From 9d33840bab4e10d701dd36f9b8660f6a13f05afe Mon Sep 17 00:00:00 2001 From: Francesco Montorsi Date: Tue, 13 Jan 2009 18:09:21 +0000 Subject: [PATCH] reorder the classes, putting first the basic ones and towards the end of the file the derived ones; document OnSysXXX functions return values to allow the user to implement new stream classes without the need of guessing from source code the inner workings of the streams (closes #4487) git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58076 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775 --- interface/wx/stream.h | 746 ++++++++++++++++++++++-------------------- 1 file changed, 390 insertions(+), 356 deletions(-) diff --git a/interface/wx/stream.h b/interface/wx/stream.h index da9e126d7a..6398891aa7 100644 --- a/interface/wx/stream.h +++ b/interface/wx/stream.h @@ -6,95 +6,103 @@ // Licence: wxWindows license ///////////////////////////////////////////////////////////////////////////// + /** - @class wxCountingOutputStream + These enumeration values are returned by various functions in the context + of wxStream classes. +*/ +enum wxStreamError +{ + wxSTREAM_NO_ERROR = 0, //!< No error occurred. + wxSTREAM_EOF, //!< EOF reached in Read() or similar. + wxSTREAM_WRITE_ERROR, //!< generic write error on the last write call. + wxSTREAM_READ_ERROR //!< generic read error on the last read call. +}; - wxCountingOutputStream is a specialized output stream which does not write any - data anywhere, instead it counts how many bytes would get written if this were a - normal stream. This can sometimes be useful or required if some data gets - serialized to a stream or compressed by using stream compression and thus the - final size of the stream cannot be known other than pretending to write the stream. - One case where the resulting size would have to be known is if the data has - to be written to a piece of memory and the memory has to be allocated before - writing to it (which is probably always the case when writing to a memory stream). +/** + @class wxStreamBase + + This class is the base class of most stream related classes in wxWidgets. + It must not be used directly. @library{wxbase} @category{streams} + + @see wxStreamBuffer */ -class wxCountingOutputStream : public wxOutputStream +class wxStreamBase { public: /** - Creates a wxCountingOutputStream object. + Creates a dummy stream object. It doesn't do anything. */ - wxCountingOutputStream(); + wxStreamBase(); /** Destructor. */ - virtual ~wxCountingOutputStream(); + virtual ~wxStreamBase(); /** - Returns the current size of the stream. + This function returns the last error. */ - size_t GetSize() const; -}; - + wxStreamError GetLastError() const; + /** + Returns the length of the stream in bytes. If the length cannot be + determined (this is always the case for socket streams for example), + returns ::wxInvalidOffset. -/** - @class wxBufferedInputStream + @since 2.5.4 + */ + virtual wxFileOffset GetLength() const; - This stream acts as a cache. It caches the bytes read from the specified - input stream (see wxFilterInputStream). - It uses wxStreamBuffer and sets the default in-buffer size to 1024 bytes. - This class may not be used without some other stream to read the data - from (such as a file stream or a memory stream). + /** + This function returns the size of the stream. + For example, for a file it is the size of the file. - @library{wxbase} - @category{streams} + @warning + There are streams which do not have size by definition, such as socket + streams. In that cases, GetSize() returns 0 so you should always test its + return value. + */ + virtual size_t GetSize() const; - @see wxStreamBuffer, wxInputStream, wxBufferedOutputStream -*/ -class wxBufferedInputStream : public wxFilterInputStream -{ -public: /** - Constructor using the provided buffer or default. + Returns @true if no error occurred on the stream. - @param stream - The associated low-level stream. - @param buffer - The buffer to use if non-@NULL. Notice that the ownership of this - buffer is taken by the stream, i.e. it will delete it. If this - parameter is @NULL a default 1KB buffer is used. + @see GetLastError() */ - wxBufferedInputStream(wxInputStream& stream, - wxStreamBuffer *buffer = NULL); + virtual bool IsOk() const; /** - Constructor allowing to specify the size of the buffer. + Returns @true if the streams supports seeking to arbitrary offsets. + */ + virtual bool IsSeekable() const; - This is just a more convenient alternative to creating a wxStreamBuffer - of the given size and using the other overloaded constructor of this - class. +protected: - @param stream - The associated low-level stream. - @param bufsize - The size of the