source/io/zlibcompressed.cpp

   1 #ifdef WITH_ZLIB
   2 #include <zlib.h>
   3 #endif
   4 #include "zlibcompressed.h"
   5
   6 using namespace std;
   7
   8 namespace Msp {
   9 namespace IO {
  10
  11 zlib_error::zlib_error(const std::string &w, int c):
  12 #ifdef WITH_ZLIB
  13         runtime_error(w+": "+zError(c)),
  14 #else
  15         runtime_error(w),
  16 #endif
  17         code_(c)
  18 { }
  19
  20
  21 struct ZlibCompressed::Private
  22 {
  23 #ifdef WITH_ZLIB
  24         z_stream stream;
  25 #endif
  26
  27         Private();
  28 };
  29
  30 ZlibCompressed::Private::Private()
  31 {
  32 #ifdef WITH_ZLIB
  33         stream.zalloc = 0;
  34         stream.zfree = 0;
  35         stream.opaque = 0;
  36 #endif
  37 }
  38
  39
  40 ZlibCompressed::ZlibCompressed(Base &b, unsigned level):
  41         below(b)
  42 {
  43         mode = below.get_mode()&M_RDWR;
  44         if(mode!=M_READ && mode!=M_WRITE)
  45                 throw invalid_access(mode);
  46
  47         init(level);
  48 }
  49
  50 ZlibCompressed::ZlibCompressed(Base &b, Mode m, unsigned level):
  51         below(b)
  52 {
  53         mode = m&below.get_mode()&M_RDWR;
  54         if(mode!=M_READ && mode!=M_WRITE)
  55                 throw invalid_access(m);
  56
  57         init(level);
  58 }
  59
  60 void ZlibCompressed::init(unsigned level)
  61 {
  62 #ifdef WITH_ZLIB
  63         buffer_size = 1024;
  64         in_buffer = 0;
  65         out_buffer = 0;
  66         stream_end = false;
  67         priv = new Private;
  68
  69         if(mode==M_WRITE)
  70         {
  71                 int ret = deflateInit(&priv->stream, level);
  72                 if(ret!=Z_OK)
  73                         throw zlib_error("deflateInit", ret);
  74         }
  75         else
  76         {
  77                 int ret = inflateInit(&priv->stream);
  78                 if(ret!=Z_OK)
  79                         throw zlib_error("inflateInit", ret);
  80         }
  81
  82         in_buffer = new unsigned char[buffer_size];
  83         out_buffer = new unsigned char[buffer_size];
  84
  85         priv->stream.next_in = in_buffer;
  86         priv->stream.avail_in = 0;
  87         priv->stream.next_out = out_buffer;
  88         priv->stream.avail_out = buffer_size;
  89
  90         below.signal_flush_required.connect(sigc::mem_fun(this, &ZlibCompressed::flush));
  91 #else
  92         (void)buffer_size;
  93         (void)stream_end;
  94         (void)level;
  95         throw zlib_error("unsupported", -1);
  96 #endif
  97 }
  98
  99 ZlibCompressed::~ZlibCompressed()
 100 {
 101 #ifdef WITH_ZLIB
 102         if(mode==M_WRITE)
 103         {
 104                 while(compress_data(Z_FINISH)) ;
 105                 deflateEnd(&priv->stream);
 106         }
 107         else
 108                 inflateEnd(&priv->stream);
 109 #endif
 110
 111         delete[] in_buffer;
 112         delete[] out_buffer;
 113         delete priv;
 114 }
 115
 116 void ZlibCompressed::set_block(bool)
 117 {
 118         throw logic_error("ZlibCompressed::set_block");
 119 }
 120
 121 void ZlibCompressed::flush()
 122 {
 123 #ifdef WITH_ZLIB
 124         if(mode==M_WRITE)
 125         {
 126                 while(1)
 127                 {
 128                         if(!compress_data(Z_SYNC_FLUSH))
 129                                 break;
 130
 131                         // The flush is done when all input data has been consumed
 132                         if(!priv->stream.avail_in)
 133                                 break;
 134                 }
 135         }
 136 #endif
 137 }
 138
 139 unsigned ZlibCompressed::do_write(const char *data, unsigned size)
 140 {
 141         check_access(M_WRITE);
 142
 143         unsigned processed = 0;
 144 #ifdef WITH_ZLIB
 145         while(processed<size)
 146         {
 147                 unsigned free_in = (in_buffer+buffer_size-priv->stream.next_in);
 148                 if(free_in<size && priv->stream.next_in>in_buffer)
 149                 {
 150                         // Not all of the data fits in the buffer, so make some more room
 151                         copy(priv->stream.next_in, priv->stream.next_in+priv->stream.avail_in, in_buffer);
 152                         priv->stream.next_in = in_buffer;
 153                         free_in = buffer_size-priv->stream.avail_in;
 154                 }
 155
 156                 if(free_in)
 157                 {
 158                         // Copy as much data into the input buffer as possible
 159                         unsigned len = min(free_in, size-processed);
