DeDRM_tools/Kindle_Mobi_Tools/skindle-06/b64.c

81 lines
2.8 KiB
C

/*********************************************************************\
LICENCE: Copyright (c) 2001 Bob Trower, Trantor Standard Systems Inc.
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated
documentation files (the "Software"), to deal in the
Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall
be included in all copies or substantial portions of the
Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
VERSION HISTORY:
Bob Trower 08/04/01 -- Create Version 0.00.00B
\******************************************************************* */
#include <stdlib.h>
/*
** Translation Table as described in RFC1113
*/
static const char cb64[]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/*
** encodeblock
**
** encode 3 8-bit binary bytes as 4 '6-bit' characters
*/
void encodeblock(unsigned char in[3], unsigned char out[4], int len) {
out[0] = cb64[ in[0] >> 2 ];
out[1] = cb64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4) ];
out[2] = (unsigned char) (len > 1 ? cb64[ ((in[1] & 0x0f) << 2) | ((in[2] & 0xc0) >> 6) ] : '=');
out[3] = (unsigned char) (len > 2 ? cb64[ in[2] & 0x3f ] : '=');
}
/*
** encode
**
** base64 encode a stream adding padding and line breaks as per spec.
*/
unsigned int base64(unsigned char *inbuf, unsigned int len, unsigned char *outbuf) {
unsigned char in[3], out[4];
int c;
unsigned int i = 0;
unsigned int outlen = 0;
while (i < len) {
int n = 0;
for(c = 0; c < 3; c++, i++) {
if (i < len) {
in[c] = inbuf[i];
n++;
}
else {
in[c] = 0;
}
}
if (n) {
encodeblock(in, out, n);
for(c = 0; c < 4; c++) {
outbuf[outlen++] = out[c];
}
}
}
return outlen;
}