/// <summary>
/// Reads the source code within the given span.
/// </summary>
/// <param name="span"> The start and end positions within the source code. </param>
/// <returns> The source code within the given span. </returns>
internal string ReadSpan(Compiler.SourceCodeSpan span)
{
if (span == null)
{
throw new ArgumentNullException("span");
}
int line = 1, column = 1;
var reader = this.GetReader();
var spanText = new System.Text.StringBuilder();
bool insideSpan = false;
while (true)
{
// Detect the start and end of the span.
if (insideSpan == false)
{
// Check for the start of the span.
if (line == span.StartLine && column == span.StartColumn)
{
insideSpan = true;
}
}
if (insideSpan)
{
// Check for the end of the span.
if (line == span.EndLine && column == span.EndColumn)
{
break;
}
}
// Read the next character.
int c = reader.Read();
if (c == -1)
{
break;
}
// Collect text
if (insideSpan)
{
spanText.Append((char)c);
}
// Update the line and column count.
if (c == '\r' || c == '\n')
{
if (c == '\r' && reader.Peek() == '\n')
{
reader.Read();
}
line++;
column = 1;
}
else
{
column++;
}
}
return(spanText.ToString());
}