gdiplus: Only release device contexts created internally.
[wine/hacks.git] / server / user.c
blob6be1c8fe82d325cbc0f873c0869a52a2269d1b55
1 /*
2 * Server-side USER handles
4 * Copyright (C) 2001 Alexandre Julliard
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
21 #include "thread.h"
22 #include "user.h"
24 struct user_handle
26 void *ptr; /* pointer to object */
27 unsigned short type; /* object type (0 if free) */
28 unsigned short generation; /* generation counter */
31 static struct user_handle *handles;
32 static struct user_handle *freelist;
33 static int nb_handles;
34 static int allocated_handles;
36 static struct user_handle *handle_to_entry( user_handle_t handle )
38 unsigned short generation;
39 int index = ((handle & 0xffff) - FIRST_USER_HANDLE) >> 1;
40 if (index < 0 || index >= nb_handles) return NULL;
41 if (!handles[index].type) return NULL;
42 generation = handle >> 16;
43 if (generation == handles[index].generation || !generation || generation == 0xffff)
44 return &handles[index];
45 return NULL;
48 static inline user_handle_t entry_to_handle( struct user_handle *ptr )
50 unsigned int index = ptr - handles;
51 return (index << 1) + FIRST_USER_HANDLE + (ptr->generation << 16);
54 static inline struct user_handle *alloc_user_entry(void)
56 struct user_handle *handle;
58 if (freelist)
60 handle = freelist;
61 freelist = handle->ptr;
62 return handle;
64 if (nb_handles >= allocated_handles) /* need to grow the array */
66 struct user_handle *new_handles;
67 /* grow array by 50% (but at minimum 32 entries) */
68 int growth = max( 32, allocated_handles / 2 );
69 int new_size = min( allocated_handles + growth, (LAST_USER_HANDLE-FIRST_USER_HANDLE+1) >> 1 );
70 if (new_size <= allocated_handles) return NULL;
71 if (!(new_handles = realloc( handles, new_size * sizeof(*handles) )))
72 return NULL;
73 handles = new_handles;
74 allocated_handles = new_size;
76 handle = &handles[nb_handles++];
77 handle->generation = 0;
78 return handle;
81 static inline void *free_user_entry( struct user_handle *ptr )
83 void *ret;
84 ret = ptr->ptr;
85 ptr->ptr = freelist;
86 ptr->type = 0;
87 freelist = ptr;
88 return ret;
91 /* allocate a user handle for a given object */
92 user_handle_t alloc_user_handle( void *ptr, enum user_object type )
94 struct user_handle *entry = alloc_user_entry();
95 if (!entry) return 0;
96 entry->ptr = ptr;
97 entry->type = type;
98 if (++entry->generation >= 0xffff) entry->generation = 1;
99 return entry_to_handle( entry );
102 /* return a pointer to a user object from its handle */
103 void *get_user_object( user_handle_t handle, enum user_object type )
105 struct user_handle *entry;
107 if (!(entry = handle_to_entry( handle )) || entry->type != type) return NULL;
108 return entry->ptr;
111 /* get the full handle for a possibly truncated handle */
112 user_handle_t get_user_full_handle( user_handle_t handle )
114 struct user_handle *entry;
116 if (handle >> 16) return handle;
117 if (!(entry = handle_to_entry( handle ))) return handle;
118 return entry_to_handle( entry );
121 /* same as get_user_object plus set the handle to the full 32-bit value */
122 void *get_user_object_handle( user_handle_t *handle, enum user_object type )
124 struct user_handle *entry;
126 if (!(entry = handle_to_entry( *handle )) || entry->type != type) return NULL;
127 *handle = entry_to_handle( entry );
128 return entry->ptr;
131 /* free a user handle and return a pointer to the object */
132 void *free_user_handle( user_handle_t handle )
134 struct user_handle *entry;
136 if (!(entry = handle_to_entry( handle )))
138 set_error( STATUS_INVALID_HANDLE );
139 return NULL;
141 return free_user_entry( entry );
144 /* return the next user handle after 'handle' that is of a given type */
145 void *next_user_handle( user_handle_t *handle, enum user_object type )
147 struct user_handle *entry;
149 if (!*handle) entry = handles;
150 else
152 int index = ((*handle & 0xffff) - FIRST_USER_HANDLE) >> 1;
153 if (index < 0 || index >= nb_handles) return NULL;
154 entry = handles + index + 1; /* start from the next one */
156 while (entry < handles + nb_handles)
158 if (!type || entry->type == type)
160 *handle = entry_to_handle( entry );
161 return entry->ptr;
163 entry++;
165 return NULL;