dotpython/src/DotPython.Language/Text/SourceText.cs at main · kidoz/dotpython · GitHub

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namespace DotPython.Language.Text;

public sealed class SourceText

{

private readonly int[] _lineStarts;

public SourceText(string text, string? filePath = null)

{

ArgumentNullException.ThrowIfNull(text);

Content = text;

FilePath = filePath;

_lineStarts = FindLineStarts(text);

}

public string Content { get; }

public string? FilePath { get; }

public int Length => Content.Length;

public int LineCount => _lineStarts.Length;

public char this[int index] => Content[index];

public string GetText(TextSpan span)

{

ValidateSpan(span);

return Content.Substring(span.Start, span.Length);

}

public LinePosition GetLinePosition(int position)

{

ArgumentOutOfRangeException.ThrowIfNegative(position);

ArgumentOutOfRangeException.ThrowIfGreaterThan(position, Length);

var line = Array.BinarySearch(_lineStarts, position);

if (line < 0)

{

line = ~line - 1;

}

return new LinePosition(line, position - _lineStarts[line]);

}

public TextSpan GetLineSpan(int line)

{

ArgumentOutOfRangeException.ThrowIfNegative(line);

ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual(line, LineCount);

var start = _lineStarts[line];

var end = line + 1 < LineCount ? _lineStarts[line + 1] : Length;

return TextSpan.FromBounds(start, end);

}

private static int[] FindLineStarts(string text)

{

var starts = new List<int> { 0 };

for (var position = 0; position < text.Length; position++)

{

switch (text[position])

{

case '\r' when position + 1 < text.Length && text[position + 1] == '\n':

position++;

starts.Add(position + 1);

break;

case '\r':

case '\n':

starts.Add(position + 1);

break;

}

return [.. starts];

}

private void ValidateSpan(TextSpan span)

{

if (span.End > Length)

{

throw new ArgumentOutOfRangeException(nameof(span));

}

dotpython/src/DotPython.Language/Text/SourceText.cs at main · kidoz/dotpython · GitHub

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