Module Name: src
Committed By: christos
Date: Mon Oct 13 00:40:36 UTC 2014
Modified Files:
src/lib/libc/stdio: Makefile.inc
Added Files:
src/lib/libc/stdio: open_memstream.3 open_memstream.c open_wmemstream.c
Log Message:
PR/49279: Justin Cormack: add open_memstream
To generate a diff of this commit:
cvs rdiff -u -r1.45 -r1.46 src/lib/libc/stdio/Makefile.inc
cvs rdiff -u -r0 -r1.1 src/lib/libc/stdio/open_memstream.3 \
src/lib/libc/stdio/open_memstream.c src/lib/libc/stdio/open_wmemstream.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/stdio/Makefile.inc
diff -u src/lib/libc/stdio/Makefile.inc:1.45 src/lib/libc/stdio/Makefile.inc:1.46
--- src/lib/libc/stdio/Makefile.inc:1.45 Wed Jun 18 13:50:55 2014
+++ src/lib/libc/stdio/Makefile.inc Sun Oct 12 20:40:36 2014
@@ -1,5 +1,5 @@
# from: @(#)Makefile.inc 5.7 (Berkeley) 6/27/91
-# $NetBSD: Makefile.inc,v 1.45 2014/06/18 17:50:55 christos Exp $
+# $NetBSD: Makefile.inc,v 1.46 2014/10/13 00:40:36 christos Exp $
# stdio sources
.PATH: ${.CURDIR}/stdio
@@ -21,7 +21,7 @@ SRCS+= clrerr.c dprintf.c fclose.c fdope
vasprintf.c vdprintf.c vfprintf.c vfscanf.c vfwprintf.c vfwscanf.c \
vprintf.c vscanf.c vsnprintf.c vsnprintf_ss.c vsscanf.c vswprintf.c \
vswscanf.c vwprintf.c vwscanf.c wbuf.c wprintf.c wscanf.c wsetup.c
-SRCS+= fmemopen.c
+SRCS+= fmemopen.c open_memstream.c open_wmemstream.c
.if !defined(AUDIT)
SRCS+= gets.c vsprintf.c tempnam.c tmpnam.c mktemp.c
@@ -31,7 +31,7 @@ MAN+= fclose.3 ferror.3 fflush.3 fgetln.
flockfile.3 fmemopen.3 fopen.3 fparseln.3 fputs.3 fputws.3 fread.3 \
fseek.3 funopen.3 fwide.3 getc.3 getdelim.3 getwc.3 mktemp.3 printf.3 \
putc.3 putwc.3 remove.3 scanf.3 setbuf.3 stdio.3 tmpnam.3 \
- ungetc.3 ungetwc.3 wprintf.3 wscanf.3
+ ungetc.3 ungetwc.3 wprintf.3 wscanf.3 open_memstream.3
MLINKS+=ferror.3 clearerr.3 ferror.3 feof.3 ferror.3 fileno.3
MLINKS+=fflush.3 fpurge.3
@@ -66,3 +66,4 @@ MLINKS+=wprintf.3 fwprintf.3 wprintf.3 s
MLINKS+=wprintf.3 vwprintf.3 wprintf.3 vfwprintf.3 wprintf.3 vswprintf.3
MLINKS+=wscanf.3 fwscanf.3 wscanf.3 swscanf.3 wscanf.3 vwscanf.3
MLINKS+=wscanf.3 vswscanf.3 wscanf.3 vfwscanf.3
+MLINKS+=open_memstream.3 open_wmemstream.3
Added files:
Index: src/lib/libc/stdio/open_memstream.3
diff -u /dev/null src/lib/libc/stdio/open_memstream.3:1.1
--- /dev/null Sun Oct 12 20:40:36 2014
+++ src/lib/libc/stdio/open_memstream.3 Sun Oct 12 20:40:36 2014
@@ -0,0 +1,156 @@
+.\" $NetBSD: open_memstream.3,v 1.1 2014/10/13 00:40:36 christos Exp $
+.\" Copyright (c) 2013 Advanced Computing Technologies LLC
+.\" Written by: John H. Baldwin <j...@freebsd.org>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD: head/lib/libc/stdio/open_memstream.3 247415 2013-02-27 20:09:25Z joel $
+.\"
+.Dd October 12, 2014
+.Dt OPEN_MEMSTREAM 3
+.Os
+.Sh NAME
+.Nm open_memstream ,
+.Nm open_wmemstream
+.Nd dynamic memory buffer stream open functions
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In stdio.h
+.Ft FILE *
+.Fn open_memstream "char **bufp" "size_t **sizep"
+.In wchar.h
+.Ft FILE *
+.Fn open_wmemstream "wchar_t **bufp" "size_t **sizep"
+.Sh DESCRIPTION
+The
+.Fn open_memstream
+and
+.Fn open_wmemstream
+functions create a write-only, seekable stream backed by a dynamically
+allocated memory buffer.
