Hi All,

Is there any library available for base64 encoding/decoding on redhat9
for 'C'?
Please help me with sample code to use it if it is available.

Thanks In Advance,
regards,
torpedo

torpedo@bluebottle.com wrote:
> Hi All,
>
> Is there any library available for base64 encoding/decoding on redhat9
> for 'C'?
> Please help me with sample code to use it if it is available.
>

I think Base64 encoding is one of those things in C where everybody rolls
their own. Except unlike configuration file parsing, one size can fit all.
My guess is everybody understands it's a good excercise to write their own
endoder/decoder. I'm sure there are more than a few libraries that export
this functionality. Non ubiquitous, AFAIK.

Basically, you'll collect three bytes of 8-bits each and convert them to
four bytes representing only 6-bits each. Here's some pseudo code which
should work on any Unix (when fleshed out and any bugs fixed ;)

	unsigned long group = 0;
	int nchars          = 0;
	struct { char *pos, *end } src, dst;

	/* Setup src and dst pointers. */

	while (src.pos < src.end) {
		group <<= 8;                /* Make room for next char. */
		group |= (0xff & *src.pos); /* Push char onto queue. */

		src.pos++;
		nchars++;

		if (nchars == 3) {
			const char map[64] = { 'A', /* A - Z, a - z, ... */ };
			int i;

			if (dst.end - dst.pos < 4) {
				/* Bail. No space to flush this group. */
			}

			/* Take the 4th, 3rd, 2nd and then 1st 6-bit set. */
			for (i = 0; i < 4; i++) {
				value    = 0x40 & (group >> (6 * (3 - i)));
				*dst.pos = map[value];
			}

			nchar = 0;
		}
	}

	if (nchar) {
		/*
		 * Extra code to flush out any stragglers. Pad the output
		 * according to the spec--RFCs 1421 and 2045.
		 */
	}

torpedo@bluebottle.com wrote:
> Hi All,
> 
> Is there any library available for base64 encoding/decoding on redhat9
> for 'C'?
> Please help me with sample code to use it if it is available.
> 
> Thanks In Advance,
> regards,
> torpedo
> 
One of the sub-capabilities of openssl is the Base64 encoder/decoder.
openssl is freely available.

--

Fletcher Glenn

Thanks All,

I dont  want to implement it.
I think i should better go for openssl library.

regards,
torpedo

 torpedo@bluebottle.com wrote:
> Thanks All, 
 > I dont	want to implement it. I think i should better go for
> openssl library. 
 > regards, torpedo 

 Oh, no! Openssl is BIG and quite a mess. You will spend more time
 learning its concepts than it is needed to write simple base64
 encoder/decoder from specifications.

 If you want JUST base64, take a look on the Perl MIME::Base64 module.
 It has C version which you can cut'n'paste.

Fletcher Glenn <fletcher@removethisfoglight.com> wrote:
> torpedo@bluebottle.com wrote:
> > Hi All,
> > 
> > Is there any library available for base64 encoding/decoding on redhat9
> > for 'C'?
> > Please help me with sample code to use it if it is available.
> > 
> > Thanks In Advance,
> > regards,
> > torpedo
> > 
> One of the sub-capabilities of openssl is the Base64 encoder/decoder.
> openssl is freely available.

I thought so. I quickly checked the man pages, greped the installed
header files, and couldn't find it, though.

Which part of the API?

William Ahern <william@wilbur.25thandclement.com> wrote:
: Fletcher Glenn <fletcher@removethisfoglight.com> wrote:
: > One of the sub-capabilities of openssl is the Base64 encoder/decoder.
: > openssl is freely available.
: I thought so. I quickly checked the man pages, greped the installed
: header files, and couldn't find it, though.
: Which part of the API?

Look into BIO_f_base64 man page. 
Base 64 encoder/decoder is part of openssl BIO I/O abstraction (bio(3))

Once again - unless you are using lot of other OpenSSL API, it doesn't
look sensible to use openssl BIOs just to encode/decode base64.

It is better to look into c-client library which is part of pine mail
reader. It contains base64 functions which are easily detachable from
rest of library.

-- 

William Ahern <william@wilbur.25thandClement.com> writes:

> Fletcher Glenn <fletcher@removethisfoglight.com> wrote:
>> torpedo@bluebottle.com wrote:
>> > Hi All,
>> > 
>> > Is there any library available for base64 encoding/decoding on redhat9
>> > for 'C'?
>> > Please help me with sample code to use it if it is available.
>> > 
>> > Thanks In Advance,
>> > regards,
>> > torpedo
>> > 
>> One of the sub-capabilities of openssl is the Base64 encoder/decoder.
>> openssl is freely available.
>
> I thought so. I quickly checked the man pages, greped the installed
> header files, and couldn't find it, though.
>
> Which part of the API?

man BIO_f_base64, and anything referenced therein.  It's not the most
straight-forward way to base64 encode a small piece of data, but is
good for longer streams.

