code:

---

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

#define BAD     -1
#define DECODE64(c)  (isascii(c) ? base64val[c] : BAD)

static const char base64digits[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char base64val[] =
    	{
		BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,
		BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,
		BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD,BAD, 62,BAD,BAD,BAD, 63,
		 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,BAD,BAD,BAD,BAD,BAD,BAD,
		BAD,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
		 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,BAD,BAD,BAD,BAD,BAD,
		BAD, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
		 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,BAD,BAD,BAD,BAD,BAD
		};

int isascii(int num);
void to64frombits(unsigned char *out, const unsigned char *in, int inlen);
int from64tobits(char *out, const char *in);

int main(void)
{
	char buffer[100];
	char buffer2[100];
	char teststring[] = "test123";
	int i;
	printf("Decodiere String: %sn", teststring);
	to64frombits(buffer, teststring, strlen(teststring));
	printf("base64 String: %snund zurückn", buffer);
	i = from64tobits(buffer2, buffer);
	buffer2[i] = 0;
	printf("alter String: %sn", buffer2);

    return 0;
}

void to64frombits(unsigned char *out, const unsigned char *in, int inlen)
{
    unsigned char fragment;
	
    for (; inlen >= 3; inlen -= 3)
	{
		*out++ = base64digits[in[0] >> 2];
		*out++ = base64digits[((in[0] << 4) & 0x30) | (in[1] >> 4)];
		*out++ = base64digits[((in[1] << 2) & 0x3c) | (in[2] >> 6)];
		*out++ = base64digits[in[2] & 0x3f];
		in += 3;
	}

	if (inlen > 0)
	{
		*out++ = base64digits[in[0] >> 2];
		fragment = (in[0] << 4) & 0x30;

        if (inlen > 1)
			fragment |= in[1] >> 4;

        *out++ = base64digits[fragment];
        *out++ = (inlen < 2) ? '=' : base64digits[(in[1] << 2) & 0x3c];
        *out++ = '=';
	}
    *out = '';
}

int from64tobits(char *out, const char *in)
{
	int len = 0;
	register unsigned char digit1, digit2, digit3, digit4;

    if (in[0] == '+' && in[1] == ' ')
		in += 2;

    if (*in == 'r')
		return(0);

    do
    {
		digit1 = in[0];
		/*if (DECODE64(digit1) == BAD)  */
		if((isascii(digit1) ? base64val[digit1] : BAD) == BAD)
			return(-1);
		digit2 = in[1];
		/*if (DECODE64(digit2) == BAD)*/
        if((isascii(digit2) ? base64val[digit2] : BAD) == BAD)
			return(-1);
		digit3 = in[2];
		/*if (digit3 != '=' && DECODE64(digit3) == BAD)  */
        if (digit3 != '=' && (isascii(digit3) ? base64val[digit3] : BAD) == BAD)
			return(-1);
		digit4 = in[3];
		/*if (digit4 != '=' && DECODE64(digit4) == BAD)    */
		if(digit3 != '=' && (isascii(digit4) ? base64val[digit4] : BAD) ==BAD)
			return(-1);
		in += 4;
		/**out++ = (DECODE64(digit1) << 2) | (DECODE64(digit2) >> 4);  */
		*out++ = ((isascii(digit1) ? base64val[digit1] : BAD) << 2) |
        		 ((isascii(digit2) ? base64val[digit2] : BAD) >> 4);
        ++len;
		if (digit3 != '=')
		{
			/**out++ = ((DECODE64(digit2) << 4) & 0xf0) | (DECODE64(digit3) >> 2);  */
			*out++ = (((isascii(digit2) ? base64val[digit2] : BAD) << 4) & 0xf0) |
                      ((isascii(digit3) ? base64val[digit3] : BAD) >> 2);
            ++len;
			if (digit4 != '=')
			{
				/**out++ = ((DECODE64(digit3) << 6) & 0xc0) | DECODE64(digit4); */
                *out++ = (((isascii(digit3) ? base64val[digit3] : BAD) << 6) & 0xc0) |
                      	   (isascii(digit4) ? base64val[digit4] : BAD);
				++len;
			}
		}
	} while (*in && *in != 'r' && digit4 != '=');

	return (len);
}

int isascii(int num)
{
	if(num >= 0 && num <= 127)
		return 1;
	else
		return 0;
}

---

Einer ne Ahnung was der GNU von mir möchte?
--
Micha

Look at my HPs:
http://www.Silicon-Wizards.com

http://www.RealmsofPower.de.vu