gtk/gdk/gdkarrayimpl.c
Benjamin Otte 4814c5f653 array: Don't overflow array size
Copy what gcc's libstdc++ does for vectors to avoid overflows:

1. Define a max size macro and assert against it
   Note that we don't assert but actually check, because this needs
   to abort even if assertions are disabled.
2. Don't do fancy math to compute new capacity.
   Just size *= 2 instead and be careful about overflow.
2024-05-10 21:22:03 -04:00

335 lines
7.9 KiB
C

/*
* Copyright © 2020 Benjamin Otte
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
* Authors: Benjamin Otte <otte@gnome.org>
*/
#include <glib.h>
G_BEGIN_DECLS
#ifndef GDK_ARRAY_TYPE_NAME
#define GDK_ARRAY_TYPE_NAME GdkArray
#endif
#ifndef GDK_ARRAY_NAME
#define GDK_ARRAY_NAME gdk_array
#endif
#ifndef GDK_ARRAY_ELEMENT_TYPE
#define GDK_ARRAY_ELEMENT_TYPE gpointer
#endif
#ifdef GDK_ARRAY_PREALLOC
#if GDK_ARRAY_PREALLOC == 0
#undef GDK_ARRAY_PREALLOC
#endif
#endif
#ifdef GDK_ARRAY_NULL_TERMINATED
#define GDK_ARRAY_REAL_SIZE(_size) ((_size) + 1)
#define GDK_ARRAY_MAX_SIZE (G_MAXSIZE / sizeof (_T_) - 1)
#else
#define GDK_ARRAY_REAL_SIZE(_size) (_size)
#define GDK_ARRAY_MAX_SIZE (G_MAXSIZE / sizeof (_T_))
#endif
/* make this readable */
#define _T_ GDK_ARRAY_ELEMENT_TYPE
#define GdkArray GDK_ARRAY_TYPE_NAME
#define gdk_array_paste_more(GDK_ARRAY_NAME, func_name) GDK_ARRAY_NAME ## _ ## func_name
#define gdk_array_paste(GDK_ARRAY_NAME, func_name) gdk_array_paste_more (GDK_ARRAY_NAME, func_name)
#define gdk_array(func_name) gdk_array_paste (GDK_ARRAY_NAME, func_name)
typedef struct GdkArray GdkArray;
struct GdkArray
{
_T_ *start;
_T_ *end;
_T_ *end_allocation;
#ifdef GDK_ARRAY_PREALLOC
_T_ preallocated[GDK_ARRAY_REAL_SIZE(GDK_ARRAY_PREALLOC)];
#endif
};
/* no G_GNUC_UNUSED here, if you don't use an array type, remove it. */
static inline void
gdk_array(init) (GdkArray *self)
{
#ifdef GDK_ARRAY_PREALLOC
self->start = self->preallocated;
self->end = self->start;
self->end_allocation = self->start + GDK_ARRAY_PREALLOC;
#ifdef GDK_ARRAY_NULL_TERMINATED
*self->start = *(_T_[1]) { 0 };
#endif
#else
self->start = NULL;
self->end = NULL;
self->end_allocation = NULL;
#endif
}
G_GNUC_UNUSED static inline gsize
gdk_array(get_capacity) (const GdkArray *self)
{
return self->end_allocation - self->start;
}
G_GNUC_UNUSED static inline gsize
gdk_array(get_size) (const GdkArray *self)
{
return self->end - self->start;
}
static inline void
gdk_array(free_elements) (_T_ *start,
_T_ *end)
{
#ifdef GDK_ARRAY_FREE_FUNC
_T_ *e;
for (e = start; e < end; e++)
#ifdef GDK_ARRAY_BY_VALUE
GDK_ARRAY_FREE_FUNC (e);
#else
GDK_ARRAY_FREE_FUNC (*e);
#endif
#endif
}
/* no G_GNUC_UNUSED here */
static inline void
gdk_array(clear) (GdkArray *self)
{
gdk_array(free_elements) (self->start, self->end);
#ifdef GDK_ARRAY_PREALLOC
if (self->start != self->preallocated)
#endif
g_free (self->start);
gdk_array(init) (self);
}
/*
* gdk_array_steal:
* @self: the array
*
* Steals all data in the array and clears the array.
*
* If you need to know the size of the data, you should query it
* beforehand.
*
* Returns: The array's data
**/
G_GNUC_UNUSED static inline _T_ *
gdk_array(steal) (GdkArray *self)
{
_T_ *result;
#ifdef GDK_ARRAY_PREALLOC
if (self->start == self->preallocated)
{
gsize size = GDK_ARRAY_REAL_SIZE (gdk_array(get_size) (self));
result = g_new (_T_, size);
memcpy (result, self->preallocated, sizeof (_T_) * size);
}
else
#endif
result = self->start;
gdk_array(init) (self);
return result;
}
G_GNUC_UNUSED static inline _T_ *