-- 
M�ns Rullg�rd
mru@inprovide.com

Victor Wagner wrote:
> torpedo@bluebottle.com wrote:
> > Thanks All,
>  > I dont	want to implement it. I think i should better go for
> > openssl library.
>  > regards, torpedo
>
>  Oh, no! Openssl is BIG and quite a mess. You will spend more time
>  learning its concepts than it is needed to write simple base64
>  encoder/decoder from specifications.
>
>  If you want JUST base64, take a look on the Perl MIME::Base64 module.
>  It has C version which you can cut'n'paste.


Ya its true, I checked out Openssl is really bad choice for just
Base64.
How about Perl MIME::Base64 ?
Where can I find this Perl MIME::Base64 C version in the system, as I
never worked on Perl.

Thanks,
torpedo

torpedo@bluebottle.com writes:

>Ya its true, I checked out Openssl is really bad choice for just
>Base64.
>How about Perl MIME::Base64 ?
>Where can I find this Perl MIME::Base64 C version in the system, as I
>never worked on Perl.


Why has this basic thread persisted so long?



/*
 * Copyright (c) 1996 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/*
 * Portions Copyright (c) 1995 by International Business Machines, Inc.
 *
 * International Business Machines, Inc. (hereinafter called IBM) grants
 * permission under its copyrights to use, copy, modify, and distribute this
 * Software with or without fee, provided that the above copyright notice and
 * all paragraphs of this notice appear in all copies, and that the name of IBM
 * not be used in connection with the marketing of any product incorporating
 * the Software or modifications thereof, without specific, written prior
 * permission.
 *
 * To the extent it has a right to do so, IBM grants an immunity from suit
 * under its patents, if any, for the use, sale or manufacture of products to
 * the extent that such products are used for performing Domain Name System
 * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
 * granted for any product per se or for any other function of any product.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <ctype.h>
#include <resolv.h>
#include <stdio.h>

#if defined(BSD) && (BSD >= 199103) && defined(AF_INET6)
# include <stdlib.h>
# include <string.h>
#endif

#define Assert(Cond) if (!(Cond)) abort()

static const char Base64[] =
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char Pad64 = '=';

/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
   The following encoding technique is taken from RFC 1521 by Borenstein
   and Freed.  It is reproduced here in a slightly edited form for
   convenience.

   A 65-character subset of US-ASCII is used, enabling 6 bits to be
   represented per printable character. (The extra 65th character, "=",
   is used to signify a special processing function.)

   The encoding process represents 24-bit groups of input bits as output
   strings of 4 encoded characters. Proceeding from left to right, a
   24-bit input group is formed by concatenating 3 8-bit input groups.
   These 24 bits are then treated as 4 concatenated 6-bit groups, each
   of which is translated into a single digit in the base64 alphabet.

   Each 6-bit group is used as an index into an array of 64 printable
   characters. The character referenced by the index is placed in the
   output string.

                         Table 1: The Base64 Alphabet

      Value Encoding  Value Encoding  Value Encoding  Value Encoding
          0 A            17 R            34 i            51 z
          1 B            18 S            35 j            52 0
          2 C            19 T            36 k            53 1
          3 D            20 U            37 l            54 2
          4 E            21 V            38 m            55 3
          5 F            22 W            39 n            56 4
          6 G            23 X            40 o            57 5
          7 H            24 Y            41 p            58 6
          8 I            25 Z            42 q            59 7
          9 J            26 a            43 r            60 8
         10 K            27 b            44 s            61 9
         11 L            28 c            45 t            62 +
         12 M            29 d            46 u            63 /
         13 N            30 e            47 v
         14 O            31 f            48 w         (pad) =
         15 P            32 g            49 x
         16 Q            33 h            50 y

   Special processing is performed if fewer than 24 bits are available
   at the end of the data being encoded.  A full encoding quantum is
   always completed at the end of a quantity.  When fewer than 24 input
   bits are available in an input group, zero bits are added (on the
   right) to form an integral number of 6-bit groups.  Padding at the
   end of the data is performed using the '=' character.

   Since all base64 input is an integral number of octets, only the
         -------------------------------------------------                       
   following cases can arise:
   
       (1) the final quantum of encoding input is an integral
           multiple of 24 bits; here, the final unit of encoded
	   output will be an integral multiple of 4 characters
	   with no "=" padding,
       (2) the final quantum of encoding input is exactly 8 bits;
           here, the final unit of encoded output will be two
	   characters followed by two "=" padding characters, or
       (3) the final quantum of encoding input is exactly 16 bits;
           here, the final unit of encoded output will be three
	   characters followed by one "=" padding character.
   */

int
b64_ntop(src, srclength, target, targsize)
	u_char const *src;
	size_t srclength;
	char *target;
	size_t targsize;
{
	size_t datalength = 0;
	u_char input[3];
	u_char output[4];
	int i;

	while (2 < srclength) {
		input[0] = *src++;
		input[1] = *src++;
		input[2] = *src++;
		srclength -= 3;

		output[0] = input[0] >> 2;
		output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
		output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
		output[3] = input[2] & 0x3f;
		Assert(output[0] < 64);
		Assert(output[1] < 64);
		Assert(output[2] < 64);
		Assert(output[3] < 64);

		if (datalength + 4 > targsize)
			return (-1);
		target[datalength++] = Base64[output[0]];
		target[datalength++] = Base64[output[1]];
		target[datalength++] = Base64[output[2]];
		target[datalength++] = Base64[output[3]];
	}
    
