diff options
Diffstat (limited to 'parts/documentation/protocols/chm/chmfile.cpp')
| -rw-r--r-- | parts/documentation/protocols/chm/chmfile.cpp | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/parts/documentation/protocols/chm/chmfile.cpp b/parts/documentation/protocols/chm/chmfile.cpp new file mode 100644 index 00000000..f69d354a --- /dev/null +++ b/parts/documentation/protocols/chm/chmfile.cpp @@ -0,0 +1,197 @@ +/* This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public License + along with this library; see the file COPYING.LIB. If not, write to + the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. +*/ + +#include <qfile.h> +#include "chmfile.h" +#include "decompress.h" + +uint Chm::getEncInt(QFile& f, uint &value) const +{ + int c; + uint result = 0; + ulong count = 0; + + do + { + c = f.getch(); + result <<= 7; + result |= (c & 0x7F); + count++; + } while (c & 0x80); + + value = result; + return count; +} + +uint Chm::getName(QFile& f, QString& name) const +{ + int len = f.getch(); + char *buf = new char[len]; + f.readBlock(buf, len); + name = QString::fromUtf8(buf, len); + if (name.startsWith("/")) + name = name.lower(); + delete [] buf; + return len + 1; +} + +uint Chm::getIntel32(QFile& f) const +{ + uint value = f.getch() | f.getch() << 8 | f.getch() << 16 | f.getch() << 24; + return value; +} + +uint Chm::getIntel64(QFile& f) const +{ + uint value = getIntel32(f); + f.at(f.at() + 4); + return value; +} + +bool Chm::getChunk(QFile& f, uint chunkSize, ChmDirectoryMap& directoryMap) const +{ + char tag[4]; + if (f.readBlock(tag, 4) != 4) return false; + + if (!qstrncmp(tag, "PMGL", 4)) + { + uint quickref_length = getIntel32(f); + f.at(f.at() + 12); + + uint pos = 20; + while (pos < chunkSize - quickref_length) + { + uint section, offset, length; + QString name; + pos += getName(f, name); + pos += getEncInt(f, section); + pos += getEncInt(f, offset); + pos += getEncInt(f, length); + directoryMap[name] = ChmDirTableEntry(section, offset, length); + if (name.endsWith(".hhc")) + directoryMap["/@contents"] = ChmDirTableEntry(section, offset, length); + } + + return (f.at(f.at() + quickref_length)); + } + else if (!qstrncmp(tag, "PMGI", 4)) + { + // evaluation of the index chunk is not yet implemented => skip it + return f.at(f.at() + chunkSize - 4); + } + else + { + return false; + } +} + +bool Chm::read(const QString& fileSpec, ChmDirectoryMap& dirMap, QByteArray& contents) const +{ + QFile f(fileSpec); + if (!f.open(IO_ReadOnly)) return false; + + // read CHM file header + char tag[4]; + if (f.readBlock(tag, 4) != 4 || qstrncmp(tag, "ITSF", 4)) return false; + uint chm_version = getIntel32(f); + if (!f.at(f.at() + 0x30)) return false; + + // read header section table + uint section_0_offset = getIntel64(f); + uint section_0_length = getIntel64(f); + uint section_1_offset = getIntel64(f); + uint section_1_length = getIntel64(f); + + uint contentStart = 0; + if (chm_version >= 3) contentStart = getIntel32(f); + + // read directory header + if (!f.at(section_1_offset)) return false; + if (f.readBlock(tag, 4) != 4 || qstrncmp(tag, "ITSP", 4)) return false; + if (!f.at(f.at() + 12)) return false; + uint directory_chunk_size = getIntel32(f); + if (!f.at(f.at() + 24)) return false; + uint num_directory_chunks = getIntel32(f); + if (!f.at(f.at() + 36)) return false; + + // read directory table + for (uint i = 0; i < num_directory_chunks; i++) + if (!getChunk(f, directory_chunk_size, dirMap)) return false; + + // current position is start of content area + if (chm_version < 3) contentStart = f.at(); + + // read reset table + if (!f.at(contentStart)) return false; + uint resetTableOffset = + dirMap["::DataSpace/Storage/MSCompressed/Transform/{7FC28940-9D31-11D0-9B27-00A0C91E9C7C}/InstanceData/ResetTable"].offset; + if (!f.at(f.at() + resetTableOffset + 4)) return false; + uint numResetTableEntries = getIntel32(f); + if (!f.at(f.at() + 8)) return false; + uint uncompressedLength = getIntel64(f); + uint compressedLength = getIntel64(f); + uint blockSize = getIntel64(f); + uint *resetTable = new uint[numResetTableEntries + 1]; + + for (uint i = 0; i < numResetTableEntries; i++) + resetTable[i] = getIntel64(f); + + resetTable[numResetTableEntries] = compressedLength; + + // read compressed contents + if (!f.at(contentStart)) return false; + uint contentsOffset = dirMap["::DataSpace/Storage/MSCompressed/Content"].offset; + if (!f.at(f.at() + contentsOffset)) return false; + char *compressedContents = new char[compressedLength]; + if ((uint)f.readBlock(compressedContents, compressedLength) != compressedLength) return false; + + f.close(); + + // allocate buffer for uncompressed contents + char *uncompressedContents = new char[uncompressedLength]; + + // get window size + uint window = 1; + uint tmp = blockSize; + while (tmp >>= 1) window++; + + // decompress + uint outlen = uncompressedLength; + int res = 1; + + for (uint i = 0; i < numResetTableEntries; i++) + { + if (!(i & 1)) LZXinit(window); + + uint inlen = resetTable[i+1] - resetTable[i]; + res = LZXdecompress((uchar*)&compressedContents[resetTable[i]], + inlen, + (uchar*)uncompressedContents + i * blockSize, + (outlen < blockSize) ? outlen : blockSize); + if (res) break; + outlen -= blockSize; + } + + delete [] resetTable; + delete [] compressedContents; + + if (res == 0) + contents.duplicate(uncompressedContents, uncompressedLength); + + delete [] uncompressedContents; + + return (res == 0); +} |