public static string ReadTag(string s, string tag)
{
var startIndex = s.IndexOfAny(new[] { "\"" + tag + "\"", "'" + tag + "'" }, StringComparison.Ordinal);
if (startIndex < 0)
{
return(null);
}
var res = s.Substring(startIndex + 3 + tag.Length).Trim().TrimStart(':').TrimStart();
if (res.StartsWith('"'))
{ // text
res = Json.ConvertJsonSpecialCharacters(res);
res = res.Replace("\\\"", "@__1");
int endIndex = res.IndexOf("\"}", StringComparison.Ordinal);
int endAlternate = res.IndexOf("\",", StringComparison.Ordinal);
if (endIndex < 0)
{
endIndex = endAlternate;
}
else if (endAlternate > 0 && endAlternate < endIndex)
{
endIndex = endAlternate;
}
if (endIndex < 0)
{
return(null);
}
if (res.Length > 1)
{
return(res.Substring(1, endIndex - 1).Replace("@__1", "\\\""));
}
return(string.Empty);
}
else
{ // number
var endIndex = res.IndexOfAny(new[] { ',', '}' });
if (endIndex < 0)
{
return(null);
}
return(res.Substring(0, endIndex));
}
}