/*----------------------------------------------------*/
/* b64encode.c --   Base64-Encoding Filter            */
/*----------------------------------------------------*/
/*  Usage:                                            */
/*    b64encode [infile] > <file>                     */
/*        infile: filename of the file to be encoded  */
/*                (if omitted, input from stdin)      */
/*     result(stdout) should be redirected to <file>  */
/*----------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>

int main(int argc, char *argv[])
{ int c, c1, c2, k=0, n=0;
  char b64[64]
       = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  FILE *fp;
# ifdef O_BINARY
  setmode(1,O_BINARY);
# endif
  if (argc == 1) {
    fp = stdin;
# ifdef O_BINARY
    setmode(0,O_BINARY);
# endif
  } else if ((fp=fopen(argv[1],"rb")) == NULL) {
    fprintf(stderr, "file %s not found\n", argv[1]); exit(1);
  }
  while ((c=getc(fp)) != EOF) {
    if (k == 0) {
      c2 = (c & 0xFC) >> 2; putchar(b64[c2]);    c1 = (c & 0x03) << 4; k++;
    } else if (k == 1) {
      c2 = (c & 0xF0) >> 4; putchar(b64[c1|c2]); c1 = (c & 0x0F) << 2; k++;
    } else if (k == 2) {
      c2 = (c & 0xC0) >> 6; putchar(b64[c1|c2]); c1 = (c & 0x3F);
                            putchar(b64[c1]); n++; k = 0;
    }
    if (n > 18) { putchar('\n'); n = 0; }
  }
  if (k != 0) {
    putchar(b64[c1]); putchar('='); if (k == 1) putchar('='); n++;
  }
  if (n != 0) putchar('\n');
  fclose(fp);
  return(0);
}