Add an open_wmemstream(3) implementation and fix various issues for

fmemopen(3) and open_memstream(3).

With inputs from millert@, stsp@, guenther@, tedu@ and matthew@

1 files changed, 168 insertions, 0 deletions

diff --git a/lib/libc/stdio/open_wmemstream.c b/lib/libc/stdio/open_wmemstream.c
new file mode 100644
index 00000000000..2b8677c3b6a
--- /dev/null
+++ b/lib/libc/stdio/open_wmemstream.c
@@ -0,0 +1,168 @@
+/*	$OpenBSD: open_wmemstream.c,v 1.1 2013/03/27 15:06:25 mpi Exp $	*/
+
+/*
+ * Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+#include "local.h"
+
+struct state {
+	wchar_t		 *string;	/* actual stream */
+	wchar_t		**pbuf;		/* point to the stream */
+	size_t		 *psize;	/* point to min(pos, len) */
+	size_t		  pos;		/* current position */
+	size_t		  size;		/* number of allocated wchar_t */
+	size_t		  len;		/* length of the data */
+	mbstate_t	  mbs;		/* conversion state of the stream */
+};
+
+static int
+wmemstream_write(void *v, const char *b, int l)
+{
+	struct state	*st = v;
+	wchar_t		*p;
+	size_t		 nmc, len, end;
+
+	end = (st->pos + l);
+
+	if (end >= st->size) {
+		/* 1.6 is (very) close to the golden ratio. */
+		size_t	sz = st->size * 8 / 5;
+
+		if (sz < end + 1)
+			sz = end + 1;
+		p = realloc(st->string, sz * sizeof(wchar_t));
+		if (!p)
+			return (-1);
+		bzero(p + st->size, (sz - st->size) * sizeof(wchar_t));
+		*st->pbuf = st->string = p;
+		st->size = sz;
+	}
+
+	nmc = (st->size - st->pos) * sizeof(wchar_t);
+	len = mbsnrtowcs(st->string + st->pos, &b, nmc, l, &st->mbs);
+	if (len < 0)
+		return (len);
+	st->pos += len;
+
+	if (st->pos > st->len) {
+		st->len = st->pos;
+		st->string[st->len] = L'\0';
+	}
+
+	*st->psize = st->pos;
+
+	return (len);
+}
+
+static fpos_t
+wmemstream_seek(void *v, fpos_t off, int whence)
+{
+	struct state	*st = v;
+	ssize_t		 base = 0;
+
+	switch (whence) {
+	case SEEK_SET:
+		break;
+	case SEEK_CUR:
+		base = st->pos;
+		break;
+	case SEEK_END:
+		base = st->len;
+		break;
+	}
+
+	if (off > (SIZE_MAX / sizeof(wchar_t)) - base || off < -base) {
+		errno = EOVERFLOW;
+		return (-1);
+	}
+
+	/*
+	 * XXX Clearing mbs here invalidates shift state for state-
+	 * dependent encodings, but they are not (yet) supported.
+	 */
+	bzero(&st->mbs, sizeof(st->mbs));
+
+	st->pos = base + off;
+	*st->psize = MIN(st->pos, st->len);
+
+	return (st->pos);
+}
+
+static int
+wmemstream_close(void *v)
+{
+	struct state	*st = v;
+
+	free(st);
+
+	return (0);
+}
+
+FILE *
+open_wmemstream(wchar_t **pbuf, size_t *psize)
+{
+	struct state	*st;
+	FILE		*fp;
+
+	if (pbuf == NULL || psize == NULL) {
+		errno = EINVAL;
+		return (NULL);
+	}
+
+	if ((st = malloc(sizeof(*st))) == NULL)
+		return (NULL);
+
+	if ((fp = __sfp()) == NULL) {
+		free(st);
+		return (NULL);
+	}
+
+	st->size = BUFSIZ * sizeof(wchar_t);
+	if ((st->string = calloc(1, st->size)) == NULL) {
+		free(st);
+		fp->_flags = 0;
+		return (NULL);
+	}
+
+	*st->string = L'\0';
+	st->pos = 0;
+	st->len = 0;
+	st->pbuf = pbuf;
+	st->psize = psize;
+	bzero(&st->mbs, sizeof(st->mbs));
+
+	*pbuf = st->string;
+	*psize = st->len;
+
+	fp->_flags = __SWR;
+	fp->_file = -1;
+	fp->_cookie = st;
+	fp->_read = NULL;
+	fp->_write = wmemstream_write;
+	fp->_seek = wmemstream_seek;
+	fp->_close = wmemstream_close;
+
+	return (fp);
+}