package com.walker.security;
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public final class Base64 {
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private static final byte[] encodingTable = {
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(byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E',
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(byte) 'F', (byte) 'G', (byte) 'H', (byte) 'I', (byte) 'J',
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(byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O',
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(byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T',
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(byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y',
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(byte) 'Z', (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd',
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(byte) 'e', (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i',
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(byte) 'j', (byte) 'k', (byte) 'l', (byte) 'm', (byte) 'n',
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(byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's',
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(byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x',
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(byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2',
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(byte) '3', (byte) '4', (byte) '5', (byte) '6', (byte) '7',
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(byte) '8', (byte) '9', (byte) '+', (byte) '/'
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};
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private static final byte[] decodingTable;
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static {
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decodingTable = new byte[128];
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for (int i = 0; i < 128; i++) {
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decodingTable[i] = (byte) -1;
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}
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for (int i = 'A'; i <= 'Z'; i++) {
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decodingTable[i] = (byte) (i - 'A');
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}
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for (int i = 'a'; i <= 'z'; i++) {
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decodingTable[i] = (byte) (i - 'a' + 26);
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}
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for (int i = '0'; i <= '9'; i++) {
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decodingTable[i] = (byte) (i - '0' + 52);
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}
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decodingTable['+'] = 62;
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decodingTable['/'] = 63;
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}
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public static byte[] encode(byte[] data)
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{
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byte[] bytes;
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int modulus = data.length % 3;
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if (modulus == 0) {
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bytes = new byte[(4 * data.length) / 3];
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} else {
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bytes = new byte[4 * ((data.length / 3) + 1)];
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}
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int dataLength = (data.length - modulus);
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int a1;
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int a2;
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int a3;
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for (int i = 0, j = 0; i < dataLength; i += 3, j += 4) {
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a1 = data[i] & 0xff;
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a2 = data[i + 1] & 0xff;
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a3 = data[i + 2] & 0xff;
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bytes[j] = encodingTable[(a1 >>> 2) & 0x3f];
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bytes[j + 1] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f];
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bytes[j + 2] = encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f];
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bytes[j + 3] = encodingTable[a3 & 0x3f];
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}
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int b1;
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int b2;
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int b3;
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int d1;
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int d2;
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switch (modulus) {
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case 0: /* nothing left to do */
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break;
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case 1:
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d1 = data[data.length - 1] & 0xff;
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b1 = (d1 >>> 2) & 0x3f;
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b2 = (d1 << 4) & 0x3f;
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bytes[bytes.length - 4] = encodingTable[b1];
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bytes[bytes.length - 3] = encodingTable[b2];
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bytes[bytes.length - 2] = (byte) '=';
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bytes[bytes.length - 1] = (byte) '=';
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break;
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case 2:
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d1 = data[data.length - 2] & 0xff;
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d2 = data[data.length - 1] & 0xff;
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b1 = (d1 >>> 2) & 0x3f;
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b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
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b3 = (d2 << 2) & 0x3f;
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bytes[bytes.length - 4] = encodingTable[b1];
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bytes[bytes.length - 3] = encodingTable[b2];
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bytes[bytes.length - 2] = encodingTable[b3];
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bytes[bytes.length - 1] = (byte) '=';
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break;
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}
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return bytes;
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}
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public static byte[] encodeBase64(byte[] sourceBytes){
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return Base64.encode(sourceBytes);
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}
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public static byte[] decode(byte[] data) {
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byte[] bytes;
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byte b1;
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byte b2;
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byte b3;
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byte b4;
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data = discardNonBase64Bytes(data);
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if (data[data.length - 2] == '=') {
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bytes = new byte[(((data.length / 4) - 1) * 3) + 1];
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} else if (data[data.length - 1] == '=') {
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bytes = new byte[(((data.length / 4) - 1) * 3) + 2];
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} else {
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bytes = new byte[((data.length / 4) * 3)];
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}
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for (int i = 0, j = 0; i < (data.length - 4); i += 4, j += 3) {
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b1 = decodingTable[data[i]];
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b2 = decodingTable[data[i + 1]];
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b3 = decodingTable[data[i + 2]];
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b4 = decodingTable[data[i + 3]];
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bytes[j] = (byte) ((b1 << 2) | (b2 >> 4));
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bytes[j + 1] = (byte) ((b2 << 4) | (b3 >> 2));
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bytes[j + 2] = (byte) ((b3 << 6) | b4);
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}
