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// re2java $INPUT -o $OUTPUT
class Parser {
private String yyinput;
private int yycursor;
private int yymarker;
private int number;
private void add_digit(int base, int offset) throws ArithmeticException {
number = Math.addExact(
Math.multiplyExact(number, base),
yyinput.charAt(yycursor - 1) - offset);
}
public int parse(String str) throws ArithmeticException, IllegalArgumentException {
yyinput = str;
yycursor = 0;
number = 0;
try {
/*!re2c
re2c:YYCTYPE = "char";
re2c:YYPEEK = "yyinput.charAt(yycursor)";
re2c:yyfill:enable = 0;
end = "\x00";
'0b' / [01] { return parse_bin(); }
"0" { return parse_oct(); }
"" / [1-9] { return parse_dec(); }
'0x' / [0-9a-fA-F] { return parse_hex(); }
* { throw new IllegalArgumentException("not a number"); }
*/
} catch (Exception e) {
return -1;
}
}
private int parse_bin() throws ArithmeticException, IllegalArgumentException {
/*!re2c
end { return number; }
[01] { add_digit(2, 48); return parse_bin(); }
* { throw new IllegalArgumentException("ill-formed binary number"); }
*/
}
private int parse_oct() throws ArithmeticException, IllegalArgumentException {
/*!re2c
end { return number; }
[0-7] { add_digit(8, 48); return parse_oct(); }
* { throw new IllegalArgumentException("ill-formed octal number"); }
*/
}
private int parse_dec() throws ArithmeticException, IllegalArgumentException {
/*!re2c
end { return number; }
[0-9] { add_digit(10, 48); return parse_dec(); }
* { throw new IllegalArgumentException("ill-formed decimal number"); }
*/
}
private int parse_hex() throws ArithmeticException, IllegalArgumentException {
/*!re2c
end { return number; }
[0-9] { add_digit(16, 48); return parse_hex(); }
[a-f] { add_digit(16, 87); return parse_hex(); }
[A-F] { add_digit(16, 55); return parse_hex(); }
* { throw new IllegalArgumentException("ill-formed hexadecimal number"); }
*/
}
public static void main(String []args) {
Parser parser = new Parser();
assert parser.parse("1234567890\0") == 1234567890;
assert parser.parse("0b1101\0") == 0b1101;
assert parser.parse("0x007Fe\0") == 0x7fe;
assert parser.parse("0644\0") == 0644;
assert parser.parse("9999999999\0") == -1;
assert parser.parse("123??\0") == -1;
}
};
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