Base64Encoderpublic class Base64Encoder extends Object implements Encoder
| Fields Summary |
|---|
| protected final byte[] | encodingTable | | protected byte | padding | | protected final byte[] | decodingTable |
| Constructors Summary |
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public Base64Encoder()
initialiseDecodingTable();
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| Methods Summary |
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| public int | decode(byte[] data, int off, int length, java.io.OutputStream out)decode the base 64 encoded byte data writing it to the given output stream,
whitespace characters will be ignored.
byte b1, b2, b3, b4;
int outLen = 0;
int end = off + length;
while (end > off)
{
if (!ignore((char)data[end - 1]))
{
break;
}
end--;
}
int i = off;
int finish = end - 4;
i = nextI(data, i, finish);
while (i < finish)
{
b1 = decodingTable[data[i++]];
i = nextI(data, i, finish);
b2 = decodingTable[data[i++]];
i = nextI(data, i, finish);
b3 = decodingTable[data[i++]];
i = nextI(data, i, finish);
b4 = decodingTable[data[i++]];
out.write((b1 << 2) | (b2 >> 4));
out.write((b2 << 4) | (b3 >> 2));
out.write((b3 << 6) | b4);
outLen += 3;
i = nextI(data, i, finish);
}
outLen += decodeLastBlock(out, (char)data[end - 4], (char)data[end - 3], (char)data[end - 2], (char)data[end - 1]);
return outLen;
| | public int | decode(java.lang.String data, java.io.OutputStream out)decode the base 64 encoded String data writing it to the given output stream,
whitespace characters will be ignored.
byte b1, b2, b3, b4;
int length = 0;
int end = data.length();
while (end > 0)
{
if (!ignore(data.charAt(end - 1)))
{
break;
}
end--;
}
int i = 0;
int finish = end - 4;
i = nextI(data, i, finish);
while (i < finish)
{
b1 = decodingTable[data.charAt(i++)];
i = nextI(data, i, finish);
b2 = decodingTable[data.charAt(i++)];
i = nextI(data, i, finish);
b3 = decodingTable[data.charAt(i++)];
i = nextI(data, i, finish);
b4 = decodingTable[data.charAt(i++)];
out.write((b1 << 2) | (b2 >> 4));
out.write((b2 << 4) | (b3 >> 2));
out.write((b3 << 6) | b4);
length += 3;
i = nextI(data, i, finish);
}
length += decodeLastBlock(out, data.charAt(end - 4), data.charAt(end - 3), data.charAt(end - 2), data.charAt(end - 1));
return length;
| | private int | decodeLastBlock(java.io.OutputStream out, char c1, char c2, char c3, char c4)
byte b1, b2, b3, b4;
if (c3 == padding)
{
b1 = decodingTable[c1];
b2 = decodingTable[c2];
out.write((b1 << 2) | (b2 >> 4));
return 1;
}
else if (c4 == padding)
{
b1 = decodingTable[c1];
b2 = decodingTable[c2];
b3 = decodingTable[c3];
out.write((b1 << 2) | (b2 >> 4));
out.write((b2 << 4) | (b3 >> 2));
return 2;
}
else
{
b1 = decodingTable[c1];
b2 = decodingTable[c2];
b3 = decodingTable[c3];
b4 = decodingTable[c4];
out.write((b1 << 2) | (b2 >> 4));
out.write((b2 << 4) | (b3 >> 2));
out.write((b3 << 6) | b4);
return 3;
}
| | public int | encode(byte[] data, int off, int length, java.io.OutputStream out)encode the input data producing a base 64 output stream.
int modulus = length % 3;
int dataLength = (length - modulus);
int a1, a2, a3;
for (int i = off; i < off + dataLength; i += 3)
{
a1 = data[i] & 0xff;
a2 = data[i + 1] & 0xff;
a3 = data[i + 2] & 0xff;
out.write(encodingTable[(a1 >>> 2) & 0x3f]);
out.write(encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f]);
out.write(encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f]);
out.write(encodingTable[a3 & 0x3f]);
}
/*
* process the tail end.
*/
int b1, b2, b3;
int d1, d2;
switch (modulus)
{
case 0: /* nothing left to do */
break;
case 1:
d1 = data[off + dataLength] & 0xff;
b1 = (d1 >>> 2) & 0x3f;
b2 = (d1 << 4) & 0x3f;
out.write(encodingTable[b1]);
out.write(encodingTable[b2]);
out.write(padding);
out.write(padding);
break;
case 2:
d1 = data[off + dataLength] & 0xff;
d2 = data[off + dataLength + 1] & 0xff;
b1 = (d1 >>> 2) & 0x3f;
b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
b3 = (d2 << 2) & 0x3f;
out.write(encodingTable[b1]);
out.write(encodingTable[b2]);
out.write(encodingTable[b3]);
out.write(padding);
break;
}
return (dataLength / 3) * 4 + ((modulus == 0) ? 0 : 4);
| | private boolean | ignore(char c)
return (c == '\n" || c =='\r" || c == '\t" || c == ' ");
| | protected void | initialiseDecodingTable()
for (int i = 0; i < encodingTable.length; i++)
{
decodingTable[encodingTable[i]] = (byte)i;
}
| | private int | nextI(byte[] data, int i, int finish)
while ((i < finish) && ignore((char)data[i]))
{
i++;
}
return i;
| | private int | nextI(java.lang.String data, int i, int finish)
while ((i < finish) && ignore(data.charAt(i)))
{
i++;
}
return i;
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