+static const int SizeOfInfinity = 8;
+
+static bool isInfinity(const UChar* data, const UChar* end)
+{
+ return (end - data) >= SizeOfInfinity
+ && data[0] == 'I'
+ && data[1] == 'n'
+ && data[2] == 'f'
+ && data[3] == 'i'
+ && data[4] == 'n'
+ && data[5] == 'i'
+ && data[6] == 't'
+ && data[7] == 'y';
+}
+
+// See ecma-262 9.3.1
+static double jsHexIntegerLiteral(const UChar*& data, const UChar* end)
+{
+ // Hex number.
+ data += 2;
+ const UChar* firstDigitPosition = data;
+ double number = 0;
+ while (true) {
+ number = number * 16 + toASCIIHexValue(*data);
+ ++data;
+ if (data == end)
+ break;
+ if (!isASCIIHexDigit(*data))
+ break;
+ }
+ if (number >= mantissaOverflowLowerBound)
+ number = parseIntOverflow(firstDigitPosition, data - firstDigitPosition, 16);
+
+ return number;
+}
+
+// See ecma-262 9.3.1
+static double jsStrDecimalLiteral(const UChar*& data, const UChar* end)
+{
+ ASSERT(data < end);
+
+ // Copy the sting into a null-terminated byte buffer, and call strtod.
+ Vector<char, 32> byteBuffer;
+ for (const UChar* characters = data; characters < end; ++characters) {
+ UChar character = *characters;
+ byteBuffer.append(isASCII(character) ? character : 0);
+ }
+ byteBuffer.append(0);
+ char* endOfNumber;
+ double number = WTF::strtod(byteBuffer.data(), &endOfNumber);
+
+ // Check if strtod found a number; if so return it.
+ ptrdiff_t consumed = endOfNumber - byteBuffer.data();
+ if (consumed) {
+ data += consumed;
+ return number;
+ }
+
+ // Check for [+-]?Infinity
+ switch (*data) {
+ case 'I':
+ if (isInfinity(data, end)) {
+ data += SizeOfInfinity;
+ return Inf;
+ }
+ break;
+
+ case '+':
+ if (isInfinity(data + 1, end)) {
+ data += SizeOfInfinity + 1;
+ return Inf;
+ }
+ break;
+
+ case '-':
+ if (isInfinity(data + 1, end)) {
+ data += SizeOfInfinity + 1;
+ return -Inf;
+ }
+ break;
+ }
+
+ // Not a number.
+ return NaN;
+}
+
+// See ecma-262 9.3.1
+double jsToNumber(const UString& s)
+{
+ unsigned size = s.length();
+
+ if (size == 1) {
+ UChar c = s.characters()[0];
+ if (isASCIIDigit(c))
+ return c - '0';
+ if (isStrWhiteSpace(c))
+ return 0;
+ return NaN;
+ }
+
+ const UChar* data = s.characters();
+ const UChar* end = data + size;
+
+ // Skip leading white space.
+ for (; data < end; ++data) {
+ if (!isStrWhiteSpace(*data))
+ break;
+ }
+
+ // Empty string.
+ if (data == end)
+ return 0.0;
+
+ double number;
+ if (data[0] == '0' && data + 2 < end && (data[1] | 0x20) == 'x' && isASCIIHexDigit(data[2]))
+ number = jsHexIntegerLiteral(data, end);
+ else
+ number = jsStrDecimalLiteral(data, end);
+
+ // Allow trailing white space.
+ for (; data < end; ++data) {
+ if (!isStrWhiteSpace(*data))
+ break;
+ }
+ if (data != end)
+ return NaN;
+
+ return number;
+}
+
projects / apple / javascriptcore.git / blobdiff