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 #include "zlib.h"
  23
  24 /* report a zlib or i/o error */
  25 void zerr(int ret)
  26 {
  27     fputs("zerr: ", stderr);
  28     switch (ret) {
  29     case Z_ERRNO:
  30         if (ferror(stdin))
  31             fputs("error reading stdin\n", stderr);
  32         if (ferror(stdout))
  33             fputs("error writing stdout\n", stderr);
  34         break;
  35     case Z_STREAM_ERROR:
  36         fputs("invalid compression level\n", stderr);
  37         break;
  38     case Z_DATA_ERROR:
  39         fputs("invalid or incomplete deflate data\n", stderr);
  40         break;
  41     case Z_MEM_ERROR:
  42         fputs("out of memory\n", stderr);
  43         break;
  44     case Z_VERSION_ERROR:
  45         fputs("zlib version mismatch!\n", stderr);
  46                 break;
  47         default:
  48                 dstream<<"return value = "<<ret<<"\n";
  49     }
  50 }
  51
  52 void compressZlib(SharedBuffer<u8> data, std::ostream &os)
  53 {
  54         z_stream z;
  55         const s32 bufsize = 16384;
  56         //char input_buffer[bufsize];
  57         char output_buffer[bufsize];
  58         int input_i = 0;
  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, -1);
  67         if(ret != Z_OK)
  68                 throw SerializationError("compressZlib: deflateInit failed");
  69
  70         z.avail_in = 0;
  71
  72         for(;;)
  73         {
  74                 int flush = Z_NO_FLUSH;
  75                 z.next_out = (Bytef*)output_buffer;
  76                 z.avail_out = bufsize;
  77
  78                 if(z.avail_in == 0)
  79                 {
  80                         //z.next_in = (char*)&data[input_i];
  81                         z.next_in = (Bytef*)&data[input_i];
  82                         z.avail_in = data.getSize() - input_i;
  83                         input_i += z.avail_in;
  84                         if(input_i == (int)data.getSize())
  85                                 flush = Z_FINISH;
  86                 }
  87                 if(z.avail_in == 0)
  88                         break;
  89                 status = deflate(&z, flush);
  90                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
  91                                 || status == Z_MEM_ERROR)
  92                 {
  93                         zerr(status);
  94                         throw SerializationError("compressZlib: deflate failed");
  95                 }
  96                 int count = bufsize - z.avail_out;
  97                 if(count)
  98                         os.write(output_buffer, count);
  99         }
 100
 101         deflateEnd(&z);
 102
 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("compressZlib: 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                         input_buffer_len = is.readsome(input_buffer, bufsize);
 137                         z.avail_in = input_buffer_len;
 138                         //dstream<<"read fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 139                 }
 140                 if(z.avail_in == 0)
 141                 {
 142                         //dstream<<"z.avail_in == 0"<<std::endl;
 143                         break;
 144                 }
 145
 146                 //dstream<<"1 z.avail_in="<<z.avail_in<<std::endl;
 147                 status = inflate(&z, Z_NO_FLUSH);
 148                 //dstream<<"2 z.avail_in="<<z.avail_in<<std::endl;
 149                 bytes_read += is.gcount() - z.avail_in;
 150                 //dstream<<"bytes_read="<<bytes_read<<std::endl;
 151
 152                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
 153                                 || status == Z_MEM_ERROR)
 154                 {
 155                         zerr(status);
 156                         throw SerializationError("compressZlib: inflate failed");
 157                 }
 158                 int count = bufsize - z.avail_out;
 159                 //dstream<<"count="<<count<<std::endl;
 160                 if(count)
 161                         os.write(output_buffer, count);
 162                 if(status == Z_STREAM_END)
 163                 {
 164                         //dstream<<"Z_STREAM_END"<<std::endl;
 165
 166                         //dstream<<"z.avail_in="<<z.avail_in<<std::endl;
 167                         //dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 168                         // Unget all the data that inflate didn't take
 169                         for(u32 i=0; i < z.avail_in; i++)
 170                         {
 171                                 is.unget();
 172                                 if(is.fail() || is.bad())
 173                                 {
 174                                         dstream<<"unget #"<<i<<" failed"<<std::endl;
 175                                         dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 176                                         throw SerializationError("compressZlib: unget failed");
 177                                 }
 178                         }
 179
 180                         break;
 181                 }
 182         }
 183
 184         inflateEnd(&z);
 185 }
 186
 187 void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
 188 {
 189         if(version >= 11)
 190         {
 191                 compressZlib(data, os);
 192                 return;
 193         }
 194
 195         if(data.getSize() == 0)
 196                 return;
 197
 198         // Write length (u32)
 199
 200         u8 tmp[4];
 201         writeU32(tmp, data.getSize());
 202         os.write((char*)tmp, 4);
 203
 204         // We will be writing 8-bit pairs of more_count and byte
 205         u8 more_count = 0;
 206         u8 current_byte = data[0];
 207         for(u32 i=1; i<data.getSize(); i++)
 208         {
 209                 if(
 210                         data[i] != current_byte
 211                         || more_count == 255
 212                 )
 213                 {
 214                         // write count and byte
 215                         os.write((char*)&more_count, 1);
 216                         os.write((char*)&current_byte, 1);
 217                         more_count = 0;
 218                         current_byte = data[i];
 219                 }
 220                 else
 221                 {
 222                         more_count++;
 223                 }
 224         }
 225         // write count and byte
 226         os.write((char*)&more_count, 1);
 227         os.write((char*)&current_byte, 1);
 228 }
 229
 230 void decompress(std::istream &is, std::ostream &os, u8 version)
 231 {
 232         if(version >= 11)
 233         {
 234                 decompressZlib(is, os);
 235                 return;
 236         }
 237
 238         // Read length (u32)
 239
 240         u8 tmp[4];
 241         is.read((char*)tmp, 4);
 242         u32 len = readU32(tmp);
 243
 244         // We will be reading 8-bit pairs of more_count and byte
 245         u32 count = 0;
 246         for(;;)
 247         {
 248                 u8 more_count=0;
 249                 u8 byte=0;
 250
 251                 is.read((char*)&more_count, 1);
 252
 253                 is.read((char*)&byte, 1);
 254
 255                 if(is.eof())
 256                         throw SerializationError("decompress: stream ended halfway");
 257
 258                 for(s32 i=0; i<(u16)more_count+1; i++)
 259                         os.write((char*)&byte, 1);
 260
 261                 count += (u16)more_count+1;
 262
 263                 if(count == len)
 264                         break;
 265         }
 266 }
 267
 268