LCOV - code coverage report
Current view: top level - glib/glib - gbytes.c (source / functions) Hit Total Coverage
Test: unnamed Lines: 105 105 100.0 %
Date: 2024-03-26 05:16:46 Functions: 16 16 100.0 %
Branches: 43 44 97.7 %

           Branch data     Line data    Source code
       1                 :            : /*
       2                 :            :  * Copyright © 2009, 2010 Codethink Limited
       3                 :            :  * Copyright © 2011 Collabora Ltd.
       4                 :            :  *
       5                 :            :  * SPDX-License-Identifier: LGPL-2.1-or-later
       6                 :            :  *
       7                 :            :  * This library is free software; you can redistribute it and/or
       8                 :            :  * modify it under the terms of the GNU Lesser General Public
       9                 :            :  * License as published by the Free Software Foundation; either
      10                 :            :  * version 2.1 of the License, or (at your option) any later version.
      11                 :            :  *
      12                 :            :  * This library is distributed in the hope that it will be useful,
      13                 :            :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14                 :            :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15                 :            :  * Lesser General Public License for more details.
      16                 :            :  *
      17                 :            :  * You should have received a copy of the GNU Lesser General Public
      18                 :            :  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
      19                 :            :  *
      20                 :            :  * Author: Ryan Lortie <desrt@desrt.ca>
      21                 :            :  *         Stef Walter <stefw@collabora.co.uk>
      22                 :            :  */
      23                 :            : 
      24                 :            : #include "config.h"
      25                 :            : 
      26                 :            : #include "gbytes.h"
      27                 :            : 
      28                 :            : #include <glib/garray.h>
      29                 :            : #include <glib/gstrfuncs.h>
      30                 :            : #include <glib/gatomic.h>
      31                 :            : #include <glib/gslice.h>
      32                 :            : #include <glib/gtestutils.h>
      33                 :            : #include <glib/gmem.h>
      34                 :            : #include <glib/gmessages.h>
      35                 :            : #include <glib/grefcount.h>
      36                 :            : 
      37                 :            : #include <string.h>
      38                 :            : 
      39                 :            : /**
      40                 :            :  * GBytes:
      41                 :            :  *
      42                 :            :  * A simple refcounted data type representing an immutable sequence of zero or
      43                 :            :  * more bytes from an unspecified origin.
      44                 :            :  *
      45                 :            :  * The purpose of a #GBytes is to keep the memory region that it holds
      46                 :            :  * alive for as long as anyone holds a reference to the bytes.  When
      47                 :            :  * the last reference count is dropped, the memory is released. Multiple
      48                 :            :  * unrelated callers can use byte data in the #GBytes without coordinating
      49                 :            :  * their activities, resting assured that the byte data will not change or
      50                 :            :  * move while they hold a reference.
      51                 :            :  *
      52                 :            :  * A #GBytes can come from many different origins that may have
      53                 :            :  * different procedures for freeing the memory region.  Examples are
      54                 :            :  * memory from g_malloc(), from memory slices, from a #GMappedFile or
      55                 :            :  * memory from other allocators.
      56                 :            :  *
      57                 :            :  * #GBytes work well as keys in #GHashTable. Use g_bytes_equal() and
      58                 :            :  * g_bytes_hash() as parameters to g_hash_table_new() or g_hash_table_new_full().
      59                 :            :  * #GBytes can also be used as keys in a #GTree by passing the g_bytes_compare()
      60                 :            :  * function to g_tree_new().
      61                 :            :  *
      62                 :            :  * The data pointed to by this bytes must not be modified. For a mutable
      63                 :            :  * array of bytes see #GByteArray. Use g_bytes_unref_to_array() to create a
      64                 :            :  * mutable array for a #GBytes sequence. To create an immutable #GBytes from
      65                 :            :  * a mutable #GByteArray, use the g_byte_array_free_to_bytes() function.