	/* Now we worry about padding. */
	if (0 != srclength) {
		/* Get what's left. */
		input[0] = input[1] = input[2] = '\0';
		for (i = 0; i < srclength; i++)
			input[i] = *src++;
	
		output[0] = input[0] >> 2;
		output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
		output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
		Assert(output[0] < 64);
		Assert(output[1] < 64);
		Assert(output[2] < 64);

		if (datalength + 4 > targsize)
			return (-1);
		target[datalength++] = Base64[output[0]];
		target[datalength++] = Base64[output[1]];
		if (srclength == 1)
			target[datalength++] = Pad64;
		else
			target[datalength++] = Base64[output[2]];
		target[datalength++] = Pad64;
	}
	if (datalength >= targsize)
		return (-1);
	target[datalength] = '\0';	/* Returned value doesn't count \0. */
	return (datalength);
}

/* skips all whitespace anywhere.
   converts characters, four at a time, starting at (or after)
   src from base - 64 numbers into three 8 bit bytes in the target area.
   it returns the number of data bytes stored at the target, or -1 on error.
 */

int
b64_pton(src, target, targsize)
	char const *src;
	u_char *target;
	size_t targsize;
{
	int tarindex, state, ch;
	char *pos;

	state = 0;
	tarindex = 0;

	while ((ch = *src++) != '\0') {
		if (isspace(ch))	/* Skip whitespace anywhere. */
			continue;

		if (ch == Pad64)
			break;

		pos = (char *)strchr(Base64, ch);
		if (pos == 0) 		/* A non-base64 character. */
			return (-1);

		switch (state) {
		case 0:
			if (target) {
				if (tarindex >= targsize)
					return (-1);
				target[tarindex] = (pos - Base64) << 2;
			}
			state = 1;
			break;
		case 1:
			if (target) {
				if (tarindex + 1 >= targsize)
					return (-1);
				target[tarindex]   |=  (pos - Base64) >> 4;
				target[tarindex+1]  = ((pos - Base64) & 0x0f)
							<< 4 ;
			}
			tarindex++;
			state = 2;
			break;
		case 2:
			if (target) {
				if (tarindex + 1 >= targsize)
					return (-1);
				target[tarindex]   |=  (pos - Base64) >> 2;
				target[tarindex+1]  = ((pos - Base64) & 0x03)
							<< 6;
			}
			tarindex++;
			state = 3;
			break;
		case 3:
			if (target) {
				if (tarindex >= targsize)
					return (-1);
				target[tarindex] |= (pos - Base64);
			}
			tarindex++;
			state = 0;
			break;
		default:
			abort();
		}
	}

	/*
	 * We are done decoding Base-64 chars.  Let's see if we ended
	 * on a byte boundary, and/or with erroneous trailing characters.
	 */

	if (ch == Pad64) {		/* We got a pad char. */
		ch = *src++;		/* Skip it, get next. */
		switch (state) {
		case 0:		/* Invalid = in first position */
		case 1:		/* Invalid = in second position */
			return (-1);

		case 2:		/* Valid, means one byte of info */
			/* Skip any number of spaces. */
			for (NULL; ch != '\0'; ch = *src++)
				if (!isspace(ch))
					break;
			/* Make sure there is another trailing = sign. */
			if (ch != Pad64)
				return (-1);
			ch = *src++;		/* Skip the = */
			/* Fall through to "single trailing =" case. */
			/* FALLTHROUGH */

		case 3:		/* Valid, means two bytes of info */
			/*
			 * We know this char is an =.  Is there anything but
			 * whitespace after it?
			 */
			for (NULL; ch != '\0'; ch = *src++)
				if (!isspace(ch))
					return (-1);

			/*
			 * Now make sure for cases 2 and 3 that the "extra"
			 * bits that slopped past the last full byte were
			 * zeros.  If we don't check them, they become a
			 * subliminal channel.
			 */
			if (target && target[tarindex] != 0)
				return (-1);
		}
	} else {
		/*
		 * We ended by seeing the end of the string.  Make sure we
		 * have no partial bytes lying around.
		 */
		if (state != 0)
			return (-1);
	}

	return (tarindex);
}

int main(argc, argv) int argc; char **argv;
{
    char buf[BUFSIZ];
    char done[BUFSIZ];

    if(argc != 3) {
	(void)fprintf(stderr,"usage: %s acctname passwd\n", argv[0]);
	exit(1);
    }
    (void)sprintf(buf, "%s:%s", argv[1], argv[2]);
    (void)memset(done, 0, sizeof(done));

    if(-1 == b64_ntop(buf, strlen(buf), done, sizeof(done))) {
	(void)fprintf(stderr,"could not convert\n");
	exit(1);
    }
    (void)printf("%s => %s\n", buf, done);
    return(0);
    exit(0);
}