src/serialization.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "serialization.h"
  21
  22 #include "util/serialize.h"
  23 #ifdef _WIN32
  24         #define ZLIB_WINAPI
  25 #endif
  26 #include "zlib.h"
  27
  28 /* report a zlib or i/o error */
  29 void zerr(int ret)
  30 {
  31     dstream<<"zerr: ";
  32     switch (ret) {
  33     case Z_ERRNO:
  34         if (ferror(stdin))
  35             dstream<<"error reading stdin"<<std::endl;
  36         if (ferror(stdout))
  37             dstream<<"error writing stdout"<<std::endl;
  38         break;
  39     case Z_STREAM_ERROR:
  40         dstream<<"invalid compression level"<<std::endl;
  41         break;
  42     case Z_DATA_ERROR:
  43         dstream<<"invalid or incomplete deflate data"<<std::endl;
  44         break;
  45     case Z_MEM_ERROR:
  46         dstream<<"out of memory"<<std::endl;
  47         break;
  48     case Z_VERSION_ERROR:
  49         dstream<<"zlib version mismatch!"<<std::endl;
  50                 break;
  51         default:
  52                 dstream<<"return value = "<<ret<<std::endl;
  53     }
  54 }
  55
  56 void compressZlib(SharedBuffer<u8> data, std::ostream &os, int level)
  57 {
  58         z_stream z;
  59         const s32 bufsize = 16384;
  60         char output_buffer[bufsize];
  61         int status = 0;
  62         int ret;
  63
  64         z.zalloc = Z_NULL;
  65         z.zfree = Z_NULL;
  66         z.opaque = Z_NULL;
  67
  68         ret = deflateInit(&z, level);
  69         if(ret != Z_OK)
  70                 throw SerializationError("compressZlib: deflateInit failed");
  71
  72         // Point zlib to our input buffer
  73         z.next_in = (Bytef*)&data[0];
  74         z.avail_in = data.getSize();
  75         // And get all output
  76         for(;;)
  77         {
  78                 z.next_out = (Bytef*)output_buffer;
  79                 z.avail_out = bufsize;
  80
  81                 status = deflate(&z, Z_FINISH);
  82                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
  83                                 || status == Z_MEM_ERROR)
  84                 {
  85                         zerr(status);
  86                         throw SerializationError("compressZlib: deflate failed");
  87                 }
  88                 int count = bufsize - z.avail_out;
  89                 if(count)
  90                         os.write(output_buffer, count);
  91                 // This determines zlib has given all output
  92                 if(status == Z_STREAM_END)
  93                         break;
  94         }
  95
  96         deflateEnd(&z);
  97 }
  98
  99 void compressZlib(const std::string &data, std::ostream &os, int level)
 100 {
 101         SharedBuffer<u8> databuf((u8*)data.c_str(), data.size());
 102         compressZlib(databuf, os, level);
 103 }
 104
 105 void decompressZlib(std::istream &is, std::ostream &os)
 106 {
 107         z_stream z;
 108         const s32 bufsize = 16384;
 109         char input_buffer[bufsize];
 110         char output_buffer[bufsize];
 111         int status = 0;
 112         int ret;
 113         int bytes_read = 0;
 114         int input_buffer_len = 0;
 115
 116         z.zalloc = Z_NULL;
 117         z.zfree = Z_NULL;
 118         z.opaque = Z_NULL;
 119
 120         ret = inflateInit(&z);
 121         if(ret != Z_OK)
 122                 throw SerializationError("dcompressZlib: inflateInit failed");
 123
 124         z.avail_in = 0;
 125
 126         //dstream<<"initial fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 127
 128         for(;;)
 129         {
 130                 z.next_out = (Bytef*)output_buffer;
 131                 z.avail_out = bufsize;
 132
 133                 if(z.avail_in == 0)
 134                 {
 135                         z.next_in = (Bytef*)input_buffer;
 136                         is.read(input_buffer, bufsize);
 137                         input_buffer_len = is.gcount();
 138                         z.avail_in = input_buffer_len;
 139                         //dstream<<"read fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 140                 }
 141                 if(z.avail_in == 0)
 142                 {
 143                         //dstream<<"z.avail_in == 0"<<std::endl;
 144                         break;
 145                 }
 146
 147                 //dstream<<"1 z.avail_in="<<z.avail_in<<std::endl;
