src/serialization.cpp

   1 /*
   2 Minetest-c55
   3 Copyright (C) 2010 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 input_buffer[bufsize];
  61         char output_buffer[bufsize];
  62         int input_i = 0;
  63         int status = 0;
  64         int ret;
  65
  66         z.zalloc = Z_NULL;
  67         z.zfree = Z_NULL;
  68         z.opaque = Z_NULL;
  69
  70         ret = deflateInit(&z, -1);
  71         if(ret != Z_OK)
  72                 throw SerializationError("compressZlib: deflateInit failed");
  73
  74         z.avail_in = 0;
  75
  76         for(;;)
  77         {
  78                 int flush = Z_NO_FLUSH;
  79                 z.next_out = (Bytef*)output_buffer;
  80                 z.avail_out = bufsize;
  81
  82                 if(z.avail_in == 0)
  83                 {
  84                         //z.next_in = (char*)&data[input_i];
  85                         z.next_in = (Bytef*)&data[input_i];
  86                         z.avail_in = data.getSize() - input_i;
  87                         input_i += z.avail_in;
  88                         if(input_i == (int)data.getSize())
  89                                 flush = Z_FINISH;
  90                 }
  91                 if(z.avail_in == 0)
  92                         break;
  93                 status = deflate(&z, flush);
  94                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
  95                                 || status == Z_MEM_ERROR)
  96                 {
  97                         zerr(status);
  98                         throw SerializationError("compressZlib: deflate failed");
  99                 }
 100                 int count = bufsize - z.avail_out;
 101                 if(count)
 102                         os.write(output_buffer, count);
 103         }
 104
 105         deflateEnd(&z);
 106
 107 }
 108
 109 void compressZlib(const std::string &data, std::ostream &os)
 110 {
 111         SharedBuffer<u8> databuf((u8*)data.c_str(), data.size());
 112         compressZlib(databuf, os);
 113 }
 114
 115 void decompressZlib(std::istream &is, std::ostream &os)
 116 {
 117         z_stream z;
 118         const s32 bufsize = 16384;
 119         char input_buffer[bufsize];
 120         char output_buffer[bufsize];
 121         int status = 0;
 122         int ret;
 123         int bytes_read = 0;
 124         int input_buffer_len = 0;
 125
 126         z.zalloc = Z_NULL;
 127         z.zfree = Z_NULL;
 128         z.opaque = Z_NULL;
 129
 130         ret = inflateInit(&z);
 131         if(ret != Z_OK)
 132                 throw SerializationError("dcompressZlib: inflateInit failed");
 133
 134         z.avail_in = 0;
 135
 136         //dstream<<"initial fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 137
 138         for(;;)
 139         {
 140                 z.next_out = (Bytef*)output_buffer;
 141                 z.avail_out = bufsize;
 142
 143                 if(z.avail_in == 0)
 144                 {
 145                         z.next_in = (Bytef*)input_buffer;
 146                         input_buffer_len = is.readsome(input_buffer, bufsize);
 147                         z.avail_in = input_buffer_len;
 148                         //dstream<<"read fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 149                 }
 150                 if(z.avail_in == 0)
 151                 {
 152                         //dstream<<"z.avail_in == 0"<<std::endl;
 153                         break;
 154                 }
 155
 156                 //dstream<<"1 z.avail_in="<<z.avail_in<<std::endl;
 157                 status = inflate(&z, Z_NO_FLUSH);
 158                 //dstream<<"2 z.avail_in="<<z.avail_in<<std::endl;
 159                 bytes_read += is.gcount() - z.avail_in;
 160                 //dstream<<"bytes_read="<<bytes_read<<std::endl;
 161
 162                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
 163                                 || status == Z_MEM_ERROR)
 164                 {
 165                         zerr(status);
 166                         throw SerializationError("decompressZlib: inflate failed");
 167                 }
 168                 int count = bufsize - z.avail_out;
 169                 //dstream<<"count="<<count<<std::endl;
 170                 if(count)
 171                         os.write(output_buffer, count);
 172                 if(status == Z_STREAM_END)
 173                 {
 174                         //dstream<<"Z_STREAM_END"<<std::endl;
 175
 176                         //dstream<<"z.avail_in="<<z.avail_in<<std::endl;
 177                         //dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 178                         // Unget all the data that inflate didn't take
 179                         for(u32 i=0; i < z.avail_in; i++)
 180                         {
 181                                 is.unget();
 182                                 if(is.fail() || is.bad())
 183                                 {
 184                                         dstream<<"unget #"<<i<<" failed"<<std::endl;
 185                                         dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 186                                         throw SerializationError("decompressZlib: unget failed");
 187                                 }
 188                         }
 189
 190                         break;
 191                 }
 192         }
 193
 194         inflateEnd(&z);
 195 }
 196
 197 void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
 198 {
 199         if(version >= 11)
 200         {
 201                 compressZlib(data, os);
 202                 return;
 203         }
 204
 205         if(data.getSize() == 0)
 206                 return;
 207
 208         // Write length (u32)
 209
 210         u8 tmp[4];
 211         writeU32(tmp, data.getSize());
 212         os.write((char*)tmp, 4);
 213
 214         // We will be writing 8-bit pairs of more_count and byte
 215         u8 more_count = 0;
 216         u8 current_byte = data[0];
 217         for(u32 i=1; i<data.getSize(); i++)
 218         {
 219                 if(
 220                         data[i] != current_byte
 221                         || more_count == 255
 222                 )
 223                 {
 224                         // write count and byte
 225                         os.write((char*)&more_count, 1);
 226                         os.write((char*)&current_byte, 1);
 227                         more_count = 0;
 228                         current_byte = data[i];
 229                 }
 230                 else
 231                 {
 232                         more_count++;
 233                 }
 234         }
 235         // write count and byte
 236         os.write((char*)&more_count, 1);
 237         os.write((char*)&current_byte, 1);
 238 }
 239
 240 void decompress(std::istream &is, std::ostream &os, u8 version)
 241 {
 242         if(version >= 11)
 243         {
 244                 decompressZlib(is, os);
 245                 return;
 246         }
 247
 248         // Read length (u32)
 249
 250         u8 tmp[4];
 251         is.read((char*)tmp, 4);
 252         u32 len = readU32(tmp);
 253
 254         // We will be reading 8-bit pairs of more_count and byte
 255         u32 count = 0;
 256         for(;;)
 257         {
 258                 u8 more_count=0;
 259                 u8 byte=0;
 260
 261                 is.read((char*)&more_count, 1);
 262
 263                 is.read((char*)&byte, 1);
 264
 265                 if(is.eof())
 266                         throw SerializationError("decompress: stream ended halfway");
 267
 268                 for(s32 i=0; i<(u16)more_count+1; i++)
 269                         os.write((char*)&byte, 1);
 270
 271                 count += (u16)more_count+1;
 272
 273                 if(count == len)
 274                         break;
 275         }
 276 }
 277
 278