/**
* Copyright 2008 - 2011
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*
* @project loon
* @author cping
* @email：javachenpeng@yahoo.com
* @version 0.1
*/
package loon.net;
import loon.utils.StringUtils;
/**
* 自0.3.2版起新增类，用以统一跨平台的BASE64处理方法
*/
public class Base64Coder {
private static final int BASELENGTH = 255;
private static final int LOOKUPLENGTH = 64;
private static final int TWENTYFOURBITGROUP = 24;
private static final int EIGHTBIT = 8;
private static final int SIXTEENBIT = 16;
private static final int FOURBYTE = 4;
private static final int SIGN = -128;
private static final byte PAD = (byte) '=';
private static byte[] BASE64_ALPHABET;
private static byte[] LOOKUP_BASE64_ALPHABET;
private Base64Coder() {
}
public static byte[] fromBinHexString(String s) {
char[] chars = s.toCharArray();
byte[] bytes = new byte[chars.length / 2 + chars.length % 2];
fromBinHexString(chars, 0, chars.length, bytes);
return bytes;
}
public static int fromBinHexString(char[] chars, int offset,
int charLength, byte[] buffer) {
int bufIndex = offset;
for (int i = 0; i < charLength - 1; i += 2) {
buffer[bufIndex] = (chars[i] > '9' ? (byte) (chars[i] - 'A' + 10)
: (byte) (chars[i] - '0'));
buffer[bufIndex] <<= 4;
buffer[bufIndex] += chars[i + 1] > '9' ? (byte) (chars[i + 1] - 'A' + 10)
: (byte) (chars[i + 1] - '0');
bufIndex++;
}
if (charLength % 2 != 0)
buffer[bufIndex++] = (byte) ((chars[charLength - 1] > '9' ? (byte) (chars[charLength - 1] - 'A' + 10)
: (byte) (chars[charLength - 1] - '0')) << 4);
return bufIndex - offset;
}
private final static void checking() {
if (BASE64_ALPHABET == null) {
BASE64_ALPHABET = new byte[BASELENGTH];
for (int i = 0; i < BASELENGTH; i++) {
BASE64_ALPHABET[i] = -1;
}
for (int i = 'Z'; i >= 'A'; i--) {
BASE64_ALPHABET[i] = (byte) (i - 'A');
}
for (int i = 'z'; i >= 'a'; i--) {
BASE64_ALPHABET[i] = (byte) (i - 'a' + 26);
}
for (int i = '9'; i >= '0'; i--) {
BASE64_ALPHABET[i] = (byte) (i - '0' + 52);
}
BASE64_ALPHABET['+'] = 62;
BASE64_ALPHABET['/'] = 63;
}
if (LOOKUP_BASE64_ALPHABET == null) {
LOOKUP_BASE64_ALPHABET = new byte[LOOKUPLENGTH];
for (int i = 0; i <= 25; i++) {
LOOKUP_BASE64_ALPHABET[i] = (byte) ('A' + i);
}
for (int i = 26, j = 0; i <= 51; i++, j++) {
LOOKUP_BASE64_ALPHABET[i] = (byte) ('a' + j);
}
for (int i = 52, j = 0; i <= 61; i++, j++) {
LOOKUP_BASE64_ALPHABET[i] = (byte) ('0' + j);
}
LOOKUP_BASE64_ALPHABET[62] = (byte) '+';
LOOKUP_BASE64_ALPHABET[63] = (byte) '/';
}
}
public static boolean isBase64(String v) {
return isArrayByteBase64(StringUtils.getAsciiBytes(v));
}
public static boolean isArrayByteBase64(byte[] bytes) {
checking();
int length = bytes.length;
if (length == 0) {
return true;
}
for (int i = 0; i < length; i++) {
if (!Base64Coder.isBase64(bytes[i])) {
return false;
}
}
return true;
}
private static boolean isBase64(byte octect) {
return (octect == PAD || BASE64_ALPHABET[octect] != -1);
}
public static byte[] encode(byte[] binaryData) {
checking();
int lengthDataBits = binaryData.length * EIGHTBIT;
int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
byte encodedData[] = null;
if (fewerThan24bits != 0) {
encodedData = new byte[(numberTriplets + 1) * 4];
} else {
encodedData = new byte[numberTriplets * 4];
}
byte k = 0;
byte l = 0;
byte b1 = 0;
byte b2 = 0;
byte b3 = 0;
int encodedIndex = 0;
int dataIndex = 0;
int i = 0;
