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glib/glib/garray.h
Thomas Haller ee247c0a2d array: add support for %NULL termination in GPtrArray 
GArray supports a "zero_terminated" flag, but GPtrArray doesn't.
This is odd, because especially for a pointer array it makes sense
to have a %NULL sentinel. This would be for example useful to track
or construct a strv array with a GPtrArray.

As workaround for this missing feature you could use a GArray instead
(ugly) or to explicitly add the %NULL element. However the latter increases
the "len" of the array, which can be problematic if you want to still use
the GPtrArray for other purposes.

Add API for marking a GPtrArray as %NULL terminated. In that case, the
API will ensure that there is always a valid %NULL sentinel after the
array. Note that the API does not enforce that a %NULL terminated API
actually has any data allocated. That means, even with a %NULL terminated
array, pdata can still be %NULL (only if len is zero).

Add g_ptr_array_new_null_terminated() constructor. The null-terminated flag
cannot be cleared. Once the GPtrArray is flagged to be %NULL terminated, it
sticks. The purpose is that once a user checks whether a GPtrArray instance
is safe to be treated as a %NULL terminated array, the decision does
not need to be re-evaluated.

Also add a g_ptr_array_is_null_terminated(). That is useful because it
allows you to check whether a GPtrArray created by somebody else is safe
to use as a %NULL terminated array. Since there is no API to make an
array not %NULL terminated anymore, this is not error prone.

The new flag is tracked as a guint8 in GRealPtrArray. On common 64 bit
architectures this does not increase the size of the struct as it fits
in an existing hole. Note that this is not a bitfield because it's
probably more efficient to access the entire guint8. However, there is
still a 3 bytes hole (on common 32 and 64 architectures), so if we need
to add more flags in the future, we still have space for 24 bits,
despite the new flag not being a bitfield.

The biggest downside of the patch is the runtime overhead that most
operations now need to check whether %NULL termination is requested.

Includes some tweaks and additional tests by Philip Withnall.

