|
val_ = 0;
|
|
bit_pos_ = 0;
|
|
eos_ = false;
|
|
|
|
if (length > sizeof(ulong))
|
|
length = sizeof(ulong);
|
|
|
|
ulong v = 0;
|
|
for (uint i = 0; i < length; ++i)
|
|
v |= (ulong)input[start+i] << (8 * (int)i);
|
|
|
|
val_ = v;
|
|
pos_ = (uint)start+length;
|
|
buf_ = input;
|
|
}
|
|
|
|
public void Init (BinaryReader input, uint length)
|
|
{
|
|
var buf = input.ReadBytes ((int)length);
|
|
if (buf.Length != length)
|
|
throw new EndOfStreamException();
|
|
Init (buf, 0, length);
|
|
}
|
|
|
|
public void CopyStateTo (LBitReader other)
|
|
{
|
|
other.val_ = val_;
|
|
other.buf_ = buf_;
|
|
other.len_ = len_;
|
|
other.pos_ = pos_;
|
|
other.bit_pos_ = bit_pos_;
|
|
other.eos_ = eos_;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Sets a new data buffer.
|
|
/// </summary>
|
|
public void SetBuffer (byte[] buffer, uint length)
|
|
{
|
|
buf_ = buffer;
|
|
len_ = length;
|
|
// pos_ > len_ should be considered a param error.
|
|
eos_ = (pos_ > len_) || IsEndOfStream;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Reads the specified number of bits from read buffer.
|
|
/// Flags an error in case end_of_stream or n_bits is more than the allowed limit
|
|
/// of VP8L_MAX_NUM_BIT_READ (inclusive).
|
|
/// Flags eos_ if this read attempt is going to cross the read buffer.
|
|
/// </summary>
|
|
public uint ReadBits (int n_bits)
|
|
{
|
|
// Flag an error if end_of_stream or n_bits is more than allowed limit.
|
|
if (!eos_ && n_bits <= MaxNumBitRead)
|
|
{
|
|
uint val = PrefetchBits() & kBitMask[n_bits];
|
|
int new_bits = bit_pos_ + n_bits;
|
|
bit_pos_ = new_bits;
|
|
ShiftBytes();
|
|
return val;
|
|
}
|
|
else
|
|
{
|
|
SetEndOfStream();
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Return the prefetched bits, so they can be looked up.
|
|
/// </summary>
|
|
public uint PrefetchBits ()
|
|
{
|
|
return (uint)(val_ >> (bit_pos_ & (LBITS - 1)));
|
|
}
|
|
|
|
/// <summary>
|
|
/// For jumping over a number of bits in the bit stream when accessed with
|
|
/// VP8LPrefetchBits and VP8LFillBitWindow.
|
|
/// </summary>
|
|
public void SetBitPos (int val)
|
|
{
|
|
bit_pos_ = val;
|
|
eos_ = IsEndOfStream;
|
|
}
|
|
|
|
public void SkipBits (int bits)
|
|
{
|
|
SetBitPos (bit_pos_ + bits);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Advances the read buffer by 4 bytes to make room for reading next 32 bits.
|
|
/// Speed critical, but infrequent part of the code can be non-inlined.
|
|
/// </summary>
|
|
|
|
public void FillBitWindow ()
|
|
{
|
|
if (bit_pos_ >= WBITS)
|
|
DoFillBitWindow();
|
|
}
|
|
|
|
void DoFillBitWindow ()
|
|
{
|
|
if (pos_ + sizeof(ulong) < len_)
|
|
{
|
|
val_ >>= WBITS;
|
|
bit_pos_ -= WBITS;
|
|
val_ |= (ulong)LittleEndian.ToUInt32 (buf_, (int)pos_) << (LBITS - WBITS);
|
|
pos_ += LOG8_WBITS;
|
|
return;
|
|
}
|
|
ShiftBytes(); // Slow path.
