private static int parseInt(
FastSimpleStringBufferForCSVProcessorAndJSONParser s, int startIndex, int strLen)
throws ParseException {
if (startIndex == strLen)
throw new ParseException(
"Failed to parse '" + s.toString() + "' at offset " + startIndex, startIndex);
int res = 0;
final boolean isNegative;
int i = startIndex;
if (s.charAt(i) == '-') {
isNegative = true;
i++;
} else {
isNegative = false;
}
int intValue = 0;
for (; i < strLen; i++) {
final char ch = s.charAt(i);
if (ch < '0' || ch > '9') {
throw new ParseException("Failed to parse '" + s.toString() + "' at offset " + i, i);
} else {
int val = ch - '0';
intValue = intValue * 10 + val;
}
}
return isNegative ? (-1 * intValue) : intValue;
}
public static double parseDouble(final FastSimpleStringBufferForCSVProcessorAndJSONParser s)
throws ParseException {
final int strLen = s.length();
if (strLen == 0) return Double.NaN;
final double toReturn =
strLen <= 9 ? parseUsingIntValue(s, strLen) : parseUsingLongValue(s, strLen);
if (kDEBUG_VERSUS_JAVA_PARSING) {
final double alternative = Double.parseDouble(s.toString());
if (toReturn != alternative)
throw new IllegalArgumentException(
s.toString() + " parsed differently! " + toReturn + " vs java " + alternative);
}
return toReturn;
}
private static double parseUsingIntValue(
FastSimpleStringBufferForCSVProcessorAndJSONParser s, int strLen) throws ParseException {
final boolean isNegative;
int i;
if (s.charAt(0) == '-') {
isNegative = true;
i = 1;
} else {
isNegative = false;
i = 0;
}
int intValue = 0;
int exp = 0;
int expDelta = 0;
int numDigits = 0;
for (; i < strLen; i++) {
final char ch = s.charAt(i);
if (ch == '.') {
if (expDelta == -1)
throw new ParseException("Failed to parse '" + s.toString() + "' at offset " + i, i);
expDelta = -1;
} else if (ch == 'E') {
exp += parseInt(s, i + 1, strLen);
i = strLen;
} else if (ch < '0' || ch > '9') {
throw new ParseException("Failed to parse '" + s.toString() + "' at offset " + i, i);
} else {
int val = ch - '0';
intValue = intValue * 10 + val;
exp += expDelta;
numDigits++;
}
}
if (numDigits == 0) throw new ParseException("Failed to parse '" + s.toString() + "'", 0);
// todo: we can probably optimize converToDouble knowing that it's of limited size.
return convertToDouble(intValue, exp, isNegative, numDigits);
}
private static double parseUsingLongValue(
FastSimpleStringBufferForCSVProcessorAndJSONParser s, int strLen) throws ParseException {
// If the string is ridiculously long, long type is not enough to hold the mantissa.
// In such case, use java built in double parser as we are not likely to see those numbers
// anyway...
if (strLen >= 18) return Double.parseDouble(s.toString());
final boolean isNegative;
int i;
if (s.charAt(0) == '-') {
isNegative = true;
i = 1;
} else {
isNegative = false;
i = 0;
}
long longValue = 0;
int exp = 0;
int expDelta = 0;
int numDigits = 0;
for (; i < strLen; i++) {
final char ch = s.charAt(i);
if (ch == '.') {
if (expDelta == -1)
throw new ParseException("Failed to parse '" + s.toString() + "' at offset " + i, i);
expDelta = -1;
} else if (ch == 'E') {
exp += parseInt(s, i + 1, strLen);
i = strLen;
} else if (ch < '0' || ch > '9') {
throw new ParseException("Failed to parse '" + s.toString() + "' at offset " + i, i);
} else {
int val = ch - '0';
longValue = longValue * 10 + val;
exp += expDelta;
numDigits++;
}
}
if (numDigits == 0) throw new ParseException("Failed to parse '" + s.toString() + "'", 0);
return convertToDouble((double) longValue, exp, isNegative, numDigits);
}
