plan9fox/sys/src/cmd/cmp.c

133 lines
2.4 KiB
C
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#include <u.h>
#include <libc.h>
#include <ctype.h>
#define BUF 65536
int sflag = 0;
int lflag = 0;
int Lflag = 0;
static void usage(void);
char **
seekoff(int fd, char *name, char **argv)
{
vlong o;
if(*argv){
if (!isascii(**argv) || !isdigit(**argv))
usage();
o = strtoll(*argv++, 0, 0);
if(seek(fd, o, 0) < 0){
if(!sflag) fprint(2, "cmp: %s: seek by %lld: %r\n",
name, o);
exits("seek");
}
}
return argv;
}
void
main(int argc, char *argv[])
{
int n, i;
uchar *p, *q;
uchar buf1[BUF], buf2[BUF];
int f1, f2;
vlong nc = 1, l = 1;
char *name1, *name2;
uchar *b1s, *b1e, *b2s, *b2e;
ARGBEGIN{
case 's': sflag = 1; break;
case 'l': lflag = 1; break;
case 'L': Lflag = 1; break;
default: usage();
}ARGEND
if(argc < 2 || argc > 4)
usage();
if((f1 = open(name1 = *argv++, OREAD)) == -1){
if(!sflag) perror(name1);
exits("open");
}
if((f2 = open(name2 = *argv++, OREAD)) == -1){
if(!sflag) perror(name2);
exits("open");
}
argv = seekoff(f1, name1, argv);
argv = seekoff(f2, name2, argv);
if(*argv)
usage();
b1s = b1e = buf1;
b2s = b2e = buf2;
for(;;){
if(b1s >= b1e){
if(b1s >= &buf1[BUF])
b1s = buf1;
n = read(f1, b1s, &buf1[BUF] - b1s);
b1e = b1s + n;
}
if(b2s >= b2e){
if(b2s >= &buf2[BUF])
b2s = buf2;
n = read(f2, b2s, &buf2[BUF] - b2s);
b2e = b2s + n;
}
n = b2e - b2s;
if(n > b1e - b1s)
n = b1e - b1s;
if(n <= 0)
break;
if(memcmp((void *)b1s, (void *)b2s, n) != 0){
if(sflag)
exits("differ");
for(p = b1s, q = b2s, i = 0; i < n; p++, q++, i++) {
if(*p == '\n')
l++;
if(*p != *q){
if(!lflag){
print("%s %s differ: char %lld",
name1, name2, nc+i);
print(Lflag?" line %lld\n":"\n", l);
exits("differ");
}
print("%6lld 0x%.2x 0x%.2x\n", nc+i, *p, *q);
}
}
}
if(Lflag)
for(p = b1s; p < b1e;)
if(*p++ == '\n')
l++;
nc += n;
b1s += n;
b2s += n;
}
if (b1e - b1s < 0 || b2e - b2s < 0) {
if (!sflag) {
if (b1e - b1s < 0)
print("error on %s after %lld bytes\n",
name1, nc-1);
if (b2e - b2s < 0)
print("error on %s after %lld bytes\n",
name2, nc-1);
}
exits("read error");
}
if(b1e - b1s == b2e - b2s)
exits((char *)0);
if(!sflag)
print("EOF on %s after %lld bytes\n",
(b1e - b1s > b2e - b2s)? name2 : name1, nc-1);
exits("EOF");
}
static void
usage(void)
{
print("usage: cmp [-lLs] file1 file2 [offset1 [offset2] ]\n");
exits("usage");
}