/* --------------------------------------------------------------------------- Open Asset Import Library (assimp) --------------------------------------------------------------------------- Copyright (c) 2006-2022, 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. --------------------------------------------------------------------------- */ /** @file Defines the StreamWriter class which writes data to * a binary stream with a well-defined endianness. */ #pragma once #ifndef AI_STREAMWRITER_H_INCLUDED #define AI_STREAMWRITER_H_INCLUDED #ifdef __GNUC__ # pragma GCC system_header #endif #include #include #include #include namespace Assimp { // -------------------------------------------------------------------------------------------- /** Wrapper class around IOStream to allow for consistent writing of binary data in both * little and big endian format. Don't attempt to instance the template directly. Use * StreamWriterLE to write to a little-endian stream and StreamWriterBE to write to a * BE stream. Alternatively, there is StreamWriterAny if the endianness of the output * stream is to be determined at runtime. */ // -------------------------------------------------------------------------------------------- template class StreamWriter { enum { INITIAL_CAPACITY = 1024 }; public: // --------------------------------------------------------------------- /** Construction from a given stream with a well-defined endianness. * * The StreamReader holds a permanent strong reference to the * stream, which is released upon destruction. * @param stream Input stream. The stream is not re-seeked and writing continues at the current position of the stream cursor. * @param le If @c RuntimeSwitch is true: specifies whether the * stream is in little endian byte order. Otherwise the * endianness information is defined by the @c SwapEndianess * template parameter and this parameter is meaningless. */ StreamWriter(std::shared_ptr 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(stream)) , le(le) , cursor() { ai_assert(stream); buffer.reserve(INITIAL_CAPACITY); } // --------------------------------------------------------------------- ~StreamWriter() { stream->Write(buffer.data(), 1, buffer.size()); stream->Flush(); } public: // --------------------------------------------------------------------- /** Flush the contents of the internal buffer, and the output IOStream */ void Flush() { stream->Write(buffer.data(), 1, buffer.size()); stream->Flush(); buffer.clear(); cursor = 0; } // --------------------------------------------------------------------- /** Seek to the given offset / origin in the output IOStream. * * Flushes the internal buffer and the output IOStream prior to seeking. */ aiReturn Seek(size_t pOffset, aiOrigin pOrigin=aiOrigin_SET) { Flush(); return stream->Seek(pOffset, pOrigin); } // --------------------------------------------------------------------- /** Tell the current position in the output IOStream. * * First flushes the internal buffer and the output IOStream. */ size_t Tell() { Flush(); return stream->Tell(); } public: // --------------------------------------------------------------------- /** Write a float to the stream */ void PutF4(float f) { Put(f); } // --------------------------------------------------------------------- /** Write a double to the stream */ void PutF8(double d) { Put(d); } // --------------------------------------------------------------------- /** Write a signed 16 bit integer to the stream */ void PutI2(int16_t n) { Put(n); } // --------------------------------------------------------------------- /** Write a signed 8 bit integer to the stream */ void PutI1(int8_t n) { Put(n); } // --------------------------------------------------------------------- /** Write an signed 32 bit integer to the stream */ void PutI4(int32_t n) { Put(n); } // --------------------------------------------------------------------- /** Write a signed 64 bit integer to the stream */ void PutI8(int64_t n) { Put(n); } // --------------------------------------------------------------------- /** Write a unsigned 16 bit integer to the stream */ void PutU2(uint16_t n) { Put(n); } // --------------------------------------------------------------------- /** Write a unsigned 8 bit integer to the stream */ void PutU1(uint8_t n) { Put(n); } // --------------------------------------------------------------------- /** Write an unsigned 32 bit integer to the stream */ void PutU4(uint32_t n) { Put(n); } // --------------------------------------------------------------------- /** Write a unsigned 64 bit integer to the stream */ void PutU8(uint64_t n) { Put(n); } // --------------------------------------------------------------------- /** Write a single character to the stream */ void PutChar(char c) { Put(c); } // --------------------------------------------------------------------- /** Write an aiString to the stream */ 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; } // --------------------------------------------------------------------- /** Write a std::string to the stream */ 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: // --------------------------------------------------------------------- /** overload operator<< and allow chaining of MM ops. */ template 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; } // --------------------------------------------------------------------- /** Generic write method. ByteSwap::Swap(T*) *must* be defined */ template void Put(T f) { Intern :: Getter() (&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 stream; bool le; std::vector 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 StreamWriterLE; typedef StreamWriter StreamWriterBE; #else typedef StreamWriter StreamWriterBE; typedef StreamWriter 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 StreamWriterAny; } // end namespace Assimp #endif // !! AI_STREAMWriter_H_INCLUDED