1 /*
2  * Copyright (C) 2014 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 #ifndef LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_
18 #define LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_
19 
20 #include <stddef.h>
21 #include <stdint.h>
22 
23 // Check if |length| bytes at |entry_name| constitute a valid entry name.
24 // Entry names must be valid UTF-8 and must not contain '0'.
IsValidEntryName(const uint8_t * entry_name,const size_t length)25 inline bool IsValidEntryName(const uint8_t* entry_name, const size_t length) {
26   for (size_t i = 0; i < length; ++i) {
27     const uint8_t byte = entry_name[i];
28     if (byte == 0) {
29       return false;
30     } else if ((byte & 0x80) == 0) {
31       // Single byte sequence.
32       continue;
33     } else if ((byte & 0xc0) == 0x80 || (byte & 0xfe) == 0xfe) {
34       // Invalid sequence.
35       return false;
36     } else {
37       // 2-5 byte sequences.
38       for (uint8_t first = byte << 1; first & 0x80; first <<= 1) {
39         ++i;
40 
41         // Missing continuation byte..
42         if (i == length) {
43           return false;
44         }
45 
46         // Invalid continuation byte.
47         const uint8_t continuation_byte = entry_name[i];
48         if ((continuation_byte & 0xc0) != 0x80) {
49           return false;
50         }
51       }
52     }
53   }
54 
55   return true;
56 }
57 
58 
59 #endif  // LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_
60