quazipfile.h

#ifndef QUA_ZIPFILE_H
#define QUA_ZIPFILE_H

/*
-- A kind of "standard" GPL license statement --
QuaZIP - a Qt/C++ wrapper for the ZIP/UNZIP package
Copyright (C) 2005-2008 Sergey A. Tachenov

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; either version 2 of the License, or (at your
option) any later version.

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; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

-- A kind of "standard" GPL license statement ends here --

See COPYING file for GPL.

You are also permitted to use QuaZIP under the terms of LGPL (see
COPYING.LGPL). You are free to choose either license, but please note
that QuaZIP makes use of Qt, which is not licensed under LGPL. So if
you are using Open Source edition of Qt, you therefore MUST use GPL for
your code based on QuaZIP, since it would be also based on Qt in this
case. If you are Qt commercial license owner, then you are free to use
QuaZIP as long as you respect either GPL or LGPL for QuaZIP code.
 **/

#include <QIODevice>

#include "quazip.h"
#include "quazipnewinfo.h"

/// A file inside ZIP archive.
/** \class QuaZipFile quazipfile.h <quazip/quazipfile.h>
 * This is the most interesting class. Not only it provides C++
 * interface to the ZIP/UNZIP package, but also integrates it with Qt by
 * subclassing QIODevice. This makes possible to access files inside ZIP
 * archive using QTextStream or QDataStream, for example. Actually, this
 * is the main purpose of the whole QuaZIP library.
 *
 * You can either use existing QuaZip instance to create instance of
 * this class or pass ZIP archive file name to this class, in which case
 * it will create internal QuaZip object. See constructors' descriptions
 * for details. Writing is only possible with the existing instance.
 *
 * \section quazipfile-sequential Sequential or random-access?
 *
 * At the first thought, QuaZipFile has fixed size, the start and the
 * end and should be therefore considered random-access device. But
 * there is one major obstacle to making it random-access: ZIP/UNZIP API
 * does not support seek() operation and the only way to implement it is
 * through reopening the file and re-reading to the required position,
 * but this is prohibitely slow.
 *
 * Therefore, QuaZipFile is considered to be a sequential device. This
 * has advantage of availability of the ungetChar() operation (QIODevice
 * does not implement it properly for non-sequential devices unless they
 * support seek()). Disadvantage is a somewhat strange behaviour of the
 * size() and pos() functions. This should be kept in mind while using
 * this class.
 *
 **/
class QuaZipFile: public QIODevice {
  Q_OBJECT
  private:
    QuaZip *zip;
    QString fileName;
    QuaZip::CaseSensitivity caseSensitivity;
    bool raw;
    qint64 writePos;
    // these two are for writing raw files
    ulong uncompressedSize;
    quint32 crc;
    bool internal;
    int zipError;
    // these are not supported nor implemented
    QuaZipFile(const QuaZipFile& that);
    QuaZipFile& operator=(const QuaZipFile& that);
    void resetZipError()const {setZipError(UNZ_OK);}
    // const, but sets zipError!
    void setZipError(int zipError)const;
  protected:
    /// Implementation of the QIODevice::readData().
    qint64 readData(char *data, qint64 maxSize);
    /// Implementation of the QIODevice::writeData().
    qint64 writeData(const char *data, qint64 maxSize);
  public:
    /// Constructs a QuaZipFile instance.
    /** You should use setZipName() and setFileName() or setZip() before
     * trying to call open() on the constructed object.
     **/
    QuaZipFile();
    /// Constructs a QuaZipFile instance.
    /** \a parent argument specifies this object's parent object.
     *
     * You should use setZipName() and setFileName() or setZip() before
     * trying to call open() on the constructed object.
     **/
    QuaZipFile(QObject *parent);
    /// Constructs a QuaZipFile instance.
    /** \a parent argument specifies this object's parent object and \a
     * zipName specifies ZIP archive file name.
     *
     * You should use setFileName() before trying to call open() on the
     * constructed object.
     *
     * QuaZipFile constructed by this constructor can be used for read
     * only access. Use QuaZipFile(QuaZip*,QObject*) for writing.
     **/
    QuaZipFile(const QString& zipName, QObject *parent =NULL);
    /// Constructs a QuaZipFile instance.
    /** \a parent argument specifies this object's parent object, \a
     * zipName specifies ZIP archive file name and \a fileName and \a cs
     * specify a name of the file to open inside archive.
     *
     * QuaZipFile constructed by this constructor can be used for read