      66                 :            :  *
      67                 :            :  * Since: 2.32
      68                 :            :  **/
      69                 :            : 
      70                 :            : /* Keep in sync with glib/tests/bytes.c */
      71                 :            : struct _GBytes
      72                 :            : {
      73                 :            :   gconstpointer data;  /* may be NULL iff (size == 0) */
      74                 :            :   gsize size;  /* may be 0 */
      75                 :            :   gatomicrefcount ref_count;
      76                 :            :   GDestroyNotify free_func;
      77                 :            :   gpointer user_data;
      78                 :            : };
      79                 :            : 
      80                 :            : /**
      81                 :            :  * g_bytes_new:
      82                 :            :  * @data: (transfer none) (array length=size) (element-type guint8) (nullable):
      83                 :            :  *        the data to be used for the bytes
      84                 :            :  * @size: the size of @data
      85                 :            :  *
      86                 :            :  * Creates a new #GBytes from @data.
      87                 :            :  *
      88                 :            :  * @data is copied. If @size is 0, @data may be %NULL.
      89                 :            :  *
      90                 :            :  * Returns: (transfer full): a new #GBytes
      91                 :            :  *
      92                 :            :  * Since: 2.32
      93                 :            :  */
      94                 :            : GBytes *
      95                 :    2841595 : g_bytes_new (gconstpointer data,
      96                 :            :              gsize         size)
      97                 :            : {
      98                 :    2841595 :   g_return_val_if_fail (data != NULL || size == 0, NULL);
      99                 :            : 
     100                 :    2841595 :   return g_bytes_new_take (g_memdup2 (data, size), size);
     101                 :            : }
     102                 :            : 
     103                 :            : /**
     104                 :            :  * g_bytes_new_take:
     105                 :            :  * @data: (transfer full) (array length=size) (element-type guint8) (nullable):
     106                 :            :  *        the data to be used for the bytes
     107                 :            :  * @size: the size of @data
     108                 :            :  *
     109                 :            :  * Creates a new #GBytes from @data.
     110                 :            :  *
     111                 :            :  * After this call, @data belongs to the #GBytes and may no longer be
     112                 :            :  * modified by the caller. The memory of @data has to be dynamically
     113                 :            :  * allocated and will eventually be freed with g_free().
     114                 :            :  *
     115                 :            :  * For creating #GBytes with memory from other allocators, see
     116                 :            :  * g_bytes_new_with_free_func().
     117                 :            :  *
     118                 :            :  * @data may be %NULL if @size is 0.
     119                 :            :  *
     120                 :            :  * Returns: (transfer full): a new #GBytes
     121                 :            :  *
     122                 :            :  * Since: 2.32
     123                 :            :  */
     124                 :            : GBytes *
     125                 :    2852635 : g_bytes_new_take (gpointer data,
     126                 :            :                   gsize    size)
     127                 :            : {
     128                 :    2852635 :   return g_bytes_new_with_free_func (data, size, g_free, data);
     129                 :            : }
     130                 :            : 
     131                 :            : 
     132                 :            : /**
     133                 :            :  * g_bytes_new_static: (skip)
     134                 :            :  * @data: (transfer full) (array length=size) (element-type guint8) (nullable):
     135                 :            :  *        the data to be used for the bytes
     136                 :            :  * @size: the size of @data
     137                 :            :  *
     138                 :            :  * Creates a new #GBytes from static data.
     139                 :            :  *
     140                 :            :  * @data must be static (ie: never modified or freed). It may be %NULL if @size
     141                 :            :  * is 0.