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if (data[data.length - 2] == '=') {
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b1 = decodingTable[data[data.length - 4]];
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b2 = decodingTable[data[data.length - 3]];
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bytes[bytes.length - 1] = (byte) ((b1 << 2) | (b2 >> 4));
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} else if (data[data.length - 1] == '=') {
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b1 = decodingTable[data[data.length - 4]];
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b2 = decodingTable[data[data.length - 3]];
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b3 = decodingTable[data[data.length - 2]];
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bytes[bytes.length - 2] = (byte) ((b1 << 2) | (b2 >> 4));
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bytes[bytes.length - 1] = (byte) ((b2 << 4) | (b3 >> 2));
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} else {
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b1 = decodingTable[data[data.length - 4]];
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b2 = decodingTable[data[data.length - 3]];
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b3 = decodingTable[data[data.length - 2]];
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b4 = decodingTable[data[data.length - 1]];
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bytes[bytes.length - 3] = (byte) ((b1 << 2) | (b2 >> 4));
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bytes[bytes.length - 2] = (byte) ((b2 << 4) | (b3 >> 2));
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bytes[bytes.length - 1] = (byte) ((b3 << 6) | b4);
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}
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return bytes;
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}
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public static byte[] decode(String data) {
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byte[] bytes;
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byte b1;
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byte b2;
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byte b3;
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byte b4;
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data = discardNonBase64Chars(data);
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if (data.charAt(data.length() - 2) == '=') {
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bytes = new byte[(((data.length() / 4) - 1) * 3) + 1];
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} else if (data.charAt(data.length() - 1) == '=') {
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bytes = new byte[(((data.length() / 4) - 1) * 3) + 2];
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} else {
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bytes = new byte[((data.length() / 4) * 3)];
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}
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for (int i = 0, j = 0; i < (data.length() - 4); i += 4, j += 3) {
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b1 = decodingTable[data.charAt(i)];
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b2 = decodingTable[data.charAt(i + 1)];
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b3 = decodingTable[data.charAt(i + 2)];
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b4 = decodingTable[data.charAt(i + 3)];
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bytes[j] = (byte) ((b1 << 2) | (b2 >> 4));
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bytes[j + 1] = (byte) ((b2 << 4) | (b3 >> 2));
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bytes[j + 2] = (byte) ((b3 << 6) | b4);
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}
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if (data.charAt(data.length() - 2) == '=') {
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b1 = decodingTable[data.charAt(data.length() - 4)];
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b2 = decodingTable[data.charAt(data.length() - 3)];
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bytes[bytes.length - 1] = (byte) ((b1 << 2) | (b2 >> 4));
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} else if (data.charAt(data.length() - 1) == '=') {
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b1 = decodingTable[data.charAt(data.length() - 4)];
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b2 = decodingTable[data.charAt(data.length() - 3)];
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b3 = decodingTable[data.charAt(data.length() - 2)];
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bytes[bytes.length - 2] = (byte) ((b1 << 2) | (b2 >> 4));
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bytes[bytes.length - 1] = (byte) ((b2 << 4) | (b3 >> 2));
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} else {
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b1 = decodingTable[data.charAt(data.length() - 4)];
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b2 = decodingTable[data.charAt(data.length() - 3)];
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b3 = decodingTable[data.charAt(data.length() - 2)];
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b4 = decodingTable[data.charAt(data.length() - 1)];
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bytes[bytes.length - 3] = (byte) ((b1 << 2) | (b2 >> 4));
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bytes[bytes.length - 2] = (byte) ((b2 << 4) | (b3 >> 2));
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bytes[bytes.length - 1] = (byte) ((b3 << 6) | b4);
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}
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return bytes;
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}
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public static String decodeBase64(byte[] base64EncryptBytes){
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return new String(decode(base64EncryptBytes));
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}
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private static byte[] discardNonBase64Bytes(byte[] data) {
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byte[] temp = new byte[data.length];
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int bytesCopied = 0;
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for (int i = 0; i < data.length; i++) {
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if (isValidBase64Byte(data[i])) {
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temp[bytesCopied++] = data[i];
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}
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}
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byte[] newData = new byte[bytesCopied];
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System.arraycopy(temp, 0, newData, 0, bytesCopied);
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return newData;
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}
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private static String discardNonBase64Chars(String data) {
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StringBuffer sb = new StringBuffer();
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int length = data.length();
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for (int i = 0; i < length; i++) {
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if (isValidBase64Byte((byte) (data.charAt(i)))) {
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sb.append(data.charAt(i));
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}
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}
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return sb.toString();
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}
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private static boolean isValidBase64Byte(byte b) {
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if (b == '=') {
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return true;
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} else if ((b < 0) || (b >= 128)) {
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return false;
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} else if (decodingTable[b] == -1) {
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return false;
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}
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return true;
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}
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// public static void main(String[] args) {
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// String data = "中华人民共$和国";
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// byte[] result = Base64.encode(data.getBytes());
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// System.out.println(data);
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// System.out.println(new String(result));
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// System.out.println(new String(Base64.decode(new String(result))));
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// }
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}
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