zipios  2.2.0
Zipios – a small C++ library that provides easy access to .zip files.
zipfile.cpp
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1 /*
2  Zipios -- a small C++ library that provides easy access to .zip files.
3 
4  Copyright (C) 2000-2007 Thomas Sondergaard
5  Copyright (C) 2015-2019 Made to Order Software Corporation
6 
7  This library is free software; you can redistribute it and/or
8  modify it under the terms of the GNU Lesser General Public
9  License as published by the Free Software Foundation; either
10  version 2.1 of the License, or (at your option) any later version.
11 
12  This library is distributed in the hope that it will be useful,
13  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  Lesser General Public License for more details.
16 
17  You should have received a copy of the GNU Lesser General Public
18  License along with this library; if not, write to the Free Software
19  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21 
29 #include "zipios/zipfile.hpp"
30 
32 
33 #include "backbuffer.hpp"
36 #include "zipinputstream.hpp"
37 #include "zipoutputstream.hpp"
38 
39 #include <fstream>
40 
41 
53 namespace zipios
54 {
55 
56 
307 {
308  // open zipfile, read 4 last bytes close file
309  // create ZipFile object.
310  uint32_t start_offset;
311  {
312  std::ifstream ifs(name, std::ios::in | std::ios::binary);
313  ifs.seekg(-4, std::ios::end);
314  zipRead(ifs, start_offset);
315  // todo: add support for 64 bit (files of more than 4Gb)
316  }
317  return ZipFile::pointer_t(new ZipFile(name, start_offset, 4));
318 }
319 
320 
330  //: m_vs(...) -- auto-init
331 {
332 }
333 
334 
353 ZipFile::ZipFile(std::string const& filename, offset_t s_off, offset_t e_off)
354  : FileCollection(filename)
355  , m_vs(s_off, e_off)
356 {
357  std::ifstream zipfile(m_filename, std::ios::in | std::ios::binary);
358  if(!zipfile)
359  {
360  throw IOException("Error opening Zip archive file for reading in binary mode.");
361  }
362 
363  // Find and read the End of Central Directory.
365  {
366  BackBuffer bb(zipfile, m_vs);
367  ssize_t read_p(-1);
368  for(;;)
369  {
370  if(read_p < 0)
371  {
372  if(!bb.readChunk(read_p))
373  {
374  throw FileCollectionException("Unable to find zip structure: End-of-central-directory");
375  }
376  }
377  // Note: this is pretty fast since it reads from 'bb' which
378  // caches the buffer the readChunk() function just read.
379  //
380  if(eocd.read(bb, read_p))
381  {
382  // found it!
383  break;
384  }
385  --read_p;
386  }
387  }
388 
389  // Position read pointer to start of first entry in central dir.
390  m_vs.vseekg(zipfile, eocd.getOffset(), std::ios::beg);
391 
392  // TBD -- is that ", 0" still necessary? (With VC2012 and better)
393  // Give the second argument in the next line to keep Visual C++ quiet
394  //m_entries.resize(eocd.totalCount(), 0);
395  m_entries.resize(eocd.getCount());
396 
397  size_t const max_entry(eocd.getCount());
398  for(size_t entry_num(0); entry_num < max_entry; ++entry_num)
399  {
401  m_entries[entry_num].get()->read(zipfile);
402  }
403 
404  // Consistency check #1:
405  // The virtual seeker position is exactly the start offset of the
406  // Central Directory plus the Central Directory size
407  //
408  offset_t const pos(m_vs.vtellg(zipfile));
409  if(static_cast<offset_t>(eocd.getOffset() + eocd.getCentralDirectorySize()) != pos)
410  {
411  throw FileCollectionException("Zip file consistency problem. Zip file data fields are inconsistent with zip file layout.");
412  }
413 
414  // Consistency check #2:
415  // Are local headers consistent with CD headers?
416  //
417  for(auto it = m_entries.begin(); it != m_entries.end(); ++it)
418  {
425  m_vs.vseekg(zipfile, (*it)->getEntryOffset(), std::ios::beg);
426  ZipLocalEntry zlh;
427  zlh.read(zipfile);
428  if(!zipfile || !zlh.isEqual(**it))
429  {
430  throw FileCollectionException("Zip file consistency problem. Zip file data fields are inconsistent with zip file layout.");
431  }
432  }
433 
434  // we are all good!
