public static void GetNextString(string json, ref int index, out Substring substring)
{
if (json[index] != '\"')
{
throw new Exception("No string here...");
}
index++;
int startingIndex = index;
while (index < json.Length)
{
var character = json[index];
if (character == '\\')
{
BuildNextStringFromEscaped(json, ref index, startingIndex, out substring);
return;
}
else if (character == '\"')
{
int stringLength = index - startingIndex;
substring = new Substring(json, startingIndex, stringLength);
index++;
return;
}
else
{
index++;
}
}
throw new Exception("No ending quote to string.");
}
private static void BuildNextStringFromEscaped(string json, ref int index, int startingIndex, out Substring substring)
{
int lengthFromStartToFirstBackslash = index - startingIndex;
var stringBuilder = new StringBuilder(json, startingIndex, lengthFromStartToFirstBackslash, (int)(1.6f * lengthFromStartToFirstBackslash)); ;
while (index < json.Length)
{
var character = json[index];
if (character == '\\')
{
var indexOfBackslashForEscaping = index;
index++;
character = json[index];
switch (character)
{
case '\'':
case '\"':
case '\\':
case '/':
stringBuilder.Append(character);
index++;
break;
case 'n':
stringBuilder.Append('\n');
index++;
break;
case 'r':
stringBuilder.Append('\r');
index++;
break;
case 'f':
stringBuilder.Append('\f');
index++;
break;
case 'b':
stringBuilder.Append('\b');
index++;
break;
case 't':
stringBuilder.Append('\t');
index++;
break;
case 'u':
{
const int numberOfHexCharacterForJsonEncodedUtfCharacter = 4;
index++;
var hexValue = HexSerializer.Parse(json, ref index, numberOfHexCharacterForJsonEncodedUtfCharacter);
var unicodeCharacter = (char)hexValue;
stringBuilder.Append(unicodeCharacter);
}
break;
default:
throw new Exception("Invalid escape character");
}
}
else if (character == '\"')
{
string jsonWithEscapedCharactersRemoved = stringBuilder.ToString();
substring = new Substring(jsonWithEscapedCharactersRemoved);
index++;
return;
}
else
{
stringBuilder.Append(character);
index++;
}
}
throw new Exception("No ending quote to string.");
}