From 291f5a5199b95ff1dba2925d3256debe06208a99 Mon Sep 17 00:00:00 2001 From: Jason Nelson Date: Wed, 28 Mar 2018 10:05:05 -0700 Subject: [PATCH] First pass on ExifWriter spanification --- .../MetaData/Profiles/Exif/ExifReader.cs | 6 +- .../MetaData/Profiles/Exif/ExifValue.cs | 2 +- .../MetaData/Profiles/Exif/ExifWriter.cs | 115 ++++++++++++------ 3 files changed, 82 insertions(+), 41 deletions(-) diff --git a/src/ImageSharp/MetaData/Profiles/Exif/ExifReader.cs b/src/ImageSharp/MetaData/Profiles/Exif/ExifReader.cs index 407030196..05d6819b5 100644 --- a/src/ImageSharp/MetaData/Profiles/Exif/ExifReader.cs +++ b/src/ImageSharp/MetaData/Profiles/Exif/ExifReader.cs @@ -19,8 +19,6 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif /// internal sealed class ExifReader { - private delegate TDataType ConverterMethod(ReadOnlySpan data); - private readonly List invalidTags = new List(); private readonly byte[] exifData; private int position; @@ -36,6 +34,8 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif this.exifData = exifData; } + private delegate TDataType ConverterMethod(ReadOnlySpan data); + /// /// Gets the invalid tags. /// @@ -412,7 +412,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif } span = new ReadOnlySpan(this.exifData, this.position, length); - + this.position += length; return true; diff --git a/src/ImageSharp/MetaData/Profiles/Exif/ExifValue.cs b/src/ImageSharp/MetaData/Profiles/Exif/ExifValue.cs index 7b51c6d21..6367cbb83 100644 --- a/src/ImageSharp/MetaData/Profiles/Exif/ExifValue.cs +++ b/src/ImageSharp/MetaData/Profiles/Exif/ExifValue.cs @@ -696,7 +696,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif { return description; } - + switch (this.DataType) { case ExifDataType.Ascii: diff --git a/src/ImageSharp/MetaData/Profiles/Exif/ExifWriter.cs b/src/ImageSharp/MetaData/Profiles/Exif/ExifWriter.cs index 8d8f019c9..f7363ef31 100644 --- a/src/ImageSharp/MetaData/Profiles/Exif/ExifWriter.cs +++ b/src/ImageSharp/MetaData/Profiles/Exif/ExifWriter.cs @@ -2,8 +2,8 @@ // Licensed under the Apache License, Version 2.0. using System; +using System.Buffers.Binary; using System.Collections.Generic; -using System.Collections.ObjectModel; using System.Text; using SixLabors.ImageSharp.Primitives; @@ -24,10 +24,10 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif /// private ExifParts allowedParts; private IList values; - private IList dataOffsets; - private IList ifdIndexes; - private IList exifIndexes; - private IList gpsIndexes; + private List dataOffsets; + private List ifdIndexes; + private List exifIndexes; + private List gpsIndexes; /// /// Initializes a new instance of the class. @@ -89,6 +89,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif length += 10 + 4 + 2; byte[] result = new byte[length]; + result[0] = (byte)'E'; result[1] = (byte)'x'; result[2] = (byte)'i'; @@ -114,9 +115,9 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif this.values[gpsIndex] = this.values[gpsIndex].WithValue(ifdOffset + ifdLength + exifLength); } - i = Write(BitConverter.GetBytes(ifdOffset), result, i); + i = WriteUInt32(ifdOffset, result, i); i = this.WriteHeaders(this.ifdIndexes, result, i); - i = Write(BitConverter.GetBytes(thumbnailOffset), result, i); + i = WriteUInt32(thumbnailOffset, result, i); i = this.WriteData(this.ifdIndexes, result, i); if (exifLength > 0) @@ -131,18 +132,60 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif i = this.WriteData(this.gpsIndexes, result, i); } - Write(BitConverter.GetBytes((ushort)0), result, i); + WriteUInt16((ushort)0, result, i); return result; } - private static int Write(byte[] source, byte[] destination, int offset) + private static unsafe int WriteSingle(float value, Span destination, int offset) + { + BinaryPrimitives.WriteInt32LittleEndian(destination.Slice(offset, 4), *((int*)&value)); + + return offset + 4; + } + + private static unsafe int WriteDouble(double value, Span destination, int offset) { - Buffer.BlockCopy(source, 0, destination, offset, source.Length); + BinaryPrimitives.WriteInt64LittleEndian(destination.Slice(offset, 8), *((long*)&value)); + + return offset + 8; + } + + private static int Write(ReadOnlySpan source, Span destination, int offset) + { + source.CopyTo(destination.Slice(offset, source.Length)); return offset + source.Length; } + private static int WriteInt16(short value, Span destination, int offset) + { + BinaryPrimitives.WriteInt16LittleEndian(destination.Slice(offset, 2), value); + + return offset + 2; + } + + private static int WriteUInt16(ushort value, Span destination, int offset) + { + BinaryPrimitives.WriteUInt16LittleEndian(destination.Slice(offset, 2), value); + + return offset + 2; + } + + private static int WriteUInt32(uint value, Span destination, int offset) + { + BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(offset, 4), value); + + return offset + 4; + } + + private static int WriteInt32(int value, Span destination, int offset) + { + BinaryPrimitives.WriteInt32LittleEndian(destination.Slice(offset, 4), value); + + return