fix '%[]' specifiers and '%n' (thanks phil9)

When a match() fails, we need to unget the character we
tried to match against, rather than leaving it consumed.

Also, we can't break out of a conversion before we reach
the end of a format string, because things like the '%n'
conversion do not consume anything, and should still be
handled.

1 files changed, 4 insertions, 4 deletions

diff --git a/sys/src/ape/lib/ap/stdio/vfscanf.c b/sys/src/ape/lib/ap/stdio/vfscanf.c
index c44bd7576..95c14b7b2 100644
--- a/sys/src/ape/lib/ap/stdio/vfscanf.c
+++ b/sys/src/ape/lib/ap/stdio/vfscanf.c
@@ -72,7 +72,6 @@ int vfscanf(FILE *f, const char *s, va_list args)
 			do
 				c=ngetc(f);
 			while(isspace(c));
-			if(c==EOF) return ncvt?ncvt:EOF;
 			nungetc(c, f);
 			break;
 		}
@@ -396,13 +395,14 @@ icvt_sq(FILE *f, va_list *args, int store, int width, int)
 			if(nn==0) return 0;
 			else goto Done;
 		}
-		if(!match(c, pat))
-			break;
+		if(!match(c, pat)){
+			nungetc(c, f);
+			return 0;
+		}
 		if(store)
 			*s++=c;
 		nn++;
 	}
-	nungetc(c, f);
 Done:
 	if(store) *s='\0';
 	return 1;