 148                 status = inflate(&z, Z_NO_FLUSH);
 149                 //dstream<<"2 z.avail_in="<<z.avail_in<<std::endl;
 150                 bytes_read += is.gcount() - z.avail_in;
 151                 //dstream<<"bytes_read="<<bytes_read<<std::endl;
 152
 153                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
 154                                 || status == Z_MEM_ERROR)
 155                 {
 156                         zerr(status);
 157                         throw SerializationError("decompressZlib: inflate failed");
 158                 }
 159                 int count = bufsize - z.avail_out;
 160                 //dstream<<"count="<<count<<std::endl;
 161                 if(count)
 162                         os.write(output_buffer, count);
 163                 if(status == Z_STREAM_END)
 164                 {
 165                         //dstream<<"Z_STREAM_END"<<std::endl;
 166
 167                         //dstream<<"z.avail_in="<<z.avail_in<<std::endl;
 168                         //dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 169                         // Unget all the data that inflate didn't take
 170                         is.clear(); // Just in case EOF is set
 171                         for(u32 i=0; i < z.avail_in; i++)
 172                         {
 173                                 is.unget();
 174                                 if(is.fail() || is.bad())
 175                                 {
 176                                         dstream<<"unget #"<<i<<" failed"<<std::endl;
 177                                         dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 178                                         throw SerializationError("decompressZlib: unget failed");
 179                                 }
 180                         }
 181
 182                         break;
 183                 }
 184         }
 185
 186         inflateEnd(&z);
 187 }
 188
 189 void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
 190 {
 191         if(version >= 11)
 192         {
 193                 compressZlib(data, os);
 194                 return;
 195         }
 196
 197         if(data.getSize() == 0)
 198                 return;
 199
 200         // Write length (u32)
 201
 202         u8 tmp[4];
 203         writeU32(tmp, data.getSize());
 204         os.write((char*)tmp, 4);
 205
 206         // We will be writing 8-bit pairs of more_count and byte
 207         u8 more_count = 0;
 208         u8 current_byte = data[0];
 209         for(u32 i=1; i<data.getSize(); i++)
 210         {
 211                 if(
 212                         data[i] != current_byte
 213                         || more_count == 255
 214                 )
 215                 {
 216                         // write count and byte
 217                         os.write((char*)&more_count, 1);
 218                         os.write((char*)&current_byte, 1);
 219                         more_count = 0;
 220                         current_byte = data[i];
 221                 }
 222                 else
 223                 {
 224                         more_count++;
 225                 }
 226         }
 227         // write count and byte
 228         os.write((char*)&more_count, 1);
 229         os.write((char*)&current_byte, 1);
 230 }
 231
 232 void decompress(std::istream &is, std::ostream &os, u8 version)
 233 {
 234         if(version >= 11)
 235         {
 236                 decompressZlib(is, os);
 237                 return;
 238         }
 239
 240         // Read length (u32)
 241
 242         u8 tmp[4];
 243         is.read((char*)tmp, 4);
 244         u32 len = readU32(tmp);
 245
 246         // We will be reading 8-bit pairs of more_count and byte
 247         u32 count = 0;
 248         for(;;)
 249         {
 250                 u8 more_count=0;
 251                 u8 byte=0;
 252
 253                 is.read((char*)&more_count, 1);
 254
 255                 is.read((char*)&byte, 1);
 256
 257                 if(is.eof())
 258                         throw SerializationError("decompress: stream ended halfway");
 259
 260                 for(s32 i=0; i<(u16)more_count+1; i++)
 261                         os.write((char*)&byte, 1);
 262
 263                 count += (u16)more_count+1;
 264
 265                 if(count == len)
 266                         break;
 267         }
 268 }
 269
 270