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52 lines
1.4 KiB
C++
52 lines
1.4 KiB
C++
#ifndef OPENMW_COMPONENTS_FILES_MEMORYSTREAM_H
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#define OPENMW_COMPONENTS_FILES_MEMORYSTREAM_H
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#include <istream>
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namespace Files
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{
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struct MemBuf : std::streambuf
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{
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MemBuf(char const* buffer, size_t size)
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// a streambuf isn't specific to istreams, so we need a non-const pointer :/
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: bufferStart(const_cast<char*>(buffer))
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, bufferEnd(bufferStart + size)
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{
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this->setg(bufferStart, bufferStart, bufferEnd);
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}
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pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode which) override
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{
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if (dir == std::ios_base::cur)
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gbump(off);
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else
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setg(bufferStart, (dir == std::ios_base::beg ? bufferStart : bufferEnd) + off, bufferEnd);
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return gptr() - bufferStart;
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}
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pos_type seekpos(pos_type pos, std::ios_base::openmode which) override
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{
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return seekoff(pos, std::ios_base::beg, which);
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}
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protected:
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char* bufferStart;
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char* bufferEnd;
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};
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/// @brief A variant of std::istream that reads from a constant in-memory buffer.
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struct IMemStream : virtual MemBuf, std::istream
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{
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IMemStream(char const* buffer, size_t size)
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: MemBuf(buffer, size)
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, std::istream(static_cast<std::streambuf*>(this))
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{
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}
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};
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}
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#endif
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