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 RAPIDJSON_FILEWRITESTREAM_H_
16 #define RAPIDJSON_FILEWRITESTREAM_H_
17
18 #include "rapidjson.h"
19 #include <cstdio>
20
21 RAPIDJSON_NAMESPACE_BEGIN
22
23 //! Wrapper of C file stream for input using fread().
24 /*!
25 \note implements Stream concept
26 */
27 class FileWriteStream {
28 public:
29 typedef char Ch; //!< Character type. Only support char.
30
FileWriteStream(std::FILE * fp,char * buffer,size_t bufferSize)31 FileWriteStream(std::FILE* fp, char* buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferEnd_(buffer + bufferSize), current_(buffer_) {
32 RAPIDJSON_ASSERT(fp_ != 0);
33 }
34
Put(char c)35 void Put(char c) {
36 if (current_ >= bufferEnd_)
37 Flush();
38
39 *current_++ = c;
40 }
41
PutN(char c,size_t n)42 void PutN(char c, size_t n) {
43 size_t avail = static_cast<size_t>(bufferEnd_ - current_);
44 while (n > avail) {
45 std::memset(current_, c, avail);
46 current_ += avail;
47 Flush();
48 n -= avail;
49 avail = static_cast<size_t>(bufferEnd_ - current_);
50 }
51
52 if (n > 0) {
53 std::memset(current_, c, n);
54 current_ += n;
55 }
56 }
57
Flush()58 void Flush() {
59 if (current_ != buffer_) {
60 size_t result = fwrite(buffer_, 1, static_cast<size_t>(current_ - buffer_), fp_);
61 if (result < static_cast<size_t>(current_ - buffer_)) {
62 // failure deliberately ignored at this time
63 // added to avoid warn_unused_result build errors
64 }
65 current_ = buffer_;
66 }
67 }
68
69 // Not implemented
Peek()70 char Peek() const { RAPIDJSON_ASSERT(false); return 0; }
Take()71 char Take() { RAPIDJSON_ASSERT(false); return 0; }
Tell()72 size_t Tell() const { RAPIDJSON_ASSERT(false); return 0; }
PutBegin()73 char* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
PutEnd(char *)74 size_t PutEnd(char*) { RAPIDJSON_ASSERT(false); return 0; }
75
76 private:
77 // Prohibit copy constructor & assignment operator.
78 FileWriteStream(const FileWriteStream&);
79 FileWriteStream& operator=(const FileWriteStream&);
80
81 std::FILE* fp_;
82 char *buffer_;
83 char *bufferEnd_;
84 char *current_;
85 };
86
87 //! Implement specialized version of PutN() with memset() for better performance.
88 template<>
PutN(FileWriteStream & stream,char c,size_t n)89 inline void PutN(FileWriteStream& stream, char c, size_t n) {
90 stream.PutN(c, n);
91 }
92
93 RAPIDJSON_NAMESPACE_END
94
95 #endif // RAPIDJSON_FILESTREAM_H_
96