demos/maurice/example4.c

   1 /* NOCW */
   2 /*
   3         Please read the README file for condition of use, before
   4         using this software.
   5
   6         Maurice Gittens  <mgittens@gits.nl>   January 1997
   7
   8 */
   9
  10 #include <stdio.h>
  11 #include <fcntl.h>
  12 #include <sys/stat.h>
  13 #include <evp.h>
  14
  15 #define STDIN           0
  16 #define STDOUT          1
  17 #define BUFLEN          512
  18
  19 static const char *usage = "Usage: example4 [-d]\n";
  20
  21 void do_encode(void);
  22 void do_decode(void);
  23
  24 int main(int argc, char *argv[])
  25 {
  26         if ((argc == 1))
  27         {
  28                 do_encode();
  29         }
  30         else if ((argc == 2) && !strcmp(argv[1],"-d"))
  31         {
  32                 do_decode();
  33         }
  34         else
  35         {
  36                 fprintf(stderr,"%s", usage);
  37                 exit(1);
  38         }
  39
  40         return 0;
  41 }
  42
  43 void do_encode()
  44 {
  45         char buf[BUFLEN];
  46         char ebuf[BUFLEN+24];
  47         unsigned int ebuflen, rc;
  48         EVP_ENCODE_CTX ectx;
  49
  50         EVP_EncodeInit(&ectx);
  51
  52         while(1)
  53         {
  54                 int readlen = read(STDIN, buf, sizeof(buf));
  55
  56                 if (readlen <= 0)
  57                 {
  58                         if (!readlen)
  59                            break;
  60                         else
  61                         {
  62                                 perror("read");
  63                                 exit(1);
  64                         }
  65                 }
  66
  67                 EVP_EncodeUpdate(&ectx, ebuf, &ebuflen, buf, readlen);
  68
  69                 write(STDOUT, ebuf, ebuflen);
  70         }
  71
  72         EVP_EncodeFinal(&ectx, ebuf, &ebuflen);
  73
  74         write(STDOUT, ebuf, ebuflen);
  75 }
  76
  77 void do_decode()
  78 {
  79         char buf[BUFLEN];
  80         char ebuf[BUFLEN+24];
  81         unsigned int ebuflen, rc;
  82         EVP_ENCODE_CTX ectx;
  83
  84         EVP_DecodeInit(&ectx);
  85
  86         while(1)
  87         {
  88                 int readlen = read(STDIN, buf, sizeof(buf));
  89                 int rc;
  90
  91                 if (readlen <= 0)
  92                 {
  93                         if (!readlen)
  94                            break;
  95                         else
  96                         {
  97                                 perror("read");
  98                                 exit(1);
  99                         }
 100                 }
 101
 102                 rc = EVP_DecodeUpdate(&ectx, ebuf, &ebuflen, buf, readlen);
 103                 if (rc <= 0)
 104                 {
 105                         if (!rc)
 106                         {
 107                                 write(STDOUT, ebuf, ebuflen);
 108                                 break;
 109                         }
 110
 111                         fprintf(stderr, "Error: decoding message\n");
 112                         return;
 113                 }
 114
 115                 write(STDOUT, ebuf, ebuflen);
 116         }
 117
 118         EVP_DecodeFinal(&ectx, ebuf, &ebuflen);
 119
 120         write(STDOUT, ebuf, ebuflen);
 121 }
 122