private static ReadOnlyMemory ConvertToVectorOfFloats()

in src/Custom/Embeddings/OpenAIEmbedding.cs [108:148]
33 lines of code
7 McCabe index (conditional complexity)

    private static ReadOnlyMemory<float> ConvertToVectorOfFloats(BinaryData binaryData)
    {
        ReadOnlySpan<byte> base64 = binaryData.ToMemory().Span;

        // Remove quotes around base64 string.
        if (base64.Length < 2 || base64[0] != (byte)'"' || base64[base64.Length - 1] != (byte)'"')
        {
            ThrowInvalidData();
        }
        base64 = base64.Slice(1, base64.Length - 2);

        // Decode base64 string to bytes.
        byte[] bytes = ArrayPool<byte>.Shared.Rent(Base64.GetMaxDecodedFromUtf8Length(base64.Length));
        OperationStatus status = Base64.DecodeFromUtf8(base64, bytes.AsSpan(), out int bytesConsumed, out int bytesWritten);
        if (status != OperationStatus.Done || bytesWritten % sizeof(float) != 0)
        {
            ThrowInvalidData();
        }

        // Interpret bytes as floats
        float[] vector = new float[bytesWritten / sizeof(float)];
        bytes.AsSpan(0, bytesWritten).CopyTo(MemoryMarshal.AsBytes(vector.AsSpan()));
        if (!BitConverter.IsLittleEndian)
        {
            Span<int> ints = MemoryMarshal.Cast<float, int>(vector.AsSpan());
#if NET8_0_OR_GREATER
            BinaryPrimitives.ReverseEndianness(ints, ints);
#else
            for (int i = 0; i < ints.Length; i++)
            {
                ints[i] = BinaryPrimitives.ReverseEndianness(ints[i]);
            }
#endif
        }

        ArrayPool<byte>.Shared.Return(bytes);
        return new ReadOnlyMemory<float>(vector);

        static void ThrowInvalidData() =>
            throw new FormatException("The input is not a valid Base64 string of encoded floats.");
    }