We should not require both files to be present for cmp(1)

If the second file is not present, read from standard input.
This commit is contained in:
sin 2014-03-04 10:33:51 +00:00
parent 99300c9514
commit c28e2a39ec

24
cmp.c
View File

@ -10,7 +10,7 @@ enum { Same = 0, Diff = 1, Error = 2 };
static void static void
usage(void) usage(void)
{ {
enprintf(Error, "usage: %s [-ls] file1 file2\n", argv0); enprintf(Error, "usage: %s [-ls] file1 [file2]\n", argv0);
} }
int int
@ -34,13 +34,19 @@ main(int argc, char *argv[])
usage(); usage();
} ARGEND; } ARGEND;
if(argc < 2) if (argc < 1 || argc > 2)
usage(); usage();
for(i = 0; i < 2; i++) { fp[0] = fopen(argv[0], "r");
if(!(fp[i] = fopen(argv[i], "r"))) if (!fp[0])
enprintf(Error, "fopen %s:", argv[i]); enprintf(Error, "fopen %s:", argv[0]);
} fp[1] = stdin;
if (argc == 2)
fp[1] = fopen(argv[1], "r");
if (!fp[1])
enprintf(Error, "fopen %s:", argv[1]);
for(n = 1; ((b[0] = getc(fp[0])) != EOF) \ for(n = 1; ((b[0] = getc(fp[0])) != EOF) \
| ((b[1] = getc(fp[1])) != EOF); n++) { | ((b[1] = getc(fp[1])) != EOF); n++) {
if(b[0] == '\n') if(b[0] == '\n')
@ -49,11 +55,12 @@ main(int argc, char *argv[])
continue; continue;
for(i = 0; i < 2; i++) for(i = 0; i < 2; i++)
if(b[i] == EOF) if(b[i] == EOF)
enprintf(Diff, "cmp: EOF on %s\n", argv[i]); enprintf(Diff, "cmp: EOF on %s\n",
!argv[i] ? "<stdin>" : argv[1]);
if(!lflag) { if(!lflag) {
if(!sflag) if(!sflag)
printf("%s %s differ: char %ld, line %ld\n", printf("%s %s differ: char %ld, line %ld\n",
argv[0], argv[1], n, line); argv[0], !argv[1] ? "<stdin>" : argv[1], n, line);
exit(Diff); exit(Diff);
} else { } else {
printf("%4ld %3o %3o\n", n, b[0], b[1]); printf("%4ld %3o %3o\n", n, b[0], b[1]);
@ -62,4 +69,3 @@ main(int argc, char *argv[])
} }
return same ? Same : Diff; return same ? Same : Diff;
} }