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Merged
magole merged 6 commits into from
Jun 17, 2026
Merged

Update DataFormat class #17

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10c4838
Update DataFormat class
magole Jun 17, 2026
f33b0b7
Use TryWriteGuidBigEndian method
magole Jun 17, 2026
0703dc8
update UTs
magole Jun 17, 2026
0ef3bdb
Make base32 decoder strict
magole Jun 17, 2026
55c499e
Update exception message
magole Jun 17, 2026
7c97cd3
add extra ut
magole Jun 17, 2026
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66 changes: 50 additions & 16 deletions src/DataFormat.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,8 +7,19 @@
namespace Neliva
{
/// <summary>
/// Provides support to encode and decode data in hex and base32.
/// Provides support to encode and decode data, including <see cref="Guid"/> values,
/// in hexadecimal and base32 formats.
/// </summary>
/// <remarks>
/// <para>
/// Encoding methods produce lowercase output. Decoding and validation methods
/// accept both lowercase and uppercase input.
/// </para>
/// <para>
/// Base32 uses the <c>0123456789abcdefghjkmnpqrstvwxyz</c> alphabet (the
/// <c>i</c>, <c>l</c>, <c>o</c>, and <c>u</c> letters are omitted) and is produced without padding.
/// </para>
/// </remarks>
public static class DataFormat
{
/// <summary>
Expand All @@ -31,7 +42,7 @@ public static class DataFormat
/// <summary>
/// The map to decode bytes from hex characters.
/// </summary>
private static ReadOnlySpan<byte> HexMap => new byte[MC]
private static ReadOnlySpan<byte> HexMap => new byte[]
{
MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC,
MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC,
Expand All @@ -46,7 +57,7 @@ public static class DataFormat
/// <summary>
/// The map to decode bytes from base32 <c>0123456789abcdefghjkmnpqrstvwxyz</c> characters.
/// </summary>
private static ReadOnlySpan<byte> Base32Map => new byte[MC]
private static ReadOnlySpan<byte> Base32Map => new byte[]
{
MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC,
MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC, MC,
Expand Down Expand Up @@ -82,7 +93,7 @@ public static unsafe string ToHex(ReadOnlySpan<byte> value)

if (length > (int.MaxValue / 2))
{
throw new ArgumentOutOfRangeException(nameof(value), "Input is too large to be processed.");
throw new ArgumentOutOfRangeException(nameof(value), "The input is too large to be processed.");
}

fixed (byte* bytesPtr = value)
Expand Down Expand Up @@ -128,7 +139,7 @@ public static unsafe string ToBase32(ReadOnlySpan<byte> value)

if (length > (int)(((long)int.MaxValue * 5) / 8))
{
throw new ArgumentOutOfRangeException(nameof(value), "Input is too large to be processed.");
throw new ArgumentOutOfRangeException(nameof(value), "The input is too large to be processed.");
}

fixed (byte* bytesPtr = value)
Expand Down Expand Up @@ -249,6 +260,12 @@ private static void FromHex(ReadOnlySpan<char> value, Span<byte> destination)
/// <para>
/// The <paramref name="value"/> contains a non-base32 character.
/// </para>
/// <para>
/// OR
/// </para>
/// <para>
/// The <paramref name="value"/> contains non-zero trailing bits.
/// </para>
/// </exception>
public static byte[] FromBase32(ReadOnlySpan<char> value)
{
Expand Down Expand Up @@ -298,6 +315,12 @@ private static void FromBase32(ReadOnlySpan<char> value, Span<byte> destination)
bitsLeft -= 8;
}
}

// Enforce canonical encoding: the trailing (padding) bits must be zero.
if ((buffer & ((1 << bitsLeft) - 1)) != 0)
{
throw new FormatException("The input is not a valid base32 string as it contains non-zero trailing bits.");
}
}

/// <summary>
Expand All @@ -314,7 +337,7 @@ public static string ToHexGuid(Guid value)
{
Span<byte> guidBytes = stackalloc byte[16];

WriteGuidBigEndian(value, guidBytes);
TryWriteGuidBigEndian(value, guidBytes);

return ToHex(guidBytes);
}
Expand All @@ -334,7 +357,7 @@ public static string ToBase32Guid(Guid value)
{
Span<byte> guidBytes = stackalloc byte[16];

WriteGuidBigEndian(value, guidBytes);
TryWriteGuidBigEndian(value, guidBytes);

return ToBase32(guidBytes);
}
Expand Down Expand Up @@ -392,6 +415,12 @@ public static Guid FromHexGuid(ReadOnlySpan<char> value)
/// <para>
/// The <paramref name="value"/> contains a non-base32 character.
/// </para>
/// <para>
/// OR
/// </para>
/// <para>
/// The <paramref name="value"/> contains non-zero trailing bits.
/// </para>
/// </exception>
public static Guid FromBase32Guid(ReadOnlySpan<char> value)
{
Expand All @@ -415,8 +444,8 @@ public static Guid FromBase32Guid(ReadOnlySpan<char> value)
/// The span to verify.
/// </param>
/// <returns>
/// <c>true</c> if the span <paramref name="value"/> has
/// an even number of hexadecimal digits; otherwise, <c>false</c>.
/// <c>true</c> if the span <paramref name="value"/> has an even length and
/// every character is a valid hexadecimal digit; otherwise, <c>false</c>.
/// </returns>
/// <remarks>
/// This method returns <c>true</c> for an empty span.
Expand Down Expand Up @@ -450,8 +479,8 @@ public static bool IsHex(ReadOnlySpan<char> value)
/// The span to verify.
/// </param>
/// <returns>
/// <c>true</c> if the span <paramref name="value"/> has
/// correct number of base32 digits; otherwise, <c>false</c>.
/// <c>true</c> if the span <paramref name="value"/> has a valid length, contains only
/// valid base32 digits, and has zero trailing bits; otherwise, <c>false</c>.
/// </returns>
/// <remarks>
/// This method returns <c>true</c> for an empty span.
Expand Down Expand Up @@ -483,6 +512,13 @@ public static bool IsBase32(ReadOnlySpan<char> value)
}
}

int trailingBits = (5 * (length % 8)) % 8;

if (trailingBits != 0 && (Base32Map[value[length - 1]] & ((1 << trailingBits) - 1)) != 0)
{
return false;
}

return true;
}

Expand All @@ -492,12 +528,10 @@ private static Guid ReadGuidBigEndian(ReadOnlySpan<byte> value)
return new Guid(value, true);
}

private static void WriteGuidBigEndian(Guid value, Span<byte> destination)
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool TryWriteGuidBigEndian(Guid value, Span<byte> destination)
{
if (!value.TryWriteBytes(destination, true, out _))
{
throw new ArgumentOutOfRangeException(nameof(destination));
}
return value.TryWriteBytes(destination, true, out _);
}
}
}
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