Files
mars-libowfat/textcode/fmt_base64url.c
2025-01-20 18:07:12 +00:00

25 lines
644 B
C

#include <libowfat/fmt.h>
#include <libowfat/textcode.h>
#include "haveinline.h"
size_t fmt_base64url(char* dest,const char* src,size_t len) {
register const unsigned char* s=(const unsigned char*) src;
unsigned short bits=0,temp=0;
size_t written=0,i;
if (!dest) return (len>((size_t)-1)/2)?(size_t)-1:((len+2)/3)*4;
for (i=0; i<len; ++i) {
temp<<=8; temp+=s[i]; bits+=8;
while (bits>6) {
dest[written]=base64url[((temp>>(bits-6))&63)];
++written; bits-=6;
}
}
if (bits) {
temp<<=(6-bits);
dest[written]=base64url[temp&63];
++written;
}
/* no padding for base64url */
return written;
}