shithub: riscv

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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.

--- a/sys/src/ape/lib/ap/stdio/vfscanf.c

+++ b/sys/src/ape/lib/ap/stdio/vfscanf.c

@@ -72,7 +72,6 @@

 			do

 				c=ngetc(f);

 			while(isspace(c));

-			if(c==EOF) return ncvt?ncvt:EOF;

 			nungetc(c, f);

 			break;

 		}

@@ -396,13 +395,14 @@

 			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;

--- a/sys/src/libstdio/vfscanf.c

+++ b/sys/src/libstdio/vfscanf.c

@@ -68,7 +68,6 @@

 			do

 				c=ngetc(f);

 			while(isspace(c));

-			if(c==EOF) return ncvt?ncvt:EOF;

 			nungetc(c, f);

 			break;

 		}

@@ -353,11 +352,13 @@

 			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;