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ImageSharp
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Fix indexed png reader and use rented buffer

af/merge-core
James Jackson-South 10 years ago
parent
272761f2cf
commit
7d8de33a2f
3 changed files with 50 additions and 36 deletions
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  1. 2
      src/ImageSharp/Common/Extensions/ByteExtensions.cs
  2. 1
      src/ImageSharp/Formats/Png/Filters/SubFilter.cs
  3. 83
      src/ImageSharp/Formats/Png/PngDecoderCore.cs

2
src/ImageSharp/Common/Extensions/ByteExtensions.cs
View File

@ -24,7 +24,7 @@ namespace ImageSharp
public static byte[] ToArrayByBitsLength(this byte[] source, int bits)
{
Guard.NotNull(source, nameof(source));
Guard.MustBeGreaterThan(bits, 0, "bits");
Guard.MustBeGreaterThan(bits, 0, nameof(bits));
byte[] result;

1
src/ImageSharp/Formats/Png/Filters/SubFilter.cs
View File

@ -17,7 +17,6 @@ namespace ImageSharp.Formats
/// </summary>
/// <param name="scanline">The scanline to decode</param>
/// <param name="bytesPerPixel">The bytes per pixel.</param>
/// <returns>The <see cref="T:byte[]"/></returns>
public static void Decode(byte[] scanline, int bytesPerPixel)
{
// Sub(x) + Raw(x-bpp)

83
src/ImageSharp/Formats/Png/PngDecoderCore.cs
View File

@ -132,39 +132,49 @@ namespace ImageSharp.Formats
throw new ImageFormatException("Image does not end with end chunk.");
}
switch (currentChunk.Type)
try
{
case PngChunkTypes.Header:
this.ReadHeaderChunk(currentChunk.Data);
this.ValidateHeader();
break;
case PngChunkTypes.Physical:
this.ReadPhysicalChunk(currentImage, currentChunk.Data);
break;
case PngChunkTypes.Data:
dataStream.Write(currentChunk.Data, 0, currentChunk.Data.Length);
break;
case PngChunkTypes.Palette:
this.palette = currentChunk.Data;
image.Quality = this.palette.Length / 3;
break;
case PngChunkTypes.PaletteAlpha:
this.paletteAlpha = currentChunk.Data;
break;
case PngChunkTypes.Text:
this.ReadTextChunk(currentImage, currentChunk.Data);
break;
case PngChunkTypes.End:
isEndChunkReached = true;
break;
switch (currentChunk.Type)
{
case PngChunkTypes.Header:
this.ReadHeaderChunk(currentChunk.Data);
this.ValidateHeader();
break;
case PngChunkTypes.Physical:
this.ReadPhysicalChunk(currentImage, currentChunk.Data);
break;
case PngChunkTypes.Data:
dataStream.Write(currentChunk.Data, 0, currentChunk.Length);
break;
case PngChunkTypes.Palette:
byte[] pal = new byte[currentChunk.Length];
Buffer.BlockCopy(currentChunk.Data, 0, pal, 0, currentChunk.Length);
this.palette = pal;
image.Quality = pal.Length / 3;
break;
case PngChunkTypes.PaletteAlpha:
byte[] alpha = new byte[currentChunk.Length];
Buffer.BlockCopy(currentChunk.Data, 0, alpha, 0, currentChunk.Length);
this.paletteAlpha = alpha;
break;
case PngChunkTypes.Text:
this.ReadTextChunk(currentImage, currentChunk.Data, currentChunk.Length);
break;
case PngChunkTypes.End:
isEndChunkReached = true;
break;
}
}
finally
{
// Data is rented in ReadChunkData()
ArrayPool<byte>.Shared.Return(currentChunk.Data);
}
}
if (this.header.Width > image.MaxWidth || this.header.Height > image.MaxHeight)
{
throw new ArgumentOutOfRangeException(
$"The input png '{this.header.Width}x{this.header.Height}' is bigger than the "
+ $"max allowed size '{image.MaxWidth}x{image.MaxHeight}'");
throw new ArgumentOutOfRangeException($"The input png '{this.header.Width}x{this.header.Height}' is bigger than the max allowed size '{image.MaxWidth}x{image.MaxHeight}'");
}
image.InitPixels(this.header.Width, this.header.Height);
@ -396,6 +406,10 @@ namespace ImageSharp.Formats
byte b = this.palette[pixelOffset + 2];
color.PackFromBytes(r, g, b, a);
}
else
{
color.PackFromBytes(0, 0, 0, 0);
}
pixels[x, row] = color;
}
@ -460,13 +474,14 @@ namespace ImageSharp.Formats
/// <typeparam name="TPacked">The packed format. <example>uint, long, float.</example></typeparam>
/// <param name="image">The image to decode to.</param>
/// <param name="data">The <see cref="T:byte[]"/> containing data.</param>
private void ReadTextChunk<TColor, TPacked>(Image<TColor, TPacked> image, byte[] data)
/// <param name="length">The maximum length to read.</param>
private void ReadTextChunk<TColor, TPacked>(Image<TColor, TPacked> image, byte[] data, int length)
where TColor : struct, IPackedPixel<TPacked>
where TPacked : struct
{
int zeroIndex = 0;
for (int i = 0; i < data.Length; i++)
for (int i = 0; i < length; i++)
{
if (data[i] == 0)
{
@ -476,7 +491,7 @@ namespace ImageSharp.Formats
}
string name = Encoding.Unicode.GetString(data, 0, zeroIndex);
string value = Encoding.Unicode.GetString(data, zeroIndex + 1, data.Length - zeroIndex - 1);
string value = Encoding.Unicode.GetString(data, zeroIndex + 1, length - zeroIndex - 1);
image.Properties.Add(new ImageProperty(name, value));
}
@ -577,7 +592,7 @@ namespace ImageSharp.Formats
Crc32 crc = new Crc32();
crc.Update(this.chunkTypeBuffer);
crc.Update(chunk.Data);
crc.Update(chunk.Data, 0, chunk.Length);
if (crc.Value != chunk.Crc)
{
@ -591,8 +606,8 @@ namespace ImageSharp.Formats
/// <param name="chunk">The chunk.</param>
private void ReadChunkData(PngChunk chunk)
{
// TODO: It might be possible to rent this but that could also lead to issues assigning the data to various properties
chunk.Data = new byte[chunk.Length];
// We rent the buffer here to return it afterwards in Decode()
chunk.Data = ArrayPool<byte>.Shared.Rent(chunk.Length);
this.currentStream.Read(chunk.Data, 0, chunk.Length);
}
@ -645,4 +660,4 @@ namespace ImageSharp.Formats
chunk.Length = BitConverter.ToInt32(this.chunkLengthBuffer, 0);
}
}
}
}
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