@ -82,38 +82,47 @@ namespace SixLabors.ImageSharp.Formats.Webp
public Image < TPixel > Decode < TPixel > ( BufferedReadStream stream , CancellationToken cancellationToken )
where TPixel : unmanaged , IPixel < TPixel >
{
this . Metadata = new ImageMetadata ( ) ;
this . currentStream = stream ;
Image < TPixel > image = null ;
try
{
this . Metadata = new ImageMetadata ( ) ;
this . currentStream = stream ;
uint fileSize = this . ReadImageHeader ( ) ;
uint fileSize = this . ReadImageHeader ( ) ;
using ( this . webImageInfo = this . ReadVp8Info ( ) )
{
if ( this . webImageInfo . Features is { Animation : true } )
using ( this . webImageInfo = this . ReadVp8Info ( ) )
{
WebpThrowHelper . ThrowNotSupportedException ( "Animations are not supported" ) ;
}
if ( this . webImageInfo . Features is { Animation : true } )
{
WebpThrowHelper . ThrowNotSupportedException ( "Animations are not supported" ) ;
}
var image = new Image < TPixel > ( this . Configuration , ( int ) this . webImageInfo . Width , ( int ) this . webImageInfo . Height , this . Metadata ) ;
Buffer2D < TPixel > pixels = image . GetRootFramePixelBuffer ( ) ;
if ( this . webImageInfo . IsLossless )
{
var losslessDecoder = new WebpLosslessDecoder ( this . webImageInfo . Vp8LBitReader , this . memoryAllocator , this . Configuration ) ;
losslessDecoder . Decode ( pixels , image . Width , image . Height ) ;
}
else
{
var lossyDecoder = new WebpLossyDecoder ( this . webImageInfo . Vp8BitReader , this . memoryAllocator , this . Configuration ) ;
lossyDecoder . Decode ( pixels , image . Width , image . Height , this . webImageInfo ) ;
}
image = new Image < TPixel > ( this . Configuration , ( int ) this . webImageInfo . Width , ( int ) this . webImageInfo . Height , this . Metadata ) ;
Buffer2D < TPixel > pixels = image . GetRootFramePixelBuffer ( ) ;
if ( this . webImageInfo . IsLossless )
{
var losslessDecoder = new WebpLosslessDecoder ( this . webImageInfo . Vp8LBitReader , this . memoryAllocator , this . Configuration ) ;
losslessDecoder . Decode ( pixels , image . Width , image . Height ) ;
}
else
{
var lossyDecoder = new WebpLossyDecoder ( this . webImageInfo . Vp8BitReader , this . memoryAllocator , this . Configuration ) ;
lossyDecoder . Decode ( pixels , image . Width , image . Height , this . webImageInfo ) ;
}
// There can be optional chunks after the image data, like EXIF and XMP.
if ( this . webImageInfo . Features ! = null )
{
this . ParseOptionalChunks ( this . webImageInfo . Features ) ;
}
// There can be optional chunks after the image data, like EXIF and XMP.
if ( this . webImageInfo . Features ! = null )
{
this . ParseOptionalChunks ( this . webImageInfo . Features ) ;
}
return image ;
return image ;
}
}
catch
{
image ? . Dispose ( ) ;
throw ;
}
}
@ -190,7 +199,11 @@ namespace SixLabors.ImageSharp.Formats.Webp
uint fileSize = this . ReadChunkSize ( ) ;
// The first byte contains information about the image features used.
byte imageFeatures = ( byte ) this . currentStream . ReadByte ( ) ;
int imageFeatures = this . currentStream . ReadByte ( ) ;
if ( imageFeatures = = - 1 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "VP8X header doe not contain enough data" ) ;
}
// The first two bit of it are reserved and should be 0.
if ( imageFeatures > > 6 ! = 0 )
@ -214,19 +227,34 @@ namespace SixLabors.ImageSharp.Formats.Webp
features . Animation = ( imageFeatures & ( 1 < < 1 ) ) ! = 0 ;
// 3 reserved bytes should follow which are supposed to be zero.
this . currentStream . Read ( this . buffer , 0 , 3 ) ;
int bytesRead = this . currentStream . Read ( this . buffer , 0 , 3 ) ;
if ( bytesRead ! = 3 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "VP8X header does not contain enough data" ) ;
}
if ( this . buffer [ 0 ] ! = 0 | | this . buffer [ 1 ] ! = 0 | | this . buffer [ 2 ] ! = 0 )
{
WebpThrowHelper . ThrowImageFormatException ( "reserved bytes should be zero" ) ;
}
// 3 bytes for the width.
