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      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'.
     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 #endif  // LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_
     59