 160                         copy(data+processed, data+processed+len, priv->stream.next_in+priv->stream.avail_in);
 161                         priv->stream.avail_in += len;
 162                         processed += len;
 163                 }
 164
 165                 bool stalled = false;
 166                 while(priv->stream.avail_in && !stalled)
 167                         stalled = !compress_data(Z_NO_FLUSH);
 168                 if(stalled)
 169                         break;
 170         }
 171 #else
 172         (void)data;
 173         (void)size;
 174 #endif
 175
 176         return processed;
 177 }
 178
 179 bool ZlibCompressed::compress_data(int flush_mode)
 180 {
 181 #ifdef WITH_ZLIB
 182         bool can_deflate = ((priv->stream.avail_in || flush_mode) && priv->stream.avail_out);
 183         bool finished = false;
 184         if(can_deflate)
 185         {
 186                 int ret = deflate(&priv->stream, flush_mode);
 187                 if(flush_mode==Z_FINISH && ret==Z_STREAM_END)
 188                         finished = true;
 189                 else if(ret!=Z_OK)
 190                         throw zlib_error("deflate", ret);
 191         }
 192
 193         // Write compressed data into the underlying object
 194         unsigned len = 0;
 195         if(priv->stream.next_out>out_buffer)
 196                 len = below.write(reinterpret_cast<char *>(out_buffer), priv->stream.next_out-out_buffer);
 197         if(len>0)
 198         {
 199                 if(len<static_cast<unsigned>(priv->stream.next_out-out_buffer))
 200                         copy(out_buffer+len, priv->stream.next_out, out_buffer);
 201                 priv->stream.avail_out += len;
 202                 priv->stream.next_out -= len;
 203         }
 204         else if(!can_deflate)
 205                 // We weren't able to do anything
 206                 return false;
 207
 208         return !finished;
 209 #else
 210         (void)flush_mode;
 211         return false;
 212 #endif
 213 }
 214
 215 unsigned ZlibCompressed::do_read(char *data, unsigned size)
 216 {
 217         check_access(M_READ);
 218
 219         unsigned processed = 0;
 220 #ifdef WITH_ZLIB
 221         while(processed<size)
 222         {
 223                 if(priv->stream.next_out>out_buffer)
 224                 {
 225                         // We have some pending output, give it out first
 226                         unsigned len = min<unsigned>(priv->stream.next_out-out_buffer, size-processed);
 227
 228                         copy(out_buffer, out_buffer+len, data+processed);
 229                         processed += len;
 230
 231                         if(len<static_cast<unsigned>(priv->stream.next_out-out_buffer))
 232                                 copy(out_buffer+len, priv->stream.next_out, out_buffer);
 233                         priv->stream.next_out -= len;
 234                         priv->stream.avail_out += len;
 235
 236                         continue;
 237                 }
 238
 239                 bool need_more_input = !priv->stream.avail_in;
 240                 if(priv->stream.avail_in)
 241                 {
 242                         int ret = inflate(&priv->stream, Z_NO_FLUSH);
 243                         if(ret==Z_STREAM_END)
 244                                 stream_end = true;
 245                         else if(ret!=Z_OK)
 246                                 throw zlib_error("inflate", ret);
 247                         need_more_input = (priv->stream.next_out==out_buffer);
 248                 }
 249
 250                 if(need_more_input)
 251                 {
 252                         if(stream_end)
 253                                 break;
 254
 255                         if(priv->stream.next_in>in_buffer)
 256                                 copy(priv->stream.next_in, priv->stream.next_in+priv->stream.avail_in, in_buffer);
 257                         priv->stream.next_in = in_buffer;
 258
 259                         unsigned len = below.read(reinterpret_cast<char *>(priv->stream.next_in), in_buffer+buffer_size-priv->stream.next_in);
 260                         priv->stream.avail_in += len;
 261                         if(!len && below.eof())
 262                                 stream_end = true;
 263                 }
 264         }
 265
 266         if(size>0 && processed==0 && stream_end)
 267                 set_eof();
 268 #else
 269         (void)data;
 270         (void)size;
 271 #endif
 272
 273         return processed;
 274 }
 275
 276 const Handle &ZlibCompressed::get_handle(Mode)
 277 {
 278         throw logic_error("ZlibCompressed::get_handle");
 279 }
 280
 281 } // namespace IO
 282 } // namespace Msp