+The
+.Fn open_memstream
+function creates a byte-oriented stream,
+while the
+.Fn open_wmemstream
+function creates a wide-oriented stream.
+.Pp
+Each stream maintains a current position and size.
+Initially,
+the position and size are set to zero.
+Each write begins at the current position and advances it the number of
+successfully written bytes for
+.Fn open_memstream
+or wide characters for
+.Fn open_wmemstream .
+If a write moves the current position beyond the length of the buffer,
+the length of the buffer is extended and a null character is appended to the
+buffer.
+.Pp
+A stream's buffer always contains a null character at the end of the buffer
+that is not included in the current length.
+.Pp
+If a stream's current position is moved beyond the current length via a
+seek operation and a write is performed,
+the characters between the current length and the current position are filled
+with null characters before the write is performed.
+.Pp
+After a successful call to
+.Xr fclose 3
+or
+.Xr fflush 3 ,
+the pointer referenced by
+.Fa bufp
+will contain the start of the memory buffer and the variable referenced by
+.Fa sizep
+will contain the smaller of the current position and the current buffer length.
+.Pp
+After a successful call to
+.Xr fflush 3,
+the pointer referenced by
+.Fa bufp
+and the variable referenced by
+.Fa sizep
+are only valid until the next write operation or a call to
+.Xr fclose 3.
+.Pp
+Once a stream is closed,
+the allocated buffer referenced by
+.Fa bufp
+should be released via a call to
+.Xr free 3
+when it is no longer needed.
+.Sh IMPLEMENTATION NOTES
+Internally all I/O streams are effectively byte-oriented,
+so using wide-oriented operations to write to a stream opened via
+.Fn open_wmemstream
+results in wide characters being expanded to a stream of multibyte characters
+in stdio's internal buffers.
+These multibyte characters are then converted back to wide characters when
+written into the stream.
+As a result,
+the wide-oriented streams maintain an internal multibyte character conversion
+state that is cleared on any seek opertion that changes the current position.
+This should have no effect as long as wide-oriented output operations are used
+on a wide-oriented stream.
+.Sh RETURN VALUES
+Upon successful completion,
+.Fn open_memstream
+and
+.Fn open_wmemstream
+return a
+.Tn FILE
+pointer.
+Otherwise,
+.Dv NULL
+is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The
+.Fa bufp
+or
+.Fa sizep
+argument was
+.Dv NULL .
+.It Bq Er ENOMEM
+Memory for the stream or buffer could not be allocated.
+.El
+.Sh SEE ALSO
+.Xr fclose 3 ,
+.Xr fflush 3 ,
+.Xr fopen 3 ,
+.Xr free 3 ,
+.Xr fseek 3 ,
+.Xr sbuf 3 ,
+.Xr stdio 3
+.Sh STANDARDS
+The
+.Fn open_memstream
+and
+.Fn open_wmemstream
+functions conform to
+.St -p1003.1-2008 .
