// Copyright 2003-2010 Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland
// www.source-code.biz, www.inventec.ch/chdh
//
// This module is multi-licensed and may be used under the terms
// of any of the following licenses:
//
//  EPL, Eclipse Public License, V1.0 or later, http://www.eclipse.org/legal
//  LGPL, GNU Lesser General Public License, V2.1 or later, http://www.gnu.org/licenses/lgpl.html
//  GPL, GNU General Public License, V2 or later, http://www.gnu.org/licenses/gpl.html
//  AL, Apache License, V2.0 or later, http://www.apache.org/licenses
//  BSD, BSD License, http://www.opensource.org/licenses/bsd-license.php
//
// Please contact the author if you need another license.
// This module is provided "as is", without warranties of any kind.

package org.yaml.snakeyaml.external.biz.base64Coder;

A Base64 encoder/decoder.

This class is used to encode and decode data in Base64 format as described in
RFC 1521.

Project home page: www.
source-code.biz/base64coder/java

Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland

Multi-licensed: EPL / LGPL / GPL / AL / BSD.
/**
 * A Base64 encoder/decoder.
 * 
 * <p>
 * This class is used to encode and decode data in Base64 format as described in
 * RFC 1521.
 * 
 * <p>
 * Project home page: <a
 * href="http://www.source-code.biz/base64coder/java/">www.
 * source-code.biz/base64coder/java</a><br>
 * Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland<br>
 * Multi-licensed: EPL / LGPL / GPL / AL / BSD.
 */
public class Base64Coder {

    // The line separator string of the operating system.
    private static final String systemLineSeparator = System.getProperty("line.separator");

    // Mapping table from 6-bit nibbles to Base64 characters.
    private static char[] map1 = new char[64];
    static {
        int i = 0;
        for (char c = 'A'; c <= 'Z'; c++)
            map1[i++] = c;
        for (char c = 'a'; c <= 'z'; c++)
            map1[i++] = c;
        for (char c = '0'; c <= '9'; c++)
            map1[i++] = c;
        map1[i++] = '+';
        map1[i++] = '/';
    }

    // Mapping table from Base64 characters to 6-bit nibbles.
    private static byte[] map2 = new byte[128];
    static {
        for (int i = 0; i < map2.length; i++)
            map2[i] = -1;
        for (int i = 0; i < 64; i++)
            map2[map1[i]] = (byte) i;
    }

    
Encodes a string into Base64 format. No blanks or line breaks are
inserted.
Params:
s – 
           A String to be encoded.
Returns:
A String containing the Base64 encoded data./**
     * Encodes a string into Base64 format. No blanks or line breaks are
     * inserted.
     * 
     * @param s
     *            A String to be encoded.
     * @return A String containing the Base64 encoded data.
     */
    public static String encodeString(String s) {
        return new String(encode(s.getBytes()));
    }

    
Encodes a byte array into Base 64 format and breaks the output into lines
of 76 characters. This method is compatible with
sun.misc.BASE64Encoder.encodeBuffer(byte[]).
Params:
in – 
           An array containing the data bytes to be encoded.
Returns:
A String containing the Base64 encoded data, broken into lines./**
     * Encodes a byte array into Base 64 format and breaks the output into lines
     * of 76 characters. This method is compatible with
     * <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.
     * 
     * @param in
     *            An array containing the data bytes to be encoded.
     * @return A String containing the Base64 encoded data, broken into lines.
     */
    public static String encodeLines(byte[] in) {
        return encodeLines(in, 0, in.length, 76, systemLineSeparator);
    }

    
Encodes a byte array into Base 64 format and breaks the output into
lines.
Params:
in – 
           An array containing the data bytes to be encoded.
iOff – 
           Offset of the first byte in in to be processed.
iLen – 
           Number of bytes to be processed in in, starting
           at iOff.
lineLen – 
           Line length for the output data. Should be a multiple of 4.
lineSeparator – 
           The line separator to be used to separate the output lines.
Returns:
A String containing the Base64 encoded data, broken into lines./**
     * Encodes a byte array into Base 64 format and breaks the output into
     * lines.
     * 
     * @param in
     *            An array containing the data bytes to be encoded.
     * @param iOff
     *            Offset of the first byte in <code>in</code> to be processed.
     * @param iLen
     *            Number of bytes to be processed in <code>in</code>, starting
     *            at <code>iOff</code>.
     * @param lineLen
     *            Line length for the output data. Should be a multiple of 4.
     * @param lineSeparator
     *            The line separator to be used to separate the output lines.
     * @return A String containing the Base64 encoded data, broken into lines.
     */
    public static String encodeLines(byte[] in, int iOff, int iLen, int lineLen,
            String lineSeparator) {
        int blockLen = (lineLen * 3) / 4;
        if (blockLen <= 0)
            throw new IllegalArgumentException();
        int lines = (iLen + blockLen - 1) / blockLen;
        int bufLen = ((iLen + 2) / 3) * 4 + lines * lineSeparator.length();
        StringBuilder buf = new StringBuilder(bufLen);
        int ip = 0;
        while (ip < iLen) {
            int l = Math.min(iLen - ip, blockLen);
            buf.append(encode(in, iOff + ip, l));
            buf.append(lineSeparator);
            ip += l;
        }
        return buf.toString();
    }