this . currentStream . Read ( this . buffer , 0 , 3 ) ;
bytesRead = this . currentStream . Read ( this . buffer , 0 , 3 ) ;
if ( bytesRead ! = 3 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "VP8 header does not contain enough data to read the width" ) ;
}
this . buffer [ 3 ] = 0 ;
uint width = ( uint ) BinaryPrimitives . ReadInt32LittleEndian ( this . buffer ) + 1 ;
// 3 bytes for the height.
this . currentStream . Read ( this . buffer , 0 , 3 ) ;
bytesRead = this . currentStream . Read ( this . buffer , 0 , 3 ) ;
if ( bytesRead ! = 3 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "VP8 header does not contain enough data to read the height" ) ;
}
this . buffer [ 3 ] = 0 ;
uint height = ( uint ) BinaryPrimitives . ReadInt32LittleEndian ( this . buffer ) + 1 ;
@ -272,7 +300,12 @@ namespace SixLabors.ImageSharp.Formats.Webp
this . webpMetadata . FileFormat = WebpFileFormatType . Lossy ;
// VP8 data size (not including this 4 bytes).
this . currentStream . Read ( this . buffer , 0 , 4 ) ;
int bytesRead = this . currentStream . Read ( this . buffer , 0 , 4 ) ;
if ( bytesRead ! = 4 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "Not enough data to read the VP8 data size" ) ;
}
uint dataSize = BinaryPrimitives . ReadUInt32LittleEndian ( this . buffer ) ;
// remaining counts the available image data payload.
@ -284,7 +317,12 @@ namespace SixLabors.ImageSharp.Formats.Webp
// - A 3-bit version number.
// - A 1-bit show_frame flag.
// - A 19-bit field containing the size of the first data partition in bytes.
this . currentStream . Read ( this . buffer , 0 , 3 ) ;
bytesRead = this . currentStream . Read ( this . buffer , 0 , 3 ) ;
if ( bytesRead ! = 3 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "Not enough data to read the VP8 frame tag" ) ;
}
uint frameTag = ( uint ) ( this . buffer [ 0 ] | ( this . buffer [ 1 ] < < 8 ) | ( this . buffer [ 2 ] < < 1 6 ) ) ;
remaining - = 3 ;
bool isNoKeyFrame = ( frameTag & 0x1 ) = = 1 ;
@ -312,13 +350,23 @@ namespace SixLabors.ImageSharp.Formats.Webp
}
// Check for VP8 magic bytes.
this . currentStream . Read ( this . buffer , 0 , 3 ) ;
bytesRead = this . currentStream . Read ( this . buffer , 0 , 3 ) ;
if ( bytesRead ! = 3 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "Not enough data to read the VP8 magic bytes" ) ;
}
if ( ! this . buffer . AsSpan ( 0 , 3 ) . SequenceEqual ( WebpConstants . Vp8HeaderMagicBytes ) )
{
WebpThrowHelper . ThrowImageFormatException ( "VP8 magic bytes not found" ) ;
}
this . currentStream . Read ( this . buffer , 0 , 4 ) ;
bytesRead = this . currentStream . Read ( this . buffer , 0 , 4 ) ;
if ( bytesRead ! = 4 )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "VP8 header does not contain enough data to read the image width and height" ) ;
}
uint tmp = ( uint ) BinaryPrimitives . ReadInt16LittleEndian ( this . buffer ) ;
uint width = tmp & 0x3fff ;
sbyte xScale = ( sbyte ) ( tmp > > 6 ) ;
@ -429,54 +477,15 @@ namespace SixLabors.ImageSharp.Formats.Webp
switch ( chunkType )
{
case WebpChunkType . Iccp :
uint iccpChunkSize = this . ReadChunkSize ( ) ;
if ( this . IgnoreMetadata )
{
this . currentStream . Skip ( ( int ) iccpChunkSize ) ;
}
else
{
byte [ ] iccpData = new byte [ iccpChunkSize ] ;
this . currentStream . Read ( iccpData , 0 , ( int ) iccpChunkSize ) ;
var profile = new IccProfile ( iccpData ) ;
if ( profile . CheckIsValid ( ) )
{
this . Metadata . IccProfile = profile ;
}
}
this . ReadIccProfile ( ) ;
break ;
case WebpChunkType . Exif :
uint exifChunkSize = this . ReadChunkSize ( ) ;
if ( this . IgnoreMetadata )
{
this . currentStream . Skip ( ( int ) exifChunkSize ) ;
}
else
{
byte [ ] exifData = new byte [ exifChunkSize ] ;
this . currentStream . Read ( exifData , 0 , ( int ) exifChunkSize ) ;
var profile = new ExifProfile ( exifData ) ;
this . Metadata . ExifProfile = profile ;
}
this . ReadExifProfile ( ) ;
break ;
case WebpChunkType . Xmp :
uint xmpChunkSize = this . ReadChunkSize ( ) ;
if ( this . IgnoreMetadata )
{
this . currentStream . Skip ( ( int ) xmpChunkSize ) ;
}
else
{
byte [ ] xmpData = new byte [ xmpChunkSize ] ;
this . currentStream . Read ( xmpData , 0 , ( int ) xmpChunkSize ) ;
var profile = new XmpProfile ( xmpData ) ;
this . Metadata . XmpProfile = profile ;
}
this . ReadXmpProfile ( ) ;
break ;
case WebpChunkType . Animation :
@ -488,7 +497,12 @@ namespace SixLabors.ImageSharp.Formats.Webp
features . AlphaChunkHeader = ( byte ) this . currentStream . ReadByte ( ) ;
int alphaDataSize = ( int ) ( alphaChunkSize - 1 ) ;
features . AlphaData = this . memoryAllocator . Allocate < byte > ( alphaDataSize ) ;
this . currentStream . Read ( features . AlphaData . Memory . Span , 0 , alphaDataSize ) ;
int bytesRead = this . currentStream . Read ( features . AlphaData . Memory . Span , 0 , alphaDataSize ) ;
if ( bytesRead ! = alphaDataSize )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "Not enough data to read the alpha chunk" ) ;
}
break ;
default :
WebpThrowHelper . ThrowImageFormatException ( "Unexpected chunk followed VP8X header" ) ;
@ -514,22 +528,100 @@ namespace SixLabors.ImageSharp.Formats.Webp
{
// Read chunk header.
