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97 lines
2.1 KiB
C++
97 lines
2.1 KiB
C++
#pragma once
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/*
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* CInputStream.h, part of VCMI engine
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*
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* Authors: listed in file AUTHORS in main folder
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*
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* License: GNU General Public License v2.0 or later
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* Full text of license available in license.txt file, in main folder
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*
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*/
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/**
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* Abstract class which provides method definitions for reading from a stream.
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*/
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class DLL_LINKAGE CInputStream : private boost::noncopyable
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{
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public:
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/**
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* D-tor.
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*/
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virtual ~CInputStream() {}
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/**
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* Reads n bytes from the stream into the data buffer.
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*
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* @param data A pointer to the destination data array.
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* @param size The number of bytes to read.
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* @return the number of bytes read actually.
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*/
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virtual si64 read(ui8 * data, si64 size) = 0;
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/**
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* Seeks the internal read pointer to the specified position.
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*
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* @param position The read position from the beginning.
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* @return the position actually moved to, -1 on error.
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*/
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virtual si64 seek(si64 position) = 0;
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/**
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* Gets the current read position in the stream.
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*
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* @return the read position.
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*/
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virtual si64 tell() = 0;
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/**
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* Skips delta numbers of bytes.
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*
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* @param delta The count of bytes to skip.
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* @return the count of bytes skipped actually.
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*/
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virtual si64 skip(si64 delta) = 0;
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/**
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* Gets the length in bytes of the stream.
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*
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* @return the length in bytes of the stream.
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*/
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virtual si64 getSize() = 0;
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/**
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* @brief for convenience, reads whole stream at once
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*
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* @return pair, first = raw data, second = size of data
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*/
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std::pair<std::unique_ptr<ui8[]>, si64> readAll()
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{
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std::unique_ptr<ui8[]> data(new ui8[getSize()]);
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seek(0);
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auto readSize = read(data.get(), getSize());
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assert(readSize == getSize());
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UNUSED(readSize);
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return std::make_pair(std::move(data), getSize());
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}
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/**
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* @brief calculateCRC32 calculates CRC32 checksum for the whole file
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* @return calculated checksum
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*/
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virtual ui32 calculateCRC32()
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{
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si64 originalPos = tell();
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boost::crc_32_type checksum;
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auto data = readAll();
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checksum.process_bytes(reinterpret_cast<const void *>(data.first.get()), data.second);
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seek(originalPos);
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return checksum.checksum();
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}
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};
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