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     fputs("zerr: ", stderr);
  31     switch (ret) {
  32     case Z_ERRNO:
  33         if (ferror(stdin))
  34             fputs("error reading stdin\n", stderr);
  35         if (ferror(stdout))
  36             fputs("error writing stdout\n", stderr);
  37         break;
  38     case Z_STREAM_ERROR:
  39         fputs("invalid compression level\n", stderr);
  40         break;
  41     case Z_DATA_ERROR:
  42         fputs("invalid or incomplete deflate data\n", stderr);
  43         break;
  44     case Z_MEM_ERROR:
  45         fputs("out of memory\n", stderr);
  46         break;
  47     case Z_VERSION_ERROR:
  48         fputs("zlib version mismatch!\n", stderr);
  49                 break;
  50         default:
  51                 dstream<<"return value = "<<ret<<"\n";
  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 decompressZlib(std::istream &is, std::ostream &os)
 109 {
 110         z_stream z;
 111         const s32 bufsize = 16384;
 112         char input_buffer[bufsize];
 113         char output_buffer[bufsize];
 114         int status = 0;
 115         int ret;
 116         int bytes_read = 0;
 117         int input_buffer_len = 0;
 118
 119         z.zalloc = Z_NULL;
 120         z.zfree = Z_NULL;
 121         z.opaque = Z_NULL;
 122
 123         ret = inflateInit(&z);
 124         if(ret != Z_OK)
 125                 throw SerializationError("compressZlib: inflateInit failed");
 126
 127         z.avail_in = 0;
 128
 129         //dstream<<"initial fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 130
 131         for(;;)
 132         {
 133                 z.next_out = (Bytef*)output_buffer;
 134                 z.avail_out = bufsize;
 135
 136                 if(z.avail_in == 0)
 137                 {
 138                         z.next_in = (Bytef*)input_buffer;
 139                         input_buffer_len = is.readsome(input_buffer, bufsize);
 140                         z.avail_in = input_buffer_len;
 141                         //dstream<<"read fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 142                 }
 143                 if(z.avail_in == 0)
 144                 {
 145                         //dstream<<"z.avail_in == 0"<<std::endl;
 146                         break;
 147                 }
 148
 149                 //dstream<<"1 z.avail_in="<<z.avail_in<<std::endl;
 150                 status = inflate(&z, Z_NO_FLUSH);
 151                 //dstream<<"2 z.avail_in="<<z.avail_in<<std::endl;
 152                 bytes_read += is.gcount() - z.avail_in;
 153                 //dstream<<"bytes_read="<<bytes_read<<std::endl;
 154
 155                 if(status == Z_NEED_DICT || status == Z_DATA_ERROR
 156                                 || status == Z_MEM_ERROR)
 157                 {
 158                         zerr(status);
 159                         throw SerializationError("compressZlib: inflate failed");
 160                 }
 161                 int count = bufsize - z.avail_out;
 162                 //dstream<<"count="<<count<<std::endl;
 163                 if(count)
 164                         os.write(output_buffer, count);
 165                 if(status == Z_STREAM_END)
 166                 {
 167                         //dstream<<"Z_STREAM_END"<<std::endl;
 168
 169                         //dstream<<"z.avail_in="<<z.avail_in<<std::endl;
 170                         //dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 171                         // Unget all the data that inflate didn't take
 172                         for(u32 i=0; i < z.avail_in; i++)
 173                         {
 174                                 is.unget();
 175                                 if(is.fail() || is.bad())
 176                                 {
 177                                         dstream<<"unget #"<<i<<" failed"<<std::endl;
 178                                         dstream<<"fail="<<is.fail()<<" bad="<<is.bad()<<std::endl;
 179                                         throw SerializationError("compressZlib: unget failed");
 180                                 }
 181                         }
 182
 183                         break;
 184                 }
 185         }
 186
 187         inflateEnd(&z);
 188 }
 189
 190 void compress(SharedBuffer<u8> data, std::ostream &os, u8 version)
 191 {
 192         if(version >= 11)
 193         {
 194                 compressZlib(data, os);
 195                 return;
 196         }
 197
 198         if(data.getSize() == 0)
 199                 return;
 200
 201         // Write length (u32)
 202
 203         u8 tmp[4];
 204         writeU32(tmp, data.getSize());
 205         os.write((char*)tmp, 4);
 206
 207         // We will be writing 8-bit pairs of more_count and byte
 208         u8 more_count = 0;
 209         u8 current_byte = data[0];
 210         for(u32 i=1; i<data.getSize(); i++)
 211         {
 212                 if(
 213                         data[i] != current_byte
 214                         || more_count == 255
 215                 )
 216                 {
 217                         // write count and byte
 218                         os.write((char*)&more_count, 1);
 219                         os.write((char*)&current_byte, 1);
 220                         more_count = 0;
 221                         current_byte = data[i];
 222                 }
 223                 else
 224                 {
 225                         more_count++;
 226                 }
 227         }
 228         // write count and byte
 229         os.write((char*)&more_count, 1);
 230         os.write((char*)&current_byte, 1);
 231 }
 232
 233 void decompress(std::istream &is, std::ostream &os, u8 version)
 234 {
 235         if(version >= 11)
 236         {
 237                 decompressZlib(is, os);
 238                 return;
 239         }
 240
 241         // Read length (u32)
 242
 243         u8 tmp[4];
 244         is.read((char*)tmp, 4);
 245         u32 len = readU32(tmp);
 246
 247         // We will be reading 8-bit pairs of more_count and byte
 248         u32 count = 0;
 249         for(;;)
 250         {
 251                 u8 more_count=0;
 252                 u8 byte=0;
 253
 254                 is.read((char*)&more_count, 1);
 255
 256                 is.read((char*)&byte, 1);
 257
 258                 if(is.eof())
 259                         throw SerializationError("decompress: stream ended halfway");
 260
 261                 for(s32 i=0; i<(u16)more_count+1; i++)
 262                         os.write((char*)&byte, 1);
 263
 264                 count += (u16)more_count+1;
 265
 266                 if(count == len)
 267                         break;
 268         }
 269 }
 270
 271