gdk_array(get_data) (const GdkArray *self)
{
return self->start;
}
G_GNUC_UNUSED static inline _T_ *
gdk_array(index) (const GdkArray *self,
gsize pos)
{
return self->start + pos;
}
G_GNUC_UNUSED static inline gboolean
gdk_array(is_empty) (const GdkArray *self)
{
return self->end == self->start;
}
G_GNUC_UNUSED static inline void
gdk_array(reserve) (GdkArray *self,
gsize n)
{
gsize new_capacity, size, capacity;
if (G_UNLIKELY (n > GDK_ARRAY_MAX_SIZE))
g_error ("requesting array size of %zu, but maximum size is %zu", n, GDK_ARRAY_MAX_SIZE);
capacity = gdk_array(get_capacity) (self);
if (n <= capacity)
return;
size = gdk_array(get_size) (self);
/* capacity * 2 can overflow, that's why we MAX() */
new_capacity = MAX (GDK_ARRAY_REAL_SIZE (n), capacity * 2);
#ifdef GDK_ARRAY_PREALLOC
if (self->start == self->preallocated)
{
self->start = g_new (_T_, new_capacity);
memcpy (self->start, self->preallocated, sizeof (_T_) * GDK_ARRAY_REAL_SIZE (size));
}
else
#endif
#ifdef GDK_ARRAY_NULL_TERMINATED
if (self->start == NULL)
{
self->start = g_new (_T_, new_capacity);
*self->start = *(_T_[1]) { 0 };
}
else
#endif
self->start = g_renew (_T_, self->start, new_capacity);
self->end = self->start + size;
self->end_allocation = self->start + new_capacity;
#ifdef GDK_ARRAY_NULL_TERMINATED
self->end_allocation--;
#endif
}
G_GNUC_UNUSED static inline void
gdk_array(splice) (GdkArray *self,
gsize pos,
gsize removed,
gboolean stolen,
#ifdef GDK_ARRAY_BY_VALUE
const _T_ *additions,
#else
_T_ *additions,
#endif
gsize added)
{
gsize size;
gsize remaining;
size = gdk_array(get_size) (self);
g_assert (pos + removed <= size);
remaining = size - pos - removed;
if (!stolen)
gdk_array(free_elements) (gdk_array(index) (self, pos),
gdk_array(index) (self, pos + removed));
gdk_array(reserve) (self, size - removed + added);
if (GDK_ARRAY_REAL_SIZE (remaining) && removed != added)
memmove (gdk_array(index) (self, pos + added),
gdk_array(index) (self, pos + removed),
GDK_ARRAY_REAL_SIZE (remaining) * sizeof (_T_));
if (added)
{
if (additions)
memcpy (gdk_array(index) (self, pos),
additions,
added * sizeof (_T_));
#ifndef GDK_ARRAY_NO_MEMSET
else
memset (gdk_array(index) (self, pos), 0, added * sizeof (_T_));
#endif
}
/* might overflow, but does the right thing */
self->end += added - removed;
}
G_GNUC_UNUSED static void
gdk_array(set_size) (GdkArray *self,
gsize new_size)
{
gsize old_size = gdk_array(get_size) (self);
if (new_size > old_size)
gdk_array(splice) (self, old_size, 0, FALSE, NULL, new_size - old_size);
else
gdk_array(splice) (self, new_size, old_size - new_size, FALSE, NULL, 0);
}
G_GNUC_UNUSED static void
gdk_array(append) (GdkArray *self,
#ifdef GDK_ARRAY_BY_VALUE
_T_ *value)
#else
_T_ value)
#endif
{
gdk_array(splice) (self,
gdk_array(get_size) (self),
0,
FALSE,
#ifdef GDK_ARRAY_BY_VALUE
value,
#else
&value,
#endif
1);
}
#ifdef GDK_ARRAY_BY_VALUE
G_GNUC_UNUSED static _T_ *
gdk_array(get) (const GdkArray *self,
gsize pos)
{
return gdk_array(index) (self, pos);
}
#else
G_GNUC_UNUSED static _T_
gdk_array(get) (const GdkArray *self,
gsize pos)
{
return *gdk_array(index) (self, pos);
}
#endif
#ifndef GDK_ARRAY_NO_UNDEF
#undef _T_
#undef GdkArray
#undef gdk_array_paste_more
#undef gdk_array_paste
#undef gdk_array
#undef GDK_ARRAY_REAL_SIZE
#undef GDK_ARRAY_MAX_SIZE
#undef GDK_ARRAY_BY_VALUE
#undef GDK_ARRAY_ELEMENT_TYPE
#undef GDK_ARRAY_FREE_FUNC
#undef GDK_ARRAY_NAME
#undef GDK_ARRAY_NULL_TERMINATED
#undef GDK_ARRAY_PREALLOC
#undef GDK_ARRAY_TYPE_NAME
#undef GDK_ARRAY_NO_MEMSET
#endif
G_END_DECLS