     142                 :            :  *
     143                 :            :  * Returns: (transfer full): a new #GBytes
     144                 :            :  *
     145                 :            :  * Since: 2.32
     146                 :            :  */
     147                 :            : GBytes *
     148                 :       1725 : g_bytes_new_static (gconstpointer data,
     149                 :            :                     gsize         size)
     150                 :            : {
     151                 :       1725 :   return g_bytes_new_with_free_func (data, size, NULL, NULL);
     152                 :            : }
     153                 :            : 
     154                 :            : /**
     155                 :            :  * g_bytes_new_with_free_func: (skip)
     156                 :            :  * @data: (array length=size) (element-type guint8) (nullable):
     157                 :            :  *        the data to be used for the bytes
     158                 :            :  * @size: the size of @data
     159                 :            :  * @free_func: the function to call to release the data
     160                 :            :  * @user_data: data to pass to @free_func
     161                 :            :  *
     162                 :            :  * Creates a #GBytes from @data.
     163                 :            :  *
     164                 :            :  * When the last reference is dropped, @free_func will be called with the
     165                 :            :  * @user_data argument.
     166                 :            :  *
     167                 :            :  * @data must not be modified after this call is made until @free_func has
     168                 :            :  * been called to indicate that the bytes is no longer in use.
     169                 :            :  *
     170                 :            :  * @data may be %NULL if @size is 0.
     171                 :            :  *
     172                 :            :  * Returns: (transfer full): a new #GBytes
     173                 :            :  *
     174                 :            :  * Since: 2.32
     175                 :            :  */
     176                 :            : GBytes *
     177                 :    2872271 : g_bytes_new_with_free_func (gconstpointer  data,
     178                 :            :                             gsize          size,
     179                 :            :                             GDestroyNotify free_func,
     180                 :            :                             gpointer       user_data)
     181                 :            : {
     182                 :            :   GBytes *bytes;
     183                 :            : 
     184                 :    2872271 :   g_return_val_if_fail (data != NULL || size == 0, NULL);
     185                 :            : 
     186                 :    2872271 :   bytes = g_slice_new (GBytes);
     187                 :    2872271 :   bytes->data = data;
     188                 :    2872271 :   bytes->size = size;
     189                 :    2872271 :   bytes->free_func = free_func;
     190                 :    2872271 :   bytes->user_data = user_data;
     191                 :    2872271 :   g_atomic_ref_count_init (&bytes->ref_count);
     192                 :            : 
     193                 :    2872271 :   return (GBytes *)bytes;
     194                 :            : }
     195                 :            : 
     196                 :            : /**
     197                 :            :  * g_bytes_new_from_bytes:
     198                 :            :  * @bytes: a #GBytes
     199                 :            :  * @offset: offset which subsection starts at
     200                 :            :  * @length: length of subsection
     201                 :            :  *
     202                 :            :  * Creates a #GBytes which is a subsection of another #GBytes. The @offset +
     203                 :            :  * @length may not be longer than the size of @bytes.
     204                 :            :  *
     205                 :            :  * A reference to @bytes will be held by the newly created #GBytes until
     206                 :            :  * the byte data is no longer needed.
     207                 :            :  *
     208                 :            :  * Since 2.56, if @offset is 0 and @length matches the size of @bytes, then
     209                 :            :  * @bytes will be returned with the reference count incremented by 1. If @bytes
     210                 :            :  * is a slice of another #GBytes, then the resulting #GBytes will reference
     211                 :            :  * the same #GBytes instead of @bytes. This allows consumers to simplify the
     212                 :            :  * usage of #GBytes when asynchronously writing to streams.
     213                 :            :  *
     214                 :            :  * Returns: (transfer full): a new #GBytes
     215                 :            :  *
     216                 :            :  * Since: 2.32
     217                 :            :  */
     218                 :            : GBytes *
     219                 :        449 : g_bytes_new_from_bytes (GBytes  *bytes,
     220                 :            :                         gsize    offset,
     221                 :            :                         gsize    length)
     222                 :            : {
     223                 :            :   gchar *base;
     224                 :            : 
     225                 :            :   /* Note that length may be 0. */
     226                 :        449 :   g_return_val_if_fail (bytes != NULL, NULL);
     227                 :        449 :   g_return_val_if_fail (offset <= bytes->size, NULL);
     228                 :        449 :   g_return_val_if_fail (offset + length <= bytes->size, NULL);
     229                 :            : 
     230                 :            :   /* Avoid an extra GBytes if all bytes were requested */
     231   [ +  +  +  + ]:        449 :   if (offset == 0 && length == bytes->size)
     232                 :          1 :     return g_bytes_ref (bytes);
     233                 :            : 
     234                 :        448 :   base = (gchar *)bytes->data + offset;
     235                 :            : 
     236                 :            :   /* Avoid referencing intermediate GBytes. In practice, this should
     237                 :            :    * only loop once.
