forked from BilalY/Rasagar
230 lines
10 KiB
C#
230 lines
10 KiB
C#
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using System;
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using System.Runtime.CompilerServices;
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namespace Unity.Collections
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{
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/// <summary>
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/// Provides methods for parsing numbers from FixedString*N*Bytes.
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/// </summary>
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[GenerateTestsForBurstCompatibility]
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public unsafe static partial class FixedStringMethods
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{
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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[GenerateTestsForBurstCompatibility(GenericTypeArguments = new[] { typeof(FixedString128Bytes) })]
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internal static bool ParseLongInternal<T>(ref T fs, ref int offset, out long value)
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where T : unmanaged, INativeList<byte>, IUTF8Bytes
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{
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int resetOffset = offset;
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int sign = 1;
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if (offset < fs.Length)
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{
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if (fs.Peek(offset).value == '+')
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fs.Read(ref offset);
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else if (fs.Peek(offset).value == '-')
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{
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sign = -1;
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fs.Read(ref offset);
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}
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}
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int digitOffset = offset;
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value = 0;
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while (offset < fs.Length && Unicode.Rune.IsDigit(fs.Peek(offset)))
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{
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value *= 10;
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value += fs.Read(ref offset).value - '0';
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}
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value = sign * value;
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// If there was no number parsed, revert the offset since it's a syntax error and we might
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// have erroneously parsed a '-' or '+'
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if (offset == digitOffset)
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{
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offset = resetOffset;
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return false;
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}
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return true;
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}
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/// <summary>
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/// Parses an int from this string starting at a byte offset.
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/// </summary>
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/// <remarks>
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/// Stops parsing after the last number character. (Unlike parsing methods in other API's, this method does not expect to necessarily parse the entire string.)
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///
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/// The parsed value is bitwise-identical to the result of System.Int32.Parse.
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/// </remarks>
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/// <typeparam name="T">A FixedString*N*Bytes type.</typeparam>
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/// <param name="fs">The string from which to parse.</param>
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/// <param name="offset">A reference to an index of the byte at which to parse an int.</param>
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/// <param name="output">Outputs the parsed int. Ignore if parsing fails.</param>
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/// <returns>ParseError.None if successful. Otherwise returns ParseError.Overflow or ParseError.Syntax.</returns>
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[GenerateTestsForBurstCompatibility(GenericTypeArguments = new[] { typeof(FixedString128Bytes) })]
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public static ParseError Parse<T>(ref this T fs, ref int offset, ref int output)
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where T : unmanaged, INativeList<byte>, IUTF8Bytes
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{
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if (!ParseLongInternal(ref fs, ref offset, out long value))
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return ParseError.Syntax;
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if (value > int.MaxValue)
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return ParseError.Overflow;
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if (value < int.MinValue)
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return ParseError.Overflow;
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output = (int)value;
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return ParseError.None;
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}
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/// <summary>
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/// Parses an uint from this string starting at a byte offset.
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/// </summary>
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/// <remarks>
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/// Stops parsing after the last number character. (Unlike parsing methods in other API's, this method does not expect to necessarily parse the entire string.)
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///
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/// The parsed value is bitwise-identical to the result of System.UInt32.Parse.
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/// </remarks>
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/// <typeparam name="T">A FixedString*N*Bytes type.</typeparam>
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/// <param name="fs">The string from which to parse.</param>
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/// <param name="offset">A reference to an index of the byte at which to parse a uint.</param>
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/// <param name="output">Outputs the parsed uint. Ignore if parsing fails.</param>
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/// <returns>ParseError.None if successful. Otherwise returns ParseError.Overflow or ParseError.Syntax.</returns>
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[GenerateTestsForBurstCompatibility(GenericTypeArguments = new[] { typeof(FixedString128Bytes) })]
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public static ParseError Parse<T>(ref this T fs, ref int offset, ref uint output)
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where T : unmanaged, INativeList<byte>, IUTF8Bytes
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{
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if (!ParseLongInternal(ref fs, ref offset, out long value))
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return ParseError.Syntax;
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if (value > uint.MaxValue)
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return ParseError.Overflow;
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if (value < uint.MinValue)
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return ParseError.Overflow;
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output = (uint)value;
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return ParseError.None;
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}
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/// <summary>
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/// Parses a float from this string starting at a byte offset.
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/// </summary>
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/// Stops parsing after the last number character. (Unlike parsing methods in other API's, this method does not expect to necessarily parse the entire string.)