buffer, in bytes. + /** + Internal function. + It is called when the stream needs to change the current position. - @since 2.9.0 - */ - wxBufferedInputStream(wxInputStream& stream, size_t bufsize); + @param pos + Offset to seek to. + @param mode + One of the ::wxSeekMode enumeration values. - /** - Destructor. + @return The new stream position or ::wxInvalidOffset on error. */ - virtual ~wxBufferedInputStream(); -}; + virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode); + /** + Internal function. + It is called when the stream needs to know the real position. + @return The current stream position. + */ + virtual wxFileOffset OnSysTell() const; +}; /** @class wxStreamBuffer @@ -400,6 +408,11 @@ public: @class wxOutputStream wxOutputStream is an abstract base class which may not be used directly. + It is the base class of all streams which provide a Write() function, + i.e. which can be used to output data (e.g. to a file, to a socket, etc). + + If you want to create your own output stream, you'll need to derive from this + class and implement the protected OnSysWrite() function only. @library{wxbase} @category{streams} @@ -477,245 +490,206 @@ public: by one of the two streams. */ wxOutputStream& Write(wxInputStream& stream_in); -}; +protected: + /** + Internal function. It is called when the stream wants to write data of the + specified size @a bufsize into the given @a buffer. -/** - Enumeration values used by wxFilterClassFactory. -*/ -enum wxStreamProtocolType -{ - wxSTREAM_PROTOCOL, //!< wxFileSystem protocol (should be only one). - wxSTREAM_MIMETYPE, //!< MIME types the stream handles. - wxSTREAM_ENCODING, //!< The HTTP Content-Encodings the stream handles. - wxSTREAM_FILEEXT //!< File extensions the stream handles. + It should return the size that was actually wrote (which maybe zero if + @a bufsize is zero or if an error occurred; in this last case the internal + variable @c m_lasterror should be appropriately set). + */ + size_t OnSysWrite(const void* buffer, size_t bufsize); }; /** - @class wxFilterClassFactory - - Allows the creation of filter streams to handle compression formats such - as gzip and bzip2. - - For example, given a filename you can search for a factory that will - handle it and create a stream to decompress it: + @class wxInputStream - @code - factory = wxFilterClassFactory::Find(filename, wxSTREAM_FILEEXT); - if (factory) - stream = factory->NewStream(new wxFFileInputStream(filename)); - @endcode + wxInputStream is an abstract base class which may not be used directly. + It is the base class of all streams which provide a Read() function, + i.e. which can be used to read data from a source (e.g. a file, a socket, etc). - wxFilterClassFactory::Find can also search for a factory by MIME type, - HTTP encoding or by wxFileSystem protocol. - The available factories can be enumerated using wxFilterClassFactory::GetFirst() - and wxFilterClassFactory::GetNext(). + If you want to create your own input stream, you'll need to derive from this + class and implement the protected OnSysRead() function only. @library{wxbase} @category{streams} - - @see wxFilterInputStream, wxFilterOutputStream, wxArchiveClassFactory, - @ref overview_archive */ -class wxFilterClassFactory : public wxObject +class wxInputStream : public wxStreamBase { public: /** - Returns @true if this factory can handle the given protocol, MIME type, HTTP - encoding or file extension. - - When using @c wxSTREAM_FILEEXT for the second parameter, the first parameter - can be a complete filename rather than just an extension. + Creates a dummy input stream. */ - bool CanHandle(const wxString& protocol, - wxStreamProtocolType type = wxSTREAM_PROTOCOL) const; + wxInputStream(); /** - A static member that finds a factory that can handle a given protocol, MIME - type, HTTP encoding or file extension. Returns a pointer to the class - factory if found, or @NULL otherwise. - It does not give away ownership of the factory. - - When using @c wxSTREAM_FILEEXT for the second parameter, the first parameter - can be a complete filename rather than just an extension. + Destructor. */ - static const wxFilterClassFactory* Find(const wxString& protocol, - wxStreamProtocolType type = wxSTREAM_PROTOCOL); + virtual ~wxInputStream(); - //@{ /** - GetFirst and GetNext can be used to enumerate the available factories. - For example, to list them: - - @code - wxString list; - const wxFilterClassFactory *factory = wxFilterClassFactory::GetFirst(); - - while (factory) { - list << factory->GetProtocol() << _T("\n"); - factory = factory->GetNext(); - } - @endcode - - GetFirst()/GetNext() return a pointer to a factory or @NULL if no more - are available. They do not