435  m_valid = true;
436 }
437 
438 
446 {
447  return FileCollection::pointer_t(new ZipFile(*this));
448 }
449 
450 
457 {
458  close();
459 }
460 
461 
496 ZipFile::stream_pointer_t ZipFile::getInputStream(std::string const& entry_name, MatchPath matchpath)
497 {
498  mustBeValid();
499 
500  FileEntry::pointer_t entry(getEntry(entry_name, matchpath));
501  if(entry)
502  {
503  stream_pointer_t zis(new ZipInputStream(m_filename, entry->getEntryOffset() + m_vs.startOffset()));
504  return zis;
505  }
506 
507  // no entry with that name (and match) available
508  return nullptr;
509 }
510 
511 
521 void ZipFile::saveCollectionToArchive(std::ostream & os, FileCollection & collection, std::string const & zip_comment)
522 {
523  try
524  {
525  ZipOutputStream output_stream(os);
526 
527  output_stream.setComment(zip_comment);
528 
529  FileEntry::vector_t entries(collection.entries());
530  for(auto it(entries.begin()); it != entries.end(); ++it)
531  {
532  output_stream.putNextEntry(*it);
533  // get an InputStream if available (i.e. directories do not have an input stream)
534  if(!(*it)->isDirectory())
535  {
536  FileCollection::stream_pointer_t is(collection.getInputStream((*it)->getName()));
537  if(is)
538  {
539  output_stream << is->rdbuf();
540  }
541  }
542  }
543 
544  // clean up mantually so we can get any exception
545  // (so we avoid having exceptions gobbled by the destructor)
546  output_stream.closeEntry();
547  output_stream.finish();
548  output_stream.close();
549  }
550  catch(...)
551  {
552  os.setstate(std::ios::failbit);
553  throw;
554  }
555 }
556 
557 
558 } // zipios namespace
559 
560 // Local Variables:
561 // mode: cpp
562 // indent-tabs-mode: nil
563 // c-basic-offset: 4
564 // tab-width: 4
565 // End:
566 
567 // vim: ts=4 sw=4 et
virtual FileEntry::pointer_t getEntry(std::string const &name, MatchPath matchpath=MatchPath::MATCH) const
Get an entry from this collection.
Define zipios::ZipInputStream.
virtual pointer_t clone() const override
Create a clone of this ZipFile.
Definition: zipfile.cpp:445
The zipios namespace includes the Zipios library definitions.
Definition: backbuffer.cpp:35
std::shared_ptr< FileCollection > pointer_t
size_t getCount() const
Retrieve the number of entries.
static void saveCollectionToArchive(std::ostream &os, FileCollection &collection, std::string const &zip_comment="")
Create a Zip archive from the specified FileCollection.
Definition: zipfile.cpp:521
offset_t startOffset() const
Return the start offset.
Various exceptions used throughout the Zipios library, all based on zipios::Exception.
void zipRead(std::istream &is, uint32_t &value)
offset_t getOffset() const
Retrieve the offset of the Central Directory.
void setComment(std::string const &comment)
Set the global comment.
std::shared_ptr< std::istream > stream_pointer_t
A shared pointer to an input stream.
virtual FileEntry::vector_t entries() const
Retrieve the array of entries.
Define the zipios::ZipOutputStream class.
An implementation of the FileEntry for Zip archives.
ZipFile()
Initialize a ZipFile object.
Definition: zipfile.cpp:329
void close()
Close the current stream.
virtual stream_pointer_t getInputStream(std::string const &entry_name, MatchPath matchpath=MatchPath::MATCH)=0
Retrieve pointer to an istream.
FileEntry::vector_t m_entries
Marker at the end of a Zip archive file.
VirtualSeeker m_vs
Definition: zipfile.hpp:61
virtual ~ZipFile() override
Clean up the ZipFile object.
Definition: zipfile.cpp:456
An IOException is used to signal an I/O error.
virtual void close()
Close the current FileEntry of this FileCollection.
virtual void mustBeValid() const
Check whether the collection is valid.
void putNextEntry(FileEntry::pointer_t entry)
Add an entry to the output stream.
static pointer_t openEmbeddedZipFile(std::string const &name)
Open a zip archive that was previously appened to another file.
Definition: zipfile.cpp:306
A specialization of ZipLocalEntry for.
virtual void read(std::istream &is) override
Read one local entry from is.
Declaration of the zipios::ZipCentralDirectoryEntry, which represents a directory Zip archive entry...
FileCollectionException is used to signal a FileCollection problem.
The header file for zipios::BackBuffer.
Define the zipios::ZipFile class.
void vseekg(std::istream &is, offset_t offset, std::ios::seekdir sd) const
Seek within the embedded file.
Declaration of the zipios::ZipEndOfCentralDirectory class.
std::streamoff offset_t
Base class for various file collections.
virtual bool isEqual(FileEntry const &file_entry) const override
Compare two file entries for equality.
virtual stream_pointer_t getInputStream(std::string const &entry_name, MatchPath matchpath=MatchPath::MATCH) override
Retrieve a pointer to a file in the Zip archive.
Definition: zipfile.cpp:496
ssize_t readChunk(ssize_t &read_pointer)
Read a chunk of data.
Definition: backbuffer.cpp:141
std::streampos vtellg(std::istream &is) const
Current position within the sub-file.
std::shared_ptr< FileEntry > pointer_t
Definition: fileentry.hpp:78
A ZipOutputStream to allow for data to be compressed zlib.
size_t getCentralDirectorySize() const
Retrieve the size of the Central Directory in bytes.
To read a file by chunk from the end.
Definition: backbuffer.hpp:41
bool read(::zipios::buffer_t const &buf, size_t pos)
Attempt to read an ZipEndOfCentralDirectory structure.
The ZipInputStream to read data from a Zip archive.
void finish()
Finish up the output by flushing anything left.
std::vector< pointer_t > vector_t
Definition: fileentry.hpp:79