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cdesktop/cde/lib/tt/lib/util/tt_base64.C
2018-05-24 14:25:26 -06:00

128 lines
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C

/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these libraries and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
//%% (c) Copyright 1993, 1994 Hewlett-Packard Company
//%% (c) Copyright 1993, 1994 International Business Machines Corp.
//%% (c) Copyright 1993, 1994 Sun Microsystems, Inc.
//%% (c) Copyright 1993, 1994 Novell, Inc.
//%% $XConsortium: tt_base64.C /main/4 1996/07/30 17:41:40 barstow $
/*
*
* tt_base64.cc
*
* Copyright (c) 1990 by Sun Microsystems, Inc.
*/
#include "util/tt_base64.h"
static const char base64_chars[] =
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_-";
// The following table was mechanically generated to be the inverse
// permutation of the above table. Thus for 0<=i<63,
// base_64_values[base64_chars[i]]==i.
static const char base64_values[256] = {
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 63, 64, 64,
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 64, 64, 64, 64, 64, 64,
64, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32,
33, 34, 35, 64, 64, 64, 64, 62,
64, 36, 37, 38, 39, 40, 41, 42,
43, 44, 45, 46, 47, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57, 58,
59, 60, 61, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64};
/*
* _tt_base64_encode(i) -- convert number to base-64 character string
*
* Purpose: Convert an long value (typically a time) to a "base-64"
* representation. Return a _Tt_string containing
* the representation, not including any leading zeroes.
*/
_Tt_string
_tt_base64_encode(unsigned long i)
{
int maxlen = (sizeof(long)*8+5)/6;
_Tt_string retval(maxlen);
int c = maxlen-1;
if (i==0) {
retval = "0";
} else {
while (i>0) {
retval[c--] = base64_chars[i & 077];
i >>= 6;
}
retval = retval.mid(c+1,retval.len());
}
return retval;
}
/*
* _tt_base64_decode(i) -- convert base-64 character string to number
*
* Purpose: Convert a string in a "base-64"
* representation to an unsigned long.
*/
unsigned long
_tt_base64_decode(const char *s)
{
int c,v;
unsigned long r;
r = 0;
while (c = *s++) {
v = base64_values[c];
if (v==64) { // illegal char, quit early
return r;
} else {
r = (r<<6)+v;
}
}
return r;
}