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