give away ownership of the factory. + Returns @true if some data is available in the stream right now, so that + calling Read() wouldn't block. */ - static const wxFilterClassFactory* GetFirst(); - const wxFilterClassFactory* GetNext() const; - //@} + virtual bool CanRead() const; /** - Returns the wxFileSystem protocol supported by this factory. - Equivalent to @code wxString(*GetProtocols()) @endcode. + Returns @true after an attempt has been made to read past the end of the + stream. */ - wxString GetProtocol() const; + virtual bool Eof() const; /** - Returns the protocols, MIME types, HTTP encodings or file extensions - supported by this factory, as an array of null terminated strings. - It does not give away ownership of the array or strings. - - For example, to list the file extensions a factory supports: - - @code - wxString list; - const wxChar *const *p; + Returns the first character in the input queue and removes it, + blocking until it appears if necessary. - for (p = factory->GetProtocols(wxSTREAM_FILEEXT); *p; p++) - list << *p << _T("\n"); - @endcode + On success returns a value between 0 - 255; on end of file returns @c wxEOF. */ - virtual const wxChar * const* GetProtocols(wxStreamProtocolType type = wxSTREAM_PROTOCOL) const = 0; + int GetC(); - //@{ /** - Create a new input or output stream to decompress or compress a given stream. - - If the parent stream is passed as a pointer then the new filter stream - takes ownership of it. If it is passed by reference then it does not. + Returns the last number of bytes read. */ - virtual wxFilterInputStream* NewStream(wxInputStream& stream) const = 0; - virtual wxFilterOutputStream* NewStream(wxOutputStream& stream) const = 0; - virtual wxFilterInputStream* NewStream(wxInputStream* stream) const = 0; - virtual wxFilterOutputStream* NewStream(wxOutputStream* stream) const = 0; - //@} + virtual size_t LastRead() const; /** - Remove the file extension of @a location if it is one of the file - extensions handled by this factory. + Returns the first character in the input queue without removing it. */ - wxString PopExtension(const wxString& location) const; + virtual char Peek(); /** - Adds this class factory to the list returned by GetFirst()/GetNext(). - - It is not necessary to do this to use the filter streams. It is usually - used when implementing streams, typically the implementation will - add a static instance of its factory class. + Reads the specified amount of bytes and stores the data in buffer. + To check if the call was successfull you must use LastRead() to check + if this call did actually read @a size bytes (if it didn't, GetLastError() + should return a meaningful value). - It can also be used to change the order of a factory already in the list, - bringing it to the front. This isn't a thread safe operation so can't be - done when other threads are running that will be using the list. + @warning + The buffer absolutely needs to have at least the specified size. - The list does not take ownership of the factory. + @return This function returns a reference on the current object, so the + user can test any states of the stream right away. */ - void PushFront(); + virtual wxInputStream& Read(void* buffer, size_t size); /** - Removes this class factory from the list returned by GetFirst()/GetNext(). - Removing from the list isn't a thread safe operation so can't be done - when other threads are running that will be using the list. + Reads data from the input queue and stores it in the specified output stream. + The data is read until an error is raised by one of the two streams. - The list does not own the factories, so removing a factory does not delete it. + @return This function returns a reference on the current object, so the + user can test any states of the stream right away. */ - void Remove(); -}; + wxInputStream& Read(wxOutputStream& stream_out); + /** + Changes the stream current position. + @param pos + Offset to seek to. + @param mode + One of wxFromStart, wxFromEnd, wxFromCurrent. -/** - @class wxFilterOutputStream + @return The new stream position or ::wxInvalidOffset on error. + */ + virtual wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart); - A filter stream has the capability of a normal stream but it can be placed - on top of another stream. So, for example, it can compress, encrypt the data - which are passed to it and write them to another stream. + /** + Returns the current stream position. + */ + virtual wxFileOffset TellI() const; - @note - The use of this class is exactly the same as of wxOutputStream. - Only a constructor differs and it is documented below. + /** + This function is only useful in read mode. + It is