mb_check_encoding($str, '7bit') rejects strings with bytes over 0x7F

This was the old behavior of mb_check_encoding() before 3e7acf9,
but yours truly broke it. If only we had more thorough tests at that
time, this might not have slipped through the cracks.

Thanks to divinity76 for the report.

ext/mbstring/libmbfl/filters/mbfilter_7bit.c

@@ -67,7 +67,7 @@ const struct mbfl_convert_vtbl vtbl_7bit_8bit = {
 
 int mbfl_filt_conv_7bit_any(int c, mbfl_convert_filter *filter)
 {
-	return (*filter->output_function)(c, filter->data);
+	return (*filter->output_function)(c < 0x80 ? c : MBFL_BAD_INPUT, filter->data);
 }
 
 

ext/mbstring/tests/other_encodings.phpt

@@ -14,10 +14,11 @@ mb_substitute_character(0x25);
 var_dump(mb_convert_encoding("ABC", "7bit", "ASCII"));
 var_dump(mb_convert_encoding("\x80", "7bit", "ASCII"));
 var_dump(mb_convert_encoding("ABC", "8bit", "7bit"));
+var_dump(mb_check_encoding(chr(255), '7bit'));
 echo "7bit done\n";
 
 // "8bit"
-var_dump(mb_convert_encoding("\x01\x00", "8bit", "UTF-16BE")); // codepoints over 0xFF are illegal or '8-bit'
+var_dump(mb_convert_encoding("\x01\x00", "8bit", "UTF-16BE")); // codepoints over 0xFF are illegal for '8-bit'
 echo "8bit done\n";
 
 // UCS-2
@@ -41,6 +42,7 @@ echo "UCS-4 done\n";
 string(3) "ABC"
 string(1) "%"
 string(3) "ABC"
+bool(false)
 7bit done
 string(1) "%"
 8bit done