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/*
* CInputStream.h, part of VCMI engine
*
* Authors: listed in file AUTHORS in main folder
*
* License: GNU General Public License v2.0 or later
* Full text of license available in license.txt file, in main folder
*
*/
#pragma once
#include "CStream.h"
VCMI_LIB_NAMESPACE_BEGIN
/**
* Abstract class which provides method definitions for reading from a stream.
*/
class DLL_LINKAGE CInputStream : public virtual CStream
{
public:
/**
* Reads n bytes from the stream into the data buffer.
*
* @param data A pointer to the destination data array.
* @param size The number of bytes to read.
* @return the number of bytes read actually.
*/
virtual si64 read(ui8 * data, si64 size) = 0;
/**
* @brief for convenience, reads whole stream at once
*
* @return pair, first = raw data, second = size of data
*/
std::pair<std::unique_ptr<ui8[]>, si64> readAll()
{
std::unique_ptr<ui8[]> data(new ui8[getSize()]);
seek(0);
[[maybe_unused]] auto readSize = read(data.get(), getSize());
assert(readSize == getSize());
return std::make_pair(std::move(data), getSize());
}
/**
* @brief calculateCRC32 calculates CRC32 checksum for the whole file
* @return calculated checksum
*/
virtual ui32 calculateCRC32()
{
si64 originalPos = tell();
boost::crc_32_type checksum;
auto data = readAll();
checksum.process_bytes(reinterpret_cast<const void *>(data.first.get()), data.second);
seek(originalPos);
return checksum.checksum();
}
};
VCMI_LIB_NAMESPACE_END
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