toml4j/src/main/java/com/moandjiezana/toml/ExponentConverter.java
2015-01-23 16:06:06 +02:00

71 lines
1.6 KiB
Java

package com.moandjiezana.toml;
class ExponentConverter implements ValueConverter {
public static final ExponentConverter EXPONENT_PARSER = new ExponentConverter();
@Override
public boolean canConvert(String s) {
char[] chars = s.toCharArray();
boolean whitespace = false;
boolean exponent = false;
boolean signable = true;
boolean decimal = false;
for (int i = 0; i < chars.length; i++) {
char c = chars[i];
if (Character.isDigit(c)) {
signable = false;
continue;
}
if (signable && (c == '+' || c == '-') && chars.length > i + 1 && Character.isDigit(chars[i + 1])) {
signable = false;
continue;
}
if (i > 0 && (c == 'E' || c == 'e')) {
signable = true;
exponent = true;
continue;
}
if (i > 0 && c == '.' && !decimal && !exponent) {
decimal = true;
continue;
}
if (Character.isWhitespace(c)) {
whitespace = true;
continue;
}
if (whitespace && c == '#') {
break;
}
return false;
}
return exponent && !signable;
}
@Override
public Object convert(String s) {
if (s.startsWith("+")) {
s = s.substring(1);
}
int startOfComment = s.indexOf('#');
if (startOfComment > -1) {
s = s.substring(0, startOfComment).trim();
}
String[] exponentString = s.split("[eE]");
return Double.parseDouble(exponentString[0]) * Math.pow(10, Double.parseDouble(exponentString[1]));
}
}