org.voovan.tools.security.TBase64 Maven / Gradle / Ivy
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package org.voovan.tools.security;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
/**
* Base64算法
*
* @author helyho
*
* Voovan Framework.
* WebSite: https://github.com/helyho/Voovan
* Licence: Apache v2 License
*/
public class TBase64 {
private static final char[] toBase64 = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
};
private static final int[] fromBase64 = new int[256];
static {
Arrays.fill(fromBase64, -1);
for (int i = 0; i < toBase64.length; i++)
fromBase64[toBase64[i]] = i;
fromBase64['='] = -2;
}
public static String encode(byte[] binaryData) {
int off = 0;
int end = binaryData.length;
int linemax = -1;
byte newline[] = null;
boolean doPadding = true;
byte[] src = binaryData;
byte[] dst = new byte[4 * ((src.length + 2) / 3)];
char[] base64 = toBase64;
int sp = off;
int slen = (end - off) / 3 * 3;
int sl = off + slen;
if (linemax > 0 && slen > linemax / 4 * 3)
slen = linemax / 4 * 3;
int dstLength = 0;
while (sp < sl) {
int sl0 = Math.min(sp + slen, sl);
for (int sp0 = sp, dp0 = dstLength ; sp0 < sl0; ) {
int bits = (src[sp0++] & 0xff) << 16 |
(src[sp0++] & 0xff) << 8 |
(src[sp0++] & 0xff);
dst[dp0++] = (byte)base64[(bits >>> 18) & 0x3f];
dst[dp0++] = (byte)base64[(bits >>> 12) & 0x3f];
dst[dp0++] = (byte)base64[(bits >>> 6) & 0x3f];
dst[dp0++] = (byte)base64[bits & 0x3f];
}
int dlen = (sl0 - sp) / 3 * 4;
dstLength += dlen;
sp = sl0;
if (dlen == linemax && sp < end) {
for (byte b : newline){
dst[dstLength++] = b;
}
}
}
if (sp < end) { // 1 or 2 leftover bytes
int b0 = src[sp++] & 0xff;
dst[dstLength++] = (byte)base64[b0 >> 2];
if (sp == end) {
dst[dstLength++] = (byte)base64[(b0 << 4) & 0x3f];
if (doPadding) {
dst[dstLength++] = '=';
dst[dstLength++] = '=';
}
} else {
int b1 = src[sp++] & 0xff;
dst[dstLength++] = (byte)base64[(b0 << 4) & 0x3f | (b1 >> 4)];
dst[dstLength++] = (byte)base64[(b1 << 2) & 0x3f];
if (doPadding) {
dst[dstLength++] = '=';
}
}
}
return new String(Arrays.copyOf(dst, dstLength));
}
public static byte[] decode(String encoded) {
byte[] src = encoded.getBytes(StandardCharsets.ISO_8859_1);
int sp = 0;
int sl = src.length;
if (sl%4 != 0) {
return null;//should be divisible by four
}
int numberQuadruple = (sl/4);
if (numberQuadruple == 0)
return new byte[0];
byte[] dst = new byte[numberQuadruple*3];
int[] base64 = fromBase64;
int dstLength = 0;
int bits = 0;
int shiftto = 18; // pos of first byte of 4-byte atom
while (sp < sl) {
int b = src[sp++] & 0xff;
if ((b = base64[b]) < 0) {
if (b == -2) {
if (shiftto == 6 && (sp == sl || src[sp++] != '=') ||
shiftto == 18) {
throw new IllegalArgumentException(
"Input byte array has wrong 4-byte ending unit");
}
break;
}
throw new IllegalArgumentException(
"Illegal base64 character " +
Integer.toString(src[sp - 1], 16));
}
bits |= (b << shiftto);
shiftto -= 6;
if (shiftto < 0) {
dst[dstLength++] = (byte)(bits >> 16);
dst[dstLength++] = (byte)(bits >> 8);
dst[dstLength++] = (byte)(bits);
shiftto = 18;
bits = 0;
}
}
if (shiftto == 6) {
dst[dstLength++] = (byte)(bits >> 16);
} else if (shiftto == 0) {
dst[dstLength++] = (byte)(bits >> 16);
dst[dstLength++] = (byte)(bits >> 8);
} else if (shiftto == 12) {
throw new IllegalArgumentException(
"Last unit does not have enough valid bits");
}
while (sp < sl) {
throw new IllegalArgumentException(
"Input byte array has incorrect ending byte at " + sp);
}
return Arrays.copyOf(dst, dstLength);
}
}