src/tiff/libtiff/tif_stream.cxx

   1 /* $Id: tif_stream.cxx,v 1.5 2005/07/26 08:11:13 dron Exp $ */
   2
   3 /*
   4  * Copyright (c) 1988-1996 Sam Leffler
   5  * Copyright (c) 1991-1996 Silicon Graphics, Inc.
   6  *
   7  * Permission to use, copy, modify, distribute, and sell this software and
   8  * its documentation for any purpose is hereby granted without fee, provided
   9  * that (i) the above copyright notices and this permission notice appear in
  10  * all copies of the software and related documentation, and (ii) the names of
  11  * Sam Leffler and Silicon Graphics may not be used in any advertising or
  12  * publicity relating to the software without the specific, prior written
  13  * permission of Sam Leffler and Silicon Graphics.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  17  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  18  *
  19  * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
  20  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  21  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  22  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  24  * OF THIS SOFTWARE.
  25  */
  26
  27 /*
  28  * TIFF Library UNIX-specific Routines.
  29  */
  30 #include "tiffiop.h"
  31 #include <iostream>
  32
  33 using namespace std;
  34
  35 class tiffis_data
  36 {
  37   public:
  38
  39         istream *myIS;
  40         long    myStreamStartPos;
  41 };
  42
  43 class tiffos_data
  44 {
  45   public:
  46
  47         ostream *myOS;
  48         long    myStreamStartPos;
  49 };
  50
  51 static tsize_t
  52 _tiffosReadProc(thandle_t, tdata_t, tsize_t)
  53 {
  54         return 0;
  55 }
  56
  57 static tsize_t
  58 _tiffisReadProc(thandle_t fd, tdata_t buf, tsize_t size)
  59 {
  60         tiffis_data     *data = (tiffis_data *)fd;
  61
  62         data->myIS->read((char *)buf, (int)size);
  63
  64         return data->myIS->gcount();
  65 }
  66
  67 static tsize_t
  68 _tiffosWriteProc(thandle_t fd, tdata_t buf, tsize_t size)
  69 {
  70         tiffos_data     *data = (tiffos_data *)fd;
  71         ostream         *os = data->myOS;
  72         int             pos = os->tellp();
  73
  74         os->write((const char *)buf, size);
  75
  76         return ((int)os->tellp()) - pos;
  77 }
  78
  79 static tsize_t
  80 _tiffisWriteProc(thandle_t, tdata_t, tsize_t)
  81 {
  82         return 0;
  83 }
  84
  85 static toff_t
  86 _tiffosSeekProc(thandle_t fd, toff_t off, int whence)
  87 {
  88         tiffos_data     *data = (tiffos_data *)fd;
  89         ostream *os = data->myOS;
  90
  91         // if the stream has already failed, don't do anything
  92         if( os->fail() )
  93                 return os->tellp();
  94
  95         switch(whence) {
  96         case SEEK_SET:
  97             os->seekp(data->myStreamStartPos + off, ios::beg);
  98                 break;
  99         case SEEK_CUR:
 100                 os->seekp(off, ios::cur);
 101                 break;
 102         case SEEK_END:
 103                 os->seekp(off, ios::end);
 104                 break;
 105         }
 106
 107         // Attempt to workaround problems with seeking past the end of the
 108         // stream.  ofstream doesn't have a problem with this but
 109         // ostrstream/ostringstream does. In that situation, add intermediate
 110         // '\0' characters.