    
Encodes a byte array into Base64 format. No blanks or line breaks are
inserted in the output.
Params:
in – 
           An array containing the data bytes to be encoded.
Returns:
A character array containing the Base64 encoded data./**
     * Encodes a byte array into Base64 format. No blanks or line breaks are
     * inserted in the output.
     * 
     * @param in
     *            An array containing the data bytes to be encoded.
     * @return A character array containing the Base64 encoded data.
     */
    public static char[] encode(byte[] in) {
        return encode(in, 0, in.length);
    }

    
Encodes a byte array into Base64 format. No blanks or line breaks are
inserted in the output.
Params:
in – 
           An array containing the data bytes to be encoded.
iLen – 
           Number of bytes to process in in.
Returns:
A character array containing the Base64 encoded data./**
     * Encodes a byte array into Base64 format. No blanks or line breaks are
     * inserted in the output.
     * 
     * @param in
     *            An array containing the data bytes to be encoded.
     * @param iLen
     *            Number of bytes to process in <code>in</code>.
     * @return A character array containing the Base64 encoded data.
     */
    public static char[] encode(byte[] in, int iLen) {
        return encode(in, 0, iLen);
    }

    
Encodes a byte array into Base64 format. No blanks or line breaks are
inserted in the output.
Params:
in – 
           An array containing the data bytes to be encoded.
iOff – 
           Offset of the first byte in in to be processed.
iLen – 
           Number of bytes to process in in, starting at
           iOff.
Returns:
A character array containing the Base64 encoded data./**
     * Encodes a byte array into Base64 format. No blanks or line breaks are
     * inserted in the output.
     * 
     * @param in
     *            An array containing the data bytes to be encoded.
     * @param iOff
     *            Offset of the first byte in <code>in</code> to be processed.
     * @param iLen
     *            Number of bytes to process in <code>in</code>, starting at
     *            <code>iOff</code>.
     * @return A character array containing the Base64 encoded data.
     */
    public static char[] encode(byte[] in, int iOff, int iLen) {
        int oDataLen = (iLen * 4 + 2) / 3; // output length without padding
        int oLen = ((iLen + 2) / 3) * 4; // output length including padding
        char[] out = new char[oLen];
        int ip = iOff;
        int iEnd = iOff + iLen;
        int op = 0;
        while (ip < iEnd) {
            int i0 = in[ip++] & 0xff;
            int i1 = ip < iEnd ? in[ip++] & 0xff : 0;
            int i2 = ip < iEnd ? in[ip++] & 0xff : 0;
            int o0 = i0 >>> 2;
            int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
            int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
            int o3 = i2 & 0x3F;
            out[op++] = map1[o0];
            out[op++] = map1[o1];
            out[op] = op < oDataLen ? map1[o2] : '=';
            op++;
            out[op] = op < oDataLen ? map1[o3] : '=';
            op++;
        }
        return out;
    }

    
Decodes a string from Base64 format. No blanks or line breaks are allowed
within the Base64 encoded input data.
Params:
s – 
           A Base64 String to be decoded.
Throws:
IllegalArgumentException – 
            If the input is not valid Base64 encoded data.
Returns:
A String containing the decoded data./**
     * Decodes a string from Base64 format. No blanks or line breaks are allowed
     * within the Base64 encoded input data.
     * 
     * @param s
     *            A Base64 String to be decoded.
     * @return A String containing the decoded data.
     * @throws IllegalArgumentException
     *             If the input is not valid Base64 encoded data.
     */
    public static String decodeString(String s) {
        return new String(decode(s));
    }

