realloc case

Reference: /n/atom/patch/applied/rdstrrealloc
Date: Sat May  3 06:04:42 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libbio/brdstr.c	Sat May  3 06:04:36 2014
+++ /sys/src/libbio/brdstr.c	Sat May  3 06:04:37 2014
@@ -6,10 +6,11 @@
 badd(char *p, int *np, char *data, int ndata, int delim, int nulldelim)
 {
 	int n;
+	char *oldp;
 
 	n = *np;
-	p = realloc(p, n+ndata+1);
-	if(p){
+	p = realloc(oldp = p, n+ndata+1);
+	if(p != nil){
 		memmove(p+n, data, ndata);
 		n += ndata;
 		if(n>0 && nulldelim && p[n-1]==delim)
@@ -17,6 +18,9 @@
 		else
 			p[n] = '\0';
 		*np = n;
+	}else{
+		*np = 0;
+		free(oldp);
 	}
 	return p;
 }