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#pragma once
#include "endian.hpp"
#include "types.hpp"
#include "../utils.hpp"
#include <cstring>
#include <stdexcept>
namespace sibs
{
class DeserializeException : public std::runtime_error
{
public:
DeserializeException(const std::string &errMsg) : std::runtime_error(errMsg) {}
};
/**
* Endian independent deserializer
*/
class SafeDeserializer
{
public:
SafeDeserializer(const u8 *_data, usize _size) :
data(_data),
size(_size)
{
}
/*
* Throws DeserializeException on failure
*/
template <typename T>
T extract()
{
constexpr usize typeSize = sizeof(T);
verifyExtractSize(typeSize);
size -= typeSize;
T result;
#if BYTE_ORDER == BIG_ENDIAN
switch(typeSize)
{
case 1:
result = *(T*)data;
break;
case 2:
*(u16*)&result = byteswap(*(u16*)data);
break;
case 4:
*(u32*)&result = byteswap(*(u32*)data);
break;
case 8:
*(u64*)&result = byteswap(*(u64*)data);
break;
default:
{
for(int i = 0; i < typeSize; ++i)
{
((char*)&result)[i] = data[typeSize - 1 - i];
}
break;
}
}
#else
result = *(T*)data;
#endif
data += typeSize;
return result;
}
/*
* Throws DeserializeException on failure
*/
void extract(u8 *destination, usize destinationSize)
{
if(destinationSize > 0)
{
verifyExtractSize(destinationSize);
size -= destinationSize;
memcpy(destination, data, destinationSize);
data += destinationSize;
}
}
bool empty() const
{
return size == 0;
}
const u8* getBuffer()
{
return data;
}
usize getSize() const
{
return size;
}
void skip(usize bytesToSkip)
{
bytesToSkip = bytesToSkip < size ? bytesToSkip : size;
size -= bytesToSkip;
data += bytesToSkip;
}
private:
void verifyExtractSize(usize typeSize) const
{
if(typeSize > size)
{
std::string errMsg = "Unable to extract ";
errMsg += std::to_string(typeSize);
errMsg += " bytes, only ";
errMsg += std::to_string(size);
errMsg += " bytes left in buffer";
throw DeserializeException(errMsg);
}
}
private:
const u8 *data;
usize size;
};
}
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