|
|
}
|
|
|
|
void ShiftBytes ()
|
|
{
|
|
while (bit_pos_ >= 8 && pos_ < len_)
|
|
{
|
|
val_ >>= 8;
|
|
val_ |= ((ulong)buf_[pos_]) << (LBITS - 8);
|
|
++pos_;
|
|
bit_pos_ -= 8;
|
|
}
|
|
if (IsEndOfStream)
|
|
SetEndOfStream();
|
|
}
|
|
|
|
void SetEndOfStream ()
|
|
{
|
|
eos_ = true;
|
|
bit_pos_ = 0; // To avoid undefined behaviour with shifts.
|
|
}
|
|
|
|
static readonly uint[] kBitMask = new uint[MaxNumBitRead + 1]
|
|
{
|
|
0,
|
|
0x000001, 0x000003, 0x000007, 0x00000f,
|
|
0x00001f, 0x00003f, 0x00007f, 0x0000ff,
|
|
0x0001ff, 0x0003ff, 0x0007ff, 0x000fff,
|
|
0x001fff, 0x003fff, 0x007fff, 0x00ffff,
|
|
0x01ffff, 0x03ffff, 0x07ffff, 0x0fffff,
|
|
0x1fffff, 0x3fffff, 0x7fffff, 0xffffff
|
|
};
|
|
}
|
|
|
|
// Memory needed for lookup tables of one Huffman tree group. Red, blue, alpha
|
|
// and distance alphabets are constant (256 for red, blue and alpha, 40 for
|
|
// distance) and lookup table sizes for them in worst case are 630 and 410
|
|
// respectively. Size of green alphabet depends on color cache size and is equal
|
|
// to 256 (green component values) + 24 (length prefix values)
|
|
// + color_cache_size (between 0 and 2048).
|
|
// All values computed for 8-bit first level lookup with Mark Adler's tool:
|
|
// http://www.hdfgroup.org/ftp/lib-external/zlib/zlib-1.2.5/examples/enough.c
|
|
|
|
const int FIXED_TABLE_SIZE = 630 * 3 + 410;
|
|
static readonly int[] kTableSize = {
|
|
FIXED_TABLE_SIZE + 654,
|
|
FIXED_TABLE_SIZE + 656,
|
|
FIXED_TABLE_SIZE + 658,
|
|
FIXED_TABLE_SIZE + 662,
|
|
FIXED_TABLE_SIZE + 670,
|
|
FIXED_TABLE_SIZE + 686,
|
|
FIXED_TABLE_SIZE + 718,
|
|
FIXED_TABLE_SIZE + 782,
|
|
FIXED_TABLE_SIZE + 912,
|
|
FIXED_TABLE_SIZE + 1168,
|
|
FIXED_TABLE_SIZE + 1680,
|
|
FIXED_TABLE_SIZE + 2704
|
|
};
|
|
|
|
static readonly ushort[] kAlphabetSize = new ushort[Huffman.CodesPerMetaCode]
|
|
{
|
|
Huffman.NumLiteralCodes + Huffman.NumLengthCodes,
|
|
Huffman.NumLiteralCodes,
|
|
Huffman.NumLiteralCodes,
|
|
Huffman.NumLiteralCodes,
|
|
Huffman.NumDistanceCodes
|
|
};
|
|
|
|
const int NumCodeLengthCodes = 19;
|
|
static readonly byte[] kCodeLengthCodeOrder = new byte[NumCodeLengthCodes] {
|
|
17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
|
|
};
|
|
|
|
static readonly byte[] kLiteralMap = new byte[Huffman.CodesPerMetaCode] {
|
|
0, 1, 1, 1, 0
|
|
};
|
|
|
|
const int CodeToPlaneCodes = 120;
|
|
static readonly byte[] kCodeToPlane = new byte[CodeToPlaneCodes]
|
|
{
|
|
0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
|
|
0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
|
|
0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
|
|
0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
|
|
0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
|
|
0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
|
|
0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
|
|
0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
|
|
0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
|
|
0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
|
|
0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
|
|
0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70
|
|
};
|
|
}
|
|
}
|