System.Xml.XmlBufferReader.GetDecimalCharEntity C# (CSharp) Méthode

        private int GetDecimalCharEntity(int offset, int length)
        {
            byte[] buffer = _buffer;
            DiagnosticUtility.DebugAssert(buffer[offset + 0] == '&', "");
            DiagnosticUtility.DebugAssert(buffer[offset + 1] == '#', "");
            DiagnosticUtility.DebugAssert(buffer[offset + length - 1] == ';', "");
            int value = 0;
            for (int i = 2; i < length - 1; i++)
            {
                byte ch = buffer[offset + i];
                if (ch < (byte)'0' || ch > (byte)'9')
                    XmlExceptionHelper.ThrowInvalidCharRef(_reader);
                value = value * 10 + (ch - '0');
                if (value > SurrogateChar.MaxValue)
                    XmlExceptionHelper.ThrowInvalidCharRef(_reader);
            }
            return value;
        }