     238                 :            :    */
     239         [ +  + ]:        450 :   while (bytes->free_func == (gpointer)g_bytes_unref)
     240                 :          2 :     bytes = bytes->user_data;
     241                 :            : 
     242                 :        448 :   g_return_val_if_fail (bytes != NULL, NULL);
     243                 :        448 :   g_return_val_if_fail (base >= (gchar *)bytes->data, NULL);
     244                 :        448 :   g_return_val_if_fail (base <= (gchar *)bytes->data + bytes->size, NULL);
     245                 :        448 :   g_return_val_if_fail (base + length <= (gchar *)bytes->data + bytes->size, NULL);
     246                 :            : 
     247                 :        448 :   return g_bytes_new_with_free_func (base, length,
     248                 :        448 :                                      (GDestroyNotify)g_bytes_unref, g_bytes_ref (bytes));
     249                 :            : }
     250                 :            : 
     251                 :            : /**
     252                 :            :  * g_bytes_get_data:
     253                 :            :  * @bytes: a #GBytes
     254                 :            :  * @size: (out) (optional): location to return size of byte data
     255                 :            :  *
     256                 :            :  * Get the byte data in the #GBytes. This data should not be modified.
     257                 :            :  *
     258                 :            :  * This function will always return the same pointer for a given #GBytes.
     259                 :            :  *
     260                 :            :  * %NULL may be returned if @size is 0. This is not guaranteed, as the #GBytes
     261                 :            :  * may represent an empty string with @data non-%NULL and @size as 0. %NULL will
     262                 :            :  * not be returned if @size is non-zero.
     263                 :            :  *
     264                 :            :  * Returns: (transfer none) (array length=size) (element-type guint8) (nullable):
     265                 :            :  *          a pointer to the byte data, or %NULL
     266                 :            :  *
     267                 :            :  * Since: 2.32
     268                 :            :  */
     269                 :            : gconstpointer
     270                 :    6265988 : g_bytes_get_data (GBytes *bytes,
     271                 :            :                   gsize *size)
     272                 :            : {
     273                 :    6265988 :   g_return_val_if_fail (bytes != NULL, NULL);
     274         [ +  + ]:    6265988 :   if (size)
     275                 :    6255721 :     *size = bytes->size;
     276                 :    6265988 :   return bytes->data;
     277                 :            : }
     278                 :            : 
     279                 :            : /**
     280                 :            :  * g_bytes_get_size:
     281                 :            :  * @bytes: a #GBytes
     282                 :            :  *
     283                 :            :  * Get the size of the byte data in the #GBytes.
     284                 :            :  *
     285                 :            :  * This function will always return the same value for a given #GBytes.
     286                 :            :  *
     287                 :            :  * Returns: the size
     288                 :            :  *
     289                 :            :  * Since: 2.32
     290                 :            :  */
     291                 :            : gsize
     292                 :    1076490 : g_bytes_get_size (GBytes *bytes)
     293                 :            : {
     294                 :    1076490 :   g_return_val_if_fail (bytes != NULL, 0);
     295                 :    1076490 :   return bytes->size;
     296                 :            : }
     297                 :            : 
     298                 :            : 
     299                 :            : /**
     300                 :            :  * g_bytes_ref:
     301                 :            :  * @bytes: a #GBytes
     302                 :            :  *
     303                 :            :  * Increase the reference count on @bytes.
