coreutils/cmp.c

   1 /* @cmp.c */
   2
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <errno.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8
   9 #define CMP_BUFSIZE 65536
  10
  11 char buf1[CMP_BUFSIZE];
  12 char buf2[CMP_BUFSIZE];
  13
  14 int main(int argc, char **argv) {
  15  int c,lflag=0,sflag=0,ret=0;
  16  int linenum=1,bytenum=1;
  17  int l1,l2;
  18  int i;
  19  FILE *f1, *f2;
  20  while((c=getopt(argc,argv,"ls"))!=-1) {
  21   if(c=='l')
  22    lflag=1;
  23   else if(c=='s')
  24    sflag=1;
  25   else {
  26    fprintf(stderr,"%s: unrecognised option '%c'\n",argv[0],optopt);
  27    return 2;
  28   }
  29  }
  30  if(sflag&&lflag) {
  31   fprintf(stderr,"%s: s and l options are mutually exclusive\n",argv[0]);
  32   return 2;
  33  }
  34  if(argc-optind<2) {
  35   fprintf(stderr,"usage: %s [-l | -s] file1 file2\n",argv[0]);
  36   return 2;
  37  }
  38  if(!(f1=fopen(argv[optind++],"rb"))||!(f2=fopen(argv[optind++],"rb"))) {
  39   fprintf(stderr,"%s: cannot open %s: %s\n",argv[0],argv[optind-1],strerror(errno));
  40   return 2;
  41  }
  42  while((l1=fread(buf1,1,CMP_BUFSIZE,f1))&&(l2=fread(buf2,1,CMP_BUFSIZE,f2))) {
  43   for(i=0;l1&&l2;i++,l1--,l2--) {
  44    if(buf1[i]!=buf2[i]) {
  45     if(!sflag) {
  46      if(!lflag) {
  47       printf("%s %s differ: char %d, line %d\n",argv[optind-2],argv[optind-1],bytenum+i,linenum);
  48      return_differ:
  49       fclose(f1);
  50       fclose(f2);
  51       return 1;
  52      } else
  53       printf("%d %o %o\n",bytenum+i,buf1[i],buf2[i]);
  54     }
  55     ret=1;
  56    }
  57    if(buf1[i]=='\n') linenum++;
  58   }
  59   if(l1 && !sflag) {
  60    printf("cmp: EOF on %s\n",argv[optind-1]);
  61    goto return_differ;
  62   } else if(l2 && !sflag) {
  63    printf("cmp: EOF on %s\n",argv[optind-2]);
  64    goto return_differ;
  65   }
  66   bytenum+=l1;
  67  }
  68  fclose(f1);
  69  fclose(f2);
  70  return ret;
  71 }