private static int ParseUtf32EscapeSequence(string s, int startIndex, int limit, StringBuilder sb)
{
if (limit - startIndex < 8)
{
throw new ParseException("UTF-32 escape sequence missing.", startIndex, 0);
}
var utf32 = CharUtils.CharToHexValue(s[startIndex++]) << 28 |
CharUtils.CharToHexValue(s[startIndex++]) << 24 |
CharUtils.CharToHexValue(s[startIndex++]) << 20 |
CharUtils.CharToHexValue(s[startIndex++]) << 16 |
CharUtils.CharToHexValue(s[startIndex++]) << 12 |
CharUtils.CharToHexValue(s[startIndex++]) << 8 |
CharUtils.CharToHexValue(s[startIndex++]) << 4 |
CharUtils.CharToHexValue(s[startIndex++]) << 0;
const int highSurrogateStart = 0xd800;
const int highSurrogateEnd = 0xdbff;
const int lowSurrogateStart = 0xdc00;
const int lowSurrogateEnd = 0xdfff;
if (utf32 < 0 || utf32 > 0x10ffff || (utf32 >= highSurrogateStart && utf32 <= lowSurrogateEnd))
{
throw new ParseException("Invalid UTF-32 escape sequence.", startIndex - 8, 8);
}
if (utf32 < 0x10000)
{
sb.Append((char)utf32);
}
else
{
var highSurrogate = (char)(((utf32 >> 10) - 0x40) + highSurrogateStart);
var lowSurrogate = (char)((utf32 & 0x3FF) + lowSurrogateStart);
Debug.Assert(highSurrogate >= highSurrogateStart && highSurrogate <= highSurrogateEnd);
Debug.Assert(lowSurrogate >= lowSurrogateStart && lowSurrogate <= lowSurrogateEnd);
sb.Append(highSurrogate);
sb.Append(lowSurrogate);
}
return(startIndex);
}
private static int ParseUtf16EscapeSequence(string s, int startIndex, int limit, StringBuilder sb)
{
if (limit - startIndex < 4)
{
throw new ParseException("UTF-16 escape sequence missing.", startIndex, 0);
}
var utf16 = CharUtils.CharToHexValue(s[startIndex++]) << 12 |
CharUtils.CharToHexValue(s[startIndex++]) << 8 |
CharUtils.CharToHexValue(s[startIndex++]) << 4 |
CharUtils.CharToHexValue(s[startIndex++]) << 0;
if (utf16 < 0)
{
throw new ParseException("Invalid UTF-16 escape sequence.", startIndex - 4, 4);
}
sb.Append((char)utf16);
return(startIndex);
}
private static string InternalByteArrayToString(byte[] buffer, int offset, int count)
{
if (count == 0)
{
return(string.Empty);
}
if (count > int.MaxValue / 2)
{
throw new ArgumentOutOfRangeException(nameof(count), FormattableString.Invariant($"The specified length exceeds the maximum value of {int.MaxValue / 2}."));
}
var result = new char[2 * count];
var resultIndex = 0;
var limit = offset + count;
for (; offset < limit; offset++)
{
result[resultIndex++] = CharUtils.HexValueToChar(buffer[offset] >> 4);
result[resultIndex++] = CharUtils.HexValueToChar(buffer[offset] & 0xF);
}
return(new string(result));
}
private static int InternalTryParseHexStringToByteArray(string s, int startIndex, int length, byte[] buffer, int offset, int count)
{
var lastChar = startIndex + length;
var lastByte = offset + count;
while (lastByte > offset)
{
if (lastChar <= startIndex)
{
break;
}
var lo = CharUtils.CharToHexValue(s[--lastChar]);
if (lo < 0)
{
return(~lastChar);
}
if (lastChar <= startIndex)
{
buffer[--lastByte] = (byte)lo;
break;
}
var hi = CharUtils.CharToHexValue(s[--lastChar]);
if (hi < 0)
{
return(~lastChar);
}
buffer[--lastByte] = (byte)((hi << 4) | (lo << 0));
}
return(offset + count - lastByte);
}
public static void EscapeString(string s, int startIndex, int limit, StringBuilder sb)
{
for (; startIndex < limit; startIndex++)
{
var c = s[startIndex];
switch (c)
{
case '\0':
sb.Append("\\0");
break;
case '\a':
sb.Append("\\a");
break;
case '\b':
sb.Append("\\b");
break;
case '\t':
sb.Append("\\t");
break;
case '\n':
sb.Append("\\n");
break;
case '\v':
sb.Append("\\v");
break;
case '\f':
sb.Append("\\f");
break;
case '\r':
sb.Append("\\r");
break;
case '"':
sb.Append("\\\"");
break;
case '\\':
sb.Append("\\\\");
break;
default:
if (CharUtils.RequiresEscaping(c))
{
sb.Append("\\u");
sb.Append(CharUtils.HexValueToChar((c >> 12) & 0xF));
sb.Append(CharUtils.HexValueToChar((c >> 8) & 0xF));
sb.Append(CharUtils.HexValueToChar((c >> 4) & 0xF));
sb.Append(CharUtils.HexValueToChar((c >> 0) & 0xF));
continue;
}
sb.Append(c);
break;
}
}
}
