Function httpEncode64_2

cups/http-support.c:690–774

 */

char *					/* O - Encoded string */
httpEncode64_2(char       *out,		/* I - String to write to */
	       int        outlen,	/* I - Maximum size of output string */
               const char *in,		/* I - String to read from */
	       int        inlen)	/* I - Size of input string */
{
  char		*outptr,		/* Output pointer */
		*outend;		/* End of output buffer */
  static const char base64[] =		/* Base64 characters... */
  		{
		  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
		  "abcdefghijklmnopqrstuvwxyz"
		  "0123456789"
		  "+/"
  		};


 /*
  * Range check input...
  */

  if (!out || outlen < 1 || !in)
    return (NULL);

 /*
  * Convert bytes to base-64...
  */

  for (outptr = out, outend = out + outlen - 1; inlen > 0; in ++, inlen --)
  {
   /*
    * Encode the up to 3 characters as 4 Base64 numbers...
    */

    if (outptr < outend)
      *outptr ++ = base64[(in[0] & 255) >> 2];

    if (outptr < outend)
    {
      if (inlen > 1)
        *outptr ++ = base64[(((in[0] & 255) << 4) | ((in[1] & 255) >> 4)) & 63];
      else
        *outptr ++ = base64[(in[0] << 4) & 63];
    }

    in ++;
    inlen --;
    if (inlen <= 0)
    {
      if (outptr < outend)
        *outptr ++ = '=';
      if (outptr < outend)
        *outptr ++ = '=';
      break;
    }

    if (outptr < outend)
    {