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Member "zsync-0.6.2/base64.c" (16 Sep 2010, 2558 Bytes) of package /linux/privat/old/zsync-0.6.2.tar.gz:

    1 /*
    2  *
    3  * Copyright 1997 Massachusetts Institute of Technology
    4  *
    5  * Permission to use, copy, modify, and distribute this software and
    6  * its documentation for any purpose and without fee is hereby
    7  * granted, provided that both the above copyright notice and this
    8  * permission notice appear in all copies, that both the above
    9  * copyright notice and this permission notice appear in all
   10  * supporting documentation, and that the name of M.I.T. not be used
   11  * in advertising or publicity pertaining to distribution of the
   12  * software without specific, written prior permission.  M.I.T. makes
   13  * no representations about the suitability of this software for any
   14  * purpose.  It is provided "as is" without express or implied
   15  * warranty.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
   18  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
   19  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   20  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
   21  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   22  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   23  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   24  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   25  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   26  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   27  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  */
   30 
   31 #include <stdlib.h>
   32 #include <string.h>
   33 
   34 /*
   35  * Base64 encoding
   36  */
   37 char * base64(const char *src)
   38 {
   39     static const char base64[] =
   40         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
   41         "abcdefghijklmnopqrstuvwxyz"
   42         "0123456789+/";
   43     char *str, *dst;
   44     size_t l;
   45     int t, r;
   46 
   47     l = strlen(src);
   48     if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
   49         return (NULL);
   50     dst = str;
   51     r = 0;
   52 
   53     while (l >= 3) {
   54         t = (src[0] << 16) | (src[1] << 8) | src[2];
   55         dst[0] = base64[(t >> 18) & 0x3f];
   56         dst[1] = base64[(t >> 12) & 0x3f];
   57         dst[2] = base64[(t >> 6) & 0x3f];
   58         dst[3] = base64[(t >> 0) & 0x3f];
   59         src += 3; l -= 3;
   60         dst += 4; r += 4;
   61     }
   62 
   63     switch (l) {
   64     case 2:
   65         t = (src[0] << 16) | (src[1] << 8);
   66         dst[0] = base64[(t >> 18) & 0x3f];
   67         dst[1] = base64[(t >> 12) & 0x3f];
   68         dst[2] = base64[(t >> 6) & 0x3f];
   69         dst[3] = '=';
   70         dst += 4;
   71         r += 4;
   72         break;
   73     case 1:
   74         t = src[0] << 16;
   75         dst[0] = base64[(t >> 18) & 0x3f];
   76         dst[1] = base64[(t >> 12) & 0x3f];
   77         dst[2] = dst[3] = '=';
   78         dst += 4;
   79         r += 4;
   80         break;
   81     case 0:
   82         break;
   83     }
   84 
   85     *dst = 0;
   86     return (str);
   87 }
   88 
   89