static int parseDouble(const CharacterType* string, const CharacterType* end, const char terminator, double& value)
{
int length = checkForValidDouble(string, end, terminator);
if (!length)
return 0;
int position = 0;
double localValue = 0;
// The consumed characters here are guaranteed to be
// ASCII digits with or without a decimal mark
for (; position < length; ++position) {
if (string[position] == '.')
break;
localValue = localValue * 10 + string[position] - '0';
}
if (++position == length) {
value = localValue;
return length;
}
double fraction = 0;
double scale = 1;
const double maxScale = 1000000;
while (position < length && scale < maxScale) {
fraction = fraction * 10 + string[position++] - '0';
scale *= 10;
}
value = localValue + fraction / scale;
return length;
}
static inline bool parseAlphaValue(const CharacterType*& string,
const CharacterType* end,
const char terminator,
int& value) {
while (string != end && isHTMLSpace<CharacterType>(*string))
string++;
bool negative = false;
if (string != end && *string == '-') {
negative = true;
string++;
}
value = 0;
int length = end - string;
if (length < 2)
return false;
if (string[length - 1] != terminator || !isASCIIDigit(string[length - 2]))
return false;
if (string[0] != '0' && string[0] != '1' && string[0] != '.') {
if (checkForValidDouble(string, end, terminator)) {
value = negative ? 0 : 255;
string = end;
return true;
}
return false;
}
if (length == 2 && string[0] != '.') {
value = !negative && string[0] == '1' ? 255 : 0;
string = end;
return true;
}
if (isTenthAlpha(string, length - 1)) {
static const int tenthAlphaValues[] = {0, 25, 51, 76, 102,
127, 153, 179, 204, 230};
value = negative ? 0 : tenthAlphaValues[string[length - 2] - '0'];
string = end;
return true;
}
double alpha = 0;
if (!parseDouble(string, end, terminator, alpha))
return false;
value = negative ? 0 : static_cast<int>(alpha * nextafter(256.0, 0.0));
string = end;
return true;
}
