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Reduce duplication in scan decoder

pull/525/head
James Jackson-South 8 years ago
parent
50e057b76b
commit
4943c1ecbf
1 changed files with 44 additions and 188 deletions
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  1. 232
      src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsScanDecoder.cs

232
src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsScanDecoder.cs
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@ -139,28 +139,10 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
}
else
{
if (this.specStart == 0)
{
if (successivePrev == 0)
{
this.DecodeScanDCFirst(dcHuffmanTables, components, componentsLength, mcusPerLine, mcuToRead, ref mcu, stream);
}
else
{
this.DecodeScanDCSuccessive(components, componentsLength, mcusPerLine, mcuToRead, ref mcu, stream);
}
}
else
{
if (successivePrev == 0)
{
this.DecodeScanACFirst(acHuffmanTables, components, componentsLength, mcusPerLine, mcuToRead, ref mcu, stream);
}
else
{
this.DecodeScanACSuccessive(acHuffmanTables, components, componentsLength, mcusPerLine, mcuToRead, ref mcu, stream);
}
}
bool isAc = this.specStart != 0;
bool isFirst = successivePrev == 0;
PdfJsHuffmanTables huffmanTables = isAc ? acHuffmanTables : dcHuffmanTables;
this.DecodeScanProgressive(huffmanTables, isAc, isFirst, components, componentsLength, mcusPerLine, mcuToRead, ref mcu, stream);
}
// Find marker
@ -275,8 +257,10 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void DecodeScanDCFirst(
PdfJsHuffmanTables dcHuffmanTables,
private void DecodeScanProgressive(
PdfJsHuffmanTables huffmanTables,
bool isAC,
bool isFirst,
PdfJsFrameComponent[] components,
int componentsLength,
int mcusPerLine,
@ -288,7 +272,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
{
PdfJsFrameComponent component = components[this.compIndex];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
ref PdfJsHuffmanTable dcHuffmanTable = ref dcHuffmanTables[component.DCHuffmanTableId];
ref PdfJsHuffmanTable huffmanTable = ref huffmanTables[isAC ? component.ACHuffmanTableId : component.DCHuffmanTableId];
for (int n = 0; n < mcuToRead; n++)
{
@ -297,181 +281,32 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
continue;
}
this.DecodeBlockDCFirst(ref dcHuffmanTable, component, ref blockDataRef, mcu, stream);
mcu++;
}
}
else
{
for (int n = 0; n < mcuToRead; n++)
{
for (int i = 0; i < componentsLength; i++)
if (isAC)
{
PdfJsFrameComponent component = components[i];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
ref PdfJsHuffmanTable dcHuffmanTable = ref dcHuffmanTables[component.DCHuffmanTableId];
int h = component.HorizontalSamplingFactor;
int v = component.VerticalSamplingFactor;
for (int j = 0; j < v; j++)
if (isFirst)
{
for (int k = 0; k < h; k++)
{
if (this.endOfStreamReached || this.unexpectedMarkerReached)
{
continue;
}
this.DecodeMcuDCFirst(ref dcHuffmanTable, component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
this.DecodeBlockACFirst(ref huffmanTable, component, ref blockDataRef, mcu, stream);
}
}
mcu++;
}
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void DecodeScanDCSuccessive(
PdfJsFrameComponent[] components,
int componentsLength,
int mcusPerLine,
int mcuToRead,
ref int mcu,
Stream stream)
{
if (componentsLength == 1)
{
PdfJsFrameComponent component = components[this.compIndex];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
for (int n = 0; n < mcuToRead; n++)
{
if (this.endOfStreamReached || this.unexpectedMarkerReached)
{
continue;
}
this.DecodeBlockDCSuccessive(component, ref blockDataRef, mcu, stream);
mcu++;
}
}
else
{
for (int n = 0; n < mcuToRead; n++)
{
for (int i = 0; i < componentsLength; i++)
{
PdfJsFrameComponent component = components[i];
int h = component.HorizontalSamplingFactor;
int v = component.VerticalSamplingFactor;
