lio-cpp/livox/common/rapidjson/stream.h

// Tencent is pleased to support the open source community by making RapidJSON
// available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All
// rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file
// except in compliance with the License. You may obtain a copy of the License
// at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

#include "rapidjson.h"

#ifndef RAPIDJSON_STREAM_H_
#define RAPIDJSON_STREAM_H_

#include "encodings.h"

RAPIDJSON_NAMESPACE_BEGIN

///////////////////////////////////////////////////////////////////////////////
//  Stream

/*! \class rapidjson::Stream
    \brief Concept for reading and writing characters.

    For read-only stream, no need to implement PutBegin(), Put(), Flush() and
PutEnd().

    For write-only stream, only need to implement Put() and Flush().

\code
concept Stream {
    typename Ch;    //!< Character type of the stream.

    //! Read the current character from stream without moving the read cursor.
    Ch Peek() const;

    //! Read the current character from stream and moving the read cursor to
next character. Ch Take();

    //! Get the current read cursor.
    //! \return Number of characters read from start.
    size_t Tell();

    //! Begin writing operation at the current read pointer.
    //! \return The begin writer pointer.
    Ch* PutBegin();

    //! Write a character.
    void Put(Ch c);

    //! Flush the buffer.
    void Flush();

    //! End the writing operation.
    //! \param begin The begin write pointer returned by PutBegin().
    //! \return Number of characters written.
    size_t PutEnd(Ch* begin);
}
\endcode
*/

//! Provides additional information for stream.
/*!
    By using traits pattern, this type provides a default configuration for
   stream. For custom stream, this type can be specialized for other
   configuration. See TEST(Reader, CustomStringStream) in readertest.cpp for
   example.
*/
template <typename Stream>
struct StreamTraits {
  //! Whether to make local copy of stream for optimization during parsing.
  /*!
      By default, for safety, streams do not use local copy optimization.
      Stream that can be copied fast should specialize this, like
     StreamTraits<StringStream>.
  */
  enum { copyOptimization = 0 };
};

//! Reserve n characters for writing to a stream.
template <typename Stream>
inline void PutReserve(Stream &stream, size_t count) {
  (void)stream;
  (void)count;
}

//! Write character to a stream, presuming buffer is reserved.
template <typename Stream>
inline void PutUnsafe(Stream &stream, typename Stream::Ch c) {
  stream.Put(c);
}

//! Put N copies of a character to a stream.
template <typename Stream, typename Ch>
inline void PutN(Stream &stream, Ch c, size_t n) {
  PutReserve(stream, n);
  for (size_t i = 0; i < n; i++) PutUnsafe(stream, c);
}

///////////////////////////////////////////////////////////////////////////////
// GenericStreamWrapper

//! A Stream Wrapper
/*! \tThis string stream is a wrapper for any stream by just forwarding any
    \treceived message to the origin stream.
    \note implements Stream concept
*/

#if defined(_MSC_VER) && _MSC_VER <= 1800
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(4702)  // unreachable code
RAPIDJSON_DIAG_OFF(4512)  // assignment operator could not be generated
#endif

template <typename InputStream, typename Encoding = UTF8<>>
class GenericStreamWrapper {
 public:
  typedef typename Encoding::Ch Ch;
  GenericStreamWrapper(InputStream &is) : is_(is) {}

  Ch Peek() const { return is_.Peek(); }
  Ch Take() { return is_.Take(); }
  size_t Tell() { return is_.Tell(); }
  Ch *PutBegin() { return is_.PutBegin(); }
  void Put(Ch ch) { is_.Put(ch); }
  void Flush() { is_.Flush(); }
  size_t PutEnd(Ch *ch) { return is_.PutEnd(ch); }

  // wrapper for MemoryStream
  const Ch *Peek4() const { return is_.Peek4(); }

  // wrapper for AutoUTFInputStream
  UTFType GetType() const { return is_.GetType(); }
  bool HasBOM() const { return is_.HasBOM(); }

 protected:
  InputStream &is_;
};

#if defined(_MSC_VER) && _MSC_VER <= 1800
RAPIDJSON_DIAG_POP
#endif

///////////////////////////////////////////////////////////////////////////////
// StringStream

//! Read-only string stream.
/*! \note implements Stream concept
 */
template <typename Encoding>
struct GenericStringStream {
  typedef typename Encoding::Ch Ch;

  GenericStringStream(const Ch *src) : src_(src), head_(src) {}

  Ch Peek() const { return *src_; }
  Ch Take() { return *src_++; }
  size_t Tell() const { return static_cast<size_t>(src_ - head_); }

  Ch *PutBegin() {
    RAPIDJSON_ASSERT(false);
    return 0;
  }
  void Put(Ch) { RAPIDJSON_ASSERT(false); }
  void Flush() { RAPIDJSON_ASSERT(false); }
  size_t PutEnd(Ch *) {
    RAPIDJSON_ASSERT(false);
    return 0;
  }

  const Ch *src_;   //!< Current read position.
  const Ch *head_;  //!< Original head of the string.
};

template <typename Encoding>
struct StreamTraits<GenericStringStream<Encoding>> {
  enum { copyOptimization = 1 };
};

//! String stream with UTF8 encoding.
typedef GenericStringStream<UTF8<>> StringStream;

///////////////////////////////////////////////////////////////////////////////
// InsituStringStream

//! A read-write string stream.
/*! This string stream is particularly designed for in-situ parsing.
    \note implements Stream concept
*/
template <typename Encoding>
struct GenericInsituStringStream {
  typedef typename Encoding::Ch Ch;

  GenericInsituStringStream(Ch *src) : src_(src), dst_(0), head_(src) {}

  // Read
  Ch Peek() { return *src_; }
  Ch Take() { return *src_++; }
  size_t Tell() { return static_cast<size_t>(src_ - head_); }

  // Write
  void Put(Ch c) {
    RAPIDJSON_ASSERT(dst_ != 0);
    *dst_++ = c;
  }

  Ch *PutBegin() { return dst_ = src_; }
  size_t PutEnd(Ch *begin) { return static_cast<size_t>(dst_ - begin); }
  void Flush() {}

  Ch *Push(size_t count) {
    Ch *begin = dst_;
    dst_ += count;
    return begin;
  }
  void Pop(size_t count) { dst_ -= count; }

  Ch *src_;
  Ch *dst_;
  Ch *head_;
};

template <typename Encoding>
struct StreamTraits<GenericInsituStringStream<Encoding>> {
  enum { copyOptimization = 1 };
};

//! Insitu string stream with UTF8 encoding.
typedef GenericInsituStringStream<UTF8<>> InsituStringStream;

RAPIDJSON_NAMESPACE_END

#endif  // RAPIDJSON_STREAM_H_