Created
December 29, 2012 08:24
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JAVA - Long parseLong
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| public static long parseLong(String s, int radix) | |
| throws NumberFormatException | |
| { | |
| if (s == null) { | |
| throw new NumberFormatException("null"); | |
| } | |
| if (radix < Character.MIN_RADIX) { | |
| throw new NumberFormatException("radix " + radix + | |
| " less than Character.MIN_RADIX"); | |
| } | |
| if (radix > Character.MAX_RADIX) { | |
| throw new NumberFormatException("radix " + radix + | |
| " greater than Character.MAX_RADIX"); | |
| } | |
| long result = 0; | |
| boolean negative = false; | |
| int i = 0, len = s.length(); | |
| long limit = -Long.MAX_VALUE; | |
| long multmin; | |
| int digit; | |
| if (len > 0) { | |
| char firstChar = s.charAt(0); | |
| if (firstChar < '0') { // Possible leading "+" or "-" | |
| if (firstChar == '-') { | |
| negative = true; | |
| limit = Long.MIN_VALUE; | |
| } else if (firstChar != '+') | |
| throw NumberFormatException.forInputString(s); | |
| if (len == 1) // Cannot have lone "+" or "-" | |
| throw NumberFormatException.forInputString(s); | |
| i++; | |
| } | |
| multmin = limit / radix; | |
| while (i < len) { | |
| // Accumulating negatively avoids surprises near MAX_VALUE | |
| digit = Character.digit(s.charAt(i++),radix); | |
| if (digit < 0) { | |
| throw NumberFormatException.forInputString(s); | |
| } | |
| if (result < multmin) { | |
| throw NumberFormatException.forInputString(s); | |
| } | |
| result *= radix; | |
| if (result < limit + digit) { | |
| throw NumberFormatException.forInputString(s); | |
| } | |
| result -= digit; | |
| } | |
| } else { | |
| throw NumberFormatException.forInputString(s); | |
| } | |
| return negative ? result : -result; | |
| }π |
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