WebpChunkType chunkType = this . ReadChunkType ( ) ;
uint chunkLength = this . ReadChunkSize ( ) ;
if ( chunkType = = WebpChunkType . Exif & & this . Metadata . ExifProfile = = null )
{
byte [ ] exifData = new byte [ chunkLength ] ;
this . currentStream . Read ( exifData , 0 , ( int ) chunkLength ) ;
this . Metadata . ExifProfile = new ExifProfile ( exifData ) ;
this . ReadExifProfile ( ) ;
}
else if ( chunkType = = WebpChunkType . Xmp & & this . Metadata . XmpProfile = = null )
{
this . ReadXmpProfile ( ) ;
}
else
{
// Skip XMP chunk data or any duplicate EXIF chunk.
// Skip duplicate XMP or EXIF chunk.
uint chunkLength = this . ReadChunkSize ( ) ;
this . currentStream . Skip ( ( int ) chunkLength ) ;
}
}
}
/// <summary>
/// Reads the EXIF profile from the stream.
/// </summary>
private void ReadExifProfile ( )
{
uint exifChunkSize = this . ReadChunkSize ( ) ;
if ( this . IgnoreMetadata )
{
this . currentStream . Skip ( ( int ) exifChunkSize ) ;
}
else
{
byte [ ] exifData = new byte [ exifChunkSize ] ;
int bytesRead = this . currentStream . Read ( exifData , 0 , ( int ) exifChunkSize ) ;
if ( bytesRead ! = exifChunkSize )
{
// Ignore invalid chunk.
return ;
}
var profile = new ExifProfile ( exifData ) ;
this . Metadata . ExifProfile = profile ;
}
}
/// <summary>
/// Reads the XMP profile the stream.
/// </summary>
private void ReadXmpProfile ( )
{
uint xmpChunkSize = this . ReadChunkSize ( ) ;
if ( this . IgnoreMetadata )
{
this . currentStream . Skip ( ( int ) xmpChunkSize ) ;
}
else
{
byte [ ] xmpData = new byte [ xmpChunkSize ] ;
int bytesRead = this . currentStream . Read ( xmpData , 0 , ( int ) xmpChunkSize ) ;
if ( bytesRead ! = xmpChunkSize )
{
// Ignore invalid chunk.
return ;
}
var profile = new XmpProfile ( xmpData ) ;
this . Metadata . XmpProfile = profile ;
}
}
/// <summary>
/// Reads the ICCP chunk from the stream.
/// </summary>
private void ReadIccProfile ( )
{
uint iccpChunkSize = this . ReadChunkSize ( ) ;
if ( this . IgnoreMetadata )
{
this . currentStream . Skip ( ( int ) iccpChunkSize ) ;
}
else
{
byte [ ] iccpData = new byte [ iccpChunkSize ] ;
int bytesRead = this . currentStream . Read ( iccpData , 0 , ( int ) iccpChunkSize ) ;
if ( bytesRead ! = iccpChunkSize )
{
WebpThrowHelper . ThrowInvalidImageContentException ( "Not enough data to read the iccp chunk" ) ;
}
var profile = new IccProfile ( iccpData ) ;
if ( profile . CheckIsValid ( ) )
{
this . Metadata . IccProfile = profile ;
}
}
}
/// <summary>
/// Identifies the chunk type from the chunk.
/// </summary>
James Jackson-South
4 years ago
GitHub