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
for (int j = 0; j < v; j++)
else
{
for (int k = 0; k < h; k++)
{
if (this.endOfStreamReached || this.unexpectedMarkerReached)
{
continue;
}
this.DecodeMcuDCSuccessive(component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
this.DecodeBlockACSuccessive(ref huffmanTable, component, ref blockDataRef, mcu, stream);
}
}
mcu++;
}
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void DecodeScanACFirst(
PdfJsHuffmanTables acHuffmanTables,
PdfJsFrameComponent[] components,
int componentsLength,
int mcusPerLine,
int mcuToRead,
ref int mcu,
Stream stream)
{
if (componentsLength == 1)
{
PdfJsFrameComponent component = components[this.compIndex];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
ref PdfJsHuffmanTable acHuffmanTable = ref acHuffmanTables[component.ACHuffmanTableId];
for (int n = 0; n < mcuToRead; n++)
{
if (this.endOfStreamReached || this.unexpectedMarkerReached)
{
continue;
}
this.DecodeBlockACFirst(ref acHuffmanTable, component, ref blockDataRef, mcu, stream);
mcu++;
}
}
else
{
for (int n = 0; n < mcuToRead; n++)
{
for (int i = 0; i < componentsLength; i++)
else
{
PdfJsFrameComponent component = components[i];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
ref PdfJsHuffmanTable acHuffmanTable = ref acHuffmanTables[component.ACHuffmanTableId];
int h = component.HorizontalSamplingFactor;
int v = component.VerticalSamplingFactor;
for (int j = 0; j < v; j++)
if (isFirst)
{
for (int k = 0; k < h; k++)
{
if (this.endOfStreamReached || this.unexpectedMarkerReached)
{
continue;
}
this.DecodeMcuACFirst(ref acHuffmanTable, component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
this.DecodeBlockDCFirst(ref huffmanTable, component, ref blockDataRef, mcu, stream);
}
else
{
this.DecodeBlockDCSuccessive(component, ref blockDataRef, mcu, stream);
}
}
mcu++;
}
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void DecodeScanACSuccessive(
PdfJsHuffmanTables acHuffmanTables,
PdfJsFrameComponent[] components,
int componentsLength,
int mcusPerLine,
int mcuToRead,
ref int mcu,
Stream stream)
{
if (componentsLength == 1)
{
PdfJsFrameComponent component = components[this.compIndex];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
ref PdfJsHuffmanTable acHuffmanTable = ref acHuffmanTables[component.ACHuffmanTableId];
for (int n = 0; n < mcuToRead; n++)
{
if (this.endOfStreamReached || this.unexpectedMarkerReached)
{
continue;
}
this.DecodeBlockACSuccessive(ref acHuffmanTable, component, ref blockDataRef, mcu, stream);
mcu++;
}
}
else
{
for (int n = 0; n < mcuToRead; n++)
@ -480,7 +315,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
{
PdfJsFrameComponent component = components[i];
ref short blockDataRef = ref MemoryMarshal.GetReference(MemoryMarshal.Cast<Block8x8, short>(component.SpectralBlocks.Span));
ref PdfJsHuffmanTable acHuffmanTable = ref acHuffmanTables[component.ACHuffmanTableId];
ref PdfJsHuffmanTable huffmanTable = ref huffmanTables[isAC ? component.ACHuffmanTableId : component.DCHuffmanTableId];
int h = component.HorizontalSamplingFactor;
int v = component.VerticalSamplingFactor;
@ -493,7 +328,28 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
continue;
}
this.DecodeMcuACSuccessive(ref acHuffmanTable, component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
if (isAC)
{
if (isFirst)
{
this.DecodeMcuACFirst(ref huffmanTable, component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
else
{
this.DecodeMcuACSuccessive(ref huffmanTable, component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
}
else
{
if (isFirst)
{
this.DecodeMcuDCFirst(ref huffmanTable, component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
else
{
this.DecodeMcuDCSuccessive(component, ref blockDataRef, mcusPerLine, mcu, j, k, stream);
}
}
}
}
}

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