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///
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/// <remarks>The parsed value is bitwise-identical to the result of System.Single.Parse.</remarks>
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/// <typeparam name="T">A FixedString*N*Bytes type.</typeparam>
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/// <param name="fs">The string from which to parse.</param>
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/// <param name="offset">Index of the byte at which to parse a float.</param>
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/// <param name="output">Outputs the parsed float. Ignore if parsing fails.</param>
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/// <param name="decimalSeparator">The character used to separate the integer part of the number from the fractional part. Defaults to '.' (period).</param>
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/// <returns>ParseError.None if successful. Otherwise returns ParseError.Overflow, ParseError.Underflow, or ParseError.Syntax.</returns>
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[GenerateTestsForBurstCompatibility(GenericTypeArguments = new[] { typeof(FixedString128Bytes) })]
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public static ParseError Parse<T>(ref this T fs, ref int offset, ref float output, char decimalSeparator = '.')
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where T : unmanaged, INativeList<byte>, IUTF8Bytes
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{
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int resetOffset = offset;
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int sign = 1;
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if (offset < fs.Length)
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{
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if (fs.Peek(offset).value == '+')
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fs.Read(ref offset);
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else if (fs.Peek(offset).value == '-')
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{
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sign = -1;
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fs.Read(ref offset);
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}
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}
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if (fs.Found(ref offset, 'n', 'a', 'n'))
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{
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FixedStringUtils.UintFloatUnion ufu = new FixedStringUtils.UintFloatUnion();
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ufu.uintValue = 4290772992U;
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output = ufu.floatValue;
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return ParseError.None;
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}
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if (fs.Found(ref offset, 'i', 'n', 'f', 'i', 'n', 'i', 't', 'y'))
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{
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output = (sign == 1) ? Single.PositiveInfinity : Single.NegativeInfinity;
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return ParseError.None;
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}
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ulong decimalMantissa = 0;
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int significantDigits = 0;
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int digitsAfterDot = 0;
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int mantissaDigits = 0;
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while (offset < fs.Length && Unicode.Rune.IsDigit(fs.Peek(offset)))
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{
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++mantissaDigits;
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if (significantDigits < 9)
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{
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var temp = decimalMantissa * 10 + (ulong)(fs.Peek(offset).value - '0');
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if (temp > decimalMantissa)
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++significantDigits;
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decimalMantissa = temp;
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}
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else
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--digitsAfterDot;
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fs.Read(ref offset);
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}
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if (offset < fs.Length && fs.Peek(offset).value == decimalSeparator)
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{
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fs.Read(ref offset);
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while (offset < fs.Length && Unicode.Rune.IsDigit(fs.Peek(offset)))
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{
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++mantissaDigits;
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if (significantDigits < 9)
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{
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var temp = decimalMantissa * 10 + (ulong)(fs.Peek(offset).value - '0');
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if (temp > decimalMantissa)
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++significantDigits;
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decimalMantissa = temp;
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++digitsAfterDot;
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}
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fs.Read(ref offset);
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}
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}
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if (mantissaDigits == 0)
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{
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// Reset offset in case '+' or '-' was erroneously parsed
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offset = resetOffset;
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return ParseError.Syntax;
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}
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int decimalExponent = 0;
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int decimalExponentSign = 1;
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if (offset < fs.Length && (fs.Peek(offset).value | 32) == 'e')
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{
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fs.Read(ref offset);
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if (offset < fs.Length)
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{
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if (fs.Peek(offset).value == '+')
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fs.Read(ref offset);
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else if (fs.Peek(offset).value == '-')
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{
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decimalExponentSign = -1;
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fs.Read(ref offset);
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}
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}
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int digitOffset = offset;
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while (offset < fs.Length && Unicode.Rune.IsDigit(fs.Peek(offset)))
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{
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decimalExponent = decimalExponent * 10 + (fs.Peek(offset).value - '0');
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fs.Read(ref offset);
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}
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if (offset == digitOffset)
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{
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// Reset offset in case '+' or '-' was erroneously parsed
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offset = resetOffset;
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return ParseError.Syntax;
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}
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if (decimalExponent > 38)
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{
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if (decimalExponentSign == 1)
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return ParseError.Overflow;
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else
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return ParseError.Underflow;
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}
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}
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decimalExponent = decimalExponent * decimalExponentSign - digitsAfterDot;
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var error = FixedStringUtils.Base10ToBase2(ref output, decimalMantissa, decimalExponent);
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if (error != ParseError.None)
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return error;
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output *= sign;
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return ParseError.None;
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}
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}
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}
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