com.mixpanel.mixpanelapi.Base64Coder Maven / Gradle / Ivy

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package com.mixpanel.mixpanelapi;

//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.
//
// This file has been modified from it's original version by Mixpanel, Inc

/* package */ class Base64Coder {

    // 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; iin.
    * @return     A character array with the Base64 encoded data.
    */
    public static char[] encode (byte[] in, 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 = 0;
       int op = 0;
       while (ip < iLen) {
          int i0 = in[ip++] & 0xff;
          int i1 = ip < iLen ? in[ip++] & 0xff : 0;
          int i2 = ip < iLen ? 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.
    * @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.
    * @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 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) {
       int iLen = in.length;
       if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
       while (iLen > 0 && in[iLen-1] == '=') iLen--;
       int oLen = (iLen*3) / 4;
       byte[] out = new byte[oLen];
       int ip = 0;
       int op = 0;
       while (ip < iLen) {
          int i0 = in[ip++];
          int i1 = in[ip++];
          int i2 = ip < iLen ? in[ip++] : 'A';
          int i3 = ip < iLen ? 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