Android Open Source - snakk-ads-android-sample-app Base64

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License

The source code is released under:

Copyright (c) 2012, Snakk! Media Group All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are m...

Java Source Code

package com.snakk.adview;
/*from   w w  w  .  j  a  va2 s  . c o m*/
/**
 * A Base64 Encoder/Decoder.
 */

public class Base64 {

  // 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.
   * 
   * @param s
   *            a String to be encoded.
   * @return A String with the Base64 encoded data.
   */
  public static String encodeString(String s) {
    return new String(encode(s.getBytes()));
  }

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

  /**
   * Encodes a byte array into Base64 format. No blanks or line breaks are
   * inserted.
   * 
   * @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 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. "
            + i0);
      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 Base64() {
  }

}

Java Source Code List

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