#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ctype.h>

void getu(Biobuf* bin, Biobuf* bout){
	char d[5];
	int i;
	int u;

	for(i=0; i<4 ; i++){
		d[i] = Bgetc(bin);
		if (!isxdigit(d[i])){
			goto loose;
		}
	}
	d[i--] = 0;
	u = strtoul(d, 0, 16);
	if (u<=Runemax){
		Bprint(bout, "%C", u);
		return;
	}
	
loose:
	if (-1 == d[i]){
		i--;
	}
	if (i>0){
		Bprint(bout, "%.*s", i, d);
	}
}

void convert(Biobuf * bin, Biobuf * bout)
{
	int c;

	for(;;){
		c = Bgetrune(bin);
top:		switch(c){
		default:
			Bputrune(bout, c);
			break;
		case '\\':
			c = Bgetrune(bin);
			if ('u' != c){
				Bputrune(bout, '\\');
				goto top;
			}

			getu(bin, bout);
			break;	
		case -1:
			return;
		}
	}
}

void main(int c, char **v)
{
	int i;
	Biobuf *b, bin, bout;

	Binit(&bout, 1, OWRITE);

	if (c == 1) {
		Binit(&bin, 0, OREAD);
		convert(&bin, &bout);
	} else {
		for (i = 1; i < c; i++) {
			if ((b = Bopen(v[i], OREAD)) == nil)
				sysfatal("open %s: %r", v[i]);
			convert(b, &bout);
			Bterm(b);
		}
	}
	Bterm(&bout);
	exits(nil);
}