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 General Public License as published by
   7 the Free Software Foundation; either version 2 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 General Public License for more details.
  14
  15 You should have received a copy of the GNU 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 #include "utility.h"
  22 #ifdef _WIN32
  23         #define ZLIB_WINAPI
  24 #endif
  25 #include "zlib.h"
  26
  27 /* report a zlib or i/o error */
  28 void zerr(int ret)
  29 {
  30     dstream<<"zerr: ";
  31     switch (ret) {
  32     case Z_ERRNO:
  33         if (ferror(stdin))
  34             dstream<<"error reading stdin"<<std::endl;
  35         if (ferror(stdout))
  36             dstream<<"error writing stdout"<<std::endl;
  37         break;
  38     case Z_STREAM_ERROR:
  39         dstream<<"invalid compression level"<<std::endl;
  40         break;
  41     case Z_DATA_ERROR:
  42         dstream<<"invalid or incomplete deflate data"<<std::endl;
  43         break;
  44     case Z_MEM_ERROR:
  45         dstream<<"out of memory"<<std::endl;
  46         break;
  47     case Z_VERSION_ERROR:
  48         dstream<<"zlib version mismatch!"<<std::endl;
  49                 break;
  50         default:
  51                 dstream<<"return value = "<<ret<<std::endl;
  52     }
  53 }
  54
  55 void compressZlib(SharedBuffer<u8> data, std::ostream &os)
  56 {
  57         z_stream z;
  58         const s32 bufsize = 16384;
  59         //char input_buffer[bufsize];
  60         char output_buffer[bufsize];
  61         int input_i = 0;
  62         int status = 0;
  63         int ret;
  64
  65         z.zalloc = Z_NULL;
  66         z.zfree = Z_NULL;
  67         z.opaque = Z_NULL;
  68
  69         ret = deflateInit(&z, -1);
  70         if(ret != Z_OK)
  71                 throw SerializationError("compressZlib: deflateInit failed");
  72
  73         z.avail_in = 0;
  74
  75         for(;;)
  76         {
  77                 int flush = Z_NO_FLUSH;
  78                 z.next_out = (Bytef*)output_buffer;
  79                 z.avail_out = bufsize;
  80
  81                 if(z.avail_in == 0)
  82                 {
  83                         //z.next_in = (char*)&data[input_i];
  84                         z.next_in = (Bytef*)&data[input_i];
  85                         z.avail_in = data.getSize() - input_i;
  86                         input_i += z.avail_in;
  87                         if(input_i == (int)data.getSize())
  88                                 flush = Z_FINISH;
  89                 }
  90                 if(z.avail_in == 0)
  91                         break;
  92                 status = deflate(&z, flush);
  93                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
  94                                 || status == Z_MEM_ERROR)
  95                 {
  96                         zerr(status);
  97                         throw SerializationError("compressZlib: deflate failed");
  98                 }
  99                 int count = bufsize - z.avail_out;
 100                 if(count)
 101                         os.write(output_buffer, count);
 102         }
 103
 104         deflateEnd(&z);
 105
 106 }
 107
 108 void compressZlib(const std::string &data, std::ostream &os)
 109 {
 110         SharedBuffer<u8> databuf((u8*)data.c_str(), data.size());
 111         compressZlib(databuf, os);
 112 }
 113
 114 void decompressZlib(std::istream &is, std::ostream &os)
 115 {
 116         z_stream z;
 117         const s32 bufsize = 16384;
 118         char input_buffer[bufsize];
 119         char output_buffer[bufsize];
 120         int status = 0;
 121         int ret;
 122         int bytes_read = 0;
 123         int input_buffer_len = 0;
 124
 125         z.zalloc = Z_NULL;
 126         z.zfree = Z_NULL;
 127         z.opaque = Z_NULL;
 128
 129         ret = inflateInit(&z);
 130         if(ret != Z_OK)
 131                 throw SerializationError("dcompressZlib: inflateInit failed");
 132
 133         z.avail_in = 0;
 134
 135         //dstream<<"initial fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 136
 137         for(;;)
 138         {
 139                 z.next_out = (Bytef*)output_buffer;
 140                 z.avail_out = bufsize;
 141
 142                 if(z.avail_in == 0)
 143                 {
 144                         z.next_in = (Bytef*)input_buffer;
 145                         input_buffer_len = is.readsome(input_buffer, bufsize);
 146                         z.avail_in = input_buffer_len;
 147                         //dstream<<"read fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 148                 }
