GetCharCount() [2/5]

unsafe override int System.Text.UTF32Encoding.GetCharCount ( byte * bytes, int count, DecoderNLS baseDecoder )

inlinepackagevirtual

Reimplemented from System.Text.Encoding.

Definition at line 545 of file UTF32Encoding.cs.

    {
        UTF32Decoder uTF32Decoder = (UTF32Decoder)baseDecoder;
        int num = 0;
        byte* ptr = bytes + count;
        byte* byteStart = bytes;
        int num2 = 0;
        uint num3 = 0u;
        DecoderFallbackBuffer decoderFallbackBuffer = null;
        if (uTF32Decoder != null)
        {
            num2 = uTF32Decoder.readByteCount;
            num3 = (uint)uTF32Decoder.iChar;
            decoderFallbackBuffer = uTF32Decoder.FallbackBuffer;
        }
        else
        {
            decoderFallbackBuffer = decoderFallback.CreateFallbackBuffer();
        }
        decoderFallbackBuffer.InternalInitialize(byteStart, null);
        while (bytes < ptr && num >= 0)
        {
            if (_bigEndian)
            {
                num3 <<= 8;
                num3 += *(bytes++);
            }
            else
            {
                num3 >>= 8;
                num3 += (uint)(*(bytes++) << 24);
            }
            num2++;
            if (num2 < 4)
            {
                continue;
            }
            num2 = 0;
            if (num3 > 1114111 || (num3 >= 55296 && num3 <= 57343))
            {
                byte[] bytes2 = ((!_bigEndian) ? new byte[4]
                {
                    (byte)num3,
                    (byte)(num3 >> 8),
                    (byte)(num3 >> 16),
                    (byte)(num3 >> 24)
                } : new byte[4]
                {
                    (byte)(num3 >> 24),
                    (byte)(num3 >> 16),
                    (byte)(num3 >> 8),
                    (byte)num3
                });
                num += decoderFallbackBuffer.InternalFallback(bytes2, bytes);
                num3 = 0u;
            }
            else
            {
                if (num3 >= 65536)
                {
                    num++;
                }
                num++;
                num3 = 0u;
            }
        }
        if (num2 > 0 && (uTF32Decoder == null || uTF32Decoder.MustFlush))
        {
            byte[] array = new byte[num2];
            if (_bigEndian)
            {
                while (num2 > 0)
                {
                    array[--num2] = (byte)num3;
                    num3 >>= 8;
                }
            }
            else
            {
                while (num2 > 0)
                {
                    array[--num2] = (byte)(num3 >> 24);
                    num3 <<= 8;
                }
            }
            num += decoderFallbackBuffer.InternalFallback(array, bytes);
        }
        if (num < 0)
        {
            throw new ArgumentOutOfRangeException("count", SR.ArgumentOutOfRange_GetByteCountOverflow);
        }
        return num;
    }

References System.Text.UTF32Encoding._bigEndian, System.SR.ArgumentOutOfRange_GetByteCountOverflow, System.array, System.bytes, System.count, System.Text.DecoderFallback.CreateFallbackBuffer(), System.Text.Encoding.decoderFallback, System.Text.DecoderNLS.FallbackBuffer, System.Text.UTF32Encoding.UTF32Decoder.iChar, System.Text.DecoderFallbackBuffer.InternalFallback(), System.Text.DecoderFallbackBuffer.InternalInitialize(), System.Text.DecoderNLS.MustFlush, and System.Text.UTF32Encoding.UTF32Decoder.readByteCount.