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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.primitives;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import javax.annotation.CheckForNull;
/**
* Static utility methods derived from Android's {@code Integer.java}.
*/
final class AndroidInteger {
/**
* See {@link Ints#tryParse(String)} for the public interface.
*/
@CheckForNull
static Integer tryParse(String string) {
return tryParse(string, 10);
}
/**
* See {@link Ints#tryParse(String, int)} for the public interface.
*/
@CheckForNull
static Integer tryParse(String string, int radix) {
checkNotNull(string);
checkArgument(radix >= Character.MIN_RADIX,
"Invalid radix %s, min radix is %s", radix, Character.MIN_RADIX);
checkArgument(radix <= Character.MAX_RADIX,
"Invalid radix %s, max radix is %s", radix, Character.MAX_RADIX);
int length = string.length(), i = 0;
if (length == 0) {
return null;
}
boolean negative = string.charAt(i) == '-';
if (negative && ++i == length) {
return null;
}
return tryParse(string, i, radix, negative);
}
@CheckForNull
private static Integer tryParse(String string, int offset, int radix,
boolean negative) {
int max = Integer.MIN_VALUE / radix;
int result = 0, length = string.length();
while (offset < length) {
int digit = Character.digit(string.charAt(offset++), radix);
if (digit == -1) {
return null;
}
if (max > result) {
return null;
}
int next = result * radix - digit;
if (next > result) {
return null;
}
result = next;
}
if (!negative) {
result = -result;
if (result < 0) {
return null;
}
}
// For GWT where ints do not overflow
if (result > Integer.MAX_VALUE || result < Integer.MIN_VALUE) {
return null;
}
return result;
}
private AndroidInteger() {}
}
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