Ejemplo n.º 1
0
 // Returns true iff this Unicode category represents a symbol
 private static bool IsCategorySymbol(UnicodeCategory category)
 {
     return(UnicodeUtility.IsInRangeInclusive((uint)category, (uint)UnicodeCategory.MathSymbol, (uint)UnicodeCategory.OtherSymbol));
 }
Ejemplo n.º 2
0
 // Returns true iff this Unicode category represents a punctuation mark
 private static bool IsCategoryPunctuation(UnicodeCategory category)
 {
     return(UnicodeUtility.IsInRangeInclusive((uint)category, (uint)UnicodeCategory.ConnectorPunctuation, (uint)UnicodeCategory.OtherPunctuation));
 }
Ejemplo n.º 3
0
 // Returns true iff this Unicode category represents a separator
 private static bool IsCategorySeparator(UnicodeCategory category)
 {
     return(UnicodeUtility.IsInRangeInclusive((uint)category, (uint)UnicodeCategory.SpaceSeparator, (uint)UnicodeCategory.ParagraphSeparator));
 }
Ejemplo n.º 4
0
 // Returns true iff this Unicode category represents a letter or a decimal digit
 private static bool IsCategoryLetterOrDecimalDigit(UnicodeCategory category)
 {
     return(UnicodeUtility.IsInRangeInclusive((uint)category, (uint)UnicodeCategory.UppercaseLetter, (uint)UnicodeCategory.OtherLetter) ||
            (category == UnicodeCategory.DecimalDigitNumber));
 }
Ejemplo n.º 5
0
 // Returns true iff this Unicode category represents a number
 private static bool IsCategoryNumber(UnicodeCategory category)
 {
     return(UnicodeUtility.IsInRangeInclusive((uint)category, (uint)UnicodeCategory.DecimalDigitNumber, (uint)UnicodeCategory.OtherNumber));
 }
Ejemplo n.º 6
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 public static bool IsValid(uint value) => UnicodeUtility.IsValidUnicodeScalar(value);
Ejemplo n.º 7
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 // Returns true iff this Unicode category represents a letter
 private static bool IsCategoryLetter(UnicodeCategory category)
 {
     return(UnicodeUtility.IsInRangeInclusive((uint)category, (uint)UnicodeCategory.UppercaseLetter, (uint)UnicodeCategory.OtherLetter));
 }
 internal static void AssertIsValidSupplementaryPlaneScalar(uint scalarValue)
 {
     Debug.Assert(UnicodeUtility.IsValidUnicodeScalar(scalarValue) && !UnicodeUtility.IsBmpCodePoint(scalarValue), $"The value {ToHexString(scalarValue)} is not a valid supplementary plane Unicode scalar value.");
 }
 internal static void AssertIsValidScalar(uint scalarValue)
 {
     Debug.Assert(UnicodeUtility.IsValidUnicodeScalar(scalarValue), $"The value {ToHexString(scalarValue)} is not a valid Unicode scalar value.");
 }
 internal static void AssertIsValidCodePoint(uint codePoint)
 {
     Debug.Assert(UnicodeUtility.IsValidCodePoint(codePoint), $"The value {ToHexString(codePoint)} is not a valid Unicode code point.");
 }
 internal static void AssertIsLowSurrogateCodePoint(uint codePoint)
 {
     Debug.Assert(UnicodeUtility.IsLowSurrogateCodePoint(codePoint), $"The value {ToHexString(codePoint)} is not a valid UTF-16 low surrogate code point.");
 }
Ejemplo n.º 12
0
        /// <summary>
        /// Decodes the <see cref="Rune"/> at the beginning of the provided UTF-8 source buffer.
        /// </summary>
        /// <returns>
        /// <para>
        /// If the source buffer begins with a valid UTF-8 encoded scalar value, returns <see cref="OperationStatus.Done"/>,
        /// and outs via <paramref name="result"/> the decoded <see cref="Rune"/> and via <paramref name="bytesConsumed"/> the
        /// number of <see langword="byte"/>s used in the input buffer to encode the <see cref="Rune"/>.
        /// </para>
        /// <para>
        /// If the source buffer is empty or contains only a partial UTF-8 subsequence, returns <see cref="OperationStatus.NeedMoreData"/>,
        /// and outs via <paramref name="result"/> <see cref="ReplacementChar"/> and via <paramref name="bytesConsumed"/> the length of the input buffer.
        /// </para>
        /// <para>
        /// If the source buffer begins with an ill-formed UTF-8 encoded scalar value, returns <see cref="OperationStatus.InvalidData"/>,
        /// and outs via <paramref name="result"/> <see cref="ReplacementChar"/> and via <paramref name="bytesConsumed"/> the number of
        /// <see langword="char"/>s used in the input buffer to encode the ill-formed sequence.
        /// </para>
        /// </returns>
        /// <remarks>
        /// The general calling convention is to call this method in a loop, slicing the <paramref name="source"/> buffer by
        /// <paramref name="bytesConsumed"/> elements on each iteration of the loop. On each iteration of the loop <paramref name="result"/>
        /// will contain the real scalar value if successfully decoded, or it will contain <see cref="ReplacementChar"/> if
        /// the data could not be successfully decoded. This pattern provides convenient automatic U+FFFD substitution of
        /// invalid sequences while iterating through the loop.
        /// </remarks>
        public static OperationStatus DecodeFromUtf8(ReadOnlySpan <byte> source, out Rune result, out int bytesConsumed)
        {
            // This method follows the Unicode Standard's recommendation for detecting
            // the maximal subpart of an ill-formed subsequence. See The Unicode Standard,
            // Ch. 3.9 for more details. In summary, when reporting an invalid subsequence,
            // it tries to consume as many code units as possible as long as those code
            // units constitute the beginning of a longer well-formed subsequence per Table 3-7.

