119 lines
2.6 KiB
C
119 lines
2.6 KiB
C
/*
|
|
* File: base64.c
|
|
* Description: Simple BASE64 conversion methods
|
|
* Author: Ari Edelkind
|
|
* License: Public Domain
|
|
* Website: http://episec.com/people/edelkind/c.html
|
|
*/
|
|
|
|
#include <string.h>
|
|
|
|
char b64string[] =
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
|
|
long base64_encode (to, from, len)
|
|
char *to, *from;
|
|
unsigned int len;
|
|
{
|
|
char *fromp = from;
|
|
char *top = to;
|
|
unsigned char cbyte;
|
|
unsigned char obyte;
|
|
char end[3];
|
|
|
|
for (; len >= 3; len -= 3) {
|
|
cbyte = *fromp++;
|
|
*top++ = b64string[(int)(cbyte >> 2)];
|
|
obyte = (cbyte << 4) & 0x30; /* 0011 0000 */
|
|
|
|
cbyte = *fromp++;
|
|
obyte |= (cbyte >> 4); /* 0000 1111 */
|
|
*top++ = b64string[(int)obyte];
|
|
obyte = (cbyte << 2) & 0x3C; /* 0011 1100 */
|
|
|
|
cbyte = *fromp++;
|
|
obyte |= (cbyte >> 6); /* 0000 0011 */
|
|
*top++ = b64string[(int)obyte];
|
|
*top++ = b64string[(int)(cbyte & 0x3F)];/* 0011 1111 */
|
|
}
|
|
|
|
if (len) {
|
|
end[0] = *fromp++;
|
|
if (--len) end[1] = *fromp++; else end[1] = 0;
|
|
end[2] = 0;
|
|
|
|
cbyte = end[0];
|
|
*top++ = b64string[(int)(cbyte >> 2)];
|
|
obyte = (cbyte << 4) & 0x30; /* 0011 0000 */
|
|
|
|
cbyte = end[1];
|
|
obyte |= (cbyte >> 4);
|
|
*top++ = b64string[(int)obyte];
|
|
obyte = (cbyte << 2) & 0x3C; /* 0011 1100 */
|
|
|
|
if (len) *top++ = b64string[(int)obyte];
|
|
else *top++ = '=';
|
|
*top++ = '=';
|
|
}
|
|
*top = 0;
|
|
return top - to;
|
|
}
|
|
|
|
/* badchar(): check if c is decent; puts either the */
|
|
/* location of c or null into p. */
|
|
#define badchar(c,p) (!(p = memchr(b64string, c, 64)))
|
|
|
|
long base64_decode (to, from, len)
|
|
char *to, *from;
|
|
unsigned int len;
|
|
{
|
|
char *fromp = from;
|
|
char *top = to;
|
|
char *p;
|
|
unsigned char cbyte;
|
|
unsigned char obyte;
|
|
int padding = 0;
|
|
|
|
for (; len >= 4; len -= 4) {
|
|
if ((cbyte = *fromp++) == '=') cbyte = 0;
|
|
else {
|
|
if (badchar(cbyte, p)) return -1;
|
|
cbyte = (p - b64string);
|
|
}
|
|
obyte = cbyte << 2; /* 1111 1100 */
|
|
|
|
if ((cbyte = *fromp++) == '=') cbyte = 0;
|
|
else {
|
|
if (badchar(cbyte, p)) return -1;
|
|
cbyte = p - b64string;
|
|
}
|
|
obyte |= cbyte >> 4; /* 0000 0011 */
|
|
*top++ = obyte;
|
|
|
|
obyte = cbyte << 4; /* 1111 0000 */
|
|
if ((cbyte = *fromp++) == '=') { cbyte = 0; padding++; }
|
|
else {
|
|
padding = 0;
|
|
if (badchar (cbyte, p)) return -1;
|
|
cbyte = p - b64string;
|
|
}
|
|
obyte |= cbyte >> 2; /* 0000 1111 */
|
|
*top++ = obyte;
|
|
|
|
obyte = cbyte << 6; /* 1100 0000 */
|
|
if ((cbyte = *fromp++) == '=') { cbyte = 0; padding++; }
|
|
else {
|
|
padding = 0;
|
|
if (badchar (cbyte, p)) return -1;
|
|
cbyte = p - b64string;
|
|
}
|
|
obyte |= cbyte; /* 0011 1111 */
|
|
*top++ = obyte;
|
|
}
|
|
|
|
*top = 0;
|
|
if (len) return -1;
|
|
return (top - to) - padding;
|
|
}
|
|
|