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/*
(c) 2010 Perttu Ahola <celeron55@gmail.com>
*/
#include "serialization.h"
#include "utility.h"
void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
{
if(data.getSize() == 0)
return;
// Write length (u32)
u8 tmp[4];
writeU32(tmp, data.getSize());
os.write((char*)tmp, 4);
// We will be writing 8-bit pairs of more_count and byte
u8 more_count = 0;
u8 current_byte = data[0];
for(u32 i=1; i<data.getSize(); i++)
{
if(
data[i] != current_byte
|| more_count == 255
)
{
// write count and byte
os.write((char*)&more_count, 1);
os.write((char*)¤t_byte, 1);
more_count = 0;
current_byte = data[i];
}
else
{
more_count++;
}
}
// write count and byte
os.write((char*)&more_count, 1);
os.write((char*)¤t_byte, 1);
}
void decompress(std::istream &is, std::ostream &os, u8 version)
{
// Read length (u32)
u8 tmp[4];
is.read((char*)tmp, 4);
u32 len = readU32(tmp);
// We will be reading 8-bit pairs of more_count and byte
u32 count = 0;
for(;;)
{
u8 more_count=0;
u8 byte=0;
is.read((char*)&more_count, 1);
is.read((char*)&byte, 1);
if(is.eof())
throw SerializationError("decompress: stream ended halfway");
for(s32 i=0; i<(u16)more_count+1; i++)
os.write((char*)&byte, 1);
count += (u16)more_count+1;
if(count == len)
break;
}
}
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