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Diffstat (limited to 'kfile-plugins/png/kfile_png.cpp')
| -rw-r--r-- | kfile-plugins/png/kfile_png.cpp | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/kfile-plugins/png/kfile_png.cpp b/kfile-plugins/png/kfile_png.cpp new file mode 100644 index 00000000..c3e54b66 --- /dev/null +++ b/kfile-plugins/png/kfile_png.cpp @@ -0,0 +1,315 @@ +/* This file is part of the KDE project + * Copyright (C) 2001, 2002 Rolf Magnus <[email protected]> + * + * 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" |