// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.tools;
import java.nio.ByteBuffer;
/**
* This class implements an encoder for encoding byte and character data using the
* Base64 encoding scheme as specified in
* RFC 2045 ("base64", default) and
* RFC 4648 ("base64url").
* @since 195
*/
public final class Base64 {
// TODO: Remove this class when switching to Java 8 (finally integrated in Java SE as java.util.Base64.Encoder)
private Base64() {
// Hide default constructor for utils classes
}
/** "base64": RFC 2045 default encoding */
private static String encDefault = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/** "base64url": RFC 4648 url-safe encoding */
private static String encUrlSafe = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
/**
* Encodes all characters from the specified string into a new String using the Base64 default encoding scheme.
* @param s the string to encode
* @return A new string containing the resulting encoded characters.
*/
public static String encode(String s) {
return encode(s, false);
}
/**
* Encodes all characters from the specified string into a new String using a supported Base64 encoding scheme.
* @param s the string to encode
* @param urlsafe if {@code true}, uses "base64url" encoding, otherwise use the "base64" default encoding
* @return A new string containing the resulting encoded characters.
* @since 3840
*/
public static String encode(String s, boolean urlsafe) {
StringBuilder out = new StringBuilder();
String enc = urlsafe ? encUrlSafe : encDefault;
for (int i = 0; i < (s.length()+2)/3; ++i) {
int l = Math.min(3, s.length()-i*3);
String buf = s.substring(i*3, i*3+l);
out.append(enc.charAt(buf.charAt(0) >> 2));
out.append(enc.charAt(
(buf.charAt(0) & 0x03) << 4 |
(l == 1 ? 0 : (buf.charAt(1) & 0xf0) >> 4)));
out.append(l > 1 ? enc.charAt((buf.charAt(1) & 0x0f) << 2 | (l == 2 ? 0 : (buf.charAt(2) & 0xc0) >> 6)) : '=');
out.append(l > 2 ? enc.charAt(buf.charAt(2) & 0x3f) : '=');
}
return out.toString();
}
/**
* Encodes all remaining bytes from the specified byte buffer into a new string using the Base64 default encoding scheme.
* Upon return, the source buffer's position will be updated to its limit; its limit will not have been changed.
* @param s the source ByteBuffer to encode
* @return A new string containing the resulting encoded characters.
*/
public static String encode(ByteBuffer s) {
return encode(s, false);
}
/**
* Encodes all remaining bytes from the specified byte buffer into a new string using a supported Base64 encoding scheme.
* Upon return, the source buffer's position will be updated to its limit; its limit will not have been changed.
* @param s the source ByteBuffer to encode
* @param urlsafe if {@code true}, uses "base64url" encoding, otherwise use the "base64" default encoding
* @return A new string containing the resulting encoded characters.
* @since 3840
*/
public static String encode(ByteBuffer s, boolean urlsafe) {
StringBuilder out = new StringBuilder();
String enc = urlsafe ? encUrlSafe : encDefault;
// Read 3 bytes at a time.
for (int i = 0; i < (s.limit()+2)/3; ++i) {
int l = Math.min(3, s.limit()-i*3);
int byte0 = s.get() & 0xff;
int byte1 = l > 1 ? s.get() & 0xff : 0;
int byte2 = l > 2 ? s.get() & 0xff : 0;
out.append(enc.charAt(byte0 >> 2));
out.append(enc.charAt(
(byte0 & 0x03) << 4 |
(l == 1 ? 0 : (byte1 & 0xf0) >> 4)));
out.append(l > 1 ? enc.charAt((byte1 & 0x0f) << 2 | (l == 2 ? 0 : (byte2 & 0xc0) >> 6)) : '=');
out.append(l > 2 ? enc.charAt(byte2 & 0x3f) : '=');
}
return out.toString();
}
}