Exemplo n.º 1
0
        public readonly int                  Value; // = U+0000 if using default init

        /// <summary>
        /// Constructs a Unicode scalar from the given UTF-16 code point.
        /// The code point must not be a surrogate.
        /// </summary>
        /// <param name="char"></param>
        public UnicodeScalar(char @char)
            : this((uint)@char)
        {
            // None of the APIs on this type are guaranteed to produce correct results
            // if we don't validate the input during construction.

            if (Utf8Util.IsLowWordSurrogate((uint)Value))
            {
                throw new ArgumentOutOfRangeException(
                          message: "Value must be between U+0000 and U+D7FF, inclusive; or value must be between U+E000 and U+FFFF, inclusive.",
                          paramName: nameof(@char));
            }
        }
Exemplo n.º 2
0
            /// <summary>
            /// Calculates the byte count needed to encode the UTF-16 bytes from the specified UTF-8 sequence.
            ///
            /// This method will consume as many of the input bytes as possible.
            /// </summary>
            /// <param name="source">A span containing a sequence of UTF-8 bytes.</param>
            /// <param name="bytesNeeded">On exit, contains the number of bytes required for encoding from the <paramref name="source"/>.</param>
            /// <returns>A <see cref="OperationStatus"/> value representing the expected state of the conversion.</returns>
            public static OperationStatus ToUtf16Length(ReadOnlySpan <byte> source, out int bytesNeeded)
            {
                if (Utf8Util.GetIndexOfFirstInvalidUtf8Sequence(source, out int scalarCount, out int surrogatePairCount) < 0)
                {
                    // Well-formed UTF-8 string.

                    // 'scalarCount + surrogatePairCount' is guaranteed not to overflow because
                    // the UTF-16 representation of a string will never have a greater number of
                    // of code units than its UTF-8 representation.
                    int numCodeUnits = scalarCount + surrogatePairCount;

                    // UTF-8 code units are 2 bytes.
                    bytesNeeded = checked (numCodeUnits * 2);
                    return(OperationStatus.Done);
                }
Exemplo n.º 3
0
 private static bool IsValidScalar(uint value) =>
 (value < 0xD800U) || Utf8Util.IsInRangeInclusive(value, 0xE000U, 0x10FFFFU);