cb85a0fa35
* Improvement in Base64 Added a private constructor to hide the implicit public one. Modified the switch statement by the 'if' statement to increase readability. Merge 'if' blocks with equal implementations. Extracted the ternary operation nested in an independent declaration. * Removed unnecessary method. Bringing back the braces. Clarifying ternary operation with parentheses.
86 lines
2.4 KiB
Java
86 lines
2.4 KiB
Java
package com.rarchives.ripme.utils;
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/**
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* Base64 encoder/decoder
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* From http://stackoverflow.com/a/4265472
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*/
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public class Base64 {
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private final static char[] ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
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private static int[] toInt = new int[128];
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static {
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for (int i = 0; i < ALPHABET.length; i++) {
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toInt[ALPHABET[i]] = i;
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}
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}
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private Base64() {
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}
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/**
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* Translates the specified byte array into Base64 string.
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*
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* @param buf the byte array (not null)
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* @return the translated Base64 string (not null)
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*/
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public static String encode(byte[] buf) {
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int size = buf.length;
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char[] ar = new char[((size + 2) / 3) * 4];
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int a = 0;
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int i = 0;
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while (i < size) {
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byte b0 = buf[i++];
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byte b1 = (i < size) ? buf[i++] : 0;
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byte b2 = (i < size) ? buf[i++] : 0;
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int mask = 0x3F;
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ar[a++] = ALPHABET[(b0 >> 2) & mask];
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ar[a++] = ALPHABET[((b0 << 4) | ((b1 & 0xFF) >> 4)) & mask];
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ar[a++] = ALPHABET[((b1 << 2) | ((b2 & 0xFF) >> 6)) & mask];
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ar[a++] = ALPHABET[b2 & mask];
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}
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if (size % 3 == 1 || size % 3 == 2) {
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ar[--a] = '=';
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}
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return new String(ar);
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}
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/**
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* Translates the specified Base64 string into a byte array.
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*
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* @param s the Base64 string (not null)
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* @return the byte array (not null)
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*/
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public static byte[] decode(String s) {
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int delta = s.endsWith("==") ? 2 : (s.endsWith("=") ? 1 : 0);
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byte[] buffer = new byte[s.length() * 3 / 4 - delta];
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int mask = 0xFF;
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int index = 0;
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for (int i = 0; i < s.length(); i += 4) {
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int c0 = toInt[s.charAt(i)];
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int c1 = toInt[s.charAt(i + 1)];
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buffer[index++] = (byte) (((c0 << 2) | (c1 >> 4)) & mask);
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if (index >= buffer.length) {
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return buffer;
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}
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int c2 = toInt[s.charAt(i + 2)];
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buffer[index++] = (byte) (((c1 << 4) | (c2 >> 2)) & mask);
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if (index >= buffer.length) {
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return buffer;
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}
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int c3 = toInt[s.charAt(i + 3)];
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buffer[index++] = (byte) (((c2 << 6) | c3) & mask);
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}
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return buffer;
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}
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} |