1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "proto_format.h"
18 
19 #include <string.h>
20 
21 extern int const PROTO_FORMAT_STRING_POOL_SIZE;
22 extern int const PROTO_FORMAT_ENUM_LABELS_LENGTH;
23 extern int const PROTO_FORMAT_MESSAGES_LENGTH;
24 extern int const PROTO_FORMAT_FIELDS_LENGTH;
25 
26 extern char const PROTO_FORMAT_STRING_POOL[];
27 extern ProtoFieldFormat const PROTO_FORMAT_FIELDS[];
28 extern ProtoEnumLabel const PROTO_FORMAT_ENUM_LABELS[];
29 extern ProtoMessageFormat const PROTO_FORMAT_MESSAGES[];
30 
31 static const char*
get_string(int index)32 get_string(int index)
33 {
34     if (index >= 0 && index < PROTO_FORMAT_STRING_POOL_SIZE) {
35         return PROTO_FORMAT_STRING_POOL + index;
36     } else {
37         // These indices all come from within the generated table, so just crash now.
38         *(int*)NULL = 42;
39         return NULL;
40     }
41 }
42 
43 static ProtoMessageFormat const*
get_message(int index)44 get_message(int index)
45 {
46     if (index >= 0 && index < PROTO_FORMAT_MESSAGES_LENGTH) {
47         return PROTO_FORMAT_MESSAGES + index;
48     } else {
49         // These indices all come from within the generated table, so just crash now.
50         *(int*)NULL = 42;
51         return NULL;
52     }
53 }
54 
55 static int
compare_name(const char * full,const char * package,const char * clazz)56 compare_name(const char* full, const char* package, const char* clazz)
57 {
58     int const packageLen = strlen(package);
59     int cmp = strncmp(full, package, packageLen);
60     if (cmp == 0) {
61         cmp = full[packageLen] - '.';
62         if (cmp == 0) {
63             return strcmp(full + packageLen, clazz);
64         }
65     }
66     return cmp;
67 }
68 
69 int
find_message_index(const char * name)70 find_message_index(const char* name)
71 {
72     size_t low = 0;
73     size_t high = PROTO_FORMAT_FIELDS_LENGTH - 1;
74 
75     while (low <= high) {
76         size_t mid = (low + high) >> 1;
77         ProtoMessageFormat const* msg = get_message(mid);
78 
79         int cmp = compare_name(name, get_string(msg->package_name), get_string(msg->package_name));
80         if (cmp < 0) {
81             low = mid + 1;
82         } else if (cmp > 0) {
83             high = mid - 1;
84         } else {
85             return mid;
86         }
87     }
88     return -1;
89 }
90