fix core text and map ownership

str.c

@@ -1,11 +1,6 @@
 #include "dat.h"
 #include "fn.h"
 
-enum
-{
-	Maxrunes = nelem(((Str*)0)->r),
-};
-
 void
 sinit(Str *s, char *src, int n)
 {
@@ -13,7 +8,11 @@ sinit(Str *s, char *src, int n)
 
 	s->n = 0;
 	while(n > 0 && s->n < Maxrunes){
+		if(!fullrune(src, n))
+			break;
 		len = chartorune(&s->r[s->n], src);
+		if(len > n)
+			break;
 		s->n++;
 		src += len;
 		n -= len;
@@ -44,9 +43,10 @@ spopr(Str *s)
 void
 sappend(Str *dst, Str *src)
 {
-	int i;
+	int i, n;
 
-	for(i = 0; i < src->n && dst->n < Maxrunes; i++)
+	n = src->n;
+	for(i = 0; i < n && dst->n < Maxrunes; i++)
 		dst->r[dst->n++] = src->r[i];
 }
 
@@ -66,11 +66,17 @@ scmp(Str *a, Str *b)
 int
 stoutf(Str *s, char *buf, int sz)
 {
+	char tmp[UTFmax];
 	int i, n, len;
 
+	if(sz <= 0)
+		return 0;
 	n = 0;
-	for(i = 0; i < s->n && n < sz - UTFmax; i++){
-		len = runetochar(buf + n, &s->r[i]);
+	for(i = 0; i < s->n; i++){
+		len = runetochar(tmp, &s->r[i]);
+		if(len > sz - n - 1)
+			break;
+		memmove(buf + n, tmp, len);
 		n += len;
 	}
 	buf[n] = '\0';