sbase/comm.c

106 lines
1.8 KiB
C

/* See LICENSE file for copyright and license details. */
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "util.h"
#define CLAMP(x, l, h) MIN(h, MAX(l, x))
static void printline(int, char *);
static char *nextline(char *, int, FILE *, char *);
static void finish(int, FILE *, char *);
static int show = 0x07;
static void
usage(void)
{
eprintf("usage: %s [-123] file1 file2\n", argv0);
}
int
main(int argc, char *argv[])
{
int i, diff = 0;
FILE *fp[2];
char lines[2][LINE_MAX+1];
ARGBEGIN {
case '1':
case '2':
case '3':
show &= 0x07 ^ (1 << (ARGC() - '1'));
break;
default:
usage();
} ARGEND;
if(argc != 2)
usage();
for(i = 0; i < LEN(fp); i++) {
if(!(fp[i] = fopen(argv[i], "r")))
eprintf("comm: '%s':", argv[i]);
}
for(;;) {
if(diff <= 0) {
if(!nextline(lines[0], sizeof(lines[0]),
fp[0], argv[0])) {
finish(1, fp[1], argv[1]);
}
}
if(diff >= 0) {
if(!nextline(lines[1], sizeof(lines[1]),
fp[1], argv[1])) {
finish(0, fp[0], argv[0]);
}
}
diff = strcmp(lines[0], lines[1]);
diff = CLAMP(diff, -1, 1);
printline((2-diff) % 3, lines[MAX(0, diff)]);
}
return EXIT_SUCCESS;
}
static void
printline(int pos, char *line)
{
int i;
if(!(show & (0x1 << pos)))
return;
for(i = 0; i < pos; i++) {
if(show & (0x1 << i))
putchar('\t');
}
printf("%s", line);
}
static char *
nextline(char *buf, int n, FILE *f, char *name)
{
buf = fgets(buf, n, f);
if(!buf && !feof(f))
eprintf("comm: '%s':", name);
if(buf && !strchr(buf, '\n'))
eprintf("comm: '%s': line too long.\n", name);
return buf;
}
static void
finish(int pos, FILE *f, char *name)
{
char buf[LINE_MAX+1];
while(nextline(buf, sizeof(buf), f, name))
printline(pos, buf);
exit(EXIT_FAILURE);
}