libc/stdio: Rework custom streams interface similar to glibc.

Save 20 bytes per FILE structure, avoid indirect call for
read/write/seek/close operations for normal streams.
Additionally, custom streams has fileno = -2 now, like in glibc.

bloat-o-meter report (UCLIBC_HAS_GLIBC_CUSTOM_STREAMS=y):
function                                             old     new   delta
fopencookie                                           69     131     +62
ftello64                                             233     260     +27
fseeko64                                             298     319     +21
fclose                                               423     442     +19
.rodata                                            16696   16708     +12
fileno_unlocked                                       53      45      -8
__ns_name_pack                                       859     851      -8
vswscanf                                             184     144     -40
vdprintf                                             231     187     -44
vsscanf                                              210     151     -59
vswprintf                                            269     201     -68
vsnprintf                                            249     181     -68
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/7 up/down: 141/-295)         Total: -154 bytes

Signed-off-by: Leonid Lisovskiy <lly.dev@gmail.com>
Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>

1 files changed, 21 insertions, 8 deletions

diff --git a/libc/stdio/fopencookie.c b/libc/stdio/fopencookie.c
index c4927e0bd..216dac39d 100644
--- a/libc/stdio/fopencookie.c
+++ b/libc/stdio/fopencookie.c
@@ -39,21 +39,34 @@ FILE *_fopencookie(void * __restrict cookie, const char * __restrict mode,
 #endif
 {
 	FILE *stream;
+	_IO_cookie_file_t *new_f;
 
+	new_f = malloc(sizeof(_IO_cookie_file_t));
+	if (new_f == NULL) {
+		return NULL;
+	}
+	new_f->__fp.__modeflags = __FLAG_FREEFILE;
+#ifdef __STDIO_BUFFERS
+	new_f->__fp.__bufstart = NULL; /* We allocate a buffer below. */
+#endif
+#ifdef __UCLIBC_HAS_THREADS__
+	/* We only initialize the mutex in the non-freopen case. */
+	STDIO_INIT_MUTEX(new_f->__fp.__lock);
+#endif
 	/* Fake an fdopen guaranteed to pass the _stdio_fopen basic agreement
 	 * check without an fcntl call. */
-	stream = _stdio_fopen(((intptr_t)(INT_MAX-1)), mode, NULL, INT_MAX);
+	stream = _stdio_fopen(((intptr_t)(INT_MAX-1)), mode, &new_f->__fp, INT_MAX);
 	if (stream) {
-		stream->__filedes = -1;
+		stream->__filedes = __STDIO_STREAM_GLIBC_CUSTOM_FILEDES;
 #ifndef __BCC__
-		stream->__gcs = io_functions;
+		new_f->__gcs = io_functions;
 #else
-		stream->__gcs.read  = io_functions->read;
-		stream->__gcs.write = io_functions->write;
-		stream->__gcs.seek  = io_functions->seek;
-		stream->__gcs.close = io_functions->close;
+		new_f->__gcs.read  = io_functions->read;
+		new_f->__gcs.write = io_functions->write;
+		new_f->__gcs.seek  = io_functions->seek;
+		new_f->__gcs.close = io_functions->close;
 #endif
-		stream->__cookie = cookie;
+		new_f->__cookie = cookie;
 
 		__STDIO_STREAM_VALIDATE(stream);
 	}