74 lines
2.1 KiB
C#
74 lines
2.1 KiB
C#
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// dnlib: See LICENSE.txt for more info
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using System;
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using dnlib.IO;
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namespace dnlib.DotNet.MD {
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/// <summary>
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/// Represents the #Blob stream
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/// </summary>
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public sealed class BlobStream : HeapStream {
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/// <inheritdoc/>
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public BlobStream() {
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}
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/// <inheritdoc/>
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public BlobStream(DataReaderFactory mdReaderFactory, uint metadataBaseOffset, StreamHeader streamHeader)
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: base(mdReaderFactory, metadataBaseOffset, streamHeader) {
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}
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/// <summary>
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/// Reads data
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/// </summary>
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/// <param name="offset">Offset of data</param>
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/// <returns>The data or <c>null</c> if invalid offset</returns>
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public byte[] Read(uint offset) {
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// The CLR has a special check for offset 0. It always interprets it as
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// 0-length data, even if that first byte isn't 0 at all.
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if (offset == 0)
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return Array2.Empty<byte>();
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if (!TryCreateReader(offset, out var reader))
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return null;
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return reader.ToArray();
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}
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/// <summary>
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/// Reads data just like <see cref="Read"/>, but returns an empty array if
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/// offset is invalid
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/// </summary>
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/// <param name="offset">Offset of data</param>
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/// <returns>The data</returns>
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public byte[] ReadNoNull(uint offset) => Read(offset) ?? Array2.Empty<byte>();
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/// <summary>
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/// Creates a reader that can access a blob
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/// </summary>
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/// <param name="offset">Offset of blob</param>
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/// <returns>A new stream</returns>
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public DataReader CreateReader(uint offset) {
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if (TryCreateReader(offset, out var reader))
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return reader;
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return default;
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}
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/// <summary>
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/// Creates a reader that can access a blob or returns false on failure
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/// </summary>
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/// <param name="offset">Offset of blob</param>
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/// <param name="reader">Updated with the reader</param>
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/// <returns></returns>
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public bool TryCreateReader(uint offset, out DataReader reader) {
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reader = dataReader;
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if (!IsValidOffset(offset))
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return false;
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reader.Position = offset;
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if (!reader.TryReadCompressedUInt32(out uint length))
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return false;
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if (!reader.CanRead(length))
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return false;
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reader = reader.Slice(reader.Position, length);
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return true;
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}
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}
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}
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