#include <u.h>
#include <libc.h>
#include <bio.h>
enum{MINREAD = 8192};
char *buf;
int i, c, sz = MINREAD;
void
slurp(char *f){
	int fd, n;
	fd = open(f, OREAD);
	if(fd < 0) sysfatal("open: %r");
	for(;;){
		if(sz - i <= MINREAD){
			buf = realloc(buf, sz <<= 1);
			if(buf == nil) sysfatal("realloc: %r");
		}
		n = read(fd, buf + i, sz - i);
		if(n == 0) break;
		if(n < 0) sysfatal("read: %r");
		while(n--) if(buf[i++] == '\n') c++;
	}
	close(fd);
	if(i && buf[i - 1] != '\n'){
		if(i == sz){
			buf = realloc(buf, ++sz);
			if(buf == nil) sysfatal("realloc: %r");
		}
		fprint(2, "adding newline at end of %s\n", f);
		buf[i++] = '\n';
		c++;
	}
}
void
main(int argc, char *argv[]){
	Biobuf *out;
	int j, *start, *len;
	if(argc == 1) slurp("/fd/0");
	else while(--argc) slurp(argv[argc]);
	if(c == 0) exits(nil);
	start = calloc(c, sizeof(int));
	len = calloc(c, sizeof(int));
	if(start == nil || len == nil) sysfatal("calloc: %r");
	len[j = 0] = --i;
	while(i--){
		if(buf[i] == '\n'){
			len[j] -= i;
			start[j] = i + 1;
			len[++j] = i;
		}
	}
	len[j]++;
	assert(j + 1 == c);
	out = Bfdopen(1, OWRITE);
	if(out == nil) sysfatal("Bfdopen: %r");
	srand(truerand());
	while(c){
		j = nrand(c--);
		Bwrite(out, buf + start[j], len[j]);
		start[j] = start[c];
		len[j] = len[c];
	}
	exits(nil);
}