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tdegraphics/kfile-plugins/png/kfile_png.cpp

316 lines
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/* 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 "kfile_png.h"
#include <kurl.h>
#include <kprocess.h>
#include <klocale.h>
#include <kgenericfactory.h>
#include <kdebug.h>
#include <qcstring.h>
#include <qfile.h>
#include <qdatetime.h>
#include <qdict.h>
#include <qvalidator.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(kfile_png, PngFactory("kfile_png"))
KPngPlugin::KPngPlugin(QObject *parent, const char *name,
const QStringList &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, QVariant::String, 0);
// technical group
group = addGroupInfo(info, "Technical", i18n("Technical Details"));
item = addItemInfo(group, "Dimensions", i18n("Dimensions"), QVariant::Size);
setHint( item, KFileMimeTypeInfo::Size );
setUnit(item, KFileMimeTypeInfo::Pixels);
item = addItemInfo(group, "BitDepth", i18n("Bit Depth"), QVariant::Int);
setUnit(item, KFileMimeTypeInfo::BitsPerPixel);
addItemInfo(group, "ColorMode", i18n("Color Mode"), QVariant::String);
addItemInfo(group, "Compression", i18n("Compression"), QVariant::String);
addItemInfo(group, "InterlaceMode", i18n("Interlace Mode"),QVariant::String);
}
bool KPngPlugin::readInfo( KFileMetaInfo& info, uint what)
{
if ( info.path().isEmpty() ) // remote file
return false;
QFile f(info.path());
if ( !f.open(IO_ReadOnly) )
return false;
QIODevice::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", QSize(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;
QByteArray 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 = QByteArray(textsize).duplicate((const char*)text,
textsize);
} else {
kdDebug(7034) << "We found a field, not expected though\n";
goto end;
}
appendItem(commentGroup,
QString(reinterpret_cast<char*>(key)),
QString(arr));
kdDebug(7034) << "adding " << key << " / "
<< QString(arr) << endl;
index += CHUNK_SIZE(data, index) + CHUNK_HEADER_SIZE;
}
}
}
}
end:
delete[] data;
return true;
}
#include "kfile_png.moc"