     304                 :            :  *
     305                 :            :  * Returns: the #GBytes
     306                 :            :  *
     307                 :            :  * Since: 2.32
     308                 :            :  */
     309                 :            : GBytes *
     310                 :    4616292 : g_bytes_ref (GBytes *bytes)
     311                 :            : {
     312                 :    4616292 :   g_return_val_if_fail (bytes != NULL, NULL);
     313                 :            : 
     314                 :    4616292 :   g_atomic_ref_count_inc (&bytes->ref_count);
     315                 :            : 
     316                 :    4616292 :   return bytes;
     317                 :            : }
     318                 :            : 
     319                 :            : /**
     320                 :            :  * g_bytes_unref:
     321                 :            :  * @bytes: (nullable): a #GBytes
     322                 :            :  *
     323                 :            :  * Releases a reference on @bytes.  This may result in the bytes being
     324                 :            :  * freed. If @bytes is %NULL, it will return immediately.
     325                 :            :  *
     326                 :            :  * Since: 2.32
     327                 :            :  */
     328                 :            : void
     329                 :    7487497 : g_bytes_unref (GBytes *bytes)
     330                 :            : {
     331         [ +  + ]:    7487497 :   if (bytes == NULL)
     332                 :          2 :     return;
     333                 :            : 
     334         [ +  + ]:    7487495 :   if (g_atomic_ref_count_dec (&bytes->ref_count))
     335                 :            :     {
     336         [ +  + ]:    2871207 :       if (bytes->free_func != NULL)
     337                 :    2869412 :         bytes->free_func (bytes->user_data);
     338                 :    2871207 :       g_slice_free (GBytes, bytes);
     339                 :            :     }
     340                 :            : }
     341                 :            : 
     342                 :            : /**
     343                 :            :  * g_bytes_equal:
     344                 :            :  * @bytes1: (type GLib.Bytes): a pointer to a #GBytes
     345                 :            :  * @bytes2: (type GLib.Bytes): a pointer to a #GBytes to compare with @bytes1
     346                 :            :  *
     347                 :            :  * Compares the two #GBytes values being pointed to and returns
     348                 :            :  * %TRUE if they are equal.
     349                 :            :  *
     350                 :            :  * This function can be passed to g_hash_table_new() as the @key_equal_func
     351                 :            :  * parameter, when using non-%NULL #GBytes pointers as keys in a #GHashTable.
     352                 :            :  *
     353                 :            :  * Returns: %TRUE if the two keys match.
     354                 :            :  *
     355                 :            :  * Since: 2.32
     356                 :            :  */
     357                 :            : gboolean
     358                 :         13 : g_bytes_equal (gconstpointer bytes1,
     359                 :            :                gconstpointer bytes2)
     360                 :            : {
     361                 :         13 :   const GBytes *b1 = bytes1;
     362                 :         13 :   const GBytes *b2 = bytes2;
     363                 :            : 
     364                 :         13 :   g_return_val_if_fail (bytes1 != NULL, FALSE);
     365                 :         13 :   g_return_val_if_fail (bytes2 != NULL, FALSE);
     366                 :            : 
     367         [ +  + ]:         23 :   return b1->size == b2->size &&
     368   [ +  +  +  + ]:         10 :          (b1->size == 0 || memcmp (b1->data, b2->data, b1->size) == 0);
     369                 :            : }
     370                 :            : 
     371                 :            : /**
     372                 :            :  * g_bytes_hash:
     373                 :            :  * @bytes: (type GLib.Bytes): a pointer to a #GBytes key
     374                 :            :  *
     375                 :            :  * Creates an integer hash code for the byte data in the #GBytes.
     376                 :            :  *
     377                 :            :  * This function can be passed to g_hash_table_new() as the @key_hash_func
     378                 :            :  * parameter, when using non-%NULL #GBytes pointers as keys in a #GHashTable.
     379                 :            :  *
     380                 :            :  * Returns: a hash value corresponding to the key.
