1 /* 2 * Copyright (C) 2019 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 ANDROID_ML_NN_COMMON_TOKEN_HASHER_H 18 #define ANDROID_ML_NN_COMMON_TOKEN_HASHER_H 19 20 #include <cstring> 21 #include <vector> 22 23 #include <android-base/macros.h> 24 #include <openssl/sha.h> 25 26 namespace android { 27 namespace nn { 28 29 class TokenHasher { 30 DISALLOW_COPY_AND_ASSIGN(TokenHasher); 31 32 public: 33 // Initializes the hasher with token. If token is nullptr, the hasher is set to be empty; 34 // otherwise, it must be of length ANEURALNETWORKS_BYTE_SIZE_OF_CACHE_TOKEN. 35 TokenHasher(const uint8_t* token); 36 37 // Updates with a byte array. Returns false and sets to be empty on fail. 38 // The client must check if the hasher is valid before invoking this method. 39 bool update(const void* bytes, size_t length); 40 41 // Updates with a string ended with '\0'. Returns false and sets to be empty on fail. 42 // The client must check if the hasher is valid before invoking this method. 43 bool updateFromString(const char* s) { return update(s, strlen(s)); } 44 45 // Finishes the hasher, and writes re-hashed token to mToken. 46 // Returns false and sets to be empty on fail. 47 // The client must check if the hasher is valid before invoking this method. 48 bool finish(); 49 50 // Returns a pointer to the transformed token if the hasher is successfully finished. 51 // Returns nullptr if the hasher is initialized with a nullptr, or some call on the 52 // hasher failed. 53 // Aborts if the hasher is valid but finish has not been called. 54 const uint8_t* getCacheToken() const; 55 56 bool ok() const { return !mIsError; } 57 58 private: 59 // Stores the transformed token, non-empty iff the hasher is not initialized 60 // with nullptr and finish is called. 61 std::vector<uint8_t> mToken; 62 SHA256_CTX mHasher; 63 // Indicates that either the hasher is initialized with a nullptr, or some call on 64 // the hasher failed. 65 bool mIsError; 66 }; 67 68 } // namespace nn 69 } // namespace android 70 71 #endif // ANDROID_ML_NN_COMMON_TOKEN_HASHER_H 72