the manager of the "Write-Back" buffer. This buffer acts like a + temporary buffer where data which has to be read during the next read IO + call are put. This is useful when you get a big block of data which you + didn't want to read: you can replace them at the top of the input queue + by this way. - @library{wxbase} - @category{streams} + Be very careful about this call in connection with calling SeekI() on + the same stream. Any call to SeekI() will invalidate any previous call + to this method (otherwise you could SeekI() to one position, "unread" a + few bytes there, SeekI() to another position and data would be either + lost or corrupted). + + @return Returns the amount of bytes saved in the Write-Back buffer. + */ + size_t Ungetch(const void* buffer, size_t size); - @see wxFilterClassFactory, wxFilterInputStream -*/ -class wxFilterOutputStream : public wxOutputStream -{ -public: - //@{ /** - Initializes a "filter" stream. + This function acts like the previous one except that it takes only one + character: it is sometimes shorter to use than the generic function. + */ + bool Ungetch(char c); - If the parent stream is passed as a pointer then the new filter stream - takes ownership of it. If it is passed by reference then it does not. +protected: + + /** + Internal function. It is called when the stream wants to read data of the + specified size @a bufsize and wants it to be placed inside @a buffer. + + It should return the size that was actually read or zero if EOF has been + reached or an error occurred (in this last case the internal @c m_lasterror + variable should be set accordingly as well). */ - wxFilterOutputStream(wxOutputStream& stream); - wxFilterOutputStream(wxOutputStream* stream); - //@} + size_t OnSysRead(void* buffer, size_t bufsize); }; -/** - @class wxFilterInputStream - A filter stream has the capability of a normal stream but it can be placed on - top of another stream. So, for example, it can uncompress or decrypt the data which - are read from another stream and pass it to the requester. +/** + @class wxCountingOutputStream - @note - The interface of this class is the same as that of wxInputStream. - Only a constructor differs and it is documented below. + wxCountingOutputStream is a specialized output stream which does not write any + data anywhere, instead it counts how many bytes would get written if this were a + normal stream. This can sometimes be useful or required if some data gets + serialized to a stream or compressed by using stream compression and thus the + final size of the stream cannot be known other than pretending to write the stream. + One case where the resulting size would have to be known is if the data has + to be written to a piece of memory and the memory has to be allocated before + writing to it (which is probably always the case when writing to a memory stream). @library{wxbase} @category{streams} - - @see wxFilterClassFactory, wxFilterOutputStream */ -class wxFilterInputStream : public wxInputStream +class wxCountingOutputStream : public wxOutputStream { public: - //@{ /** - Initializes a "filter" stream. + Creates a wxCountingOutputStream object. + */ + wxCountingOutputStream(); - If the parent stream is passed as a pointer then the new filter stream - takes ownership of it. If it is passed by reference then it does not. + /** + Destructor. */ - wxFilterInputStream(wxInputStream& stream); - wxFilterInputStream(wxInputStream* stream); - //@} -}; + virtual ~wxCountingOutputStream(); + /** + Returns the current size of the stream. + */ + size_t GetSize() const; +}; /** - @class wxBufferedOutputStream - - This stream acts as a cache. It caches the bytes to be written to the specified - output stream (See wxFilterOutputStream). The data is only written when the - cache is full, when the buffered stream is destroyed or when calling SeekO(). + @class wxBufferedInputStream - This class may not be used without some other stream to write the data - to (such as a file stream or a memory stream). + This stream acts as a cache. It caches the bytes read from the specified + input stream (see wxFilterInputStream). + It uses wxStreamBuffer and sets the default in-buffer size to 1024 bytes. + This class may not be used without some other stream to read the data + from (such as a file stream or a memory stream). @library{wxbase} @category{streams} - @see wxStreamBuffer, wxOutputStream + @see wxStreamBuffer, wxInputStream, wxBufferedOutputStream */ -class wxBufferedOutputStream : public wxFilterOutputStream +class wxBufferedInputStream : public wxFilterInputStream { public: /** @@ -728,8 +702,8 @@ public: buffer is taken by the stream, i.e. it will delete it. If this parameter is @NULL a default 1KB buffer is used. */ - wxBufferedOutputStream(wxOutputStream& stream, - wxStreamBuffer *buffer = NULL); + wxBufferedInputStream(wxInputStream& stream, + wxStreamBuffer *buffer = NULL); /** Constructor allowing to specify the size of the buffer. @@ -745,237 +719,297 @@ public: @since 2.9.0 */ - wxBufferedOutputStream(wxOutputStream& stream, size_t bufsize); + wxBufferedInputStream(wxInputStream& stream, size_t bufsize); /** - Destructor. Calls Sync() and destroys the internal buffer. + Destructor. */ - virtual ~wxBufferedOutputStream(); + virtual ~wxBufferedInputStream(); +}; - /** - Calls Sync() and changes the stream position. - */ - virtual wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart); - /** - Flushes the buffer and calls Sync() on the parent stream. - */ - virtual void Sync(); -}; +/** + Enumeration values used by wxFilterClassFactory. +*/ +enum wxStreamProtocolType +{ + wxSTREAM_PROTOCOL, //!< wxFileSystem protocol (should be only one). + wxSTREAM_MIMETYPE, //!< MIME types the stream handles. + wxSTREAM_ENCODING, //!< The HTTP Content-Encodings the stream handles. + wxSTREAM_FILEEXT //!< File extensions the stream handles. +}; /** - @class wxInputStream + @class wxFilterClassFactory - wxInputStream is an abstract base class which may not be used directly. + Allows the creation of filter streams to handle compression formats such + as gzip and bzip2. + + For example, given a filename you can search for a factory that will + handle it and create a stream to decompress it: + + @code + factory = wxFilterClassFactory::Find(filename, wxSTREAM_FILEEXT); + if (factory) + stream = factory->NewStream(new wxFFileInputStream(filename)); + @endcode + + wxFilterClassFactory::Find can also search for a factory by MIME type, + HTTP encoding or by wxFileSystem protocol. + The available factories can be enumerated using wxFilterClassFactory::GetFirst() + and wxFilterClassFactory::GetNext(). @library{wxbase} @category{streams} + + @see wxFilterInputStream, wxFilterOutputStream, wxArchiveClassFactory, + @ref overview_archive */ -class wxInputStream : public wxStreamBase +class wxFilterClassFactory : public wxObject { public: /** - Creates a dummy input stream. - */ - wxInputStream(); + Returns @true if this factory can handle the given protocol, MIME type, HTTP + encoding or file extension. - /** - Destructor. + When using @c wxSTREAM_FILEEXT for the second parameter, the first parameter + can be a complete filename rather than just an extension. */ - virtual ~wxInputStream(); + bool CanHandle(const wxString& protocol, + wxStreamProtocolType type = wxSTREAM_PROTOCOL) const; /** - Returns @true if some data is available in the stream right now, so that - calling Read() wouldn't block. - */ - virtual bool CanRead() const; + A static member that finds a factory that can handle a given protocol, MIME + type, HTTP encoding or file extension. Returns a pointer to the class + factory if found, or @NULL otherwise. + It does not give away ownership of the factory. - /** - Returns @true after an attempt has been made to read past the end of the - stream. + When using @c wxSTREAM_FILEEXT for the second parameter, the first parameter + can be a complete filename rather than just an extension. */ - virtual bool Eof() const; + static const wxFilterClassFactory* Find(const wxString& protocol, + wxStreamProtocolType type = wxSTREAM_PROTOCOL); + //@{ /** - Returns the first character in the input queue and removes it, - blocking until it appears if necessary. + GetFirst and GetNext can be used to enumerate the available factories. + For example, to list them: - On success returns a value between 0 - 255; on end of file returns @c wxEOF. - */ - int GetC(); + @code + wxString list; + const wxFilterClassFactory *factory = wxFilterClassFactory::GetFirst(); - /** - Returns the last number of bytes read. + while (factory) { + list << factory->GetProtocol() << _T("\n"); + factory = factory->GetNext(); + } + @endcode + + GetFirst()/GetNext() return a pointer to a factory or @NULL if no more + are available. They do not give away ownership of the factory. */ - virtual size_t LastRead() const; + static const wxFilterClassFactory* GetFirst(); + const wxFilterClassFactory* GetNext() const; + //@} /** - Returns the first character in the input queue without removing it. + Returns the wxFileSystem protocol supported by this factory. + Equivalent to @code wxString(*GetProtocols()) @endcode. */ - virtual char Peek(); + wxString GetProtocol() const; /** - Reads the specified amount of bytes and stores the data in buffer. - - @warning - The buffer absolutely needs to have at least the specified size. + Returns the protocols, MIME types, HTTP