     381                 :            :  *
     382                 :            :  * Since: 2.32
     383                 :            :  */
     384                 :            : guint
     385                 :          6 : g_bytes_hash (gconstpointer bytes)
     386                 :            : {
     387                 :          6 :   const GBytes *a = bytes;
     388                 :            :   const signed char *p, *e;
     389                 :          6 :   guint32 h = 5381;
     390                 :            : 
     391                 :          6 :   g_return_val_if_fail (bytes != NULL, 0);
     392                 :            : 
     393         [ +  + ]:         90 :   for (p = (signed char *)a->data, e = (signed char *)a->data + a->size; p != e; p++)
     394                 :         84 :     h = (h << 5) + h + *p;
     395                 :            : 
     396                 :          6 :   return h;
     397                 :            : }
     398                 :            : 
     399                 :            : /**
     400                 :            :  * g_bytes_compare:
     401                 :            :  * @bytes1: (type GLib.Bytes): a pointer to a #GBytes
     402                 :            :  * @bytes2: (type GLib.Bytes): a pointer to a #GBytes to compare with @bytes1
     403                 :            :  *
     404                 :            :  * Compares the two #GBytes values.
     405                 :            :  *
     406                 :            :  * This function can be used to sort GBytes instances in lexicographical order.
     407                 :            :  *
     408                 :            :  * If @bytes1 and @bytes2 have different length but the shorter one is a
     409                 :            :  * prefix of the longer one then the shorter one is considered to be less than
     410                 :            :  * the longer one. Otherwise the first byte where both differ is used for
     411                 :            :  * comparison. If @bytes1 has a smaller value at that position it is
     412                 :            :  * considered less, otherwise greater than @bytes2.
     413                 :            :  *
     414                 :            :  * Returns: a negative value if @bytes1 is less than @bytes2, a positive value
     415                 :            :  *          if @bytes1 is greater than @bytes2, and zero if @bytes1 is equal to
     416                 :            :  *          @bytes2
     417                 :            :  *
     418                 :            :  *
     419                 :            :  * Since: 2.32
     420                 :            :  */
     421                 :            : gint
     422                 :          6 : g_bytes_compare (gconstpointer bytes1,
     423                 :            :                  gconstpointer bytes2)
     424                 :            : {
     425                 :          6 :   const GBytes *b1 = bytes1;
     426                 :          6 :   const GBytes *b2 = bytes2;
     427                 :            :   gint ret;
     428                 :            : 
     429                 :          6 :   g_return_val_if_fail (bytes1 != NULL, 0);
     430                 :          6 :   g_return_val_if_fail (bytes2 != NULL, 0);
     431                 :            : 
     432                 :          6 :   ret = memcmp (b1->data, b2->data, MIN (b1->size, b2->size));
     433   [ +  +  +  + ]:          6 :   if (ret == 0 && b1->size != b2->size)
     434         [ +  + ]:          2 :       ret = b1->size < b2->size ? -1 : 1;
     435                 :          6 :   return ret;
     436                 :            : }
     437                 :            : 
     438                 :            : static gpointer
     439                 :          9 : try_steal_and_unref (GBytes         *bytes,
     440                 :            :                      GDestroyNotify  free_func,
     441                 :            :                      gsize          *size)
     442                 :            : {
     443                 :            :   gpointer result;
     444                 :            : 
     445   [ +  +  +  + ]:          9 :   if (bytes->free_func != free_func || bytes->data == NULL ||
     446         [ -  + ]:          5 :       bytes->user_data != bytes->data)
     447                 :          4 :     return NULL;
     448                 :            : 
     449                 :            :   /* Are we the only reference? */
     450         [ +  + ]:          5 :   if (g_atomic_ref_count_compare (&bytes->ref_count, 1))
     451                 :            :     {
     452                 :          3 :       *size = bytes->size;
     453                 :          3 :       result = (gpointer)bytes->data;
     454                 :          3 :       g_slice_free (GBytes, bytes);
     455                 :          3 :       return result;
     456                 :            :     }
     457                 :            : 
     458                 :          2 :   return NULL;
     459                 :            : }
     460                 :            : 
     461                 :            : 
     462                 :            : /**
     463                 :            :  * g_bytes_unref_to_data:
     464                 :            :  * @bytes: (transfer full): a #GBytes
     465                 :            :  * @size: (out): location to place the length of the returned data
     466                 :            :  *
     467                 :            :  * Unreferences the bytes, and returns a pointer the same byte data
     468                 :            :  * contents.
