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StringParser.cs
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StringParser.cs
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// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See https://github.com/dotnet/coreclr/blob/master/LICENSE.TXT for full license information.
// Lifted from the Corefx repo ( https://github.com/dotnet/corefx/blob/1f79ba743cf84dc88cdc0dc9a64b02907d4f21b0/src/Common/src/System/IO/StringParser.cs )
// Thanks you Microsoft for making my life easier (and using the same license as me)
using System;
using System.Globalization;
namespace GCMonitor
{
/// <summary>
/// Provides a string parser that may be used instead of String.Split
/// to avoid unnecessary string and array allocations.
/// </summary>
internal struct StringParser
{
/// <summary>The string being parsed.</summary>
private readonly string _buffer;
/// <summary>The separator character used to separate subcomponents of the larger string.</summary>
private readonly char _separator;
/// <summary>true if empty subcomponents should be skipped; false to treat them as valid entries.</summary>
private readonly bool _skipEmpty;
/// <summary>The starting index from which to parse the current entry.</summary>
private int _startIndex;
/// <summary>The ending index that represents the next index after the last character that's part of the current entry.</summary>
private int _endIndex;
/// <summary>Initialize the StringParser.</summary>
/// <param name="buffer">The string to parse.</param>
/// <param name="separator">The separator character used to separate subcomponents of <paramref name="buffer"/>.</param>
/// <param name="skipEmpty">true if empty subcomponents should be skipped; false to treat them as valid entries. Defaults to false.</param>
public StringParser(string buffer, char separator, bool skipEmpty = false)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
_buffer = buffer;
_separator = separator;
_skipEmpty = skipEmpty;
_startIndex = -1;
_endIndex = -1;
}
/// <summary>Moves to the next component of the string.</summary>
/// <returns>true if there is a next component to be parsed; otherwise, false.</returns>
public bool MoveNext()
{
if (_buffer == null)
{
throw new InvalidOperationException();
}
while (true)
{
if (_endIndex >= _buffer.Length)
{
_startIndex = _endIndex;
return false;
}
int nextSeparator = _buffer.IndexOf(_separator, _endIndex + 1);
_startIndex = _endIndex + 1;
_endIndex = nextSeparator >= 0 ? nextSeparator : _buffer.Length;
if (!_skipEmpty || _endIndex > _startIndex + 1)
{
return true;
}
}
}
/// <summary>
/// Moves to the next component of the string. If there isn't one, it throws an exception.
/// </summary>
public void MoveNextOrFail()
{
if (!MoveNext())
{
ThrowForInvalidData();
}
}
/// <summary>
/// Moves to the next component of the string and returns it as a string.
/// </summary>
/// <returns></returns>
public string MoveAndExtractNext()
{
MoveNextOrFail();
return _buffer.Substring(_startIndex, _endIndex - _startIndex);
}
/// <summary>
/// Gets the current subcomponent of the string as a string.
/// </summary>
public string ExtractCurrent()
{
if (_buffer == null || _startIndex == -1)
{
throw new InvalidOperationException();
}
return _buffer.Substring(_startIndex, _endIndex - _startIndex);
}
/// <summary>Moves to the next component and parses it as an Int32.</summary>
public int ParseNextInt32()
{
int result;
if (!int.TryParse(MoveAndExtractNext(), NumberStyles.Integer, CultureInfo.InvariantCulture, out result))
{
ThrowForInvalidData();
}
return result;
}
/// <summary>Moves to the next component and parses it as an Int64.</summary>
public long ParseNextInt64()
{
long result;
if (!long.TryParse(MoveAndExtractNext(), NumberStyles.Integer, CultureInfo.InvariantCulture, out result))
{
ThrowForInvalidData();
}
return result;
}
/// <summary>Moves to the next component and parses it as a UInt32.</summary>
public uint ParseNextUInt32()
{
uint result;
if (!uint.TryParse(MoveAndExtractNext(), NumberStyles.Integer, CultureInfo.InvariantCulture, out result))
{
ThrowForInvalidData();
}
return result;
}
/// <summary>Moves to the next component and parses it as a UInt64.</summary>
public ulong ParseNextUInt64()
{
ulong result;
if (!ulong.TryParse(MoveAndExtractNext(), NumberStyles.Integer, CultureInfo.InvariantCulture, out result))
{
ThrowForInvalidData();
}
return result;
}
/// <summary>Moves to the next component and parses it as a Char.</summary>
public char ParseNextChar()
{
char result;
if (!char.TryParse(MoveAndExtractNext(), out result))
{
ThrowForInvalidData();
}
return result;
}
internal delegate T ParseRawFunc<T>(string buffer, ref int startIndex, ref int endIndex);
/// <summary>
/// Moves to the next component and hands the raw buffer and indexing data to a selector function
/// that can validate and return the appropriate data from the component.
/// </summary>
internal T ParseRaw<T>(ParseRawFunc<T> selector)
{
MoveNextOrFail();
return selector(_buffer, ref _startIndex, ref _endIndex);
}
/// <summary>Throws unconditionally for invalid data.</summary>
private static void ThrowForInvalidData()
{
throw new InvalidDataException();
}
}
public sealed class InvalidDataException : Exception
{
public InvalidDataException()
{
}
public InvalidDataException(string message)
: base(message)
{
}
public InvalidDataException(string message, Exception innerException)
: base(message, innerException)
{
}
}
}