            int index = 0;

            // Try reading input[0].

            if ((uint)index >= (uint)source.Length)
            {
                goto NeedsMoreData;
            }

            uint tempValue = source[index];

            if (!UnicodeUtility.IsAsciiCodePoint(tempValue))
            {
                goto NotAscii;
            }

Finish:

            bytesConsumed = index + 1;
            Debug.Assert(1 <= bytesConsumed && bytesConsumed <= 4); // Valid subsequences are always length [1..4]
            result = UnsafeCreate(tempValue);
            return(OperationStatus.Done);

NotAscii:

            // Per Table 3-7, the beginning of a multibyte sequence must be a code unit in
            // the range [C2..F4]. If it's outside of that range, it's either a standalone
            // continuation byte, or it's an overlong two-byte sequence, or it's an out-of-range
            // four-byte sequence.

            if (!UnicodeUtility.IsInRangeInclusive(tempValue, 0xC2, 0xF4))
            {
                goto FirstByteInvalid;
            }

            tempValue = (tempValue - 0xC2) << 6;

            // Try reading input[1].

            index++;
            if ((uint)index >= (uint)source.Length)
            {
                goto NeedsMoreData;
            }

            // Continuation bytes are of the form [10xxxxxx], which means that their two's
            // complement representation is in the range [-65..-128]. This allows us to
            // perform a single comparison to see if a byte is a continuation byte.

            int thisByteSignExtended = (sbyte)source[index];

            if (thisByteSignExtended >= -64)
            {
                goto Invalid;
            }

            tempValue += (uint)thisByteSignExtended;
            tempValue += 0x80;               // remove the continuation byte marker
            tempValue += (0xC2 - 0xC0) << 6; // remove the leading byte marker

            if (tempValue < 0x0800)
            {
                Debug.Assert(UnicodeUtility.IsInRangeInclusive(tempValue, 0x0080, 0x07FF));
                goto Finish; // this is a valid 2-byte sequence
            }

            // This appears to be a 3- or 4-byte sequence. Since per Table 3-7 we now have
            // enough information (from just two code units) to detect overlong or surrogate
            // sequences, we need to perform these checks now.

            if (!UnicodeUtility.IsInRangeInclusive(tempValue, ((0xE0 - 0xC0) << 6) + (0xA0 - 0x80), ((0xF4 - 0xC0) << 6) + (0x8F - 0x80)))
            {
                // The first two bytes were not in the range [[E0 A0]..[F4 8F]].
                // This is an overlong 3-byte sequence or an out-of-range 4-byte sequence.
                goto Invalid;
            }

            if (UnicodeUtility.IsInRangeInclusive(tempValue, ((0xED - 0xC0) << 6) + (0xA0 - 0x80), ((0xED - 0xC0) << 6) + (0xBF - 0x80)))
            {
                // This is a UTF-16 surrogate code point, which is invalid in UTF-8.
                goto Invalid;
            }

            if (UnicodeUtility.IsInRangeInclusive(tempValue, ((0xF0 - 0xC0) << 6) + (0x80 - 0x80), ((0xF0 - 0xC0) << 6) + (0x8F - 0x80)))
            {
                // This is an overlong 4-byte sequence.
                goto Invalid;
            }

            // The first two bytes were just fine. We don't need to perform any other checks
            // on the remaining bytes other than to see that they're valid continuation bytes.

            // Try reading input[2].

            index++;
            if ((uint)index >= (uint)source.Length)
            {
                goto NeedsMoreData;
            }

            thisByteSignExtended = (sbyte)source[index];
            if (thisByteSignExtended >= -64)
            {
                goto Invalid; // this byte is not a UTF-8 continuation byte
            }

            tempValue <<= 6;
            tempValue  += (uint)thisByteSignExtended;
            tempValue  += 0x80;                // remove the continuation byte marker
            tempValue  -= (0xE0 - 0xC0) << 12; // remove the leading byte marker

            if (tempValue <= 0xFFFF)
            {
                Debug.Assert(UnicodeUtility.IsInRangeInclusive(tempValue, 0x0800, 0xFFFF));
                goto Finish; // this is a valid 3-byte sequence
            }

            // Try reading input[3].

            index++;
            if ((uint)index >= (uint)source.Length)
            {
                goto NeedsMoreData;
            }

            thisByteSignExtended = (sbyte)source[index];
            if (thisByteSignExtended >= -64)
            {
                goto Invalid; // this byte is not a UTF-8 continuation byte
            }

            tempValue <<= 6;
            tempValue  += (uint)thisByteSignExtended;
            tempValue  += 0x80;                // remove the continuation byte marker
            tempValue  -= (0xF0 - 0xE0) << 18; // remove the leading byte marker

            UnicodeDebug.AssertIsValidSupplementaryPlaneScalar(tempValue);
            goto Finish; // this is a valid 4-byte sequence

FirstByteInvalid:

            index = 1; // Invalid subsequences are always at least length 1.

Invalid:

            Debug.Assert(1 <= index && index <= 3); // Invalid subsequences are always length 1..3
            bytesConsumed = index;
            result        = ReplacementChar;
            return(OperationStatus.InvalidData);

NeedsMoreData:

            Debug.Assert(0 <= index && index <= 3); // Incomplete subsequences are always length 0..3
            bytesConsumed = index;
            result        = ReplacementChar;
            return(OperationStatus.NeedMoreData);
        }