summaryrefslogtreecommitdiffstats
path: root/tdefile-plugins/png/tdefile_png.cpp
blob: 8a558aa65bee7032766559f600b3cf5a1044591e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
/* This file is part of the KDE project
 * Copyright (C) 2001, 2002 Rolf Magnus <ramagnus@kde.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation version 2.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 *  $Id$
 */

#include <stdlib.h>
#include "tdefile_png.h"

#include <kurl.h>
#include <kprocess.h>
#include <tdelocale.h>
#include <kgenericfactory.h>
#include <kdebug.h>

#include <tqcstring.h>
#include <tqfile.h>
#include <tqdatetime.h>
#include <tqdict.h>
#include <tqvalidator.h>
#include <zlib.h>

// some defines to make it easier
// don't tell me anything about preprocessor usage :)
#define CHUNK_SIZE(data, index) ((data[index  ]<<24) + (data[index+1]<<16) + \
                                 (data[index+2]<< 8) +  data[index+3])
#define CHUNK_TYPE(data, index)  &data[index+4]
#define CHUNK_HEADER_SIZE 12
#define CHUNK_DATA(data, index, offset) data[8+index+offset]

// known translations for common png keys
static const char* knownTranslations[]
#ifdef __GNUC__
__attribute__((unused))
#endif
 = {
  I18N_NOOP("Title"),
  I18N_NOOP("Author"),
  I18N_NOOP("Description"),
  I18N_NOOP("Copyright"),
  I18N_NOOP("Creation Time"),
  I18N_NOOP("Software"),
  I18N_NOOP("Disclaimer"),
  I18N_NOOP("Warning"),
  I18N_NOOP("Source"),
  I18N_NOOP("Comment")
};

// and for the colors
static const char* colors[] = {
  I18N_NOOP("Grayscale"),
  I18N_NOOP("Unknown"),
  I18N_NOOP("RGB"),
  I18N_NOOP("Palette"),
  I18N_NOOP("Grayscale/Alpha"),
  I18N_NOOP("Unknown"),
  I18N_NOOP("RGB/Alpha")
};

  // and compressions
static const char* compressions[] =
{
  I18N_NOOP("Deflate")
};

  // interlaced modes
static const char* interlaceModes[] = {
  I18N_NOOP("None"),
  I18N_NOOP("Adam7")
};

typedef KGenericFactory<KPngPlugin> PngFactory;

K_EXPORT_COMPONENT_FACTORY(tdefile_png, PngFactory("tdefile_png"))

KPngPlugin::KPngPlugin(TQObject *parent, const char *name,
                       const TQStringList &args)
    : KFilePlugin(parent, name, args)
{
    kdDebug(7034) << "png plugin\n";

    // set up our mime type
    KFileMimeTypeInfo* info = addMimeTypeInfo( "image/png" );

    KFileMimeTypeInfo::GroupInfo* group = 0;
    KFileMimeTypeInfo::ItemInfo* item = 0;

    // comment group
    group = addGroupInfo(info, "Comment", i18n("Comment"));
    addVariableInfo(group, TQVariant::String, 0);

    // technical group
    group = addGroupInfo(info, "Technical", i18n("Technical Details"));

    item = addItemInfo(group, "Dimensions", i18n("Dimensions"), TQVariant::Size);
    setHint( item, KFileMimeTypeInfo::Size );
    setUnit(item, KFileMimeTypeInfo::Pixels);

    item = addItemInfo(group, "BitDepth", i18n("Bit Depth"), TQVariant::Int);
    setUnit(item, KFileMimeTypeInfo::BitsPerPixel);

    addItemInfo(group, "ColorMode", i18n("Color Mode"), TQVariant::String);
    addItemInfo(group, "Compression", i18n("Compression"), TQVariant::String);
    addItemInfo(group, "InterlaceMode", i18n("Interlace Mode"),TQVariant::String);
}

bool KPngPlugin::readInfo( KFileMetaInfo& info, uint what)
{
    if ( info.path().isEmpty() ) // remote file
        return false;
    TQFile f(info.path());
    if ( !f.open(IO_ReadOnly) )
        return false;

    TQIODevice::Offset fileSize = f.size();

    if (fileSize < 29) return false;
    // the technical group will be read from the first 29 bytes. If the file
    // is smaller, we can't even read this.

    bool readComments = false;
    if (what & (KFileMetaInfo::Fastest |
                KFileMetaInfo::DontCare |
                KFileMetaInfo::ContentInfo)) readComments = true;
    else
	fileSize = 29; // No need to read more

    uchar *data = new uchar[fileSize+1];
    f.readBlock(reinterpret_cast<char*>(data), fileSize);
    data[fileSize]='\n';

    // find the start
    if (data[0] == 137 && data[1] == 80 && data[2] == 78 && data[3] == 71 &&
        data[4] ==  13 && data[5] == 10 && data[6] == 26 && data[7] == 10 )
    {
        // ok
        // the IHDR chunk should be the first
        if (!strncmp((char*)&data[12], "IHDR", 4))
        {
            // we found it, get the dimensions
            ulong x,y;
            x = (data[16]<<24) + (data[17]<<16) + (data[18]<<8) + data[19];
            y = (data[20]<<24) + (data[21]<<16) + (data[22]<<8) + data[23];

            uint type = data[25];
            uint bpp =  data[24];
            kdDebug(7034) << "dimensions " << x << "*" << y << endl;