     * only access. Use QuaZipFile(QuaZip*,QObject*) for writing.
     *
     * \sa QuaZip::setCurrentFile()
     **/
    QuaZipFile(const QString& zipName, const QString& fileName,
        QuaZip::CaseSensitivity cs =QuaZip::csDefault, QObject *parent =NULL);
    /// Constructs a QuaZipFile instance.
    /** \a parent argument specifies this object's parent object.
     *
     * \a zip is the pointer to the existing QuaZip object. This
     * QuaZipFile object then can be used to read current file in the
     * \a zip or to write to the file inside it.
     *
     * \warning Using this constructor for reading current file can be
     * tricky. Let's take the following example:
     * \code
     * QuaZip zip("archive.zip");
     * zip.open(QuaZip::mdUnzip);
     * zip.setCurrentFile("file-in-archive");
     * QuaZipFile file(&zip);
     * file.open(QIODevice::ReadOnly);
     * // ok, now we can read from the file
     * file.read(somewhere, some);
     * zip.setCurrentFile("another-file-in-archive"); // oops...
     * QuaZipFile anotherFile(&zip);
     * anotherFile.open(QIODevice::ReadOnly);
     * anotherFile.read(somewhere, some); // this is still ok...
     * file.read(somewhere, some); // and this is NOT
     * \endcode
     * So, what exactly happens here? When we change current file in the
     * \c zip archive, \c file that references it becomes invalid
     * (actually, as far as I understand ZIP/UNZIP sources, it becomes
     * closed, but QuaZipFile has no means to detect it).
     *
     * Summary: do not close \c zip object or change its current file as
     * long as QuaZipFile is open. Even better - use another constructors
     * which create internal QuaZip instances, one per object, and
     * therefore do not cause unnecessary trouble. This constructor may
     * be useful, though, if you already have a QuaZip instance and do
     * not want to access several files at once. Good example:
     * \code
     * QuaZip zip("archive.zip");
     * zip.open(QuaZip::mdUnzip);
     * // first, we need some information about archive itself
     * QByteArray comment=zip.getComment();
     * // and now we are going to access files inside it
     * QuaZipFile file(&zip);
     * for(bool more=zip.goToFirstFile(); more; more=zip.goToNextFile()) {
     *   file.open(QIODevice::ReadOnly);
     *   // do something cool with file here
     *   file.close(); // do not forget to close!
     * }
     * zip.close();
     * \endcode
     **/
    QuaZipFile(QuaZip *zip, QObject *parent =NULL);
    /// Destroys a QuaZipFile instance.
    /** Closes file if open, destructs internal QuaZip object (if it
     * exists and \em is internal, of course).
     **/
    virtual ~QuaZipFile();
    /// Returns the ZIP archive file name.
    /** If this object was created by passing QuaZip pointer to the
     * constructor, this function will return that QuaZip's file name
     * (or null string if that object does not have file name yet).
     *
     * Otherwise, returns associated ZIP archive file name or null
     * string if there are no name set yet.
     *
     * \sa setZipName() getFileName()
     **/
    QString getZipName()const;
    /// Returns a pointer to the associated QuaZip object.
    /** Returns \c NULL if there is no associated QuaZip or it is
     * internal (so you will not mess with it).
     **/
    QuaZip* getZip()const;
    /// Returns file name.
    /** This function returns file name you passed to this object either
     * by using
     * QuaZipFile(const QString&,const QString&,QuaZip::CaseSensitivity,QObject*)
     * or by calling setFileName(). Real name of the file may differ in
     * case if you used case-insensitivity.
     *
     * Returns null string if there is no file name set yet. This is the
     * case when this QuaZipFile operates on the existing QuaZip object
     * (constructor QuaZipFile(QuaZip*,QObject*) or setZip() was used).
     * 
     * \sa getActualFileName
     **/
    QString getFileName()const {return fileName;}
    /// Returns case sensitivity of the file name.
    /** This function returns case sensitivity argument you passed to
     * this object either by using
     * QuaZipFile(const QString&,const QString&,QuaZip::CaseSensitivity,QObject*)
     * or by calling setFileName().
     *
     * Returns unpredictable value if getFileName() returns null string
     * (this is the case when you did not used setFileName() or
     * constructor above).
     *
     * \sa getFileName
     **/
    QuaZip::CaseSensitivity getCaseSensitivity()const {return caseSensitivity;}
    /// Returns the actual file name in the archive.
    /** This is \em not a ZIP archive file name, but a name of file inside
