1 // Tencent is pleased to support the open source community by making RapidJSON available. 2 // 3 // Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved. 4 // 5 // Licensed under the MIT License (the "License"); you may not use this file except 6 // in compliance with the License. You may obtain a copy of the License at 7 // 8 // http://opensource.org/licenses/MIT 9 // 10 // Unless required by applicable law or agreed to in writing, software distributed 11 // under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 12 // CONDITIONS OF ANY KIND, either express or implied. See the License for the 13 // specific language governing permissions and limitations under the License. 14 15 #ifndef CEREAL_RAPIDJSON_FILEREADSTREAM_H_ 16 #define CEREAL_RAPIDJSON_FILEREADSTREAM_H_ 17 18 #include "stream.h" 19 #include <cstdio> 20 21 #ifdef __clang__ 22 CEREAL_RAPIDJSON_DIAG_PUSH 23 CEREAL_RAPIDJSON_DIAG_OFF(padded) 24 CEREAL_RAPIDJSON_DIAG_OFF(unreachable-code) 25 CEREAL_RAPIDJSON_DIAG_OFF(missing-noreturn) 26 #endif 27 28 CEREAL_RAPIDJSON_NAMESPACE_BEGIN 29 30 //! File byte stream for input using fread(). 31 /*! 32 \note implements Stream concept 33 */ 34 class FileReadStream { 35 public: 36 typedef char Ch; //!< Character type (byte). 37 38 //! Constructor. 39 /*! 40 \param fp File pointer opened for read. 41 \param buffer user-supplied buffer. 42 \param bufferSize size of buffer in bytes. Must >=4 bytes. 43 */ 44 FileReadStream(std::FILE* fp, char* buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferSize_(bufferSize), bufferLast_(0), current_(buffer_), readCount_(0), count_(0), eof_(false) { 45 CEREAL_RAPIDJSON_ASSERT(fp_ != 0); 46 CEREAL_RAPIDJSON_ASSERT(bufferSize >= 4); 47 Read(); 48 } 49 50 Ch Peek() const { return *current_; } 51 Ch Take() { Ch c = *current_; Read(); return c; } 52 size_t Tell() const { return count_ + static_cast<size_t>(current_ - buffer_); } 53 54 // Not implemented 55 void Put(Ch) { CEREAL_RAPIDJSON_ASSERT(false); } 56 void Flush() { CEREAL_RAPIDJSON_ASSERT(false); } 57 Ch* PutBegin() { CEREAL_RAPIDJSON_ASSERT(false); return 0; } 58 size_t PutEnd(Ch*) { CEREAL_RAPIDJSON_ASSERT(false); return 0; } 59 60 // For encoding detection only. 61 const Ch* Peek4() const { 62 return (current_ + 4 <= bufferLast_) ? current_ : 0; 63 } 64 65 private: 66 void Read() { 67 if (current_ < bufferLast_) 68 ++current_; 69 else if (!eof_) { 70 count_ += readCount_; 71 readCount_ = fread(buffer_, 1, bufferSize_, fp_); 72 bufferLast_ = buffer_ + readCount_ - 1; 73 current_ = buffer_; 74 75 if (readCount_ < bufferSize_) { 76 buffer_[readCount_] = '\0'; 77 ++bufferLast_; 78 eof_ = true; 79 } 80 } 81 } 82 83 std::FILE* fp_; 84 Ch *buffer_; 85 size_t bufferSize_; 86 Ch *bufferLast_; 87 Ch *current_; 88 size_t readCount_; 89 size_t count_; //!< Number of characters read 90 bool eof_; 91 }; 92 93 CEREAL_RAPIDJSON_NAMESPACE_END 94 95 #ifdef __clang__ 96 CEREAL_RAPIDJSON_DIAG_POP 97 #endif 98 99 #endif // CEREAL_RAPIDJSON_FILESTREAM_H_ 100