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)
  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, -1);
  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
 100 void compressZlib(const std::string &data, std::ostream &os)
 101 {
 102         SharedBuffer<u8> databuf((u8*)data.c_str(), data.size());
 103         compressZlib(databuf, os);
 104 }
 105
 106 void decompressZlib(std::istream &is, std::ostream &os)
 107 {
 108         z_stream z;
 109         const s32 bufsize = 16384;
 110         char input_buffer[bufsize];
 111         char output_buffer[bufsize];
 112         int status = 0;
 113         int ret;
 114         int bytes_read = 0;
 115         int input_buffer_len = 0;
 116
 117         z.zalloc = Z_NULL;
 118         z.zfree = Z_NULL;
 119         z.opaque = Z_NULL;
 120
 121         ret = inflateInit(&z);
 122         if(ret != Z_OK)
 123                 throw SerializationError("dcompressZlib: inflateInit failed");
 124
 125         z.avail_in = 0;
 126
 127         //dstream<<"initial fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 128
 129         for(;;)
 130         {
 131                 z.next_out = (Bytef*)output_buffer;
 132                 z.avail_out = bufsize;
 133
 134                 if(z.avail_in == 0)
 135                 {
 136                         z.next_in = (Bytef*)input_buffer;
 137                         input_buffer_len = is.readsome(input_buffer, bufsize);
 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                         for(u32 i=0; i < z.avail_in; i++)
 171                         {
 172                                 is.unget();
 173                                 if(is.fail() || is.bad())
 174                                 {
 175                                         dstream<<"unget #"<<i<<" failed"<<std::endl;
 176                                         dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 177                                         throw SerializationError("decompressZlib: unget failed");
 178                                 }
 179                         }
 180
 181                         break;
 182                 }
 183         }
 184
 185         inflateEnd(&z);
 186 }
 187
 188 void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
 189 {
 190         if(version >= 11)
 191         {
 192                 compressZlib(data, os);
 193                 return;
 194         }
 195
 196         if(data.getSize() == 0)
 197                 return;
 198
 199         // Write length (u32)
 200
 201         u8 tmp[4];
 202         writeU32(tmp, data.getSize());
 203         os.write((char*)tmp, 4);
 204
 205         // We will be writing 8-bit pairs of more_count and byte
 206         u8 more_count = 0;
 207         u8 current_byte = data[0];
 208         for(u32 i=1; i<data.getSize(); i++)
 209         {
 210                 if(
 211                         data[i] != current_byte
 212                         || more_count == 255
 213                 )
 214                 {
 215                         // write count and byte
 216                         os.write((char*)&more_count, 1);
 217                         os.write((char*)&current_byte, 1);
 218                         more_count = 0;
 219                         current_byte = data[i];
 220                 }
 221                 else
 222                 {
 223                         more_count++;
 224                 }
 225         }
 226         // write count and byte
 227         os.write((char*)&more_count, 1);
 228         os.write((char*)&current_byte, 1);
 229 }
 230
 231 void decompress(std::istream &is, std::ostream &os, u8 version)
 232 {
 233         if(version >= 11)
 234         {
 235                 decompressZlib(is, os);
 236                 return;
 237         }
 238
 239         // Read length (u32)
 240
 241         u8 tmp[4];
 242         is.read((char*)tmp, 4);
 243         u32 len = readU32(tmp);
 244
 245         // We will be reading 8-bit pairs of more_count and byte
 246         u32 count = 0;
 247         for(;;)
 248         {
 249                 u8 more_count=0;
 250                 u8 byte=0;
 251
 252                 is.read((char*)&more_count, 1);
 253
 254                 is.read((char*)&byte, 1);
 255
 256                 if(is.eof())
 257                         throw SerializationError("decompress: stream ended halfway");
 258
 259                 for(s32 i=0; i<(u16)more_count+1; i++)
 260                         os.write((char*)&byte, 1);
 261
 262                 count += (u16)more_count+1;
 263
 264                 if(count == len)
 265                         break;
 266         }
 267 }
 268
 269