Base64

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package com.cardvalue.sys.widget;import java.io.ByteArrayOutputStream;final class Base64 {    private static final char[] base64EncodeChars = new char[] {        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',        'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',        'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',        'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',        'o', 'p', 'q', 'r', 's', 't', 'u', 'v',        'w', 'x', 'y', 'z', '0', '1', '2', '3',        '4', '5', '6', '7', '8', '9', '+', '/' };    private static final byte[] base64DecodeChars = new byte[] {    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,    -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };    private Base64() {}    public static final String encode(byte[] data) {        StringBuilder sb = new StringBuilder();        int r = data.length % 3;        int len = data.length - r;        int i = 0;        int c;        while (i < len) {            c = (0x000000ff & data[i++]) << 16 |                (0x000000ff & data[i++]) << 8  |                (0x000000ff & data[i++]);            sb.append(base64EncodeChars[c >> 18]);            sb.append(base64EncodeChars[c >> 12 & 0x3f]);            sb.append(base64EncodeChars[c >> 6  & 0x3f]);            sb.append(base64EncodeChars[c & 0x3f]);        }        if (r == 1) {            c = 0x000000ff & data[i++];            sb.append(base64EncodeChars[c >> 2]);            sb.append(base64EncodeChars[(c & 0x03) << 4]);            sb.append("==");        }        else if (r == 2) {            c = (0x000000ff & data[i++]) << 8 |                (0x000000ff & data[i++]);            sb.append(base64EncodeChars[c >> 10]);            sb.append(base64EncodeChars[c >> 4 & 0x3f]);            sb.append(base64EncodeChars[(c & 0x0f) << 2]);            sb.append("=");        }        return sb.toString();    }    public static final byte[] decode(String str) {        byte[] data = str.getBytes();        int len = data.length;        ByteArrayOutputStream buf = new ByteArrayOutputStream(len);        int i = 0;        int b1, b2, b3, b4;        while (i < len) {            /* b1 */            do {                b1 = base64DecodeChars[data[i++]];            } while (i < len && b1 == -1);            if (b1 == -1) {                break;            }            /* b2 */            do {                b2 = base64DecodeChars[data[i++]];            } while (i < len && b2 == -1);            if (b2 == -1) {                break;            }            buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));            /* b3 */            do {                b3 = data[i++];                if (b3 == 61) {                    return buf.toByteArray();                }                b3 = base64DecodeChars[b3];            } while (i < len && b3 == -1);            if (b3 == -1) {                break;            }            buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));            /* b4 */            do {                b4 = data[i++];                if (b4 == 61) {                    return buf.toByteArray();                }                b4 = base64DecodeChars[b4];            } while (i < len && b4 == -1);            if (b4 == -1) {                break;            }            buf.write((int) (((b3 & 0x03) << 6) | b4));        }        return buf.toByteArray();    }}
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