tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

Express readonly intent in Span parameters

af/merge-core
Jason Nelson 8 years ago
parent
997ca49679
commit
915b707fa4
2 changed files with 22 additions and 28 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Unified View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 33
      src/ImageSharp/Formats/Png/PngDecoderCore.cs
  2. 17
      src/ImageSharp/Formats/Png/PngEncoderCore.cs

33
src/ImageSharp/Formats/Png/PngDecoderCore.cs
View File

@ -349,13 +349,12 @@ namespace SixLabors.ImageSharp.Formats.Png
/// <summary> /// <summary>
/// Converts a byte array to a new array where each value in the original array is represented by the specified number of bits. /// Converts a byte array to a new array where each value in the original array is represented by the specified number of bits.
/// </summary> /// </summary>
/// <param name="source">The bytes to convert from. Cannot be null.</param> /// <param name="source">The bytes to convert from. Cannot be empty.</param>
/// <param name="bytesPerScanline">The number of bytes per scanline</param> /// <param name="bytesPerScanline">The number of bytes per scanline</param>
/// <param name="bits">The number of bits per value.</param> /// <param name="bits">The number of bits per value.</param>
/// <returns>The resulting <see cref="Span{Byte}"/> array. Is never null.</returns> /// <returns>The resulting <see cref="ReadOnlySpan{Byte}"/> array.</returns>
/// <exception cref="System.ArgumentNullException"><paramref name="source"/> is null.</exception>
/// <exception cref="System.ArgumentException"><paramref name="bits"/> is less than or equals than zero.</exception> /// <exception cref="System.ArgumentException"><paramref name="bits"/> is less than or equals than zero.</exception>
private static Span<byte> ToArrayByBitsLength(Span<byte> source, int bytesPerScanline, int bits) private static ReadOnlySpan<byte> ToArrayByBitsLength(ReadOnlySpan<byte> source, int bytesPerScanline, int bits)
{ {
Guard.MustBeGreaterThan(source.Length, 0, nameof(source)); Guard.MustBeGreaterThan(source.Length, 0, nameof(source));
Guard.MustBeGreaterThan(bits, 0, nameof(bits)); Guard.MustBeGreaterThan(bits, 0, nameof(bits));
@ -669,7 +668,7 @@ namespace SixLabors.ImageSharp.Formats.Png
} }
Span<TPixel> rowSpan = image.GetPixelRowSpan(this.currentRow); Span<TPixel> rowSpan = image.GetPixelRowSpan(this.currentRow);
this.ProcessInterlacedDefilteredScanline(this.scanline.Array, rowSpan, Adam7FirstColumn[this.pass], Adam7ColumnIncrement[this.pass]); this.ProcessInterlacedDefilteredScanline(this.scanline.Span, rowSpan, Adam7FirstColumn[this.pass], Adam7ColumnIncrement[this.pass]);
this.SwapBuffers(); this.SwapBuffers();
@ -697,20 +696,20 @@ namespace SixLabors.ImageSharp.Formats.Png
/// <typeparam name="TPixel">The pixel format.</typeparam> /// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="defilteredScanline">The de-filtered scanline</param> /// <param name="defilteredScanline">The de-filtered scanline</param>
/// <param name="pixels">The image</param> /// <param name="pixels">The image</param>
private void ProcessDefilteredScanline<TPixel>(Span<byte> defilteredScanline, ImageFrame<TPixel> pixels) private void ProcessDefilteredScanline<TPixel>(ReadOnlySpan<byte> defilteredScanline, ImageFrame<TPixel> pixels)
where TPixel : struct, IPixel<TPixel> where TPixel : struct, IPixel<TPixel>
{ {
var color = default(TPixel); var color = default(TPixel);
Span<TPixel> rowSpan = pixels.GetPixelRowSpan(this.currentRow); Span<TPixel> rowSpan = pixels.GetPixelRowSpan(this.currentRow);
// Trim the first marker byte from the buffer // Trim the first marker byte from the buffer
Span<byte> scanlineBuffer = defilteredScanline.Slice(1, defilteredScanline.Length - 1); ReadOnlySpan<byte> scanlineBuffer = defilteredScanline.Slice(1, defilteredScanline.Length - 1);
switch (this.pngColorType) switch (this.pngColorType)
{ {
case PngColorType.Grayscale: case PngColorType.Grayscale:
int factor = 255 / ((int)Math.Pow(2, this.header.BitDepth) - 1); int factor = 255 / ((int)Math.Pow(2, this.header.BitDepth) - 1);
Span<byte> newScanline1 = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth); ReadOnlySpan<byte> newScanline1 = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth);
for (int x = 0; x < this.header.Width; x++) for (int x = 0; x < this.header.Width; x++)
{ {
@ -794,10 +793,10 @@ namespace SixLabors.ImageSharp.Formats.Png
} }
else else
{ {