encodings or file extensions + supported by this factory, as an array of null terminated strings. + It does not give away ownership of the array or strings. - @return This function returns a reference on the current object, so the - user can test any states of the stream right away. - */ - virtual wxInputStream& Read(void* buffer, size_t size); + For example, to list the file extensions a factory supports: - /** - Reads data from the input queue and stores it in the specified output stream. - The data is read until an error is raised by one of the two streams. + @code + wxString list; + const wxChar *const *p; - @return This function returns a reference on the current object, so the - user can test any states of the stream right away. + for (p = factory->GetProtocols(wxSTREAM_FILEEXT); *p; p++) + list << *p << _T("\n"); + @endcode */ - wxInputStream& Read(wxOutputStream& stream_out); + virtual const wxChar * const* GetProtocols(wxStreamProtocolType type = wxSTREAM_PROTOCOL) const = 0; + //@{ /** - Changes the stream current position. - - @param pos - Offset to seek to. - @param mode - One of wxFromStart, wxFromEnd, wxFromCurrent. + Create a new input or output stream to decompress or compress a given stream. - @return The new stream position or ::wxInvalidOffset on error. + If the parent stream is passed as a pointer then the new filter stream + takes ownership of it. If it is passed by reference then it does not. */ - virtual wxFileOffset SeekI(wxFileOffset pos, wxSeekMode mode = wxFromStart); + virtual wxFilterInputStream* NewStream(wxInputStream& stream) const = 0; + virtual wxFilterOutputStream* NewStream(wxOutputStream& stream) const = 0; + virtual wxFilterInputStream* NewStream(wxInputStream* stream) const = 0; + virtual wxFilterOutputStream* NewStream(wxOutputStream* stream) const = 0; + //@} /** - Returns the current stream position. + Remove the file extension of @a location if it is one of the file + extensions handled by this factory. */ - virtual wxFileOffset TellI() const; + wxString PopExtension(const wxString& location) const; /** - This function is only useful in read mode. - It is the manager of the "Write-Back" buffer. This buffer acts like a - temporary buffer where data which has to be read during the next read IO - call are put. This is useful when you get a big block of data which you - didn't want to read: you can replace them at the top of the input queue - by this way. + Adds this class factory to the list returned by GetFirst()/GetNext(). - Be very careful about this call in connection with calling SeekI() on - the same stream. Any call to SeekI() will invalidate any previous call - to this method (otherwise you could SeekI() to one position, "unread" a - few bytes there, SeekI() to another position and data would be either - lost or corrupted). + It is not necessary to do this to use the filter streams. It is usually + used when implementing streams, typically the implementation will + add a static instance of its factory class. - @return Returns the amount of bytes saved in the Write-Back buffer. + It can also be used to change the order of a factory already in the list, + bringing it to the front. This isn't a thread safe operation so can't be + done when other threads are running that will be using the list. + + The list does not take ownership of the factory. */ - size_t Ungetch(const void* buffer, size_t size); + void PushFront(); /** - This function acts like the previous one except that it takes only one - character: it is sometimes shorter to use than the generic function. + Removes this class factory from the list returned by GetFirst()/GetNext(). + Removing from the list isn't a thread safe operation so can't be done + when other threads are running that will be using the list. + + The list does not own the factories, so removing a factory does not delete it. */ - bool Ungetch(char c); + void Remove(); }; + /** - These enumeration values are returned by various functions in the context - of wxStream classes. + @class wxFilterOutputStream + + A filter stream has the capability of a normal stream but it can be placed + on top of another stream. So, for example, it can compress, encrypt the data + which are passed to it and write them to another stream. + + @note + The use of this class is exactly the same as of wxOutputStream. + Only a constructor differs and it is documented below. + + @library{wxbase} + @category{streams} + + @see wxFilterClassFactory, wxFilterInputStream */ -enum wxStreamError +class wxFilterOutputStream : public wxOutputStream { - wxSTREAM_NO_ERROR = 0, //!< No error occurred. - wxSTREAM_EOF, //!< EOF reached in Read() or similar. - wxSTREAM_WRITE_ERROR, //!