StreamWriter.h

/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
---------------------------------------------------------------------------
 
Copyright (c) 2006-2020, assimp team
 
 
 
All rights reserved.
 
Redistribution and use of this software in source and binary forms,
with or without modification, are permitted provided that the following
conditions are met:
 
* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.
 
* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
  materials provided with the distribution.
 
* Neither the name of the assimp team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the assimp team.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
 
#pragma once
#ifndef AI_STREAMWRITER_H_INCLUDED
#define AI_STREAMWRITER_H_INCLUDED
 
#ifdef __GNUC__
#   pragma GCC system_header
#endif
 
#include <assimp/ByteSwapper.h>
#include <assimp/IOStream.hpp>
 
#include <memory>
#include <vector>
 
namespace Assimp {
 
// --------------------------------------------------------------------------------------------
// --------------------------------------------------------------------------------------------
template <bool SwapEndianess = false, bool RuntimeSwitch = false>
class StreamWriter
{
    enum {
        INITIAL_CAPACITY = 1024
    };
 
public:
 
    // ---------------------------------------------------------------------
    StreamWriter(std::shared_ptr<IOStream> stream, bool le = false)
        : stream(stream)
        , le(le)
        , cursor()
    {
        ai_assert(stream);
        buffer.reserve(INITIAL_CAPACITY);
    }
 
    // ---------------------------------------------------------------------
    StreamWriter(IOStream* stream, bool le = false)
        : stream(std::shared_ptr<IOStream>(stream))
        , le(le)
        , cursor()
    {
        ai_assert(stream);
        buffer.reserve(INITIAL_CAPACITY);
    }
 
    // ---------------------------------------------------------------------
    ~StreamWriter() {
        stream->Write(buffer.data(), 1, buffer.size());
        stream->Flush();
    }
 
public:
 
    // ---------------------------------------------------------------------
    void Flush()
    {
        stream->Write(buffer.data(), 1, buffer.size());
        stream->Flush();
        buffer.clear();
        cursor = 0;
    }
 
    // ---------------------------------------------------------------------
    aiReturn Seek(size_t pOffset, aiOrigin pOrigin=aiOrigin_SET)
    {
        Flush();
        return stream->Seek(pOffset, pOrigin);
    }
 
    // ---------------------------------------------------------------------
    size_t Tell()
    {
        Flush();
        return stream->Tell();
    }
 
public:
 
    // ---------------------------------------------------------------------
    void PutF4(float f)
    {
        Put(f);
    }
 
    // ---------------------------------------------------------------------
    void PutF8(double d)    {
        Put(d);
    }
 
    // ---------------------------------------------------------------------
    void PutI2(int16_t n)   {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutI1(int8_t n)    {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutI4(int32_t n)   {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutI8(int64_t n)   {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutU2(uint16_t n)  {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutU1(uint8_t n)   {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutU4(uint32_t n)  {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutU8(uint64_t n)  {
        Put(n);
    }
 
    // ---------------------------------------------------------------------
    void PutChar(char c)    {
        Put(c);
    }
 
    // ---------------------------------------------------------------------
    void PutString(const aiString& s)
    {
        // as Put(T f) below
        if (cursor + s.length >= buffer.size()) {
            buffer.resize(cursor + s.length);
        }
        void* dest = &buffer[cursor];
        ::memcpy(dest, s.C_Str(), s.length);
        cursor += s.length;
    }
 
    // ---------------------------------------------------------------------
    void PutString(const std::string& s)
    {
        // as Put(T f) below
        if (cursor + s.size() >= buffer.size()) {
            buffer.resize(cursor + s.size());
        }
        void* dest = &buffer[cursor];
        ::memcpy(dest, s.c_str(), s.size());
        cursor += s.size();
    }
 
public:
 
    // ---------------------------------------------------------------------
    template <typename T>
    StreamWriter& operator << (T f) {
        Put(f);
        return *this;
    }
 
    // ---------------------------------------------------------------------
    std::size_t GetCurrentPos() const {
        return cursor;
    }
 
    // ---------------------------------------------------------------------
    void SetCurrentPos(std::size_t new_cursor) {
        cursor = new_cursor;
    }
 
    // ---------------------------------------------------------------------
    template <typename T>
    void Put(T f)   {
        Intern :: Getter<SwapEndianess,T,RuntimeSwitch>() (&f, le);
 
        if (cursor + sizeof(T) >= buffer.size()) {
            buffer.resize(cursor + sizeof(T));
        }
 
        void* dest = &buffer[cursor];
 
        // reinterpret_cast + assignment breaks strict aliasing rules
        // and generally causes trouble on platforms such as ARM that
        // do not silently ignore alignment faults.
        ::memcpy(dest, &f, sizeof(T));
        cursor += sizeof(T);
    }
 
private:
 
    std::shared_ptr<IOStream> stream;
    bool le;
 
    std::vector<uint8_t> buffer;
    std::size_t cursor;
};
 
 
// --------------------------------------------------------------------------------------------
// `static` StreamWriter. Their byte order is fixed and they might be a little bit faster.
#ifdef AI_BUILD_BIG_ENDIAN
    typedef StreamWriter<true>  StreamWriterLE;
    typedef StreamWriter<false> StreamWriterBE;
#else
    typedef StreamWriter<true>  StreamWriterBE;
    typedef StreamWriter<false> StreamWriterLE;
#endif
 
// `dynamic` StreamWriter. The byte order of the input data is specified in the
// c'tor. This involves runtime branching and might be a little bit slower.
typedef StreamWriter<true,true> StreamWriterAny;
 
} // end namespace Assimp
 
#endif // !! AI_STREAMWriter_H_INCLUDED