     469                 :            :  *
     470                 :            :  * As an optimization, the byte data is returned without copying if this was
     471                 :            :  * the last reference to bytes and bytes was created with g_bytes_new(),
     472                 :            :  * g_bytes_new_take() or g_byte_array_free_to_bytes(). In all other cases the
     473                 :            :  * data is copied.
     474                 :            :  *
     475                 :            :  * Returns: (transfer full) (array length=size) (element-type guint8)
     476                 :            :  *          (not nullable): a pointer to the same byte data, which should be
     477                 :            :  *          freed with g_free()
     478                 :            :  *
     479                 :            :  * Since: 2.32
     480                 :            :  */
     481                 :            : gpointer
     482                 :          9 : g_bytes_unref_to_data (GBytes *bytes,
     483                 :            :                        gsize  *size)
     484                 :            : {
     485                 :            :   gpointer result;
     486                 :            : 
     487                 :          9 :   g_return_val_if_fail (bytes != NULL, NULL);
     488                 :          9 :   g_return_val_if_fail (size != NULL, NULL);
     489                 :            : 
     490                 :            :   /*
     491                 :            :    * Optimal path: if this is was the last reference, then we can return
     492                 :            :    * the data from this GBytes without copying.
     493                 :            :    */
     494                 :            : 
     495                 :          9 :   result = try_steal_and_unref (bytes, g_free, size);
     496         [ +  + ]:          9 :   if (result == NULL)
     497                 :            :     {
     498                 :            :       /*
     499                 :            :        * Copy: Non g_malloc (or compatible) allocator, or static memory,
     500                 :            :        * so we have to copy, and then unref.
     501                 :            :        */
     502                 :          6 :       result = g_memdup2 (bytes->data, bytes->size);
     503                 :          6 :       *size = bytes->size;
     504                 :          6 :       g_bytes_unref (bytes);
     505                 :            :     }
     506                 :            : 
     507                 :          9 :   return result;
     508                 :            : }
     509                 :            : 
     510                 :            : /**
     511                 :            :  * g_bytes_unref_to_array:
     512                 :            :  * @bytes: (transfer full): a #GBytes
     513                 :            :  *
     514                 :            :  * Unreferences the bytes, and returns a new mutable #GByteArray containing
     515                 :            :  * the same byte data.
     516                 :            :  *
     517                 :            :  * As an optimization, the byte data is transferred to the array without copying
     518                 :            :  * if this was the last reference to bytes and bytes was created with
     519                 :            :  * g_bytes_new(), g_bytes_new_take() or g_byte_array_free_to_bytes(). In all
     520                 :            :  * other cases the data is copied.
     521                 :            :  *
     522                 :            :  * Do not use it if @bytes contains more than %G_MAXUINT
     523                 :            :  * bytes. #GByteArray stores the length of its data in #guint, which
     524                 :            :  * may be shorter than #gsize, that @bytes is using.