Index: src/lib/libc/stdio/open_memstream.c
diff -u /dev/null src/lib/libc/stdio/open_memstream.c:1.1
--- /dev/null Sun Oct 12 20:40:36 2014
+++ src/lib/libc/stdio/open_memstream.c Sun Oct 12 20:40:36 2014
@@ -0,0 +1,214 @@
+/* $NetBSD: open_memstream.c,v 1.1 2014/10/13 00:40:36 christos Exp $ */
+
+/*-
+ * Copyright (c) 2013 Advanced Computing Technologies LLC
+ * Written by: John H. Baldwin <j...@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#if 0
+__FBSDID("$FreeBSD: head/lib/libc/stdio/open_memstream.c 247411 2013-02-27 19:50:46Z jhb $");
+#endif
+__RCSID("$NetBSD: open_memstream.c,v 1.1 2014/10/13 00:40:36 christos Exp $");
+
+#include "namespace.h"
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+#define OFF_MAX LLONG_MAX
+
+struct memstream {
+ char **bufp;
+ size_t *sizep;
+ size_t len;
+ size_t offset;
+};
+
+static int
+memstream_grow(struct memstream *ms, off_t newoff)
+{
+ char *buf;
+ size_t newsize;
+
+ if (newoff < 0 || newoff >= SSIZE_MAX)
+ newsize = SSIZE_MAX - 1;
+ else
+ newsize = newoff;
+ if (newsize > ms->len) {
+ buf = realloc(*ms->bufp, newsize + 1);
+ if (buf != NULL) {
+#ifdef DEBUG
+ fprintf(stderr, "MS: %p growing from %zd to %zd\n",
+ ms, ms->len, newsize);
+#endif
+ memset(buf + ms->len + 1, 0, newsize - ms->len);
+ *ms->bufp = buf;
+ ms->len = newsize;
+ return (1);
+ }
+ return (0);
+ }
+ return (1);
+}
+
+static void
+memstream_update(struct memstream *ms)
+{
+
+ *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
+}
+
+static ssize_t
+memstream_write(void *cookie, const void *buf, size_t len)
+{
+ struct memstream *ms;
+ size_t tocopy;
+ off_t more;
+
+ ms = cookie;
+ more = ms->offset;
+ more += len;
+ if (!memstream_grow(ms, more))
+ return (-1);
+ tocopy = ms->len - ms->offset;
+ if (len < tocopy)
+ tocopy = len;
+ memcpy(*ms->bufp + ms->offset, buf, tocopy);
+ ms->offset += tocopy;
+ memstream_update(ms);
+#ifdef DEBUG
+ fprintf(stderr, "MS: write(%p, %zu) = %zu\n", ms, len, tocopy);
+#endif
+ return (ssize_t)tocopy;
+}
+
+static off_t
+memstream_seek(void *cookie, off_t pos, int whence)
+{
+ struct memstream *ms;
+#ifdef DEBUG
+ size_t old;
+#endif
+
+ ms = cookie;
+#ifdef DEBUG
+ old = ms->offset;
+#endif
+ switch (whence) {
+ case SEEK_SET:
+ /* _fseeko() checks for negative offsets. */
+ assert(pos >= 0);
+ ms->offset = pos;
+ break;
+ case SEEK_CUR:
+ /* This is only called by _ftello(). */
+ assert(pos == 0);
+ break;
+ case SEEK_END:
+ if (pos < 0) {
+ if (pos + (ssize_t)ms->len < 0) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "MS: bad SEEK_END: pos %jd, len %zu\n",
+ (intmax_t)pos, ms->len);
+#endif
+ errno = EINVAL;
+ return (-1);
+ }
+ } else {
+ if (OFF_MAX - (ssize_t)ms->len < pos) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "MS: bad SEEK_END: pos %jd, len %zu\n",
+ (intmax_t)pos, ms->len);
+#endif
+ errno = EOVERFLOW;
+ return (-1);
+ }
+ }
+ ms->offset = ms->len + pos;
+ break;
+ }
+ memstream_update(ms);
+#ifdef DEBUG
+ fprintf(stderr, "MS: seek(%p, %jd, %d) %zu -> %zu\n", ms,
+ (intmax_t)pos, whence, old, ms->offset);
+#endif
+ return (ms->offset);
+}
+
+static int
+memstream_close(void *cookie)
+{
+
+ free(cookie);
+ return (0);
+}
+
+FILE *
+open_memstream(char **bufp, size_t *sizep)
+{
+ struct memstream *ms;
+ int save_errno;
+ FILE *fp;
+
+ if (bufp == NULL || sizep == NULL) {
