src/ltsha256.c

   1 /* License: public domain -or- http://www.wtfpl.net/txt/copying/ */
   2
   3 #include "lt256.h"
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <errno.h>
   7 #include <unistd.h>
   8
   9 #define READSIZE 32768
  10
  11 static const char hextab[16] = {
  12         '0', '1', '2', '3', '4', '5', '6', '7',
  13         '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
  14 };
  15 static char buffer[READSIZE];
  16
  17 int main(int arc, char *argv[])
  18 {
  19         SHA256_CTX c;
  20         unsigned char md[SHA256_DIGEST_LENGTH];
  21         char mdhex[(2*SHA256_DIGEST_LENGTH)+1];
  22         ssize_t e;
  23         unsigned i;
  24
  25         if (!SHA256_Init(&c))
  26                 return EXIT_FAILURE;
  27
  28         for (;;) {
  29                 do {
  30                         e = read(STDIN_FILENO, buffer, READSIZE);
  31                 } while (e == -1 &&
  32                         (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK));
  33                 if (e < 0)
  34                         return EXIT_FAILURE;
  35                 if (!e)
  36                         break;
  37                 if (!SHA256_Update(&c, buffer, (size_t)e))
  38                         return EXIT_FAILURE;
  39         }
  40         if (!SHA256_Final(md, &c))
  41                 return 0;
  42         for (i=0; i < SHA256_DIGEST_LENGTH; ++i) {
  43                 unsigned char c = md[i];
  44                 mdhex[i<<1] = hextab[c >> 4];
  45                 mdhex[(i<<1)+1] = hextab[c & 0xf];
  46         }
  47         mdhex[2*SHA256_DIGEST_LENGTH] = '\0';
  48         if (puts(mdhex) < 0)
  49                 return EXIT_FAILURE;
  50
  51         return 0;
  52 }
  53
  54 #include "lt256.c"