     * archive. It is not necessary the same name that you have passed
     * to the
     * QuaZipFile(const QString&,const QString&,QuaZip::CaseSensitivity,QObject*),
     * setFileName() or QuaZip::setCurrentFile() - this is the real file
     * name inside archive, so it may differ in case if the file name
     * search was case-insensitive.
     *
     * Equivalent to calling getCurrentFileName() on the associated
     * QuaZip object. Returns null string if there is no associated
     * QuaZip object or if it does not have a current file yet. And this
     * is the case if you called setFileName() but did not open the
     * file yet. So this is perfectly fine:
     * \code
     * QuaZipFile file("somezip.zip");
     * file.setFileName("somefile");
     * QString name=file.getName(); // name=="somefile"
     * QString actual=file.getActualFileName(); // actual is null string
     * file.open(QIODevice::ReadOnly);
     * QString actual=file.getActualFileName(); // actual can be "SoMeFiLe" on Windows
     * \endcode
     *
     * \sa getZipName(), getFileName(), QuaZip::CaseSensitivity
     **/
    QString getActualFileName()const;
    /// Sets the ZIP archive file name.
    /** Automatically creates internal QuaZip object and destroys
     * previously created internal QuaZip object, if any.
     *
     * Will do nothing if this file is already open. You must close() it
     * first.
     **/
    void setZipName(const QString& zipName);
    /// Returns \c true if the file was opened in raw mode.
    /** If the file is not open, the returned value is undefined.
     *
     * \sa open(OpenMode,int*,int*,bool,const char*)
     **/
    bool isRaw()const {return raw;}
    /// Binds to the existing QuaZip instance.
    /** This function destroys internal QuaZip object, if any, and makes
     * this QuaZipFile to use current file in the \a zip object for any
     * further operations. See QuaZipFile(QuaZip*,QObject*) for the
     * possible pitfalls.
     *
     * Will do nothing if the file is currently open. You must close()
     * it first.
     **/
    void setZip(QuaZip *zip);
    /// Sets the file name.
    /** Will do nothing if at least one of the following conditions is
     * met:
     * - ZIP name has not been set yet (getZipName() returns null
     *   string).
     * - This QuaZipFile is associated with external QuaZip. In this
     *   case you should call that QuaZip's setCurrentFile() function
     *   instead!
     * - File is already open so setting the name is meaningless.
     *
     * \sa QuaZip::setCurrentFile
     **/
    void setFileName(const QString& fileName, QuaZip::CaseSensitivity cs =QuaZip::csDefault);
    /// Opens a file for reading.
    /** Returns \c true on success, \c false otherwise.
     * Call getZipError() to get error code.
     *
     * \note Since ZIP/UNZIP API provides buffered reading only,
     * QuaZipFile does not support unbuffered reading. So do not pass
     * QIODevice::Unbuffered flag in \a mode, or open will fail.
     **/
    virtual bool open(OpenMode mode);
    /// Opens a file for reading.
    /** \overload
     * Argument \a password specifies a password to decrypt the file. If
     * it is NULL then this function behaves just like open(OpenMode).
     **/
    bool open(OpenMode mode, const char *password)
    {return open(mode, NULL, NULL, false, password);}
    /// Opens a file for reading.
    /** \overload
     * Argument \a password specifies a password to decrypt the file.
     *
     * An integers pointed by \a method and \a level will receive codes
     * of the compression method and level used. See unzip.h.
     *
     * If raw is \c true then no decompression is performed.
     *
     * \a method should not be \c NULL. \a level can be \c NULL if you
     * don't want to know the compression level.
     **/
    bool open(OpenMode mode, int *method, int *level, bool raw, const char *password =NULL);
    /// Opens a file for writing.
    /** \a info argument specifies information about file. It should at
     * least specify a correct file name. Also, it is a good idea to
     * specify correct timestamp (by default, current time will be
     * used). See QuaZipNewInfo.
     *
     * Arguments \a password and \a crc provide necessary information
     * for crypting. Note that you should specify both of them if you
     * need crypting. If you do not, pass \c NULL as password, but you
     * still need to specify \a crc if you are going to use raw mode
     * (see below).
     *
     * Arguments \a method and \a level specify compression method and
     * level.
     *
     * If \a raw is \c true, no compression is performed. In this case,