 111         if( os->fail() ) {
 112                 ios::iostate    old_state;
 113                 toff_t          origin;
 114
 115                 old_state = os->rdstate();
 116                 // reset the fail bit or else tellp() won't work below
 117                 os->clear(os->rdstate() & ~ios::failbit);
 118                 switch( whence ) {
 119                         case SEEK_SET:
 120                                 origin = data->myStreamStartPos;
 121                                 break;
 122                         case SEEK_CUR:
 123                                 origin = os->tellp();
 124                                 break;
 125                         case SEEK_END:
 126                                 os->seekp(0, ios::end);
 127                                 origin = os->tellp();
 128                                 break;
 129                 }
 130                 // restore original stream state
 131                 os->clear(old_state);
 132
 133                 // only do something if desired seek position is valid
 134                 if( origin + off > data->myStreamStartPos ) {
 135                         toff_t  num_fill;
 136
 137                         // clear the fail bit
 138                         os->clear(os->rdstate() & ~ios::failbit);
 139
 140                         // extend the stream to the expected size
 141                         os->seekp(0, ios::end);
 142                         num_fill = origin + off - (toff_t)os->tellp();
 143                         for( toff_t i = 0; i < num_fill; i++ )
 144                                 os->put('\0');
 145
 146                         // retry the seek
 147                         os->seekp(origin + off, ios::beg);
 148                 }
 149         }
 150
 151         return os->tellp();
 152 }
 153
 154 static toff_t
 155 _tiffisSeekProc(thandle_t fd, toff_t off, int whence)
 156 {
 157         tiffis_data     *data = (tiffis_data *)fd;
 158
 159         switch(whence) {
 160         case SEEK_SET:
 161                 data->myIS->seekg(data->myStreamStartPos + off, ios::beg);
 162                 break;
 163         case SEEK_CUR:
 164                 data->myIS->seekg(off, ios::cur);
 165                 break;
 166         case SEEK_END:
 167                 data->myIS->seekg(off, ios::end);
 168                 break;
 169         }
 170
 171         return ((long)data->myIS->tellg()) - data->myStreamStartPos;
 172 }
 173
 174 static toff_t
 175 _tiffosSizeProc(thandle_t fd)
 176 {
 177         tiffos_data     *data = (tiffos_data *)fd;
 178         ostream         *os = data->myOS;
 179         toff_t          pos = os->tellp();
 180         toff_t          len;
 181
 182         os->seekp(0, ios::end);
 183         len = os->tellp();
 184         os->seekp(pos);
 185
 186         return len;
 187 }
 188
 189 static toff_t
 190 _tiffisSizeProc(thandle_t fd)
 191 {
 192         tiffis_data     *data = (tiffis_data *)fd;
 193         int             pos = data->myIS->tellg();
 194         int             len;
 195
 196         data->myIS->seekg(0, ios::end);
 197         len = data->myIS->tellg();
 198         data->myIS->seekg(pos);
 199
 200         return len;
 201 }
 202
 203 static int
 204 _tiffosCloseProc(thandle_t fd)
 205 {
 206         // Our stream was not allocated by us, so it shouldn't be closed by us.
 207         delete (tiffos_data *)fd;
 208         return 0;
 209 }
 210
 211 static int
 212 _tiffisCloseProc(thandle_t fd)
 213 {
 214         // Our stream was not allocated by us, so it shouldn't be closed by us.
 215         delete (tiffis_data *)fd;
 216         return 0;
 217 }
 218
 219 static int
 220 _tiffDummyMapProc(thandle_t , tdata_t* , toff_t* )
 221 {
 222         return (0);
 223 }
 224
 225 static void
 226 _tiffDummyUnmapProc(thandle_t , tdata_t , toff_t )
 227 {
 228 }
 229
 230 /*
 231  * Open a TIFF file descriptor for read/writing.
 232  */
 233 static TIFF*
 234 _tiffStreamOpen(const char* name, const char* mode, void *fd)
 235 {
 236         TIFF*   tif;
 237
 238         if( strchr(mode, 'w') ) {
 239                 tiffos_data     *data = new tiffos_data;
 240                 data->myOS = (ostream *)fd;
 241                 data->myStreamStartPos = data->myOS->tellp();
 242
 243                 // Open for writing.
 244                 tif = TIFFClientOpen(name, mode,
 245                                 (thandle_t) data,
 246                                 _tiffosReadProc, _tiffosWriteProc,
 247                                 _tiffosSeekProc, _tiffosCloseProc,
 248                                 _tiffosSizeProc,
 249                                 _tiffDummyMapProc, _tiffDummyUnmapProc);
 250         } else {
 251                 tiffis_data     *data = new tiffis_data;
 252                 data->myIS = (istream *)fd;
 253                 data->myStreamStartPos = data->myIS->tellg();
 254                 // Open for reading.
 255                 tif = TIFFClientOpen(name, mode,
 256                                 (thandle_t) data,
 257                                 _tiffisReadProc, _tiffisWriteProc,
 258                                 _tiffisSeekProc, _tiffisCloseProc,
 259                                 _tiffisSizeProc,
 260                                 _tiffDummyMapProc, _tiffDummyUnmapProc);
 261         }
 262
 263         return (tif);
 264 }
 265
 266 TIFF*
 267 TIFFStreamOpen(const char* name, ostream *os)
 268 {
 269         // If os is either a ostrstream or ostringstream, and has no data
 270         // written to it yet, then tellp() will return -1 which will break us.
 271         // We workaround this by writing out a dummy character and
 272         // then seek back to the beginning.
 273         if( !os->fail() && (int)os->tellp() < 0 ) {
 274                 *os << '\0';
 275                 os->seekp(0);
 276         }
 277
 278         // NB: We don't support mapped files with streams so add 'm'
 279         return _tiffStreamOpen(name, "wm", os);
 280 }
 281
 282 TIFF*
 283 TIFFStreamOpen(const char* name, istream *is)
 284 {
 285         // NB: We don't support mapped files with streams so add 'm'
 286         return _tiffStreamOpen(name, "rm", is);
 287 }
 288
 289 /* vim: set ts=8 sts=8 sw=8 noet: */