            // the bpp are only per channel, so we need to multiply the with
            // the channel count
            switch (type)
            {
                case 0: break;           // Grayscale
                case 2: bpp *= 3; break; // RGB
                case 3: break;           // palette
                case 4: bpp *= 2; break; // grayscale w. alpha
                case 6: bpp *= 4; break; // RGBA

                default: // we don't get any sensible value here
                    bpp = 0;
            }

            KFileMetaInfoGroup techgroup = appendGroup(info, "Technical");

            appendItem(techgroup, "Dimensions", TQSize(x, y));
            appendItem(techgroup, "BitDepth", bpp);
            appendItem(techgroup, "ColorMode",
                       (type < sizeof(colors)/sizeof(colors[0]))
                       ? i18n(colors[data[25]]) : i18n("Unknown"));

            appendItem(techgroup, "Compression",
                       (data[26] < sizeof(compressions)/sizeof(compressions[0]))
                       ? i18n(compressions[data[26]]) : i18n("Unknown"));

            appendItem(techgroup, "InterlaceMode",
                       (data[28] < sizeof(interlaceModes)/sizeof(interlaceModes[0]))
                       ? i18n(interlaceModes[data[28]]) : i18n("Unknown"));
        }

        // look for a tEXt chunk
        if (readComments)
        {
            uint index = 8;
            index += CHUNK_SIZE(data, index) + CHUNK_HEADER_SIZE;
            KFileMetaInfoGroup commentGroup = appendGroup(info, "Comment");

            while(index<fileSize-12)
            {
                while (index < fileSize - 12 &&
                       strncmp((char*)CHUNK_TYPE(data,index), "tEXt", 4) &&
                       strncmp((char*)CHUNK_TYPE(data,index), "zTXt", 4))

                {
                    if (!strncmp((char*)CHUNK_TYPE(data,index), "IEND", 4))
                        goto end;

                    index += CHUNK_SIZE(data, index) + CHUNK_HEADER_SIZE;
                }

                if (index < fileSize - 12)
                {
                    // we found a tEXt or zTXt field

                    // get the key, it's a null terminated string at the
                    //  chunk start

                    uchar* key = &CHUNK_DATA(data,index,0);

                    int keysize=0;
                    for (;key[keysize]!=0; keysize++)
                        // look if we reached the end of the file
                        // (it might be corrupted)
                        if (8+index+keysize>=fileSize)
                            goto end;

		    TQByteArray arr;
		    if(!strncmp((char*)CHUNK_TYPE(data,index), "zTXt", 4)) {
			kdDebug(7034) << "We found a zTXt field\n";
			// we get the compression method after the key
			uchar* compressionMethod = &CHUNK_DATA(data,index,keysize+1);
			if ( *compressionMethod != 0x00 ) {
			    // then it isn't zlib compressed and we are sunk
			    kdDebug(7034) << "Non-standard compression method." << endl;
			    goto end;
			}
			// compressed string after the compression technique spec
			uchar* compressedText = &CHUNK_DATA(data, index, keysize+2);
			uint compressedTextSize = CHUNK_SIZE(data, index)-keysize-2;

			// security check, also considering overflow wraparound from the addition --
			// we may endup with a /smaller/ index if we wrap all the way around
			uint firstIndex       = (uint)(compressedText - data);
			uint onePastLastIndex = firstIndex + compressedTextSize;
			if ( onePastLastIndex > fileSize || onePastLastIndex <= firstIndex)
			    goto end;

			uLongf uncompressedLen = compressedTextSize * 2; // just a starting point
			int zlibResult;
			do {
			    arr.resize(uncompressedLen);
			    zlibResult = uncompress((Bytef*)arr.data(), &uncompressedLen,
						    compressedText, compressedTextSize);
			    if (Z_OK == zlibResult) {
				// then it is all OK
				arr.resize(uncompressedLen);
			    } else if (Z_BUF_ERROR == zlibResult) {
				// the uncompressedArray needs to be larger
				// kdDebug(7034) << "doubling size for decompression" << endl;
				uncompressedLen *= 2;

                                // DoS protection. can't be bigger than 64k
                                if ( uncompressedLen > 131072 )
                                    break;
			    } else {
				// something bad happened
				goto end;
			    }
			} while (Z_BUF_ERROR == zlibResult);

			if (Z_OK != zlibResult)
			    goto end;
		    } else if (!strncmp((char*)CHUNK_TYPE(data,index), "tEXt", 4)) {
			kdDebug(7034) << "We found a tEXt field\n";
			// the text comes after the key, but isn't null terminated
			uchar* text = &CHUNK_DATA(data,index, keysize+1);
			uint textsize = CHUNK_SIZE(data, index)-keysize-1;

			// security check, also considering overflow wraparound from the addition --
			// we may endup with a /smaller/ index if we wrap all the way around
			uint firstIndex       = (uint)(text - data);
			uint onePastLastIndex = firstIndex + textsize;

			if ( onePastLastIndex > fileSize || onePastLastIndex <= firstIndex)
			    goto end;

			arr.resize(textsize);
			arr = TQByteArray(textsize).duplicate((const char*)text,
							     textsize);
			
		    } else {
			kdDebug(7034) << "We found a field, not expected though\n";
			goto end;
		    }
		    appendItem(commentGroup,
			       TQString(reinterpret_cast<char*>(key)),
			       TQString(arr));
		    
		    kdDebug(7034) << "adding " << key << " / "
				  << TQString(arr) << endl;

		    index += CHUNK_SIZE(data, index) + CHUNK_HEADER_SIZE;
                }
            }
        }
    }
end:
    delete[] data;
    return true;
}

#include "tdefile_png.moc"