48 lines
1.3 KiB
Java
48 lines
1.3 KiB
Java
/*
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* This file is part of the Wildfire Chat package.
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* (c) Heavyrain2012 <[email protected]>
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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package win.liyufan.im;
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import java.util.HashMap;
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import java.util.HashSet;
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public class IDUtils {
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private static final int RADIX = 36;
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private static final int IDLEN = 9;
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private static final int[] FACTOR = {29,19,1,11,7,17,13,23,5};
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private static char getChar(long number) {
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if (number < 26) {
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return (char)('a' + number);
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} else {
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return (char)('0' + number - 26);
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}
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}
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public static String toUid(long id) {
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StringBuilder sb = new StringBuilder();
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for (int i = 0; i < IDLEN; i++) {
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long bit = ((id % RADIX) * FACTOR[i] + FACTOR[i] + 5)%RADIX;
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sb.append(getChar(bit));
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id = id / RADIX;
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}
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return sb.toString();
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}
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public static void main(String[] args) {
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HashSet<String> idset = new HashSet<>();
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for (long i = 0; i < 1000000000000L; i++) {
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String uid = toUid(i);
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if(!idset.add(uid)) {
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System.out.println("error, dupliate id");
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System.exit(-1);
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}
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}
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}
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}
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