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)level;
  93         throw zlib_error("unsupported", -1);
  94 #endif
  95 }
  96
  97 ZlibCompressed::~ZlibCompressed()
  98 {
  99 #ifdef WITH_ZLIB
 100         if(mode==M_WRITE)
 101         {
 102                 while(compress_data(Z_FINISH)) ;
 103                 deflateEnd(&priv->stream);
 104         }
 105         else
 106                 inflateEnd(&priv->stream);
 107 #endif
 108
 109         delete[] in_buffer;
 110         delete[] out_buffer;
 111         delete priv;
 112 }
 113
 114 void ZlibCompressed::flush()
 115 {
 116 #ifdef WITH_ZLIB
 117         if(mode==M_WRITE)
 118         {
 119                 while(1)
 120                 {
 121                         if(!compress_data(Z_SYNC_FLUSH))
 122                                 break;
 123
 124                         // The flush is done when all input data has been consumed
 125                         if(!priv->stream.avail_in)
 126                                 break;
 127                 }
 128         }
 129 #endif
 130 }
 131
 132 unsigned ZlibCompressed::do_write(const char *data, unsigned size)
 133 {
 134         check_access(M_WRITE);
 135
 136         unsigned processed = 0;
 137 #ifdef WITH_ZLIB
 138         while(processed<size)
 139         {
 140                 unsigned free_in = (in_buffer+buffer_size-priv->stream.next_in);
 141                 if(free_in<size && priv->stream.next_in>in_buffer)
 142                 {
 143                         // Not all of the data fits in the buffer, so make some more room
 144                         copy(priv->stream.next_in, priv->stream.next_in+priv->stream.avail_in, in_buffer);
 145                         priv->stream.next_in = in_buffer;
 146                         free_in = buffer_size-priv->stream.avail_in;
 147                 }
 148
 149                 if(free_in)
 150                 {
 151                         // Copy as much data into the input buffer as possible
 152                         unsigned len = min(free_in, size-processed);
 153                         copy(data+processed, data+processed+len, priv->stream.next_in+priv->stream.avail_in);
 154                         priv->stream.avail_in += len;
 155                         processed += len;
 156                 }
 157
 158                 bool stalled = false;
 159                 while(priv->stream.avail_in && !stalled)
 160                         stalled = !compress_data(Z_NO_FLUSH);
 161                 if(stalled)
 162                         break;
 163         }
 164 #else
 165         (void)data;
 166         (void)size;
 167 #endif
 168
 169         return processed;
 170 }
 171
 172 bool ZlibCompressed::compress_data(int flush_mode)
 173 {
 174 #ifdef WITH_ZLIB
 175         bool can_deflate = ((priv->stream.avail_in || flush_mode) && priv->stream.avail_out);
 176         bool finished = false;
 177         if(can_deflate)
 178         {
 179                 int ret = deflate(&priv->stream, flush_mode);
 180                 if(flush_mode==Z_FINISH && ret==Z_STREAM_END)
 181                         finished = true;
 182                 else if(ret!=Z_OK)
 183                         throw zlib_error("deflate", ret);
 184         }
 185
 186         // Write compressed data into the underlying object
 187         unsigned len = 0;
 188         if(priv->stream.next_out>out_buffer)
 189                 len = below.write(reinterpret_cast<char *>(out_buffer), priv->stream.next_out-out_buffer);
 190         if(len>0)
 191         {
 192                 if(len<static_cast<unsigned>(priv->stream.next_out-out_buffer))
 193                         copy(out_buffer+len, priv->stream.next_out, out_buffer);
 194                 priv->stream.avail_out += len;
 195                 priv->stream.next_out -= len;
 196         }
 197         else if(!can_deflate)
 198                 // We weren't able to do anything
 199                 return false;
 200
 201         return !finished;
 202 #else
 203         (void)flush_mode;
 204         return false;
 205 #endif
 206 }
 207
 208 unsigned ZlibCompressed::do_read(char *data, unsigned size)
 209 {
 210         check_access(M_READ);
 211
 212         unsigned processed = 0;
 213 #ifdef WITH_ZLIB
 214         while(processed<size)
 215         {
 216                 if(priv->stream.next_out>out_buffer)
 217                 {
 218                         // We have some pending output, give it out first
 219                         unsigned len = min<unsigned>(priv->stream.next_out-out_buffer, size-processed);
 220
 221                         copy(out_buffer, out_buffer+len, data+processed);
 222                         processed += len;
 223
 224                         if(len<static_cast<unsigned>(priv->stream.next_out-out_buffer))
 225                                 copy(out_buffer+len, priv->stream.next_out, out_buffer);
 226                         priv->stream.next_out -= len;
 227                         priv->stream.avail_out += len;
 228
 229                         continue;
 230                 }
 231
 232                 bool need_more_input = !priv->stream.avail_in;
 233                 if(priv->stream.avail_in)
 234                 {
 235                         int ret = inflate(&priv->stream, Z_NO_FLUSH);
 236                         if(ret==Z_STREAM_END)
 237                                 stream_end = true;
 238                         else if(ret!=Z_OK)
 239                                 throw zlib_error("inflate", ret);
 240                         need_more_input = (priv->stream.next_out==out_buffer);
 241                 }
 242
 243                 if(need_more_input)
 244                 {
 245                         if(stream_end)
 246                                 break;
 247
 248                         if(priv->stream.next_in>in_buffer)
 249                                 copy(priv->stream.next_in, priv->stream.next_in+priv->stream.avail_in, in_buffer);
 250                         priv->stream.next_in = in_buffer;
 251
 252                         unsigned len = below.read(reinterpret_cast<char *>(priv->stream.next_in), in_buffer+buffer_size-priv->stream.next_in);
 253                         priv->stream.avail_in += len;
 254                         if(!len && below.eof())
 255                                 stream_end = true;
 256                 }
 257         }
 258
 259         if(size>0 && processed==0 && stream_end)
 260                 set_eof();
 261 #else
 262         (void)data;
 263         (void)size;
 264 #endif
 265
 266         return processed;
 267 }
 268
 269 } // namespace IO
 270 } // namespace Msp