/*
* Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, version 2.0, as published by the
* Free Software Foundation.
*
* This program is also distributed with certain software (including but not
* limited to OpenSSL) that is licensed under separate terms, as designated in a
* particular file or component or in included license documentation. The
* authors of MySQL hereby grant you an additional permission to link the
* program and your derivative works with the separately licensed software that
* they have included with MySQL.
*
* Without limiting anything contained in the foregoing, this file, which is
* part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
* version 1.0, a copy of which can be found at
* http://oss.oracle.com/licenses/universal-foss-exception.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
* for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.mysql.cj.util;
/**
* This decoder implements standard Base64 decoding except it allows and silently ignores non-base64 input characters (spaces, line breaks etc)
*
* Note: Java 6+ provide standard decoders
*/
public class
Base64Decoder {
/*
* -1 means non-base64 character
* -2 means padding
*/
private static byte[]
decoderMap = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31,
32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };
public static class
IntWrapper {
public int
value;
public
IntWrapper(int
value) {
this.
value =
value;
}
}
private static byte
getNextValidByte(byte[]
in,
IntWrapper pos, int
maxPos) {
while (
pos.
value <=
maxPos) {
if (
in[
pos.
value] >= 0 &&
decoderMap[
in[
pos.
value]] >= 0) {
return
in[
pos.
value++];
}
pos.
value++;
}
// padding if reached max position
return '=';
}
public static byte[]
decode(byte[]
in, int
pos, int
length) {
IntWrapper offset = new
Base64Decoder.
IntWrapper(
pos);
byte[]
sestet = new byte[4];
int
outLen = (
length * 3) / 4; // over-estimated if non-base64 characters present
byte[]
octet = new byte[
outLen];
int
octetId = 0;
int
maxPos =
offset.
value +
length - 1;
while (
offset.
value <=
maxPos) {
sestet[0] =
decoderMap[
getNextValidByte(
in,
offset,
maxPos)];
sestet[1] =
decoderMap[
getNextValidByte(
in,
offset,
maxPos)];
sestet[2] =
decoderMap[
getNextValidByte(
in,
offset,
maxPos)];
sestet[3] =
decoderMap[
getNextValidByte(
in,
offset,
maxPos)];
if (
sestet[1] != -2) {
octet[
octetId++] = (byte) ((
sestet[0] << 2) | (
sestet[1] >>> 4));
}
if (
sestet[2] != -2) {
octet[
octetId++] = (byte) (((
sestet[1] & 0xf) << 4) | (
sestet[2] >>> 2));
}
if (
sestet[3] != -2) {
octet[
octetId++] = (byte) (((
sestet[2] & 3) << 6) |
sestet[3]);
}
}
// return real-length value
byte[]
out = new byte[
octetId];
System.
arraycopy(
octet, 0,
out, 0,
octetId);
return
out;
}
}