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Re: C++ support (2)
From: |
Paul Eggert |
Subject: |
Re: C++ support (2) |
Date: |
Tue, 31 Oct 2006 13:56:24 -0800 |
User-agent: |
Gnus/5.1008 (Gnus v5.10.8) Emacs/21.4 (gnu/linux) |
Bruno Haible <address@hidden> writes:
> * lib/xalloc.h (xrealloc, xnrealloc, x2realloc, x2nrealloc, xmemdup)
> [C++]: Add function template that provides result type propagation.
I guess something like that is OK, though I prefer to put it into
a C++ ghetto area of the code.
As for quotearg.c, I realize it's sometimes a win to support C++, but
sometimes it's otherwise, and it's not clear to me that it's worth the
hassle here. It is a borderline case, though, so I suppose we can try
it. Looking at the code, I think there are better ways to address the
problem, so I installed this patch instead.
2006-10-31 Paul Eggert <address@hidden>
Avoid some C++ diagnostics reported by Bruno Haible.
* lib/quotearg.c (clone_quoting_options): Use xmemdup rather than
xmalloc.
(quotearg_alloc): Use xcharalloc rather than xmalloc.
(struct slotvec): Move to top level.
(quotearg_n_options): Rewrite to avoid xmalloc.
* lib/xalloc.h (xcharalloc): New function.
* (xrealloc, xnrealloc, x2realloc, x2nrealloc, xmemdup):
[defined __cplusplus]: Add function template that provides result
type propagation. This part of the change is from Bruno Haible.
Index: lib/quotearg.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/quotearg.c,v
retrieving revision 1.50
diff -p -u -r1.50 quotearg.c
--- lib/quotearg.c 3 Oct 2006 06:33:39 -0000 1.50
+++ lib/quotearg.c 31 Oct 2006 21:50:00 -0000
@@ -122,8 +122,8 @@ struct quoting_options *
clone_quoting_options (struct quoting_options *o)
{
int e = errno;
- struct quoting_options *p = xmalloc (sizeof *p);
- *p = *(o ? o : &default_quoting_options);
+ struct quoting_options *p = xmemdup (o ? o : &default_quoting_options,
+ sizeof *o);
errno = e;
return p;
}
@@ -554,12 +554,19 @@ quotearg_alloc (char const *arg, size_t
{
int e = errno;
size_t bufsize = quotearg_buffer (0, 0, arg, argsize, o) + 1;
- char *buf = xmalloc (bufsize);
+ char *buf = xcharalloc (bufsize);
quotearg_buffer (buf, bufsize, arg, argsize, o);
errno = e;
return buf;
}
+/* A storage slot with size and pointer to a value. */
+struct slotvec
+{
+ size_t size;
+ char *val;
+};
+
/* Use storage slot N to return a quoted version of argument ARG.
ARG is of size ARGSIZE, but if that is SIZE_MAX, ARG is a
null-terminated string.
@@ -579,13 +586,9 @@ quotearg_n_options (int n, char const *a
static char slot0[256];
static unsigned int nslots = 1;
unsigned int n0 = n;
- struct slotvec
- {
- size_t size;
- char *val;
- };
static struct slotvec slotvec0 = {sizeof slot0, slot0};
static struct slotvec *slotvec = &slotvec0;
+ struct slotvec *sv = slotvec;
if (n < 0)
abort ();
@@ -598,31 +601,29 @@ quotearg_n_options (int n, char const *a
revert to the original type, so that the test in xalloc_oversized
is once again performed only at compile time. */
size_t n1 = n0 + 1;
+ bool preallocated = (sv == &slotvec0);
- if (xalloc_oversized (n1, sizeof *slotvec))
+ if (xalloc_oversized (n1, sizeof *sv))
xalloc_die ();
- if (slotvec == &slotvec0)
- {
- slotvec = xmalloc (sizeof *slotvec);
- *slotvec = slotvec0;
- }
- slotvec = xrealloc (slotvec, n1 * sizeof *slotvec);
- memset (slotvec + nslots, 0, (n1 - nslots) * sizeof *slotvec);
+ slotvec = sv = xrealloc (preallocated ? NULL : sv, n1 * sizeof *sv);
+ if (preallocated)
+ *sv = slotvec0;
+ memset (sv + nslots, 0, (n1 - nslots) * sizeof *sv);
nslots = n1;
}
{
- size_t size = slotvec[n].size;
- char *val = slotvec[n].val;
+ size_t size = sv[n].size;
+ char *val = sv[n].val;
size_t qsize = quotearg_buffer (val, size, arg, argsize, options);
if (size <= qsize)
{
- slotvec[n].size = size = qsize + 1;
+ sv[n].size = size = qsize + 1;
if (val != slot0)
free (val);
- slotvec[n].val = val = xmalloc (size);
+ sv[n].val = val = xcharalloc (size);
quotearg_buffer (val, size, arg, argsize, options);
}
Index: lib/xalloc.h
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/xalloc.h,v
retrieving revision 1.28
diff -p -u -r1.28 xalloc.h
--- lib/xalloc.h 14 May 2005 06:03:58 -0000 1.28
+++ lib/xalloc.h 31 Oct 2006 21:50:01 -0000
@@ -71,8 +71,51 @@ char *xstrdup (char const *str);
# define xalloc_oversized(n, s) \
((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n))
+/* Return a pointer to a new buffer of S bytes. This is like xmalloc,
+ except it returns char *. */
+static inline char *
+xcharalloc (size_t s)
+{
+ return (char *) xmalloc (s);
+}
+
# ifdef __cplusplus
}
+
+/* C++ does not allow conversions from void * to other pointer types
+ without a cast. Use templates to work around the problem when
+ possible. */
+
+template <typename T> inline T *
+xrealloc (T *p, size_t s)
+{
+ return (T *) xrealloc ((void *) p, s);
+}
+
+template <typename T> inline T *
+xnrealloc (T *p, size_t n, size_t s)
+{
+ return (T *) xnrealloc ((void *) p, n, s);
+}
+
+template <typename T> inline T *
+x2realloc (T *p, size_t *pn)
+{
+ return (T *) x2realloc ((void *) p, pn);
+}
+
+template <typename T> inline T *
+x2nrealloc (T *p, size_t *pn, size_t s)
+{
+ return (T *) x2nrealloc ((void *) p, pn, s);
+}
+
+template <typename T> inline T *
+xmemdup (T const *p, size_t s)
+{
+ return (T *) xmemdup ((void const *) p, s);
+}
+
# endif
- C++ support (2), Bruno Haible, 2006/10/31
- Re: C++ support (2),
Paul Eggert <=