/// <summary>
/// Json文字列をパースします。これは<see cref="Parse(JsonScanner)"/>の一部で使用されます。
/// </summary>
/// <param name="scanner">指定するスキャナ。</param>
/// <returns>パースに成功した場合文字列をさらに返します。</returns>
private static string ParseString(JsonScanner scanner)
{
const string b = "\b";
const string f = "\f";
const string n = "\n";
const string r = "\r";
const string t = "\t";
scanner.Empty();
if (!scanner.CheckAdvance(IsDoubleQuote))
{
throw new ArgumentMapParseException("string -> double quotation mark required", scanner.Itext.PositionInfo);
}
while (!scanner.CheckAdvance(IsDoubleQuote))
{
if (scanner.CheckAdvance(IsBackslash))
{
if (scanner.CheckAddAdvance(IsDoubleQuote))
{
continue;
}
if (scanner.CheckAddAdvance(IsBackslash))
{
continue;
}
if (scanner.CheckAddAdvance(IsSlash))
{
continue;
}
if (scanner.CheckAdvance(IsSmallB))
{
scanner.Add(b);
}
else if (scanner.CheckAdvance(IsSmallF))
{
scanner.Add(f);
}
else if (scanner.CheckAdvance(IsSmallN))
{
scanner.Add(n);
}
else if (scanner.CheckAdvance(IsSmallR))
{
scanner.Add(r);
}
else if (scanner.CheckAdvance(IsSmallT))
{
scanner.Add(t);
}
else if (scanner.CheckAdvance(IsSmallU))
{
var codepoint = 0;
for (var i = 0; i < 4; i++)
{
try
{
codepoint = codepoint * 16 + scanner.Current.ToHexValue();
scanner.Advance();
}
catch (Exception)
{
break;
}
}
scanner.Add(Convert.ToChar(codepoint).ToString());
}
else
{
throw new ArgumentMapParseException("string -> not supported escape", scanner.Itext.PositionInfo);
}
}
else if (scanner.Check(IsControl))
{
throw new ArgumentMapParseException("string -> control character", scanner.Itext.PositionInfo);
}
else
{
scanner.AddAdvance();
}
}
return(scanner.Scan);
}