/* | |
* See LICENSE file in distribution for copyright and licensing information. | |
*/ | |
package org.yaml.snakeyaml.util; | |
import org.yaml.snakeyaml.error.YAMLException; | |
public abstract class Base64Coder { | |
// Mapping table from 6-bit nibbles to Base64 characters. | |
private final static char[] map1 = new char[64]; | |
static { | |
int i = 0; | |
for (char c = 'A'; c <= 'Z'; c++) | |
map1[i++] = c; | |
for (char c = 'a'; c <= 'z'; c++) | |
map1[i++] = c; | |
for (char c = '0'; c <= '9'; c++) | |
map1[i++] = c; | |
map1[i++] = '+'; | |
map1[i++] = '/'; | |
} | |
// Mapping table from Base64 characters to 6-bit nibbles. | |
private final static byte[] map2 = new byte[128]; | |
static { | |
for (int i = 0; i < map2.length; i++) | |
map2[i] = -1; | |
for (int i = 0; i < 64; i++) | |
map2[map1[i]] = (byte) i; | |
} | |
/** | |
* Encodes a byte array into Base64 format. No blanks or line breaks are | |
* inserted. | |
* | |
* @param in | |
* an array containing the data bytes to be encoded. | |
* @return A character array with the Base64 encoded data. | |
*/ | |
public static char[] encode(byte[] in) { | |
int iLen = in.length; | |
int oDataLen = (iLen * 4 + 2) / 3; // output length without padding | |
int oLen = ((iLen + 2) / 3) * 4; // output length including padding | |
char[] out = new char[oLen]; | |
int ip = 0; | |
int op = 0; | |
while (ip < iLen) { | |
int i0 = in[ip++] & 0xff; | |
int i1 = ip < iLen ? in[ip++] & 0xff : 0; | |
int i2 = ip < iLen ? in[ip++] & 0xff : 0; | |
int o0 = i0 >>> 2; | |
int o1 = ((i0 & 3) << 4) | (i1 >>> 4); | |
int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6); | |
int o3 = i2 & 0x3F; | |
out[op++] = map1[o0]; | |
out[op++] = map1[o1]; | |
out[op] = op < oDataLen ? map1[o2] : '='; | |
op++; | |
out[op] = op < oDataLen ? map1[o3] : '='; | |
op++; | |
} | |
return out; | |
} | |
/** | |
* Decodes Base64 data. No blanks or line breaks are allowed within the | |
* Base64 encoded data. | |
* | |
* @param in | |
* a character array containing the Base64 encoded data. | |
* @return An array containing the decoded data bytes. | |
* @throws IllegalArgumentException | |
* if the input is not valid Base64 encoded data. | |
*/ | |
public static byte[] decode(char[] in) { | |
int iLen = in.length; | |
if (iLen % 4 != 0) | |
throw new YAMLException("Length of Base64 encoded input string is not a multiple of 4."); | |
while (iLen > 0 && in[iLen - 1] == '=') | |
iLen--; | |
int oLen = (iLen * 3) / 4; | |
byte[] out = new byte[oLen]; | |
int ip = 0; | |
int op = 0; | |
while (ip < iLen) { | |
int i0 = in[ip++]; | |
int i1 = in[ip++]; | |
int i2 = ip < iLen ? in[ip++] : 'A'; | |
int i3 = ip < iLen ? in[ip++] : 'A'; | |
if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127) | |
throw new YAMLException("Illegal character in Base64 encoded data."); | |
int b0 = map2[i0]; | |
int b1 = map2[i1]; | |
int b2 = map2[i2]; | |
int b3 = map2[i3]; | |
if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0) | |
throw new YAMLException("Illegal character in Base64 encoded data."); | |
int o0 = (b0 << 2) | (b1 >>> 4); | |
int o1 = ((b1 & 0xf) << 4) | (b2 >>> 2); | |
int o2 = ((b2 & 3) << 6) | b3; | |
out[op++] = (byte) o0; | |
if (op < oLen) | |
out[op++] = (byte) o1; | |
if (op < oLen) | |
out[op++] = (byte) o2; | |
} | |
return out; | |
} | |
} |