minetest/src/serialization.cpp

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/*
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Minetest
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Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
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#include "serialization.h"
#include "util/serialize.h"
#ifdef _WIN32
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#define ZLIB_WINAPI
#endif
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#include "zlib.h"
/* report a zlib or i/o error */
void zerr(int ret)
{
dstream<<"zerr: ";
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switch (ret) {
case Z_ERRNO:
if (ferror(stdin))
dstream<<"error reading stdin"<<std::endl;
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if (ferror(stdout))
dstream<<"error writing stdout"<<std::endl;
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break;
case Z_STREAM_ERROR:
dstream<<"invalid compression level"<<std::endl;
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break;
case Z_DATA_ERROR:
dstream<<"invalid or incomplete deflate data"<<std::endl;
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break;
case Z_MEM_ERROR:
dstream<<"out of memory"<<std::endl;
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break;
case Z_VERSION_ERROR:
dstream<<"zlib version mismatch!"<<std::endl;
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break;
default:
dstream<<"return value = "<<ret<<std::endl;
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}
}
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void compressZlib(SharedBuffer<u8> data, std::ostream &os, int level)
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{
z_stream z;
const s32 bufsize = 16384;
char output_buffer[bufsize];
int status = 0;
int ret;
z.zalloc = Z_NULL;
z.zfree = Z_NULL;
z.opaque = Z_NULL;
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ret = deflateInit(&z, level);
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if(ret != Z_OK)
throw SerializationError("compressZlib: deflateInit failed");
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// Point zlib to our input buffer
z.next_in = (Bytef*)&data[0];
z.avail_in = data.getSize();
// And get all output
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for(;;)
{
z.next_out = (Bytef*)output_buffer;
z.avail_out = bufsize;
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status = deflate(&z, Z_FINISH);
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if(status == Z_NEED_DICT || status == Z_DATA_ERROR
|| status == Z_MEM_ERROR)
{
zerr(status);
throw SerializationError("compressZlib: deflate failed");
}
int count = bufsize - z.avail_out;
if(count)
os.write(output_buffer, count);
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// This determines zlib has given all output
if(status == Z_STREAM_END)
break;
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}
deflateEnd(&z);
}
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void compressZlib(const std::string &data, std::ostream &os, int level)
{
SharedBuffer<u8> databuf((u8*)data.c_str(), data.size());
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compressZlib(databuf, os, level);
}
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void decompressZlib(std::istream &is, std::ostream &os)
{
z_stream z;
const s32 bufsize = 16384;
char input_buffer[bufsize];
char output_buffer[bufsize];
int status = 0;
int ret;
int bytes_read = 0;
int input_buffer_len = 0;
z.zalloc = Z_NULL;
z.zfree = Z_NULL;
z.opaque = Z_NULL;
ret = inflateInit(&z);
if(ret != Z_OK)
throw SerializationError("dcompressZlib: inflateInit failed");
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z.avail_in = 0;
//dstream<<"initial fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
for(;;)
{
z.next_out = (Bytef*)output_buffer;
z.avail_out = bufsize;
if(z.avail_in == 0)
{
z.next_in = (Bytef*)input_buffer;
input_buffer_len = is.readsome(input_buffer, bufsize);
z.avail_in = input_buffer_len;
//dstream<<"read fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
}
if(z.avail_in == 0)
{
//dstream<<"z.avail_in == 0"<<std::endl;
break;
}
//dstream<<"1 z.avail_in="<<z.avail_in<<std::endl;
status = inflate(&z, Z_NO_FLUSH);
//dstream<<"2 z.avail_in="<<z.avail_in<<std::endl;
bytes_read += is.gcount() - z.avail_in;
//dstream<<"bytes_read="<<bytes_read<<std::endl;
if(status == Z_NEED_DICT || status == Z_DATA_ERROR
|| status == Z_MEM_ERROR)
{
zerr(status);
throw SerializationError("decompressZlib: inflate failed");
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}
int count = bufsize - z.avail_out;
//dstream<<"count="<<count<<std::endl;
if(count)
os.write(output_buffer, count);
if(status == Z_STREAM_END)
{
//dstream<<"Z_STREAM_END"<<std::endl;
//dstream<<"z.avail_in="<<z.avail_in<<std::endl;
//dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
// Unget all the data that inflate didn't take
for(u32 i=0; i < z.avail_in; i++)
{
is.unget();
if(is.fail() || is.bad())
{
dstream<<"unget #"<<i<<" failed"<<std::endl;
dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
throw SerializationError("decompressZlib: unget failed");
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}
}
break;
}
}
inflateEnd(&z);
}
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void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
{
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if(version >= 11)
{
compressZlib(data, os);
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return;
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}
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if(data.getSize() == 0)
return;
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// 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*)&current_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*)&current_byte, 1);
}
void decompress(std::istream &is, std::ostream &os, u8 version)
{
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if(version >= 11)
{
decompressZlib(is, os);
return;
}
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// 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;
}
}