Span<Rgb24> rgb24Span = scanlineBuffer.NonPortableCast<byte, Rgb24>(); ReadOnlySpan<Rgb24> rgb24Span = scanlineBuffer.NonPortableCast<byte, Rgb24>();
for (int x = 0; x < this.header.Width; x++) for (int x = 0; x < this.header.Width; x++)
{ {
ref Rgb24 rgb24 = ref rgb24Span[x]; ref readonly Rgb24 rgb24 = ref rgb24Span[x];
var rgba32 = default(Rgba32); var rgba32 = default(Rgba32);
rgba32.Rgb = rgb24; rgba32.Rgb = rgb24;
rgba32.A = (byte)(rgb24.Equals(this.rgb24Trans) ? 0 : 255); rgba32.A = (byte)(rgb24.Equals(this.rgb24Trans) ? 0 : 255);
@ -838,7 +837,7 @@ namespace SixLabors.ImageSharp.Formats.Png
/// <param name="target">The target buffer</param> /// <param name="target">The target buffer</param>
/// <param name="length">The target length</param> /// <param name="length">The target length</param>
[MethodImpl(MethodImplOptions.AggressiveInlining)] [MethodImpl(MethodImplOptions.AggressiveInlining)]
private void From16BitTo8Bit(Span<byte> source, Span<byte> target, int length) private void From16BitTo8Bit(ReadOnlySpan<byte> source, Span<byte> target, int length)
{ {
for (int i = 0, j = 0; i < length; i++, j += 2) for (int i = 0, j = 0; i < length; i++, j += 2)
{ {
@ -879,10 +878,10 @@ namespace SixLabors.ImageSharp.Formats.Png
/// <typeparam name="TPixel">The type of pixel we are expanding to</typeparam> /// <typeparam name="TPixel">The type of pixel we are expanding to</typeparam>
/// <param name="defilteredScanline">The scanline</param> /// <param name="defilteredScanline">The scanline</param>
/// <param name="row">Thecurrent output image row</param> /// <param name="row">Thecurrent output image row</param>
private void ProcessScanlineFromPalette<TPixel>(Span<byte> defilteredScanline, Span<TPixel> row) private void ProcessScanlineFromPalette<TPixel>(ReadOnlySpan<byte> defilteredScanline, Span<TPixel> row)
where TPixel : struct, IPixel<TPixel> where TPixel : struct, IPixel<TPixel>
{ {
Span<byte> newScanline = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth); ReadOnlySpan<byte> newScanline = ToArrayByBitsLength(defilteredScanline, this.bytesPerScanline, this.header.BitDepth);
byte[] pal = this.palette; byte[] pal = this.palette;
var color = default(TPixel); var color = default(TPixel);
@ -929,19 +928,19 @@ namespace SixLabors.ImageSharp.Formats.Png
/// <param name="rowSpan">The current image row.</param> /// <param name="rowSpan">The current image row.</param>
/// <param name="pixelOffset">The column start index. Always 0 for none interlaced images.</param> /// <param name="pixelOffset">The column start index. Always 0 for none interlaced images.</param>
/// <param name="increment">The column increment. Always 1 for none interlaced images.</param> /// <param name="increment">The column increment. Always 1 for none interlaced images.</param>
private void ProcessInterlacedDefilteredScanline<TPixel>(byte[] defilteredScanline, Span<TPixel> rowSpan, int pixelOffset = 0, int increment = 1) private void ProcessInterlacedDefilteredScanline<TPixel>(ReadOnlySpan<byte> defilteredScanline, Span<TPixel> rowSpan, int pixelOffset = 0, int increment = 1)
where TPixel : struct, IPixel<TPixel> where TPixel : struct, IPixel<TPixel>
{ {
var color = default(TPixel); var color = default(TPixel);
// Trim the first marker byte from the buffer // Trim the first marker byte from the buffer
var scanlineBuffer = new Span<byte>(defilteredScanline, 1, defilteredScanline.Length - 1); ReadOnlySpan<byte> scanlineBuffer = defilteredScanline.Slice(1, defilteredScanline.Length - 1);
switch (this.pngColorType) switch (this.pngColorType)
{ {
case PngColorType.Grayscale: case PngColorType.Grayscale:
int factor = 255 / ((int)Math.Pow(2, this.header.BitDepth) - 1); int factor = 255 / ((int)Math.Pow(2, this.header.BitDepth) - 1);
Span<byte> newScanline1 = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth); ReadOnlySpan<byte> newScanline1 = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth);
for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o++) for (int x = pixelOffset, o = 0; x < this.header.Width; x += increment, o++)
{ {
@ -974,7 +973,7 @@ namespace SixLabors.ImageSharp.Formats.Png
case PngColorType.Palette: case PngColorType.Palette:
Span<byte> newScanline = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth); ReadOnlySpan<byte> newScanline = ToArrayByBitsLength(scanlineBuffer, this.bytesPerScanline, this.header.BitDepth);
var rgba = default(Rgba32); var rgba = default(Rgba32);
if (this.paletteAlpha != null && this.paletteAlpha.Length > 0) if (this.paletteAlpha != null && this.paletteAlpha.Length > 0)

