diff --git a/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/FixedByteBuffer512.cs b/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/FixedByteBuffer512.cs new file mode 100644 index 0000000000..c509903c98 --- /dev/null +++ b/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/FixedByteBuffer512.cs @@ -0,0 +1,24 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +using System.Runtime.CompilerServices; +using System.Runtime.InteropServices; + +namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components +{ + [StructLayout(LayoutKind.Sequential)] + internal unsafe struct FixedByteBuffer512 + { + public fixed byte Data[1 << ScanDecoder.FastBits]; + + public byte this[int idx] + { + [MethodImpl(MethodImplOptions.AggressiveInlining)] + get + { + ref byte self = ref Unsafe.As(ref this); + return Unsafe.Add(ref self, idx); + } + } + } +} \ No newline at end of file diff --git a/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsHuffmanTable.cs b/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsHuffmanTable.cs index 0541de91b0..1cc342f5ac 100644 --- a/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsHuffmanTable.cs +++ b/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsHuffmanTable.cs @@ -32,7 +32,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components /// /// Gets the lookahead array /// - public FixedInt16Buffer256 Lookahead; + public FixedByteBuffer512 Lookahead; /// /// Gets the sizes array @@ -43,19 +43,76 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components /// Initializes a new instance of the struct. /// /// The to use for buffer allocations. - /// The code lengths + /// The code lengths /// The huffman values - public PdfJsHuffmanTable(MemoryManager memoryManager, ReadOnlySpan lengths, ReadOnlySpan values) + public PdfJsHuffmanTable(MemoryManager memoryManager, ReadOnlySpan count, ReadOnlySpan values) { const int Length = 257; using (IBuffer huffcode = memoryManager.Allocate(Length)) { + // Span codes = huffcode.Span; ref short huffcodeRef = ref MemoryMarshal.GetReference(huffcode.Span); - this.GenerateSizeTable(lengths); - this.GenerateCodeTable(ref huffcodeRef, Length); - this.GenerateDecoderTables(lengths, ref huffcodeRef); - this.GenerateLookaheadTables(lengths, values, ref huffcodeRef); + this.GenerateSizeTable(count); + + //int k = 0; + //fixed (short* sizesRef = this.Sizes.Data) + //fixed (short* deltaRef = this.ValOffset.Data) + //fixed (long* maxcodeRef = this.MaxCode.Data) + //{ + // uint code = 0; + // int j; + // for (j = 1; j <= 16; j++) + // { + // // Compute delta to add to code to compute symbol id. + // deltaRef[j] = (short)(k - code); + // if (sizesRef[k] == j) + // { + // while (sizesRef[k] == j) + // { + // codes[k++] = (short)code++; + + // // Unsafe.Add(ref huffcodeRef, k++) = (short)code++; + + // // TODO: Throw if invalid? + // } + // } + + // // Compute largest code + 1 for this size. preshifted as neeed later. + // maxcodeRef[j] = code << (16 - j); + // code <<= 1; + // } + + // maxcodeRef[j] = 0xFFFFFFFF; + //} + + //fixed (short* lookaheadRef = this.Lookahead.Data) + //{ + // const int FastBits = ScanDecoder.FastBits; + // var fast = new Span(lookaheadRef, 1 << FastBits); + // fast.Fill(255); // Flag for non-accelerated + + // fixed (short* sizesRef = this.Sizes.Data) + // { + // for (int i = 0; i < k; i++) + // { + // int s = sizesRef[i]; + // if (s <= ScanDecoder.FastBits) + // { + // int c = codes[i] << (FastBits - s); + // int m = 1 << (FastBits - s); + // for (int j = 0; j < m; j++) + // { + // fast[c + j] = (byte)i; + // } + // } + // } + // } + //} + + this.GenerateCodeTable(ref huffcodeRef, Length, out int k); + this.GenerateDecoderTables(count, ref huffcodeRef); + this.GenerateLookaheadTables(count, values, ref huffcodeRef, k); } fixed (byte* huffValRef = this.Values.Data) @@ -74,18 +131,18 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components { fixed (short* sizesRef = this.Sizes.Data) { - short index = 0; - for (short l = 1; l <= 16; l++) + short k = 0; + for (short i = 1; i < 17; i++) { - byte i = lengths[l]; - for (short j = 0; j < i; j++) + byte l = lengths[i]; + for (short j = 0; j < l; j++) { - sizesRef[index] = l; - index++; + sizesRef[k] = i; + k++; } } - sizesRef[index] = 0; + sizesRef[k] = 0; } } @@ -94,11 +151,12 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components /// /// The huffman code span ref /// The length of the huffsize span - private void GenerateCodeTable(ref short huffcodeRef, int length) + /// The length of any valid codes + private void GenerateCodeTable(ref short huffcodeRef, int length, out int k) { fixed (short* sizesRef = this.Sizes.Data) { - short k = 0; + k = 0; short si = sizesRef[0]; short code = 0; for (short i = 0; i < length; i++) @@ -134,7 +192,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components // valOffsetRef[l] = huffcodeRef[] index of 1st symbol of code length i, minus the minimum code of length i valOffsetRef[i] = (short)(bitcount - Unsafe.Add(ref huffcodeRef, bitcount)); bitcount += lengths[i]; - maxcodeRef[i] = Unsafe.Add(ref huffcodeRef, bitcount - 1); // maximum code of length i + maxcodeRef[i] = Unsafe.Add(ref huffcodeRef, bitcount - 1) << (16 - i); // maximum code of length i preshifted for faster reading later } else { @@ -143,41 +201,43 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components } valOffsetRef[17] = 0; - maxcodeRef[17] = 0xFFFFFL; + maxcodeRef[17] = 0xFFFFFFFFL; } } /// - /// Generates lookup tables to speed up decoding + /// Generates non-spec lookup tables to speed up decoding /// /// The code lengths /// The huffman value array /// The huffman code span ref - private void GenerateLookaheadTables(ReadOnlySpan lengths, ReadOnlySpan huffval, ref short huffcodeRef) + /// The lengths of any valid codes + private void GenerateLookaheadTables(ReadOnlySpan lengths, ReadOnlySpan huffval, ref short huffcodeRef, int k) { // TODO: Rewrite this to match stb_Image // TODO: This generation code matches the libJpeg code but the lookahead table is not actually used yet. // To use it we need to implement fast lookup path in PdfJsScanDecoder.DecodeHuffman // This should yield much faster scan decoding as usually, more than 95% of the Huffman codes // will be 8 or fewer bits long and can be handled without looping. - fixed (short* lookaheadRef = this.Lookahead.Data) + fixed (byte* lookaheadRef = this.Lookahead.Data) { - var lookaheadSpan = new Span(lookaheadRef, 256); - - lookaheadSpan.Fill(2034); // 9 << 8; + const int FastBits = ScanDecoder.FastBits; + var lookaheadSpan = new Span(lookaheadRef, 1 << ScanDecoder.FastBits); - int p = 0; - for (int l = 1; l <= 8; l++) + lookaheadSpan.Fill(255); // Flag for non-accelerated + fixed (short* sizesRef = this.Sizes.Data) { - for (int i = 1; i <= lengths[l]; i++, p++) + for (int i = 0; i < k; ++i) { - // l = current code's length, p = its index in huffcode[] & huffval[]. - // Generate left-justified code followed by all possible bit sequences - int lookBits = Unsafe.Add(ref huffcodeRef, p) << (8 - l); - for (int ctr = 1 << (8 - l); ctr > 0; ctr--) + int s = sizesRef[i]; + if (s <= ScanDecoder.FastBits) { - lookaheadRef[lookBits] = (short)((l << 8) | huffval[p]); - lookBits++; + int c = Unsafe.Add(ref huffcodeRef, i) << (FastBits - s); + int m = 1 << (FastBits - s); + for (int j = 0; j < m; ++j) + { + lookaheadRef[c + j] = (byte)i; + } } } } diff --git a/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/ScanDecoder.cs b/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/ScanDecoder.cs index e9f91ef06c..217b3cb62b 100644 --- a/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/ScanDecoder.cs +++ b/src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/ScanDecoder.cs @@ -15,10 +15,10 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components public const int FastBits = 9; // bmask[n] = (1 << n) - 1 - private static readonly uint[] stbi__bmask = { 0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535 }; + private static readonly uint[] Bmask = { 0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535 }; // bias[n] = (-1 << n) + 1 - private static readonly int[] stbi__jbias = { 0, -1, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, -4095, -8191, -16383, -32767 }; + private static readonly int[] Bias = { 0, -1, -3, -7, -15, -31, -63, -127, -255, -511, -1023, -2047, -4095, -8191, -16383, -32767 }; private readonly DoubleBufferedStreamReader stream; private readonly PdfJsFrameComponent[] components; @@ -141,8 +141,61 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components else { // Interleaved - int i, j, k, x, y; + int mcu = 0; + int mcusPerColumn = frame.McusPerColumn; + int mcusPerLine = frame.McusPerLine; + for (int j = 0; j < mcusPerColumn; j++) + { + for (int i = 0; i < mcusPerLine; i++) + { + // Scan an interleaved mcu... process components in order + for (int k = 0; k < this.componentsLength; k++) + { + PdfJsFrameComponent component = this.components[k]; + ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast(component.SpectralBlocks.Span)); + ref PdfJsHuffmanTable dcHuffmanTable = ref dcHuffmanTables[component.DCHuffmanTableId]; + ref PdfJsHuffmanTable acHuffmanTable = ref acHuffmanTables[component.ACHuffmanTableId]; + Span fastAC = fastACTables.Tables.GetRowSpan(component.ACHuffmanTableId); + int h = component.HorizontalSamplingFactor; + int v = component.VerticalSamplingFactor; + + // Scan out an mcu's worth of this component; that's just determined + // by the basic H and V specified for the component + for (int y = 0; y < v; y++) + { + for (int x = 0; x < h; x++) + { + int mcuRow = mcu / mcusPerLine; + int mcuCol = mcu % mcusPerLine; + int blockRow = (mcuRow * v) + y; + int blockCol = (mcuCol * h) + x; + int offset = component.GetBlockBufferOffset(blockRow, blockCol); + this.DecodeBlock(component, ref Unsafe.Add(ref blockDataRef, offset), ref dcHuffmanTable, ref acHuffmanTable, fastAC); + } + } + } + + // After all interleaved components, that's an interleaved MCU, + // so now count down the restart interval + mcu++; + if (this.todo-- <= 0) + { + if (this.codeBits < 24) + { + this.GrowBufferUnsafe(); + } + + // If it's NOT a restart, then just bail, so we get corrupt data + // rather than no data + if (!this.IsRestartMarker(this.marker)) + { + return 1; + } + this.Reset(); + } + } + } } } @@ -156,11 +209,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components ref PdfJsHuffmanTable acTable, Span fac) { - if (this.codeBits < 16) - { - this.GrowBufferUnsafe(); - } - + this.CheckBits(); int t = this.DecodeHuffman(ref dcTable); if (t < 0) @@ -477,8 +526,8 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components } uint k = this.Lrot(this.codeBuffer, n); - this.codeBuffer = k & ~stbi__bmask[n]; - k &= stbi__bmask[n]; + this.codeBuffer = k & ~Bmask[n]; + k &= Bmask[n]; this.codeBits -= n; return (int)k; } @@ -503,7 +552,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components do { // TODO: EOF - uint b = (uint)(this.nomore ? 0 : this.stream.ReadByte()); + int b = this.nomore ? 0 : this.stream.ReadByte(); if (b == PdfJsJpegConstants.Markers.Prefix) { long position = this.stream.Position - 1; @@ -514,13 +563,17 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components { this.marker = (byte)c; this.nomore = true; - this.stream.Position = position; + if (!this.IsRestartMarker(this.marker)) + { + this.stream.Position = position; + } + return; } } } - this.codeBuffer |= b << (24 - this.codeBits); + this.codeBuffer |= (uint)b << (24 - this.codeBits); this.codeBits += 8; } while (this.codeBits <= 24); @@ -575,7 +628,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components } // Convert the huffman code to the symbol id - c = (int)((this.codeBuffer >> (32 - k)) & stbi__bmask[k]) + table.ValOffset[k]; + c = (int)((this.codeBuffer >> (32 - k)) & Bmask[k]) + table.ValOffset[k]; // Convert the id to a symbol this.codeBits -= k; @@ -593,10 +646,10 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components int sgn = (int)(this.codeBuffer >> 31); uint k = this.Lrot(this.codeBuffer, n); - this.codeBuffer = k & ~stbi__bmask[n]; - k &= stbi__bmask[n]; + this.codeBuffer = k & ~Bmask[n]; + k &= Bmask[n]; this.codeBits -= n; - return (int)(k + (stbi__jbias[n] & ~sgn)); + return (int)(k + (Bias[n] & ~sgn)); } [MethodImpl(MethodImplOptions.AggressiveInlining)] diff --git a/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs b/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs index 18a444c5bd..5bf4ab5aa4 100644 --- a/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs +++ b/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs @@ -731,10 +731,10 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort codeLengths.Span, huffmanValues.Span); - if (tableType != 0) + if (huffmanTableSpec >> 4 != 0) { // Build a table that decodes both magnitude and value of small ACs in one go. - this.BuildFastACTable(tableIndex); + this.BuildFastACTable(huffmanTableSpec & 15); } } } @@ -794,21 +794,35 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort int spectralStart = this.temp[0]; int spectralEnd = this.temp[1]; int successiveApproximation = this.temp[2]; - var scanDecoder = default(PdfJsScanDecoder); - - scanDecoder.DecodeScan( - this.Frame, - this.InputStream, - this.dcHuffmanTables, - this.acHuffmanTables, - this.Frame.Components, - componentIndex, - selectorsCount, - this.resetInterval, - spectralStart, - spectralEnd, - successiveApproximation >> 4, - successiveApproximation & 15); + + var sd = new ScanDecoder( + this.InputStream, + this.Frame.Components, + componentIndex, + selectorsCount, + this.resetInterval, + spectralStart, + spectralEnd, + successiveApproximation >> 4, + successiveApproximation & 15); + + sd.ParseEntropyCodedData(this.Frame, this.dcHuffmanTables, this.acHuffmanTables, this.fastACTables); + + //var scanDecoder = default(PdfJsScanDecoder); + + //scanDecoder.DecodeScan( + // this.Frame, + // this.InputStream, + // this.dcHuffmanTables, + // this.acHuffmanTables, + // this.Frame.Components, + // componentIndex, + // selectorsCount, + // this.resetInterval, + // spectralStart, + // spectralEnd, + // successiveApproximation >> 4, + // successiveApproximation & 15); } /// @@ -856,7 +870,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort int i; for (i = 0; i < (1 << FastBits); i++) { - short fast = huffman.Lookahead[i]; + byte fast = huffman.Lookahead[i]; fastac[i] = 0; if (fast < 255) {