1 // Copyright 2019 Google Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 /////////////////////////////////////////////////////////////////////////////// 16 17 #ifndef TINK_UTIL_BUFFER_H_ 18 #define TINK_UTIL_BUFFER_H_ 19 20 #include <memory> 21 22 #include "absl/memory/memory.h" 23 #include "tink/util/status.h" 24 #include "tink/util/statusor.h" 25 26 namespace crypto { 27 namespace tink { 28 namespace util { 29 30 class Buffer { 31 public: 32 // Creates a new Buffer which allocates a new memory block 33 // of size 'allocated_size' and uses it for the actual data. 34 // The allocated memory block is owned by this Buffer. 35 static util::StatusOr<std::unique_ptr<Buffer>> New(int allocated_size); 36 37 // Creates a new Buffer which uses the given 'mem_block' as a buffer 38 // for the actual data. 39 // Does NOT take the ownership of 'mem_block' which must be non-null, 40 // must allocate at least 'allocated_size' bytes, and must remain alive 41 // as long as the returned Buffer is in use. 42 static util::StatusOr<std::unique_ptr<Buffer>> NewNonOwning( 43 char* mem_block, int allocated_size); 44 45 // Returns the internal memory block of this Buffer, 46 // that holds the actual data. 47 // A reading caller may read up to size() bytes from the block. 48 // A writing caller may write up to allocated_size() bytes to the block, 49 // and should accordingly adjust size via set_size(int). 50 virtual char* const get_mem_block() const = 0; 51 52 // Returns the allocated size of this buffer. 53 virtual int allocated_size() const = 0; 54 55 // Returns the current size of this buffer. 56 virtual int size() const = 0; 57 58 // Sets the size of this buffer to 'new_size', which must 59 // be in range 0..allocated_size(). 60 // Returns OK iff 0 <= new_size <= allocated_size(); 61 virtual util::Status set_size(int new_size) = 0; 62 63 virtual ~Buffer() = default; 64 }; 65 66 } // namespace util 67 } // namespace tink 68 } // namespace crypto 69 70 #endif // TINK_UTIL_BUFFER_H_ 71