< generic write error on the last write call. - wxSTREAM_READ_ERROR //!< generic read error on the last read call. +public: + //@{ + /** + Initializes a "filter" stream. + + If the parent stream is passed as a pointer then the new filter stream + takes ownership of it. If it is passed by reference then it does not. + */ + wxFilterOutputStream(wxOutputStream& stream); + wxFilterOutputStream(wxOutputStream* stream); + //@} }; + + /** - @class wxStreamBase + @class wxFilterInputStream - This class is the base class of most stream related classes in wxWidgets. - It must not be used directly. + A filter stream has the capability of a normal stream but it can be placed on + top of another stream. So, for example, it can uncompress or decrypt the data which + are read from another stream and pass it to the requester. + + @note + The interface of this class is the same as that of wxInputStream. + Only a constructor differs and it is documented below. @library{wxbase} @category{streams} - @see wxStreamBuffer + @see wxFilterClassFactory, wxFilterOutputStream */ -class wxStreamBase +class wxFilterInputStream : public wxInputStream { public: + //@{ /** - Creates a dummy stream object. It doesn't do anything. - */ - wxStreamBase(); + Initializes a "filter" stream. - /** - Destructor. + If the parent stream is passed as a pointer then the new filter stream + takes ownership of it. If it is passed by reference then it does not. */ - virtual ~wxStreamBase(); + wxFilterInputStream(wxInputStream& stream); + wxFilterInputStream(wxInputStream* stream); + //@} +}; - /** - This function returns the last error. - */ - wxStreamError GetLastError() const; - /** - Returns the length of the stream in bytes. If the length cannot be - determined (this is always the case for socket streams for example), - returns ::wxInvalidOffset. - @since 2.5.4 - */ - virtual wxFileOffset GetLength() const; +/** + @class wxBufferedOutputStream - /** - This function returns the size of the stream. - For example, for a file it is the size of the file. + This stream acts as a cache. It caches the bytes to be written to the specified + output stream (See wxFilterOutputStream). The data is only written when the + cache is full, when the buffered stream is destroyed or when calling SeekO(). - @warning - There are streams which do not have size by definition, such as socket - streams. In that cases, GetSize returns 0 so you should always test its - return value. - */ - virtual size_t GetSize() const; + This class may not be used without some other stream to write the data + to (such as a file stream or a memory stream). + + @library{wxbase} + @category{streams} + @see wxStreamBuffer, wxOutputStream +*/ +class wxBufferedOutputStream : public wxFilterOutputStream +{ +public: /** - Returns @true if no error occurred on the stream. + Constructor using the provided buffer or default. - @see GetLastError() + @param stream + The associated low-level stream. + @param buffer + The buffer to use if non-@NULL. Notice that the ownership of this + buffer is taken by the stream, i.e. it will delete it. If this + parameter is @NULL a default 1KB buffer is used. */ - virtual bool IsOk() const; + wxBufferedOutputStream(wxOutputStream& stream, + wxStreamBuffer *buffer = NULL); /** - Returns @true if the streams supports seeking to arbitrary offsets. - */ - virtual bool IsSeekable() const; + Constructor allowing to specify the size of the buffer. - /** - Internal function. It is called when the stream wants to read data of the - specified size. It should return the size that was actually read. - */ - size_t OnSysRead(void* buffer, size_t bufsize); + This is just a more convenient alternative to creating a wxStreamBuffer + of the given size and using the other overloaded constructor of this + class. - /** - See OnSysRead(). - */ - size_t OnSysWrite(const void* buffer, size_t bufsize); + @param stream + The associated low-level stream. + @param bufsize + The size of the buffer, in bytes. + @since 2.9.0 + */ + wxBufferedOutputStream(wxOutputStream& stream, size_t bufsize); -protected: + /** + Destructor. Calls Sync() and destroys the internal buffer. + */ + virtual ~wxBufferedOutputStream(); /** - Internal function. - It is called when the stream needs to change the current position. + Calls Sync() and changes the stream position. */ - virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode); + virtual wxFileOffset SeekO(wxFileOffset pos, wxSeekMode mode = wxFromStart); /** - Internal function. - It is called when the stream needs to know the real position. + Flushes the buffer and calls Sync() on the parent stream. */ - virtual wxFileOffset OnSysTell() const; + virtual void Sync(); }; + -- 2.45.2