    
Decodes a byte array from Base64 format and ignores line separators, tabs
and blanks. CR, LF, Tab and Space characters are ignored in the input
data. This method is compatible with
sun.misc.BASE64Decoder.decodeBuffer(String).
Params:
s – 
           A Base64 String to be decoded.
Throws:
IllegalArgumentException – 
            If the input is not valid Base64 encoded data.
Returns:
An array containing the decoded data bytes./**
     * Decodes a byte array from Base64 format and ignores line separators, tabs
     * and blanks. CR, LF, Tab and Space characters are ignored in the input
     * data. This method is compatible with
     * <code>sun.misc.BASE64Decoder.decodeBuffer(String)</code>.
     * 
     * @param s
     *            A Base64 String to be decoded.
     * @return An array containing the decoded data bytes.
     * @throws IllegalArgumentException
     *             If the input is not valid Base64 encoded data.
     */
    public static byte[] decodeLines(String s) {
        char[] buf = new char[s.length()];
        int p = 0;
        for (int ip = 0; ip < s.length(); ip++) {
            char c = s.charAt(ip);
            if (c != ' ' && c != '\r' && c != '\n' && c != '\t')
                buf[p++] = c;
        }
        return decode(buf, 0, p);
    }

    
Decodes a byte array from Base64 format. No blanks or line breaks are
allowed within the Base64 encoded input data.
Params:
s – 
           A Base64 String to be decoded.
Throws:
IllegalArgumentException – 
            If the input is not valid Base64 encoded data.
Returns:
An array containing the decoded data bytes./**
     * Decodes a byte array from Base64 format. No blanks or line breaks are
     * allowed within the Base64 encoded input data.
     * 
     * @param s
     *            A Base64 String to be decoded.
     * @return An array containing the decoded data bytes.
     * @throws IllegalArgumentException
     *             If the input is not valid Base64 encoded data.
     */
    public static byte[] decode(String s) {
        return decode(s.toCharArray());
    }

    
Decodes a byte array from Base64 format. No blanks or line breaks are
allowed within the Base64 encoded input data.
Params:
in – 
           A character array containing the Base64 encoded data.
Throws:
IllegalArgumentException – 
            If the input is not valid Base64 encoded data.
Returns:
An array containing the decoded data bytes./**
     * Decodes a byte array from Base64 format. No blanks or line breaks are
     * allowed within the Base64 encoded input data.
     * 
     * @param in
     *            A character array containing the Base64 encoded data.
     * @return An array containing the decoded data bytes.
     * @throws IllegalArgumentException
     *             If the input is not valid Base64 encoded data.
     */
    public static byte[] decode(char[] in) {
        return decode(in, 0, in.length);
    }

    
Decodes a byte array from Base64 format. No blanks or line breaks are
allowed within the Base64 encoded input data.
Params:
in – 
           A character array containing the Base64 encoded data.
iOff – 
           Offset of the first character in in to be
           processed.
iLen – 
           Number of characters to process in in, starting
           at iOff.
Throws:
IllegalArgumentException – 
            If the input is not valid Base64 encoded data.
Returns:
An array containing the decoded data bytes./**
     * Decodes a byte array from Base64 format. No blanks or line breaks are
     * allowed within the Base64 encoded input data.
     * 
     * @param in
     *            A character array containing the Base64 encoded data.
     * @param iOff
     *            Offset of the first character in <code>in</code> to be
     *            processed.
     * @param iLen
     *            Number of characters to process in <code>in</code>, starting
     *            at <code>iOff</code>.
     * @return An array containing the decoded data bytes.
     * @throws IllegalArgumentException
     *             If the input is not valid Base64 encoded data.
     */
    public static byte[] decode(char[] in, int iOff, int iLen) {
        if (iLen % 4 != 0)
            throw new IllegalArgumentException(
                    "Length of Base64 encoded input string is not a multiple of 4.");
        while (iLen > 0 && in[iOff + iLen - 1] == '=')
            iLen--;
        int oLen = (iLen * 3) / 4;
        byte[] out = new byte[oLen];
        int ip = iOff;
        int iEnd = iOff + iLen;
        int op = 0;
        while (ip < iEnd) {
            int i0 = in[ip++];
            int i1 = in[ip++];
            int i2 = ip < iEnd ? in[ip++] : 'A';
            int i3 = ip < iEnd ? in[ip++] : 'A';
            if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
                throw new IllegalArgumentException("Illegal character in Base64 encoded data.");
            int b0 = map2[i0];
            int b1 = map2[i1];
            int b2 = map2[i2];
            int b3 = map2[i3];
            if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
                throw new IllegalArgumentException("Illegal character in Base64 encoded data.");
            int o0 = (b0 << 2) | (b1 >>> 4);
            int o1 = ((b1 & 0xf) << 4) | (b2 >>> 2);
            int o2 = ((b2 & 3) << 6) | b3;
            out[op++] = (byte) o0;
            if (op < oLen)
                out[op++] = (byte) o1;
            if (op < oLen)
                out[op++] = (byte) o2;
        }
        return out;
    }

    // Dummy constructor.
    private Base64Coder() {
    }

} // end class Base64Coder