17
src/ImageSharp/Formats/Png/PngEncoderCore.cs
View File

@ -255,7 +255,7 @@ namespace SixLabors.ImageSharp.Formats.Png
/// </summary> /// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam> /// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="rowSpan">The image row span.</param> /// <param name="rowSpan">The image row span.</param>
private void CollectGrayscaleBytes<TPixel>(Span<TPixel> rowSpan) private void CollectGrayscaleBytes<TPixel>(ReadOnlySpan<TPixel> rowSpan)
where TPixel : struct, IPixel<TPixel> where TPixel : struct, IPixel<TPixel>
{ {
byte[] rawScanlineArray = this.rawScanline.Array; byte[] rawScanlineArray = this.rawScanline.Array;
@ -290,7 +290,7 @@ namespace SixLabors.ImageSharp.Formats.Png
/// </summary> /// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam> /// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="rowSpan">The row span.</param> /// <param name="rowSpan">The row span.</param>
private void CollecTPixelBytes<TPixel>(Span<TPixel> rowSpan) private void CollecTPixelBytes<TPixel>(ReadOnlySpan<TPixel> rowSpan)
where TPixel : struct, IPixel<TPixel> where TPixel : struct, IPixel<TPixel>
{ {
if (this.bytesPerPixel == 4) if (this.bytesPerPixel == 4)
@ -311,7 +311,7 @@ namespace SixLabors.ImageSharp.Formats.Png
/// <param name="rowSpan">The row span.</param> /// <param name="rowSpan">The row span.</param>
/// <param name="row">The row.</param> /// <param name="row">The row.</param>
/// <returns>The <see cref="T:byte[]"/></returns> /// <returns>The <see cref="T:byte[]"/></returns>
private IManagedByteBuffer EncodePixelRow<TPixel>(Span<TPixel> rowSpan, int row) private IManagedByteBuffer EncodePixelRow<TPixel>(ReadOnlySpan<TPixel> rowSpan, int row)
where TPixel : struct, IPixel<TPixel> where TPixel : struct, IPixel<TPixel>
{ {
switch (this.pngColorType) switch (this.pngColorType)
@ -554,15 +554,14 @@ namespace SixLabors.ImageSharp.Formats.Png
byte[] buffer; byte[] buffer;
int bufferLength; int bufferLength;
MemoryStream memoryStream = null;
try using (var memoryStream = new MemoryStream())
{ {
memoryStream = new MemoryStream();
using (var deflateStream = new ZlibDeflateStream(memoryStream, this.compressionLevel)) using (var deflateStream = new ZlibDeflateStream(memoryStream, this.compressionLevel))
{ {
for (int y = 0; y < this.height; y++) for (int y = 0; y < this.height; y++)
{ {
IManagedByteBuffer r = this.EncodePixelRow(pixels.GetPixelRowSpan(y), y); IManagedByteBuffer r = this.EncodePixelRow(pixels.GetPixelRowSpan(y).AsReadOnlySpan(), y);
deflateStream.Write(r.Array, 0, resultLength); deflateStream.Write(r.Array, 0, resultLength);
IManagedByteBuffer temp = this.rawScanline; IManagedByteBuffer temp = this.rawScanline;
@ -574,10 +573,6 @@ namespace SixLabors.ImageSharp.Formats.Png
buffer = memoryStream.ToArray(); buffer = memoryStream.ToArray();
bufferLength = buffer.Length; bufferLength = buffer.Length;
} }
finally
{
memoryStream?.Dispose();
}
// Store the chunks in repeated 64k blocks. // Store the chunks in repeated 64k blocks.
// This reduces the memory load for decoding the image for many decoders. // This reduces the memory load for decoding the image for many decoders.

Write Preview
Loading…
Cancel
Save