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Base64Encoding.javaAPI DocphoneME MR2 API (J2ME)6474Wed May 02 18:00:28 BST 2007com.sun.kvem.midp.pim.formats

Base64Encoding

public class Base64Encoding extends Object
Converter to and from Base64 encoding. Base64 encoding is defined in RFC 2045.

Fields Summary
private static char[]
BASE64_CHARS
Constants for conversion of binary data to Base64. From RFC 2045.
private static byte[]
BASE64_BYTES
Constants for conversion of Base64 data to binary. The inverse of the above table.
Constructors Summary
Methods Summary
public static byte[]fromBase64(java.lang.String sdata)
Converts a BASE64 string to a byte array.

param
sdata the string to be converted
return
the byte array content of the string

    
                                
         
        if (sdata == null || sdata.length() < 2) {
            return new byte[0];
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        // copy the string to an array, and pad the end of the data with
        // '=' characters.
        int length = sdata.length();
        char[] data = new char[length + 2];
        sdata.getChars(0, length, data, 0);
        data[length] = '=";
        data[length + 1] = '=";
        for (int i = nextCharIndex(data, 0); i < data.length; ) {
            int char0 = data[i = nextCharIndex(data, i)];
            if (char0 == '=") {
                break;
            }
            int char1 = data[i = nextCharIndex(data, i + 1)];
            if (char1 == '=") {
                // stop here. this is not a valid Base64 fragment
                break;
            }
            int char2 = data[i = nextCharIndex(data, i + 1)];
            int char3 = data[i = nextCharIndex(data, i + 1)];
            i = nextCharIndex(data, i + 1);
            out.write(BASE64_BYTES[char0] << 2 | BASE64_BYTES[char1] >> 4);
            if (char2 == '=") {
                // only one byte
            } else {
                int value = BASE64_BYTES[char1] << 4 | BASE64_BYTES[char2] >> 2;
                out.write(value & 0xff);
                if (char3 == '=") {
                    // only 2 bytes
                } else {
                    value = BASE64_BYTES[char2] << 6 | BASE64_BYTES[char3];
                    out.write(value & 0xff);
                }
            }
        }
        return out.toByteArray();
private static intnextCharIndex(char[] data, int i)
Gets the index of the first character in the given array that contains valid Base64 data. Starts searching from the given index "i".

param
data input buffer
param
i starting offset in the input buffer
return
offset of first BASE64 char

        while (i < data.length &&
        (data[i] > 0x7f || BASE64_BYTES[data[i]] == -1)) {
            
            i ++;
        }
        return i;
public static java.lang.StringtoBase64(byte[] data, int lineLength, int indent)
Converts a byte array to a BASE64 string.

param
data the binary data to be converted
param
lineLength the length of lines to be created
param
indent the number of blank spaces to write at the beginning of each line
return
BASE64 string

        StringBuffer sb = new StringBuffer();
        for (int i = 0, charsInLine = 0; i < data.length; ) {
            int byte0 = ((int) data[i++]) & 0xff;
            int byte1 = (i < data.length) ? ((int) data[i++]) & 0xff : 0x100;
            int byte2 = (i < data.length) ?  ((int) data[i++]) & 0xff : 0x100;

            sb.append(BASE64_CHARS[ byte0 >> 2 ]);
            if (byte1 == 0x100) {
                sb.append(BASE64_CHARS[ (byte0 << 4) & 0x30]);
                sb.append("==");
            } else {
                sb.append(BASE64_CHARS[ (byte0 << 4 | byte1 >> 4) & 0x3f]);
                if (byte2 == 0x100) {
                    sb.append(BASE64_CHARS[ (byte1 << 2) & 0x3f]);
                    sb.append('=");
                } else {
                    sb.append(BASE64_CHARS[ (byte1 << 2 | byte2 >> 6) & 0x3f]);
                    sb.append(BASE64_CHARS[ byte2 & 0x3f ]);
                }
            }
            charsInLine += 4;
            if (charsInLine + 4 > lineLength && i < data.length) {
                sb.append("\r\n");
                for (int j = 0; j < indent; j++) {
                    sb.append(' ");
                }
            }
        }
        return sb.toString();