offset + 4; + } + private int GetIndex(IList indexes, ExifTag tag) { foreach (int index in indexes) @@ -163,7 +206,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif { if (((int)this.allowedParts & (int)part) == 0) { - return new Collection(); + return new List(); } var result = new List(); @@ -223,7 +266,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif return newOffset; } - private int WriteData(IList indexes, byte[] destination, int offset) + private int WriteData(List indexes, byte[] destination, int offset) { if (this.dataOffsets.Count == 0) { @@ -238,7 +281,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif ExifValue value = this.values[index]; if (value.Length > 4) { - Write(BitConverter.GetBytes(newOffset - StartIndex), destination, this.dataOffsets[i++]); + WriteUInt32((uint)(newOffset - StartIndex), destination, this.dataOffsets[i++]); newOffset = this.WriteValue(value, destination, newOffset); } } @@ -246,11 +289,11 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif return newOffset; } - private int WriteHeaders(IList indexes, byte[] destination, int offset) + private int WriteHeaders(List indexes, byte[] destination, int offset) { this.dataOffsets = new List(); - int newOffset = Write(BitConverter.GetBytes((ushort)indexes.Count), destination, offset); + int newOffset = WriteUInt16((ushort)indexes.Count, destination, offset); if (indexes.Count == 0) { @@ -260,9 +303,9 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif foreach (int index in indexes) { ExifValue value = this.values[index]; - newOffset = Write(BitConverter.GetBytes((ushort)value.Tag), destination, newOffset); - newOffset = Write(BitConverter.GetBytes((ushort)value.DataType), destination, newOffset); - newOffset = Write(BitConverter.GetBytes((uint)value.NumberOfComponents), destination, newOffset); + newOffset = WriteUInt16((ushort)value.Tag, destination, newOffset); + newOffset = WriteUInt16((ushort)value.DataType, destination, newOffset); + newOffset = WriteUInt32((uint)value.NumberOfComponents, destination, newOffset); if (value.Length > 4) { @@ -279,23 +322,19 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif return newOffset; } - private int WriteRational(in Rational value, byte[] destination, int offset) + private static void WriteRational(Span destination, in Rational value) { - Write(BitConverter.GetBytes(value.Numerator), destination, offset); - Write(BitConverter.GetBytes(value.Denominator), destination, offset + 4); - - return offset + 8; + BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(0, 4), value.Numerator); + BinaryPrimitives.WriteUInt32LittleEndian(destination.Slice(4, 4), value.Denominator); } - private int WriteSignedRational(in SignedRational value, byte[] destination, int offset) + private static void WriteSignedRational(Span destination, in SignedRational value) { - Write(BitConverter.GetBytes(value.Numerator), destination, offset); - Write(BitConverter.GetBytes(value.Denominator), destination, offset + 4); - - return offset + 8; + BinaryPrimitives.WriteInt32LittleEndian(destination.Slice(0, 4), value.Numerator); + BinaryPrimitives.WriteInt32LittleEndian(destination.Slice(4, 4), value.Denominator); } - private int WriteValue(ExifDataType dataType, object value, byte[] destination, int offset) + private int WriteValue(ExifDataType dataType, object value, Span destination, int offset) { switch (dataType) { @@ -306,24 +345,26 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif destination[offset] = (byte)value; return offset + 1; case ExifDataType.DoubleFloat: - return Write(BitConverter.GetBytes((double)value), destination, offset); + return WriteDouble((double)value, destination, offset); case ExifDataType.Short: - return Write(BitConverter.GetBytes((ushort)value), destination, offset); + return WriteUInt16((ushort)value, destination, offset); case ExifDataType.Long: - return Write(BitConverter.GetBytes((uint)value), destination, offset); + return WriteUInt32((uint)value, destination, offset); case ExifDataType.Rational: - return this.WriteRational((Rational)value, destination, offset); + WriteRational(destination.Slice(offset, 8), (Rational)value); + return offset + 8; case ExifDataType.SignedByte: destination[offset] = unchecked((byte)((sbyte)value)); return offset + 1; case ExifDataType.SignedLong: - return Write(BitConverter.GetBytes((int)value), destination, offset); + return WriteInt32((int)value, destination, offset); case ExifDataType.SignedShort: - return Write(BitConverter.GetBytes((short)value), destination, offset); + return WriteInt16((short)value, destination, offset); case ExifDataType.SignedRational: - return this.WriteSignedRational((SignedRational)value, destination, offset); + WriteSignedRational(destination.Slice(offset, 8), (SignedRational)value); + return offset + 8; case ExifDataType.SingleFloat: - return Write(BitConverter.GetBytes((float)value), destination, offset); + return WriteSingle((float)value, destination, offset); default: throw new NotImplementedException(); }