Monkey-patch open_memstream into gnulib

gnulib-open_memstream.patch

diff --git a/gnulib/lib/Makefile.am b/gnulib/lib/Makefile.am
index f40770b..fd85d42 100644
--- a/gnulib/lib/Makefile.am
+++ b/gnulib/lib/Makefile.am
@@ -1399,6 +1399,8 @@ EXTRA_libgnu_la_SOURCES += open.c
 
 ## end   gnulib module open
 
+libgnu_la_SOURCES += open_memstream.c
+
 ## begin gnulib module openat
 
 
diff --git a/gnulib/lib/open_memstream.c b/gnulib/lib/open_memstream.c
new file mode 100644
index 0000000..f1b4338
--- /dev/null
+++ b/gnulib/lib/open_memstream.c
@@ -0,0 +1,186 @@
+/* Open a write stream around a malloc'd string.
+   Copyright (C) 2010 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Eric Blake <address@hidden>, 2010.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdio.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "verify.h"
+
+# define INITIAL_ALLOC 64
+
+struct data
+{
+  char **buf; /* User's argument.  */
+  size_t *len; /* User's argument.  Smaller of pos or eof.  */
+  size_t pos; /* Current position.  */
+  size_t eof; /* End-of-file position.  */
+  size_t allocated; /* Allocated size of *buf, always > eof.  */
+  char c; /* Temporary storage for byte overwritten by NUL, if pos < eof.  */
+};
+typedef struct data data;
+
+/* Stupid BSD interface uses int/int instead of ssize_t/size_t.  */
+verify (sizeof (int) <= sizeof (size_t));
+verify (sizeof (int) <= sizeof (ssize_t));
+
+static int
+mem_write (void *c, const char *buf, int n)
+{
+  data *cookie = c;
+  char *cbuf = *cookie->buf;
+
+  /* Be sure we don't overflow.  */
+  if ((ssize_t) (cookie->pos + n) < 0)
+    {
+      errno = EFBIG;
+      return EOF;
+    }
+  /* Grow the buffer, if necessary.  Use geometric growth to avoid
+     quadratic realloc behavior.  Overallocate, to accomodate the
+     requirement to always place a trailing NUL not counted by length.
+     Thus, we want max(prev_size*1.5, cookie->pos+n+1).  */
+  if (cookie->allocated <= cookie->pos + n)
+    {
+      size_t newsize = cookie->allocated * 3 / 2;
+      if (newsize < cookie->pos + n + 1)
+        newsize = cookie->pos + n + 1;
+      cbuf = realloc (cbuf, newsize);
+      if (!cbuf)
+        return EOF;
+      *cookie->buf = cbuf;
+      cookie->allocated = newsize;
+    }
+  /* If we have previously done a seek beyond eof, ensure all
+     intermediate bytges are NUL.  */
+  if (cookie->eof < cookie->pos)
+    memset (cbuf + cookie->eof, '\0', cookie->pos - cookie->eof);
+  memcpy (cbuf + cookie->pos, buf, n);
+  cookie->pos += n;
+  /* If the user has previously written beyond the current position,
+     remember what the trailing NUL is overwriting.  Otherwise,
+     extend the stream.  */
+  if (cookie->eof < cookie->pos)
+    cookie->eof = cookie->pos;
+  else
+    cookie->c = cbuf[cookie->pos];
+  cbuf[cookie->pos] = '\0';
+  *cookie->len = cookie->pos;
+  return n;
+}
+
+static fpos_t
+mem_seek (void *c, fpos_t pos, int whence)
+{
+  data *cookie = c;
+  off_t offset = pos;
+
+  if (whence == SEEK_CUR)
+    offset += cookie->pos;
+  else if (whence == SEEK_END)
+    offset += cookie->eof;
+  if (offset < 0)
+    {
+      errno = EINVAL;
+      offset = -1;
+    }
+  else if ((size_t) offset != offset)
+    {
+      errno = ENOSPC;
+      offset = -1;
+    }
+  else
+    {
+      if (cookie->pos < cookie->eof)
+        {
+          (*cookie->buf)[cookie->pos] = cookie->c;
+          cookie->c = '\0';
+        }
+      cookie->pos = offset;
+      if (cookie->pos < cookie->eof)
+        {
+          cookie->c = (*cookie->buf)[cookie->pos];
+          (*cookie->buf)[cookie->pos] = '\0';
+          *cookie->len = cookie->pos;
+        }
+      else
+        *cookie->len = cookie->eof;
+    }
+  return offset;
+}
+
+static int
+mem_close (void *c)
+{
+  data *cookie = c;
+  char *buf;
+
+  /* Be nice and try to reduce excess memory.  */
+  buf = realloc (*cookie->buf, *cookie->len + 1);
+  if (buf)
+    *cookie->buf = buf;
+  free (cookie);
+  return 0;
+}
+
+FILE *
+open_memstream (char **buf, size_t *len)
+{
+  FILE *f;
+  data *cookie;
+
+  if (!buf || !len)
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+  if (!(cookie = malloc (sizeof *cookie)))
+    return NULL;
+  if (!(*buf = malloc (INITIAL_ALLOC)))
+    {
+      free (cookie);
+      errno = ENOMEM;
+      return NULL;
+    }
+  **buf = '\0';
+  *len = 0;
+
+  f = funopen (cookie, NULL, mem_write, mem_seek, mem_close);
+  if (!f)
+    {
+      int saved_errno = errno;
+      free (cookie);
+      errno = saved_errno;
+    }
+  else
+    {
+      cookie->buf = buf;
+      cookie->len = len;
+      cookie->pos = 0;
+      cookie->eof = 0;
+      cookie->c = '\0';
+      cookie->allocated = INITIAL_ALLOC;
+    }
+  return f;
+}
diff --git a/gnulib/lib/stdio.in.h b/gnulib/lib/stdio.in.h
index 1e1fe84..085f7db 100644
--- a/gnulib/lib/stdio.in.h
+++ b/gnulib/lib/stdio.in.h
@@ -774,6 +774,8 @@ _GL_CXXALIAS_SYS (obstack_vprintf, int,
 _GL_CXXALIASWARN (obstack_vprintf);
 #endif
 
+_GL_FUNCDECL_SYS (open_memstream, FILE *, (char **, size_t *));
+
 #if @GNULIB_PCLOSE@
 # if !@HAVE_PCLOSE@
 _GL_FUNCDECL_SYS (pclose, int, (FILE *stream) _GL_ARG_NONNULL ((1)));