Author: xor
Date: 2008-11-18 00:35:27 +0000 (Tue, 18 Nov 2008)
New Revision: 23713
Modified:
trunk/freenet/src/freenet/support/Base64.java
Log:
Provide functions for completely standard compliant encoding/decoding.
Modified: trunk/freenet/src/freenet/support/Base64.java
===================================================================
--- trunk/freenet/src/freenet/support/Base64.java 2008-11-17 23:27:21 UTC
(rev 23712)
+++ trunk/freenet/src/freenet/support/Base64.java 2008-11-18 00:35:27 UTC
(rev 23713)
@@ -26,21 +26,39 @@
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '~', '-'};
+
+ private static char[] base64StandardAlphabet = {
+ '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', '+', '/'};
/**
* A reverse lookup table to convert base64 letters back into the
* a 6-bit sequence.
*/
private static byte[] base64Reverse;
+ private static byte[] base64StandardReverse;
+
// Populate the base64Reverse lookup table from the base64Alphabet table.
static {
base64Reverse = new byte[128];
+ base64StandardReverse = new byte[base64Reverse.length];
+
// Set all entries to 0xFF, which means that that particular letter
// is not a legal base64 letter.
- for (int i = 0; i < base64Reverse.length; i++)
+ for (int i = 0; i < base64Reverse.length; i++) {
base64Reverse[i] = (byte) 0xFF;
- for (int i = 0; i < base64Alphabet.length; i++)
+ base64StandardReverse[i] = (byte) 0xFF;
+ }
+ for (int i = 0; i < base64Alphabet.length; i++) {
base64Reverse[base64Alphabet[i]] = (byte) i;
+ base64StandardReverse[base64StandardAlphabet[i]] = (byte) i;
+ }
}
/**
@@ -52,9 +70,24 @@
}
/**
+ * Caller should specify equalsPad=true if they want a standards compliant
padding,
+ * but not standard compliant encoding.
+ */
+ public static String encode(byte[] in, boolean equalsPad) {
+ return encode(in, equalsPad, base64Alphabet);
+ }
+
+ /**
+ * Standard compliant encoding.
+ */
+ public static String encodeStandard(byte[] in) {
+ return encode(in, true, base64StandardAlphabet);
+ }
+
+ /**
* Caller should specify equalsPad=true if they want a standards compliant
encoding.
*/
- public static String encode(byte[] in, boolean equalsPad)
+ private static String encode(byte[] in, boolean equalsPad, char[] alphabet)
{
char[] out = new char[((in.length+2)/3)*4];
int rem = in.length%3;
@@ -65,10 +98,10 @@
val |= (in[i++] & 0xFF) << 8;
if (i < in.length)
val |= (in[i++] & 0xFF);
- out[o++] = base64Alphabet[(val>>18) & 0x3F];
- out[o++] = base64Alphabet[(val>>12) & 0x3F];
- out[o++] = base64Alphabet[(val>>6) & 0x3F];
- out[o++] = base64Alphabet[val & 0x3F];
+ out[o++] = alphabet[(val>>18) & 0x3F];
+ out[o++] = alphabet[(val>>12) & 0x3F];
+ out[o++] = alphabet[(val>>6) & 0x3F];
+ out[o++] = alphabet[val & 0x3F];
}
int outLen = out.length;
switch (rem) {
@@ -83,10 +116,26 @@
}
/**
+ * Handles the standards-compliant padding (padded with '=' signs) as well
as our
+ * shortened form.
+ * @throws IllegalBase64Exception
+ */
+ public static byte[] decode(String inStr) throws IllegalBase64Exception {
+ return decode(inStr, base64Reverse);
+ }
+
+ /**
+ * Handles the standards-compliant base64 encoding.
+ */
+ public static byte[] decodeStandard(String inStr) throws
IllegalBase64Exception {
+ return decode(inStr, base64StandardReverse);
+ }
+
+ /**
* Handles the standards-compliant (padded with '=' signs) as well as our
* shortened form.
*/
- public static byte[] decode(String inStr)
+ private static byte[] decode(String inStr, byte[] reverseAlphabet)
throws IllegalBase64Exception
{
try {
@@ -114,10 +163,10 @@
int o = 0;
int i;
for (i = 0; i < wholeInLen;) {
- int in1 = base64Reverse[in[i]];
- int in2 = base64Reverse[in[i+1]];
- int in3 = base64Reverse[in[i+2]];
- int in4 = base64Reverse[in[i+3]];
+ int in1 = reverseAlphabet[in[i]];
+ int in2 = reverseAlphabet[in[i+1]];
+ int in3 = reverseAlphabet[in[i+2]];
+ int in4 = reverseAlphabet[in[i+3]];
int orValue = in1|in2|in3|in4;
if ((orValue & 0x80) != 0)
throw new IllegalBase64Exception("illegal Base64 character");
@@ -132,8 +181,8 @@
switch (remainder) {
case 2:
{
- int in1 = base64Reverse[in[i]];
- int in2 = base64Reverse[in[i+1]];
+ int in1 = reverseAlphabet[in[i]];
+ int in2 = reverseAlphabet[in[i+1]];
orValue = in1|in2;
int outVal = (in1 << 18) | (in2 << 12);
out[o] = (byte) (outVal>>16);
@@ -141,9 +190,9 @@
break;
case 3:
{
- int in1 = base64Reverse[in[i]];
- int in2 = base64Reverse[in[i+1]];
- int in3 = base64Reverse[in[i+2]];
+ int in1 = reverseAlphabet[in[i]];
+ int in2 = reverseAlphabet[in[i+1]];
+ int in3 = reverseAlphabet[in[i+2]];
orValue = in1|in2|in3;
int outVal = (in1 << 18) | (in2 << 12) | (in3 << 6);
out[o] = (byte) (outVal>>16);
@@ -159,7 +208,7 @@
return out;
}
// Illegal characters can cause an ArrayIndexOutOfBoundsException when
- // looking up base64Reverse.
+ // looking up reverseAlphabet.
catch (ArrayIndexOutOfBoundsException e) {
throw new IllegalBase64Exception("illegal Base64 character");
}
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