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Base: [skip ci] Add function to read the CD of a zip file from a std::istream

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This commit is contained in:
wmayer
2022-09-05 18:53:37 +02:00
parent 10d6a90be5
commit 3569b73965
3 changed files with 255 additions and 0 deletions
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2
src/Base/CMakeLists.txt
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@@ -277,6 +277,7 @@ SET(FreeCADBase_CPP_SRCS
ViewProj.cpp
Writer.cpp
XMLTools.cpp
ZipHeader.cpp
)
SET(SWIG_HEADERS
@@ -339,6 +340,7 @@ SET(FreeCADBase_HPP_SRCS
ViewProj.h
Writer.h
XMLTools.h
ZipHeader.h
)
SET(FreeCADBase_SRCS

171
src/Base/ZipHeader.cpp Normal file
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@@ -0,0 +1,171 @@
/***************************************************************************
* Copyright (c) 2022 Werner Mayer <wmayer[at]users.sourceforge.net> *
* *
* This file is part of the FreeCAD CAx development system. *
* *
* 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 "PreCompiled.h"
#include "ZipHeader.h"
#include <zipios++/zipinputstream.h>
using zipios::ConstEntryPointer;
using zipios::FileCollection;
using zipios::ZipHeader;
ZipHeader::ZipHeader(std::istream &inp, int s_off, int e_off)
: _input(inp)
, _vs(s_off, e_off)
{
init(_input);
}
/** Create a copy of this instance. */
FileCollection *ZipHeader::clone() const
{
return new ZipHeader(*this);
}
void ZipHeader::close()
{
_valid = false;
}
std::istream *ZipHeader::getInputStream(const ConstEntryPointer &entry)
{
if (!_valid)
throw zipios::InvalidStateException("Attempt to use an invalid FileCollection");
return getInputStream(entry->getName());
}
std::istream *ZipHeader::getInputStream(const std::string &entry_name, MatchPath matchpath)
{
if (!_valid)
throw zipios::InvalidStateException("Attempt to use an invalid ZipHeader");
zipios::ConstEntryPointer ent = getEntry(entry_name, matchpath);
if (!ent)
return nullptr;
else
return new zipios::ZipInputStream(_input,
static_cast<const zipios::ZipCDirEntry *>(ent.get())->getLocalHeaderOffset() + _vs.startOffset());
}
bool ZipHeader::init(std::istream &_zipfile)
{
// Check stream error state
if (!_zipfile) {
setError("Error reading from file");
return false;
}
_valid = readCentralDirectory(_zipfile);
return _valid;
}
bool ZipHeader::readCentralDirectory(std::istream &_zipfile)
{
// Find and read eocd.
if (!readEndOfCentralDirectory(_zipfile))
throw zipios::FCollException("Unable to find zip structure: End-of-central-directory");
// Position read pointer to start of first entry in central dir.
_vs.vseekg(_zipfile, _eocd.offset(), std::ios::beg);
int entry_num = 0;
// Giving the default argument in the next line to keep Visual C++ quiet
_entries.resize(_eocd.totalCount(), nullptr);
while ((entry_num < _eocd.totalCount())) {
zipios::ZipCDirEntry *ent = new zipios::ZipCDirEntry;
_entries[entry_num] = ent;
_zipfile >> *ent;
if (!_zipfile) {
if (_zipfile.bad())
throw zipios::IOException("Error reading zip file while reading zip file central directory");
else if (_zipfile.fail())
throw zipios::FCollException("Zip file consistency problem. Failure while reading zip file central directory");
else if (_zipfile.eof())
throw zipios::IOException("Premature end of file while reading zip file central directory");
}
++entry_num;
}
// Consistency check. eocd should start here
int pos = _vs.vtellg(_zipfile);
_vs.vseekg(_zipfile, 0, std::ios::end);
int remaining = static_cast<int>(_vs.vtellg(_zipfile)) - pos;
if (remaining != _eocd.eocdOffSetFromEnd())
throw zipios::FCollException("Zip file consistency problem. Zip file data fields are inconsistent with zip file layout");
// Consistency check 2, are local headers consistent with
// cd headers
if (!confirmLocalHeaders(_zipfile))
throw zipios::FCollException("Zip file consistency problem. Zip file data fields are inconsistent with zip file layout");
return true;
}
bool ZipHeader::readEndOfCentralDirectory(std::istream &_zipfile)
{
zipios::BackBuffer bb(_zipfile, _vs);
int read_p = -1;
bool found = false;
while (!found) {
if (read_p < 0) {
if (!bb.readChunk(read_p)) {
found = false;
break;
}
}
if (_eocd.read(bb, read_p)) {
found = true;
break;
}
--read_p;
}
return found;
}
bool ZipHeader::confirmLocalHeaders(std::istream &_zipfile)
{
zipios::Entries::const_iterator it;
zipios::ZipCDirEntry *ent;
int inconsistencies = 0;
zipios::ZipLocalEntry zlh;
for (it = _entries.begin(); it != _entries.end(); ++it) {
ent = static_cast<zipios::ZipCDirEntry *>((*it).get());
_vs.vseekg(_zipfile, ent->getLocalHeaderOffset(), std::ios::beg);
_zipfile >> zlh;
if (!_zipfile || zlh != *ent) {
inconsistencies++;
_zipfile.clear();
}
}
return !inconsistencies;
}
void ZipHeader::setError(std::string /*error_str*/)
{
_valid = false;
}

82
src/Base/ZipHeader.h Normal file
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@@ -0,0 +1,82 @@
/***************************************************************************
* Copyright (c) 2022 Werner Mayer <wmayer[at]users.sourceforge.net> *
* *
* This file is part of the FreeCAD CAx development system. *
* *
* 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 *
* *
***************************************************************************/
#ifndef ZIPIOS_ZIP_HEADER_H
#define ZIPIOS_ZIP_HEADER_H
#include <FCGlobal.h>
#include <zipios++/backbuffer.h>
#include <zipios++/fcoll.h>
namespace zipios
{
/** ZipHeader is a FileCollection, where the files are stored in a .zip file.
* The class is similar to zipios' ZipFile class with the difference that instead of
* a file a std::istream can be passed.
*/
class BaseExport ZipHeader : public FileCollection {
public:
/** Opens the zip file name. If the zip "file" is
embedded in a file that contains other data, e.g. a binary
program, the offset of the zip file start and end must be
specified.
@param inp The input stream of the zip file to open.
@param s_off Offset relative to the start of the file, that
indicates the beginning of the zip file.
@param e_off Offset relative to the end of the file, that
indicates the end of the zip file. The offset is a positive number,
even though the offset is towards the beginning of the file.
@throw FColException Thrown if the specified file name is not a valid zip
archive.
@throw IOException Thrown if an I/O problem is encountered, while the directory
of the specified zip archive is being read. */
explicit ZipHeader(std::istream &inp, int s_off = 0, int e_off = 0);
/** Create a copy of this instance. */
FileCollection *clone() const override;
~ZipHeader() override = default;
void close() override;
std::istream *getInputStream(const ConstEntryPointer &entry) override;
std::istream *getInputStream(const string &entry_name, MatchPath matchpath = MATCH) override;
private:
std::istream& _input;
VirtualSeeker _vs;
EndOfCentralDirectory _eocd;
bool init(std::istream &_zipfile);
bool readCentralDirectory(std::istream &_zipfile);
bool readEndOfCentralDirectory(std::istream &_zipfile);
bool confirmLocalHeaders(std::istream &_zipfile);
void setError(std::string error_str);
};
} //namespace zipios
#endif // ZIPIOS_ZIP_HEADER_H