for (i = 0; i < numberTriplets; i++) {
dataIndex = i * 3;
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
b3 = binaryData[dataIndex + 2];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
encodedIndex = i * 4;
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2)
: (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4)
: (byte) ((b2) >> 4 ^ 0xf0);
byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6)
: (byte) ((b3) >> 6 ^ 0xfc);
encodedData[encodedIndex] = LOOKUP_BASE64_ALPHABET[val1];
encodedData[encodedIndex + 1] = LOOKUP_BASE64_ALPHABET[val2
| (k << 4)];
encodedData[encodedIndex + 2] = LOOKUP_BASE64_ALPHABET[(l << 2)
| val3];
encodedData[encodedIndex + 3] = LOOKUP_BASE64_ALPHABET[b3 & 0x3f];
}
dataIndex = i * 3;
encodedIndex = i * 4;
if (fewerThan24bits == EIGHTBIT) {
b1 = binaryData[dataIndex];
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2)
: (byte) ((b1) >> 2 ^ 0xc0);
encodedData[encodedIndex] = LOOKUP_BASE64_ALPHABET[val1];
encodedData[encodedIndex + 1] = LOOKUP_BASE64_ALPHABET[k << 4];
encodedData[encodedIndex + 2] = PAD;
encodedData[encodedIndex + 3] = PAD;
} else if (fewerThan24bits == SIXTEENBIT) {
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2)
: (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4)
: (byte) ((b2) >> 4 ^ 0xf0);
encodedData[encodedIndex] = LOOKUP_BASE64_ALPHABET[val1];
encodedData[encodedIndex + 1] = LOOKUP_BASE64_ALPHABET[val2
| (k << 4)];
encodedData[encodedIndex + 2] = LOOKUP_BASE64_ALPHABET[l << 2];
encodedData[encodedIndex + 3] = PAD;
}
return encodedData;
}
public static byte[] decode(byte[] base64Data) {
checking();
if (base64Data.length == 0) {
return new byte[0];
}
int numberQuadruple = base64Data.length / FOURBYTE;
byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
int encodedIndex = 0;
int dataIndex = 0;
{
int lastData = base64Data.length;
while (base64Data[lastData - 1] == PAD) {
if (--lastData == 0) {
return new byte[0];
}
}
decodedData = new byte[lastData - numberQuadruple];
}
for (int i = 0; i < numberQuadruple; i++) {
dataIndex = i * 4;
marker0 = base64Data[dataIndex + 2];
marker1 = base64Data[dataIndex + 3];
b1 = BASE64_ALPHABET[base64Data[dataIndex]];
b2 = BASE64_ALPHABET[base64Data[dataIndex + 1]];
if (marker0 != PAD && marker1 != PAD) {
b3 = BASE64_ALPHABET[marker0];
b4 = BASE64_ALPHABET[marker1];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
} else if (marker0 == PAD) {
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
} else if (marker1 == PAD) {
b3 = BASE64_ALPHABET[marker0];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
}
encodedIndex += 3;
}
return decodedData;
}
public static byte[] decodeBase64(char[] data) {
checking();
int size = data.length;
int temp = size;
for (int ix = 0; ix < data.length; ix++) {
if ((data[ix] > 255) || BASE64_ALPHABET[data[ix]] < 0) {
--temp;
}
}
int len = (temp / 4) * 3;
if ((temp % 4) == 3) {
len += 2;
}
if ((temp % 4) == 2) {
len += 1;
}
byte[] out = new byte[len];
int shift = 0;
int accum = 0;
int index = 0;
for (int ix = 0; ix < size; ix++) {
int value = (data[ix] > 255) ? -1 : BASE64_ALPHABET[data[ix]];
if (value >= 0) {
accum <<= 6;
shift += 6;
accum |= value;
if (shift >= 8) {
shift -= 8;
out[index++] = (byte) ((accum >> shift) & 0xff);
}
}
}
if (index != out.length) {
throw new RuntimeException("index != " + out.length);
}
return out;
}
}