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
21RAPIDJSON_NAMESPACE_BEGIN
22
23//! Wrapper of C file stream for input using fread().
24/*!
25    \note implements Stream concept
26*/
27class FileWriteStream {
28public:
29    typedef char Ch;    //!< Character type. Only support char.
30
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
35    void Put(char c) {
36        if (current_ >= bufferEnd_)
37            Flush();
38
39        *current_++ = c;
40    }
41
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
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
70    char Peek() const { RAPIDJSON_ASSERT(false); return 0; }
71    char Take() { RAPIDJSON_ASSERT(false); return 0; }
72    size_t Tell() const { RAPIDJSON_ASSERT(false); return 0; }
73    char* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
74    size_t PutEnd(char*) { RAPIDJSON_ASSERT(false); return 0; }
75
76private:
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.
88template<>
89inline void PutN(FileWriteStream& stream, char c, size_t n) {
90    stream.PutN(c, n);
91}
92
93RAPIDJSON_NAMESPACE_END
94
95#endif // RAPIDJSON_FILESTREAM_H_
96