80b1ad21d7Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com> Co-authored-by: ericstj <8918108+ericstj@users.noreply.github.com> Co-authored-by: Eric StJohn <ericstj@microsoft.com>
59 lines
2.6 KiB
C#
59 lines
2.6 KiB
C#
using System.Buffers;
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using System.Buffers.Text;
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using System.Diagnostics;
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using System.Text;
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namespace ModelContextProtocol;
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/// <summary>Provides helper methods for encoding operations.</summary>
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internal static class EncodingUtilities
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{
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/// <summary>
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/// Converts UTF-16 characters to UTF-8 bytes without intermediate string allocations.
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/// </summary>
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/// <param name="utf16">The UTF-16 character span to convert.</param>
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/// <returns>A byte array containing the UTF-8 encoded bytes.</returns>
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public static byte[] GetUtf8Bytes(ReadOnlySpan<char> utf16)
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{
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byte[] bytes = new byte[Encoding.UTF8.GetByteCount(utf16)];
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Encoding.UTF8.GetBytes(utf16, bytes);
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return bytes;
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}
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/// <summary>
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/// Encodes binary data to base64-encoded UTF-8 bytes.
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/// </summary>
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/// <param name="data">The binary data to encode.</param>
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/// <returns>A ReadOnlyMemory containing the base64-encoded UTF-8 bytes.</returns>
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public static ReadOnlyMemory<byte> EncodeToBase64Utf8(ReadOnlyMemory<byte> data)
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{
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int maxLength = Base64.GetMaxEncodedToUtf8Length(data.Length);
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byte[] buffer = new byte[maxLength];
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OperationStatus status = Base64.EncodeToUtf8(data.Span, buffer, out _, out int bytesWritten);
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Debug.Assert(status == OperationStatus.Done, "Base64 encoding should succeed for valid input data");
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Debug.Assert(bytesWritten == buffer.Length, "Base64 encoding should always produce the same length as the max length");
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return buffer.AsMemory(0, bytesWritten);
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}
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/// <summary>
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/// Decodes base64-encoded UTF-8 bytes to binary data.
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/// </summary>
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/// <param name="base64Data">The base64-encoded UTF-8 bytes to decode.</param>
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/// <returns>A ReadOnlyMemory containing the decoded binary data.</returns>
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/// <exception cref="FormatException">The input is not valid base64 data.</exception>
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public static ReadOnlyMemory<byte> DecodeFromBase64Utf8(ReadOnlyMemory<byte> base64Data)
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{
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int maxLength = Base64.GetMaxDecodedFromUtf8Length(base64Data.Length);
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byte[] buffer = new byte[maxLength];
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if (Base64.DecodeFromUtf8(base64Data.Span, buffer, out _, out int bytesWritten) == OperationStatus.Done)
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{
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// Base64 decoding may produce fewer bytes than the max length, due to whitespace anywhere in the string or padding.
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Debug.Assert(bytesWritten <= buffer.Length, "Base64 decoding should never produce more bytes than the max length");
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return buffer.AsMemory(0, bytesWritten);
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}
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else
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{
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throw new FormatException("Invalid base64 data");
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}
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}
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}
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