 149                 if(z.avail_in == 0)
 150                 {
 151                         //dstream<<"z.avail_in == 0"<<std::endl;
 152                         break;
 153                 }
 154
 155                 //dstream<<"1 z.avail_in="<<z.avail_in<<std::endl;
 156                 status = inflate(&z, Z_NO_FLUSH);
 157                 //dstream<<"2 z.avail_in="<<z.avail_in<<std::endl;
 158                 bytes_read += is.gcount() - z.avail_in;
 159                 //dstream<<"bytes_read="<<bytes_read<<std::endl;
 160
 161                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
 162                                 || status == Z_MEM_ERROR)
 163                 {
 164                         zerr(status);
 165                         throw SerializationError("decompressZlib: inflate failed");
 166                 }
 167                 int count = bufsize - z.avail_out;
 168                 //dstream<<"count="<<count<<std::endl;
 169                 if(count)
 170                         os.write(output_buffer, count);
 171                 if(status == Z_STREAM_END)
 172                 {
 173                         //dstream<<"Z_STREAM_END"<<std::endl;
 174
 175                         //dstream<<"z.avail_in="<<z.avail_in<<std::endl;
 176                         //dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 177                         // Unget all the data that inflate didn't take
 178                         for(u32 i=0; i < z.avail_in; i++)
 179                         {
 180                                 is.unget();
 181                                 if(is.fail() || is.bad())
 182                                 {
 183                                         dstream<<"unget #"<<i<<" failed"<<std::endl;
 184                                         dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 185                                         throw SerializationError("decompressZlib: unget failed");
 186                                 }
 187                         }
 188
 189                         break;
 190                 }
 191         }
 192
 193         inflateEnd(&z);
 194 }
 195
 196 void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
 197 {
 198         if(version >= 11)
 199         {
 200                 compressZlib(data, os);
 201                 return;
 202         }
 203
 204         if(data.getSize() == 0)
 205                 return;
 206
 207         // Write length (u32)
 208
 209         u8 tmp[4];
 210         writeU32(tmp, data.getSize());
 211         os.write((char*)tmp, 4);
 212
 213         // We will be writing 8-bit pairs of more_count and byte
 214         u8 more_count = 0;
 215         u8 current_byte = data[0];
 216         for(u32 i=1; i<data.getSize(); i++)
 217         {
 218                 if(
 219                         data[i] != current_byte
 220                         || more_count == 255
 221                 )
 222                 {
 223                         // write count and byte
 224                         os.write((char*)&more_count, 1);
 225                         os.write((char*)&current_byte, 1);
 226                         more_count = 0;
 227                         current_byte = data[i];
 228                 }
 229                 else
 230                 {
 231                         more_count++;
 232                 }
 233         }
 234         // write count and byte
 235         os.write((char*)&more_count, 1);
 236         os.write((char*)&current_byte, 1);
 237 }
 238
 239 void decompress(std::istream &is, std::ostream &os, u8 version)
 240 {
 241         if(version >= 11)
 242         {
 243                 decompressZlib(is, os);
 244                 return;
 245         }
 246
 247         // Read length (u32)
 248
 249         u8 tmp[4];
 250         is.read((char*)tmp, 4);
 251         u32 len = readU32(tmp);
 252
 253         // We will be reading 8-bit pairs of more_count and byte
 254         u32 count = 0;
 255         for(;;)
 256         {
 257                 u8 more_count=0;
 258                 u8 byte=0;
 259
 260                 is.read((char*)&more_count, 1);
 261
 262                 is.read((char*)&byte, 1);
 263
 264                 if(is.eof())
 265                         throw SerializationError("decompress: stream ended halfway");
 266
 267                 for(s32 i=0; i<(u16)more_count+1; i++)
 268                         os.write((char*)&byte, 1);
 269
 270                 count += (u16)more_count+1;
 271
 272                 if(count == len)
 273                         break;
 274         }
 275 }
 276
 277