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_STRINGBUFFER_H_
 16#define RAPIDJSON_STRINGBUFFER_H_
 17
 18#include "stream.h"
 19#include "internal/stack.h"
 20
 21#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
 22#include <utility> // std::move
 23#endif
 24
 25#include "internal/stack.h"
 26
 27#if defined(__clang__)
 28RAPIDJSON_DIAG_PUSH
 29RAPIDJSON_DIAG_OFF(c++98-compat)
 30#endif
 31
 32RAPIDJSON_NAMESPACE_BEGIN
 33
 34//! Represents an in-memory output stream.
 35/*!
 36    \tparam Encoding Encoding of the stream.
 37    \tparam Allocator type for allocating memory buffer.
 38    \note implements Stream concept
 39*/
 40template <typename Encoding, typename Allocator = CrtAllocator>
 41class GenericStringBuffer {
 42public:
 43    typedef typename Encoding::Ch Ch;
 44
 45    GenericStringBuffer(Allocator* allocator = 0, size_t capacity = kDefaultCapacity) : stack_(allocator, capacity) {}
 46
 47#if RAPIDJSON_HAS_CXX11_RVALUE_REFS
 48    GenericStringBuffer(GenericStringBuffer&& rhs) : stack_(std::move(rhs.stack_)) {}
 49    GenericStringBuffer& operator=(GenericStringBuffer&& rhs) {
 50        if (&rhs != this)
 51            stack_ = std::move(rhs.stack_);
 52        return *this;
 53    }
 54#endif
 55
 56    void Put(Ch c) { *stack_.template Push<Ch>() = c; }
 57    void PutUnsafe(Ch c) { *stack_.template PushUnsafe<Ch>() = c; }
 58    void Flush() {}
 59
 60    void Clear() { stack_.Clear(); }
 61    void ShrinkToFit() {
 62        // Push and pop a null terminator. This is safe.
 63        *stack_.template Push<Ch>() = '\0';
 64        stack_.ShrinkToFit();
 65        stack_.template Pop<Ch>(1);
 66    }
 67
 68    void Reserve(size_t count) { stack_.template Reserve<Ch>(count); }
 69    Ch* Push(size_t count) { return stack_.template Push<Ch>(count); }
 70    Ch* PushUnsafe(size_t count) { return stack_.template PushUnsafe<Ch>(count); }
 71    void Pop(size_t count) { stack_.template Pop<Ch>(count); }
 72
 73    const Ch* GetString() const {
 74        // Push and pop a null terminator. This is safe.
 75        *stack_.template Push<Ch>() = '\0';
 76        stack_.template Pop<Ch>(1);
 77
 78        return stack_.template Bottom<Ch>();
 79    }
 80
 81    size_t GetSize() const { return stack_.GetSize(); }
 82
 83    static const size_t kDefaultCapacity = 256;
 84    mutable internal::Stack<Allocator> stack_;
 85
 86private:
 87    // Prohibit copy constructor & assignment operator.
 88    GenericStringBuffer(const GenericStringBuffer&);
 89    GenericStringBuffer& operator=(const GenericStringBuffer&);
 90};
 91
 92//! String buffer with UTF8 encoding
 93typedef GenericStringBuffer<UTF8<> > StringBuffer;
 94
 95template<typename Encoding, typename Allocator>
 96inline void PutReserve(GenericStringBuffer<Encoding, Allocator>& stream, size_t count) {
 97    stream.Reserve(count);
 98}
 99
100template<typename Encoding, typename Allocator>
101inline void PutUnsafe(GenericStringBuffer<Encoding, Allocator>& stream, typename Encoding::Ch c) {
102    stream.PutUnsafe(c);
103}
104
105//! Implement specialized version of PutN() with memset() for better performance.
106template<>
107inline void PutN(GenericStringBuffer<UTF8<> >& stream, char c, size_t n) {
108    std::memset(stream.stack_.Push<char>(n), c, n * sizeof(c));
109}
110
111RAPIDJSON_NAMESPACE_END
112
113#if defined(__clang__)
114RAPIDJSON_DIAG_POP
115#endif
116
117#endif // RAPIDJSON_STRINGBUFFER_H_