https://gitlab.gnome.org/GNOME/glib/-/issues/353
2022-05-27 15:27:19 +01:00

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/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* 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/>.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
#ifndef __G_ARRAY_H__
#define __G_ARRAY_H__
#if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
#error "Only <glib.h> can be included directly."
#endif
#include <glib/gtypes.h>
G_BEGIN_DECLS
typedef struct _GBytes GBytes;
typedef struct _GArray GArray;
typedef struct _GByteArray GByteArray;
typedef struct _GPtrArray GPtrArray;
struct _GArray
{
gchar *data;
guint len;
};
struct _GByteArray
{
guint8 *data;
guint len;
};
struct _GPtrArray
{
gpointer *pdata;
guint len;
};
/* Resizable arrays. remove fills any cleared spot and shortens the
* array, while preserving the order. remove_fast will distort the
* order by moving the last element to the position of the removed.
*/
#define g_array_append_val(a,v) g_array_append_vals (a, &(v), 1)
#define g_array_prepend_val(a,v) g_array_prepend_vals (a, &(v), 1)
#define g_array_insert_val(a,i,v) g_array_insert_vals (a, i, &(v), 1)
#define g_array_index(a,t,i) (((t*) (void *) (a)->data) [(i)])
GLIB_AVAILABLE_IN_ALL
GArray* g_array_new (gboolean zero_terminated,
gboolean clear_,
guint element_size);
GLIB_AVAILABLE_IN_2_64
gpointer g_array_steal (GArray *array,
gsize *len);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_sized_new (gboolean zero_terminated,
gboolean clear_,
guint element_size,
guint reserved_size);
GLIB_AVAILABLE_IN_2_62
GArray* g_array_copy (GArray *array);
GLIB_AVAILABLE_IN_ALL
gchar* g_array_free (GArray *array,
gboolean free_segment);
GLIB_AVAILABLE_IN_ALL
GArray *g_array_ref (GArray *array);
GLIB_AVAILABLE_IN_ALL
void g_array_unref (GArray *array);
GLIB_AVAILABLE_IN_ALL
guint g_array_get_element_size (GArray *array);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_append_vals (GArray *array,
gconstpointer data,
guint len);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_prepend_vals (GArray *array,
gconstpointer data,
guint len);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_insert_vals (GArray *array,
guint index_,
gconstpointer data,
guint len);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_set_size (GArray *array,
guint length);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_remove_index (GArray *array,
guint index_);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_remove_index_fast (GArray *array,
guint index_);
GLIB_AVAILABLE_IN_ALL
GArray* g_array_remove_range (GArray *array,
guint index_,
guint length);
GLIB_AVAILABLE_IN_ALL
void g_array_sort (GArray *array,
GCompareFunc compare_func);
GLIB_AVAILABLE_IN_ALL
void g_array_sort_with_data (GArray *array,
GCompareDataFunc compare_func,
gpointer user_data);
GLIB_AVAILABLE_IN_2_62
gboolean g_array_binary_search (GArray *array,
gconstpointer target,
GCompareFunc compare_func,
guint *out_match_index);
GLIB_AVAILABLE_IN_ALL
void g_array_set_clear_func (GArray *array,
GDestroyNotify clear_func);
/* Resizable pointer array. This interface is much less complicated
* than the above. Add appends a pointer. Remove fills any cleared
* spot and shortens the array. remove_fast will again distort order.
*/
#define g_ptr_array_index(array,index_) ((array)->pdata)[index_]
GLIB_AVAILABLE_IN_ALL
GPtrArray* g_ptr_array_new (void);
GLIB_AVAILABLE_IN_ALL
GPtrArray* g_ptr_array_new_with_free_func (GDestroyNotify element_free_func);
GLIB_AVAILABLE_IN_2_64
gpointer* g_ptr_array_steal (GPtrArray *array,
gsize *len);
GLIB_AVAILABLE_IN_2_62
GPtrArray *g_ptr_array_copy (GPtrArray *array,
GCopyFunc func,
gpointer user_data);
GLIB_AVAILABLE_IN_ALL
GPtrArray* g_ptr_array_sized_new (guint reserved_size);
GLIB_AVAILABLE_IN_ALL
GPtrArray* g_ptr_array_new_full (guint reserved_size,
GDestroyNotify element_free_func);
GLIB_AVAILABLE_IN_2_74
GPtrArray* g_ptr_array_new_null_terminated (guint reserved_size,
GDestroyNotify element_free_func,
gboolean null_terminated);
GLIB_AVAILABLE_IN_ALL
gpointer* g_ptr_array_free (GPtrArray *array,
gboolean free_seg);
GLIB_AVAILABLE_IN_ALL
GPtrArray* g_ptr_array_ref (GPtrArray *array);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_unref (GPtrArray *array);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_set_free_func (GPtrArray *array,
GDestroyNotify element_free_func);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_set_size (GPtrArray *array,
gint length);
GLIB_AVAILABLE_IN_ALL
gpointer g_ptr_array_remove_index (GPtrArray *array,
guint index_);
GLIB_AVAILABLE_IN_ALL
gpointer g_ptr_array_remove_index_fast (GPtrArray *array,
guint index_);
GLIB_AVAILABLE_IN_2_58
gpointer g_ptr_array_steal_index (GPtrArray *array,
guint index_);
GLIB_AVAILABLE_IN_2_58
gpointer g_ptr_array_steal_index_fast (GPtrArray *array,
guint index_);
GLIB_AVAILABLE_IN_ALL
gboolean g_ptr_array_remove (GPtrArray *array,
gpointer data);
GLIB_AVAILABLE_IN_ALL
gboolean g_ptr_array_remove_fast (GPtrArray *array,
gpointer data);
GLIB_AVAILABLE_IN_ALL
GPtrArray *g_ptr_array_remove_range (GPtrArray *array,
guint index_,
guint length);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_add (GPtrArray *array,
gpointer data);
GLIB_AVAILABLE_IN_2_62
void g_ptr_array_extend (GPtrArray *array_to_extend,
GPtrArray *array,
GCopyFunc func,
gpointer user_data);
GLIB_AVAILABLE_IN_2_62
void g_ptr_array_extend_and_steal (GPtrArray *array_to_extend,
GPtrArray *array);
GLIB_AVAILABLE_IN_2_40
void g_ptr_array_insert (GPtrArray *array,
gint index_,
gpointer data);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_sort (GPtrArray *array,
GCompareFunc compare_func);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_sort_with_data (GPtrArray *array,
GCompareDataFunc compare_func,
gpointer user_data);
GLIB_AVAILABLE_IN_ALL
void g_ptr_array_foreach (GPtrArray *array,
GFunc func,
gpointer user_data);
GLIB_AVAILABLE_IN_2_54
gboolean g_ptr_array_find (GPtrArray *haystack,
gconstpointer needle,
guint *index_);
GLIB_AVAILABLE_IN_2_54
gboolean g_ptr_array_find_with_equal_func (GPtrArray *haystack,
gconstpointer needle,
GEqualFunc equal_func,
guint *index_);
GLIB_AVAILABLE_IN_2_74
gboolean g_ptr_array_is_null_terminated (GPtrArray *array);
/* Byte arrays, an array of guint8. Implemented as a GArray,
* but type-safe.
*/
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_new (void);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_new_take (guint8 *data,
gsize len);
GLIB_AVAILABLE_IN_2_64
guint8* g_byte_array_steal (GByteArray *array,
gsize *len);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_sized_new (guint reserved_size);
GLIB_AVAILABLE_IN_ALL
guint8* g_byte_array_free (GByteArray *array,
gboolean free_segment);
GLIB_AVAILABLE_IN_ALL
GBytes* g_byte_array_free_to_bytes (GByteArray *array);
GLIB_AVAILABLE_IN_ALL
GByteArray *g_byte_array_ref (GByteArray *array);
GLIB_AVAILABLE_IN_ALL
void g_byte_array_unref (GByteArray *array);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_append (GByteArray *array,
const guint8 *data,
guint len);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_prepend (GByteArray *array,
const guint8 *data,
guint len);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_set_size (GByteArray *array,
guint length);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_remove_index (GByteArray *array,
guint index_);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_remove_index_fast (GByteArray *array,
guint index_);
GLIB_AVAILABLE_IN_ALL
GByteArray* g_byte_array_remove_range (GByteArray *array,
guint index_,
guint length);
GLIB_AVAILABLE_IN_ALL
void g_byte_array_sort (GByteArray *array,
GCompareFunc compare_func);
GLIB_AVAILABLE_IN_ALL
void g_byte_array_sort_with_data (GByteArray *array,
GCompareDataFunc compare_func,
gpointer user_data);
G_END_DECLS
#endif /* __G_ARRAY_H__ */
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