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/*******************************************************************
* base64.h
* © Copyright 1995 John Halleck
* All Rights Reserved
*
* ported to c++ by Michael Buesch <mbuesch@freenet.de>
*
* --ABSTRACT-- base64.h
* Do the base 64 encoding as used by PEM and MIME.
*
* --KEYWORDS-- base64.h
*
* --CONTENTS-- base64.h
* Date, Department, Author
* 23nov1994, John Halleck
* Revision history
* For each revision: Date, change summary, authorizing document,
* change department, section, author
* 23nov1994, Initial Creation, John Halleck
* 8apr1995, split library into hex and base64 libraries, John Halleck
* Unit purpose
* (What does this do?)
* [Nothing]
* External Units accessed
* Name, purpose, access summary
* [None]
* Exceptions propagated by this unit
* [None]
* Machine-dependencies
* Access type, purpose, and justification
* [None]
* Compiler-dependencies
* [None]
*********************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License version 2 *
* as published by the Free Software Foundation. *
* *
***************************************************************************/
#include "base64.h"
#include "globalstuff.h"
static const char prtcode[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
string Base64::encode(const string &data)
{
initCtx();
string::const_iterator i = data.begin(),
end = data.end();
while (i != end) {
encodeChar(*i);
++i;
}
encFinalizeCtx();
return ctx.buf;
}
string Base64::decode(const string &data)
{
initCtx();
string::const_iterator i = data.begin(),
end = data.end();
while (i != end) {
decodeChar(*i);
++i;
}
decFinalizeCtx();
return ctx.buf;
}
void Base64::initCtx()
{
ctx.temp = 0;
ctx.bytes = 0;
ctx.buf = "";
}
void Base64::encFinalizeCtx()
{
/* flush the output side of things, by putting out the last characters */
switch (ctx.bytes) {
case 0:
/* nothing in progress */
break;
case 2:
ctx.buf.append(1, static_cast<char>(prtcode[ctx.temp << 2 & 0x3F]));
ctx.buf.append(1, '=');
break;
case 1:
ctx.buf.append(1, static_cast<char>(prtcode[ctx.temp << 4 & 0x3F]));
ctx.buf.append(1, '=');
ctx.buf.append(1, '=');
}
}
void Base64::decFinalizeCtx()
{
if (ctx.bytes == 1)
decodeChar('A');
}
void Base64::encodeChar(unsigned char c)
{
int result;
/* Add this 8 bit byte to what we have...*/
result = ctx.temp;
result = (result << 8) | (c & 0xFF);
/* And output all 6 bit base 64 characters now formed */
switch (ctx.bytes++) {
case 0:
ctx.buf.append(1, static_cast<char>(prtcode[result >> 2 & 0x3F]));
result &= 0x3;
break;
case 1:
ctx.buf.append(1, static_cast<char>(prtcode[result >> 4 & 0x3F]));
result &= 0xF;
break;
case 2:
ctx.buf.append(1, static_cast<char>(prtcode[result >> 6 & 0x3F]));
ctx.buf.append(1, static_cast<char>(prtcode[result & 0x3F]));
result = 0;
ctx.bytes = 0;
}
ctx.temp = result;
}
void Base64::decodeChar(char c)
{
int result;
result = ctx.temp;
/* Convert Base64 character to its 6 bit nibble */
if (c == '/') {
result = (result << 6) | 63;
} else if (c == '+') {
result = (result << 6) | 62;
} else if (c >= 'A' && c <= 'Z') {
result = (result << 6) | (c - 'A');
} else if (c >= 'a' && c <= 'z') {
result = (result << 6) | (c - 'a' + 26);
} else if (c >= '0' && c <= '9') {
result = (result << 6) | (c - '0' + 52);
} else if (c == '=') {
ctx.bytes = 0;
ctx.temp = 0;
}
/* Add that nibble to the output, outputting any complete 8 bit bytes formed */
switch (ctx.bytes++) {
case 0:
break;
case 1:
ctx.buf.append(1, static_cast<char>(result >> 4 & 0xFF));
result &= 0xF;
break;
case 2:
ctx.buf.append(1, static_cast<char>(result >> 2 & 0xFF));
result &= 0x3;
break;
case 3:
ctx.buf.append(1, static_cast<char>(result & 0xFF));
ctx.bytes = 0;
result = 0;
}
if (c == '=') {
ctx.bytes = 0;
result = 0;
}
ctx.temp = result;
}
bool Base64::selfTest()
{
string plain1("Base64");
string plain2("abcdefghijklmnopqrstuvwxyz");
string enc1("QmFzZTY0");
string enc2("YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=");
string buf;
Base64 base64;
buf = base64.encode(plain1);
if (unlikely(buf != enc1))
return false;
buf = base64.decode(buf);
if (unlikely(buf != plain1))
return false;
buf = base64.encode(plain2);
if (unlikely(buf != enc2))
return false;
buf = base64.decode(buf);
if (unlikely(buf != plain2))
return false;
return true;
}
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