1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2023 Google LLC. All rights reserved.
3 //
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file or at
6 // https://developers.google.com/open-source/licenses/bsd
7
8 #include "upb/message/internal/extension.h"
9
10 #include <string.h>
11
12 #include "upb/mem/arena.h"
13 #include "upb/message/internal/extension.h"
14 #include "upb/message/internal/message.h"
15 #include "upb/message/internal/types.h"
16 #include "upb/mini_table/extension.h"
17
18 // Must be last.
19 #include "upb/port/def.inc"
20
UPB_PRIVATE(_upb_Message_Getext)21 const struct upb_Extension* UPB_PRIVATE(_upb_Message_Getext)(
22 const struct upb_Message* msg, const upb_MiniTableExtension* e) {
23 size_t n;
24 const struct upb_Extension* ext = UPB_PRIVATE(_upb_Message_Getexts)(msg, &n);
25
26 // For now we use linear search exclusively to find extensions.
27 // If this becomes an issue due to messages with lots of extensions,
28 // we can introduce a table of some sort.
29 for (size_t i = 0; i < n; i++) {
30 if (ext[i].ext == e) {
31 return &ext[i];
32 }
33 }
34
35 return NULL;
36 }
37
UPB_PRIVATE(_upb_Message_Getexts)38 const struct upb_Extension* UPB_PRIVATE(_upb_Message_Getexts)(
39 const struct upb_Message* msg, size_t* count) {
40 upb_Message_Internal* in = msg->internal;
41 if (in) {
42 *count = (in->size - in->ext_begin) / sizeof(struct upb_Extension);
43 return UPB_PTR_AT(in, in->ext_begin, void);
44 } else {
45 *count = 0;
46 return NULL;
47 }
48 }
49
UPB_PRIVATE(_upb_Message_GetOrCreateExtension)50 struct upb_Extension* UPB_PRIVATE(_upb_Message_GetOrCreateExtension)(
51 struct upb_Message* msg, const upb_MiniTableExtension* e, upb_Arena* a) {
52 struct upb_Extension* ext =
53 (struct upb_Extension*)UPB_PRIVATE(_upb_Message_Getext)(msg, e);
54 if (ext) return ext;
55 if (!UPB_PRIVATE(_upb_Message_Realloc)(msg, sizeof(struct upb_Extension), a))
56 return NULL;
57 upb_Message_Internal* in = msg->internal;
58 in->ext_begin -= sizeof(struct upb_Extension);
59 ext = UPB_PTR_AT(in, in->ext_begin, void);
60 memset(ext, 0, sizeof(struct upb_Extension));
61 ext->ext = e;
62 return ext;
63 }
64