     * \a crc and uncompressedSize field of the \a info are required.
     *
     * Arguments \a windowBits, \a memLevel, \a strategy provide zlib
     * algorithms tuning. See deflateInit2() in zlib.
     **/
    bool open(OpenMode mode, const QuaZipNewInfo& info,
        const char *password =NULL, quint32 crc =0,
        int method =Z_DEFLATED, int level =Z_DEFAULT_COMPRESSION, bool raw =false,
        int windowBits =-MAX_WBITS, int memLevel =DEF_MEM_LEVEL, int strategy =Z_DEFAULT_STRATEGY);
    /// Returns \c true, but \ref quazipfile-sequential "beware"!
    virtual bool isSequential()const;
    /// Returns current position in the file.
    /** Implementation of the QIODevice::pos(). When reading, this
     * function is a wrapper to the ZIP/UNZIP unztell(), therefore it is
     * unable to keep track of the ungetChar() calls (which is
     * non-virtual and therefore is dangerous to reimplement). So if you
     * are using ungetChar() feature of the QIODevice, this function
     * reports incorrect value until you get back characters which you
     * ungot.
     *
     * When writing, pos() returns number of bytes already written
     * (uncompressed unless you use raw mode).
     *
     * \note Although
     * \ref quazipfile-sequential "QuaZipFile is a sequential device"
     * and therefore pos() should always return zero, it does not,
     * because it would be misguiding. Keep this in mind.
     *
     * This function returns -1 if the file or archive is not open.
     *
     * Error code returned by getZipError() is not affected by this
     * function call.
     **/
    virtual qint64 pos()const;
    /// Returns \c true if the end of file was reached.
    /** This function returns \c false in the case of error. This means
     * that you called this function on either not open file, or a file
     * in the not open archive or even on a QuaZipFile instance that
     * does not even have QuaZip instance associated. Do not do that
     * because there is no means to determine whether \c false is
     * returned because of error or because end of file was reached.
     * Well, on the other side you may interpret \c false return value
     * as "there is no file open to check for end of file and there is
     * no end of file therefore".
     *
     * When writing, this function always returns \c true (because you
     * are always writing to the end of file).
     *
     * Error code returned by getZipError() is not affected by this
     * function call.
     **/
    virtual bool atEnd()const;
    /// Returns file size.
    /** This function returns csize() if the file is open for reading in
     * raw mode, usize() if it is open for reading in normal mode and
     * pos() if it is open for writing.
     *
     * Returns -1 on error, call getZipError() to get error code.
     *
     * \note This function returns file size despite that
     * \ref quazipfile-sequential "QuaZipFile is considered to be sequential device",
     * for which size() should return bytesAvailable() instead. But its
     * name would be very misguiding otherwise, so just keep in mind
     * this inconsistence.
     **/
    virtual qint64 size()const;
    /// Returns compressed file size.
    /** Equivalent to calling getFileInfo() and then getting
     * compressedSize field, but more convenient and faster.
     *
     * File must be open for reading before calling this function.
     *
     * Returns -1 on error, call getZipError() to get error code.
     **/
    qint64 csize()const;
    /// Returns uncompressed file size.
    /** Equivalent to calling getFileInfo() and then getting
     * uncompressedSize field, but more convenient and faster. See
     * getFileInfo() for a warning.
     *
     * File must be open for reading before calling this function.
     *
     * Returns -1 on error, call getZipError() to get error code.
     **/
    qint64 usize()const;
    /// Gets information about current file.
    /** This function does the same thing as calling
     * QuaZip::getCurrentFileInfo() on the associated QuaZip object,
     * but you can not call getCurrentFileInfo() if the associated
     * QuaZip is internal (because you do not have access to it), while
     * you still can call this function in that case.
     *
     * File must be open for reading before calling this function.
     *
     * Returns \c false in the case of an error.
     **/
    bool getFileInfo(QuaZipFileInfo *info);
    /// Closes the file.
    /** Call getZipError() to determine if the close was successful.
     **/
    virtual void close();
    /// Returns the error code returned by the last ZIP/UNZIP API call.
    int getZipError()const {return zipError;}
};

#endif