     525                 :            :  *
     526                 :            :  * Returns: (transfer full): a new mutable #GByteArray containing the same byte data
     527                 :            :  *
     528                 :            :  * Since: 2.32
     529                 :            :  */
     530                 :            : GByteArray *
     531                 :          4 : g_bytes_unref_to_array (GBytes *bytes)
     532                 :            : {
     533                 :            :   gpointer data;
     534                 :            :   gsize size;
     535                 :            : 
     536                 :          4 :   g_return_val_if_fail (bytes != NULL, NULL);
     537                 :            : 
     538                 :          4 :   data = g_bytes_unref_to_data (bytes, &size);
     539                 :          4 :   return g_byte_array_new_take (data, size);
     540                 :            : }
     541                 :            : 
     542                 :            : /**
     543                 :            :  * g_bytes_get_region:
     544                 :            :  * @bytes: a #GBytes
     545                 :            :  * @element_size: a non-zero element size
     546                 :            :  * @offset: an offset to the start of the region within the @bytes
     547                 :            :  * @n_elements: the number of elements in the region
     548                 :            :  *
     549                 :            :  * Gets a pointer to a region in @bytes.
     550                 :            :  *
     551                 :            :  * The region starts at @offset many bytes from the start of the data
     552                 :            :  * and contains @n_elements many elements of @element_size size.
     553                 :            :  *
     554                 :            :  * @n_elements may be zero, but @element_size must always be non-zero.
     555                 :            :  * Ideally, @element_size is a static constant (eg: sizeof a struct).
     556                 :            :  *
     557                 :            :  * This function does careful bounds checking (including checking for
     558                 :            :  * arithmetic overflows) and returns a non-%NULL pointer if the
     559                 :            :  * specified region lies entirely within the @bytes. If the region is
     560                 :            :  * in some way out of range, or if an overflow has occurred, then %NULL
     561                 :            :  * is returned.
     562                 :            :  *
     563                 :            :  * Note: it is possible to have a valid zero-size region. In this case,
     564                 :            :  * the returned pointer will be equal to the base pointer of the data of
     565                 :            :  * @bytes, plus @offset.  This will be non-%NULL except for the case
     566                 :            :  * where @bytes itself was a zero-sized region.  Since it is unlikely
     567                 :            :  * that you will be using this function to check for a zero-sized region
     568                 :            :  * in a zero-sized @bytes, %NULL effectively always means "error".
     569                 :            :  *
     570                 :            :  * Returns: (nullable): the requested region, or %NULL in case of an error
     571                 :            :  *
     572                 :            :  * Since: 2.70
     573                 :            :  */
     574                 :            : gconstpointer
     575                 :         10 : g_bytes_get_region (GBytes *bytes,
     576                 :            :                     gsize   element_size,
     577                 :            :                     gsize   offset,
     578                 :            :                     gsize   n_elements)
     579                 :            : {
     580                 :            :   gsize total_size;
     581                 :            :   gsize end_offset;
     582                 :            : 
     583                 :         10 :   g_return_val_if_fail (element_size > 0, NULL);
     584                 :            : 
     585                 :            :   /* No other assertion checks here.  If something is wrong then we will
     586                 :            :    * simply crash (via NULL dereference or divide-by-zero).
     587                 :            :    */
     588                 :            : 
     589         [ +  + ]:         10 :   if (!g_size_checked_mul (&total_size, element_size, n_elements))
     590                 :          2 :     return NULL;
     591                 :            : 
     592         [ +  + ]:          8 :   if (!g_size_checked_add (&end_offset, offset, total_size))
     593                 :          2 :     return NULL;
     594                 :            : 
     595                 :            :   /* We now have:
     596                 :            :    *
     597                 :            :    *   0 <= offset <= end_offset
     598                 :            :    *
     599                 :            :    * So we need only check that end_offset is within the range of the
     600                 :            :    * size of @bytes and we're good to go.
     601                 :            :    */
     602                 :            : 
     603         [ +  + ]:          6 :   if (end_offset > bytes->size)
     604                 :          3 :     return NULL;
     605                 :            : 
     606                 :            :   /* We now have:
     607                 :            :    *
     608                 :            :    *   0 <= offset <= end_offset <= bytes->size
     609                 :            :    */
     610                 :            : 
     611                 :          3 :   return ((guchar *) bytes->data) + offset;
     612                 :            : }

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