+ errno = EINVAL;
+ return (NULL);
+ }
+ *bufp = calloc(1, 1);
+ if (*bufp == NULL)
+ return (NULL);
+ ms = malloc(sizeof(*ms));
+ if (ms == NULL) {
+ save_errno = errno;
+ free(*bufp);
+ *bufp = NULL;
+ errno = save_errno;
+ return (NULL);
+ }
+ ms->bufp = bufp;
+ ms->sizep = sizep;
+ ms->len = 0;
+ ms->offset = 0;
+ memstream_update(ms);
+ fp = funopen2(ms, NULL, memstream_write, memstream_seek,
+ NULL, memstream_close);
+ if (fp == NULL) {
+ save_errno = errno;
+ free(ms);
+ free(*bufp);
+ *bufp = NULL;
+ errno = save_errno;
+ return (NULL);
+ }
+ fwide(fp, -1);
+ return (fp);
+}
Index: src/lib/libc/stdio/open_wmemstream.c
diff -u /dev/null src/lib/libc/stdio/open_wmemstream.c:1.1
--- /dev/null Sun Oct 12 20:40:36 2014
+++ src/lib/libc/stdio/open_wmemstream.c Sun Oct 12 20:40:36 2014
@@ -0,0 +1,273 @@
+/* $NetBSD: open_wmemstream.c,v 1.1 2014/10/13 00:40:36 christos Exp $ */
+
+/*-
+ * Copyright (c) 2013 Advanced Computing Technologies LLC
+ * Written by: John H. Baldwin <j...@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#if 0
+__FBSDID("$FreeBSD: head/lib/libc/stdio/open_wmemstream.c 247411 2013-02-27 19:50:46Z jhb $");
+#endif
+__RCSID("$NetBSD: open_wmemstream.c,v 1.1 2014/10/13 00:40:36 christos Exp $");
+
+#include "namespace.h"
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+#define OFF_MAX LLONG_MAX
+
+struct wmemstream {
+ wchar_t **bufp;
+ size_t *sizep;
+ size_t len;
+ size_t offset;
+ mbstate_t mbstate;
+};
+
+static int
+wmemstream_grow(struct wmemstream *ms, size_t newoff)
+{
+ wchar_t *buf;
+ size_t newsize;
+
+ if (newoff >= (off_t)(SSIZE_MAX / sizeof(wchar_t)))
+ newsize = SSIZE_MAX / sizeof(wchar_t) - 1;
+ else
+ newsize = newoff;
+ if (newsize > ms->len) {
+ buf = realloc(*ms->bufp, (newsize + 1) * sizeof(wchar_t));
+ if (buf != NULL) {
+#ifdef DEBUG
+ fprintf(stderr, "WMS: %p growing from %zu to %zu\n",
+ ms, ms->len, newsize);
+#endif
+ wmemset(buf + ms->len + 1, 0, newsize - ms->len);
+ *ms->bufp = buf;
+ ms->len = newsize;
+ return (1);
+ }
+ return (0);
+ }
+ return (1);
+}
+
+static void
+wmemstream_update(struct wmemstream *ms)
+{
+
+ *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset;
+}
+
+/*
+ * Based on a starting multibyte state and an input buffer, determine
+ * how many wchar_t's would be output. This doesn't use mbsnrtowcs()
+ * so that it can handle embedded null characters.
+ */
+static ssize_t
+wbuflen(const mbstate_t *state, const char *buf, size_t len)
+{
+ mbstate_t lenstate;
+ size_t charlen, count;
+
+ count = 0;
+ lenstate = *state;
+ while (len > 0) {
+ charlen = mbrlen(buf, len, &lenstate);
+ if (charlen == (size_t)-1)
+ return (-1);
+ if (charlen == (size_t)-2)
+ break;
+ if (charlen == 0)
+ /* XXX: Not sure how else to handle this. */
+ charlen = 1;
+ len -= charlen;
+ buf += charlen;
+ count++;
+ }
+ return (count);
+}
+
+static ssize_t
+wmemstream_write(void *cookie, const void *buf, size_t len)
+{
+ struct wmemstream *ms;
+ ssize_t consumed, wlen;
+ size_t charlen;
+
+ ms = cookie;
+ wlen = wbuflen(&ms->mbstate, buf, len);
+ if (wlen < 0) {
+ errno = EILSEQ;
+ return (-1);
+ }
+ if (!wmemstream_grow(ms, ms->offset + wlen))
+ return (-1);
+
+ /*
+ * This copies characters one at a time rather than using
+ * mbsnrtowcs() so it can properly handle embedded null
+ * characters.
