1 | /**
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2 | * A Base64 Encoder/Decoder.
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3 | *
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4 | * <p>
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5 | * This class is used to encode and decode data in Base64 format as described in RFC 1521.
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6 | *
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7 | * <p>
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8 | * This is "Open Source" software and released under the <a href="http://www.gnu.org/licenses/lgpl.html">GNU/LGPL</a> license.<br>
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9 | * It is provided "as is" without warranty of any kind.<br>
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10 | * Copyright 2003: Christian d'Heureuse, Inventec Informatik AG, Switzerland.<br>
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11 | * Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br>
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12 | *
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13 | * <p>
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14 | * Version history:<br>
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15 | * 2003-07-22 Christian d'Heureuse (chdh): Module created.<br>
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16 | * 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br>
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17 | * 2006-11-21 chdh:<br>
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18 | * Method encode(String) renamed to encodeString(String).<br>
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19 | * Method decode(String) renamed to decodeString(String).<br>
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20 | * New method encode(byte[],int) added.<br>
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21 | * New method decode(String) added.<br>
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22 | */
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23 | package gov.hhs.fha.nhinc.callback;
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24 |
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25 | public class Base64Coder {
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26 |
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27 | // Mapping table from 6-bit nibbles to Base64 characters.
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28 | private static char[] map1 = new char[64];
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29 | static {
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30 | int i=0;
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31 | for (char c='A'; c<='Z'; c++) map1[i++] = c;
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32 | for (char c='a'; c<='z'; c++) map1[i++] = c;
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33 | for (char c='0'; c<='9'; c++) map1[i++] = c;
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34 | map1[i++] = '+'; map1[i++] = '/'; }
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35 |
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36 | // Mapping table from Base64 characters to 6-bit nibbles.
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37 | private static byte[] map2 = new byte[128];
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38 | static {
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39 | for (int i=0; i<map2.length; i++) map2[i] = -1;
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40 | for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; }
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41 |
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42 | /**
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43 | * Encodes a string into Base64 format.
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44 | * No blanks or line breaks are inserted.
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45 | * @param s a String to be encoded.
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46 | * @return A String with the Base64 encoded data.
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47 | */
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48 | public static String encodeString (String s) {
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49 | return new String(encode(s.getBytes())); }
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50 |
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51 | /**
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52 | * Encodes a byte array into Base64 format.
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53 | * No blanks or line breaks are inserted.
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54 | * @param in an array containing the data bytes to be encoded.
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55 | * @return A character array with the Base64 encoded data.
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56 | */
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57 | public static char[] encode (byte[] in) {
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58 | return encode(in,in.length); }
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59 |
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60 | /**
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61 | * Encodes a byte array into Base64 format.
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62 | * No blanks or line breaks are inserted.
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63 | * @param in an array containing the data bytes to be encoded.
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64 | * @param iLen number of bytes to process in <code>in</code>.
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65 | * @return A character array with the Base64 encoded data.
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66 | */
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67 | public static char[] encode (byte[] in, int iLen) {
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68 | int oDataLen = (iLen*4+2)/3; // output length without padding
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69 | int oLen = ((iLen+2)/3)*4; // output length including padding
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70 | char[] out = new char[oLen];
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71 | int ip = 0;
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72 | int op = 0;
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73 | while (ip < iLen) {
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74 | int i0 = in[ip++] & 0xff;
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75 | int i1 = ip < iLen ? in[ip++] & 0xff : 0;
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76 | int i2 = ip < iLen ? in[ip++] & 0xff : 0;
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77 | int o0 = i0 >>> 2;
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78 | int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
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79 | int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
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80 | int o3 = i2 & 0x3F;
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81 | out[op++] = map1[o0];
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82 | out[op++] = map1[o1];
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83 | out[op] = op < oDataLen ? map1[o2] : '='; op++;
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84 | out[op] = op < oDataLen ? map1[o3] : '='; op++; }
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85 | return out; }
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86 |
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87 | /**
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88 | * Decodes a string from Base64 format.
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89 | * @param s a Base64 String to be decoded.
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90 | * @return A String containing the decoded data.
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91 | * @throws IllegalArgumentException if the input is not valid Base64 encoded data.
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92 | */
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93 | public static String decodeString (String s) {
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94 | return new String(decode(s)); }
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95 |
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96 | /**
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97 | * Decodes a byte array from Base64 format.
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98 | * @param s a Base64 String to be decoded.
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99 | * @return An array containing the decoded data bytes.
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100 | * @throws IllegalArgumentException if the input is not valid Base64 encoded data.
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101 | */
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102 | public static byte[] decode (String s) {
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103 | return decode(s.toCharArray()); }
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104 |
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105 | /**
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106 | * Decodes a byte array from Base64 format.
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107 | * No blanks or line breaks are allowed within the Base64 encoded data.
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108 | * @param in a character array containing the Base64 encoded data.
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109 | * @return An array containing the decoded data bytes.
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110 | * @throws IllegalArgumentException if the input is not valid Base64 encoded data.
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111 | */
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112 | public static byte[] decode (char[] in) {
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113 | int iLen = in.length;
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114 | if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
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115 | while (iLen > 0 && in[iLen-1] == '=') iLen--;
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116 | int oLen = (iLen*3) / 4;
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117 | byte[] out = new byte[oLen];
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118 | int ip = 0;
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119 | int op = 0;
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120 | while (ip < iLen) {
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121 | int i0 = in[ip++];
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122 | int i1 = in[ip++];
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123 | int i2 = ip < iLen ? in[ip++] : 'A';
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124 | int i3 = ip < iLen ? in[ip++] : 'A';
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125 | if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
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126 | throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
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127 | int b0 = map2[i0];
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128 | int b1 = map2[i1];
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129 | int b2 = map2[i2];
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130 | int b3 = map2[i3];
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131 | if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
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132 | throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
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133 | int o0 = ( b0 <<2) | (b1>>>4);
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134 | int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
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135 | int o2 = ((b2 & 3)<<6) | b3;
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136 | out[op++] = (byte)o0;
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137 | if (op<oLen) out[op++] = (byte)o1;
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138 | if (op<oLen) out[op++] = (byte)o2; }
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139 | return out; }
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140 |
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141 | // Dummy constructor.
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142 | private Base64Coder() {}
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143 |
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144 | } // end class Base64Coder
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