88 lines
1.6 KiB
C#
88 lines
1.6 KiB
C#
using System.Diagnostics.CodeAnalysis;
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using Canon.Core.Abstractions;
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namespace Canon.Console.Services;
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/// <summary>
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/// 从字符串中读取源代码
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/// </summary>
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public sealed class StringSourceReader(string source) : ISourceReader
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{
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private int _pos = -1;
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private uint _lastPos;
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public uint Line { get; private set; } = 1;
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public uint Pos { get; private set; }
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public string FileName => "string";
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public char Current
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{
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get
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{
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if (_pos == -1)
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{
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throw new InvalidOperationException("Reader at before the start.");
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}
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else
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{
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return source[_pos];
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}
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}
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}
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public bool Retract()
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{
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if (_pos <= 0)
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{
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return false;
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}
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_pos -= 1;
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if (Current == '\n')
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{
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Line -= 1;
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// TODO: 如果一直回退就完蛋了
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Pos = _lastPos;
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}
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else
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{
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Pos -= 1;
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}
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return true;
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}
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public bool MoveNext()
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{
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if (_pos >= source.Length - 1)
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{
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return false;
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}
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if (_pos != -1 && Current == '\n')
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{
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Line += 1;
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_lastPos = Pos;
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Pos = 0;
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}
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_pos += 1;
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Pos += 1;
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return true;
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}
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public bool TryPeekChar([NotNullWhen(true)] out char? c)
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{
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if (_pos >= source.Length - 1)
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{
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c = null;
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return false;
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}
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c = source[_pos + 1];
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return true;
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}
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}
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