+ */
+ consumed = 0;
+ while (len > 0 && ms->offset < ms->len) {
+ charlen = mbrtowc(*ms->bufp + ms->offset, buf, len,
+ &ms->mbstate);
+ if (charlen == (size_t)-1) {
+ if (consumed == 0) {
+ errno = EILSEQ;
+ return (-1);
+ }
+ /* Treat it as a successful short write. */
+ break;
+ }
+ if (charlen == 0)
+ /* XXX: Not sure how else to handle this. */
+ charlen = 1;
+ if (charlen == (size_t)-2) {
+ consumed += len;
+ len = 0;
+ } else {
+ consumed += charlen;
+ buf = (const char *)buf + charlen;
+ len -= charlen;
+ ms->offset++;
+ }
+ }
+ wmemstream_update(ms);
+#ifdef DEBUG
+ fprintf(stderr, "WMS: write(%p, %zu) = %zd\n", ms, len, consumed);
+#endif
+ return (consumed);
+}
+
+static off_t
+wmemstream_seek(void *cookie, off_t pos, int whence)
+{
+ struct wmemstream *ms;
+ size_t old;
+
+ ms = cookie;
+ old = ms->offset;
+ switch (whence) {
+ case SEEK_SET:
+ /* _fseeko() checks for negative offsets. */
+ assert(pos >= 0);
+ ms->offset = pos;
+ break;
+ case SEEK_CUR:
+ /* This is only called by _ftello(). */
+ assert(pos == 0);
+ break;
+ case SEEK_END:
+ if (pos < 0) {
+ if (pos + (ssize_t)ms->len < 0) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "WMS: bad SEEK_END: pos %jd, len %zd\n",
+ (intmax_t)pos, ms->len);
+#endif
+ errno = EINVAL;
+ return (-1);
+ }
+ } else {
+ if (OFF_MAX - ms->len < (size_t)pos) {
+#ifdef DEBUG
+ fprintf(stderr,
+ "WMS: bad SEEK_END: pos %jd, len %zd\n",
+ (intmax_t)pos, ms->len);
+#endif
+ errno = EOVERFLOW;
+ return (-1);
+ }
+ }
+ ms->offset = ms->len + pos;
+ break;
+ }
+ /* Reset the multibyte state if a seek changes the position. */
+ if (ms->offset != old)
+ memset(&ms->mbstate, 0, sizeof(ms->mbstate));
+ wmemstream_update(ms);
+#ifdef DEBUG
+ fprintf(stderr, "WMS: seek(%p, %jd, %d) %jd -> %jd\n", ms,
+ (intmax_t)pos, whence, (intmax_t)old, (intmax_t)ms->offset);
+#endif
+ return (ms->offset);
+}
+
+static int
+wmemstream_close(void *cookie)
+{
+
+ free(cookie);
+ return (0);
+}
+
+FILE *
+open_wmemstream(wchar_t **bufp, size_t *sizep)
+{
+ struct wmemstream *ms;
+ int save_errno;
+ FILE *fp;
+
+ if (bufp == NULL || sizep == NULL) {
+ errno = EINVAL;
+ return (NULL);
+ }
+ *bufp = calloc(1, sizeof(wchar_t));
+ if (*bufp == NULL)
+ return (NULL);
+ ms = malloc(sizeof(*ms));
+ if (ms == NULL) {
+ save_errno = errno;
+ free(*bufp);
+ *bufp = NULL;
+ errno = save_errno;
+ return (NULL);
+ }
+ ms->bufp = bufp;
+ ms->sizep = sizep;
+ ms->len = 0;
+ ms->offset = 0;
+ memset(&ms->mbstate, 0, sizeof(mbstate_t));
+ wmemstream_update(ms);
+ fp = funopen2(ms, NULL, wmemstream_write, wmemstream_seek,
+ NULL, wmemstream_close);
+ if (fp == NULL) {
+ save_errno = errno;
+ free(ms);
+ free(*bufp);
+ *bufp = NULL;
+ errno = save_errno;
+ return (NULL);
+ }
+ fwide(fp, 1);
+ return (fp);
+}
