Some improvements to the zip stream docs thanks to helpful feedback

from Andrew Ziem, Stas Sergeev and Artur Kornacki.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@33058 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Michael Wetherell 2005-03-25 22:32:27 +00:00
parent f1cbd8fac7
commit df467a9d74
3 changed files with 69 additions and 20 deletions

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@ -10,7 +10,8 @@
\section{Archive formats such as zip}\label{wxarc}
The archive classes handle archive formats such as zip, tar, rar and cab.
Currently only the wxZip classes are included.
Currently only the wxZip classes are included. wxTar classes are under
development at \urlref{wxCode}{http://wxcode.sf.net}.
For each archive type, there are the following classes (using zip here
as an example):
@ -65,31 +66,39 @@ For example:
\helpref{Archive formats such as zip}{wxarc}
\helpref{GetNextEntry()}{wxarchiveinputstreamgetnextentry} returns an
entry object containing the meta-data for the next entry in the archive
(and gives away ownership). Reading from the input stream then returns
the entry's data. Eof() becomes true after an attempt has been made to
read past the end of the entry's data.
\helpref{GetNextEntry()}{wxarchiveinputstreamgetnextentry} returns a pointer
to entry object containing the meta-data for the next entry in the archive
(and gives away ownership). Reading from the input stream then returns the
entry's data. Eof() becomes true after an attempt has been made to read past
the end of the entry's data.
When there are no more entries, GetNextEntry() returns NULL and sets Eof().
\begin{verbatim}
wxDEFINE_SCOPED_PTR_TYPE(wxZipEntry);
// 'smart pointer' type created with wxDEFINE_SCOPED_PTR_TYPE
wxZipEntryPtr entry;
wxFFileInputStream in(_T("test.zip"));
wxZipInputStream zip(in);
wxTextInputStream txt(zip);
wxString data;
while (entry.reset(zip.GetNextEntry()), entry.get() != NULL)
{
wxString name = entry->GetName(); // access meta-data
txt >> data; // access data
// access meta-data
wxString name = entry->GetName();
// read 'zip' to access the entry's data
}
\end{verbatim}
The \helpref{smart pointer}{wxscopedptr} type {\em wxZipEntryPtr}
can be created like this:
\begin{verbatim}
#include <wx/ptr_scpd.h>
wxDEFINE_SCOPED_PTR_TYPE(wxZipEntry);
\end{verbatim}
\subsection{Modifying an archive}\label{wxarcmodify}
@ -103,18 +112,22 @@ much more efficient than transferring the data using Read() and Write()
since it will copy them without decompressing and recompressing them.
In general modifications are not possible without rewriting the archive,
though it may be possible in some limited cases. Even then, rewriting
the archive is usually a better choice since a failure can be handled
without losing the whole archive.
though it may be possible in some limited cases. Even then, rewriting the
archive is usually a better choice since a failure can be handled without
losing the whole
archive. \helpref{wxTempFileOutputStream}{wxtempfileoutputstream} can
be helpful to do this.
For example to delete all entries matching the pattern "*.txt":
\begin{verbatim}
wxFFileInputStream in(_T("in.zip"));
wxFFileOutputStream out(_T("out.zip"));
wxFFileInputStreamPtr in(new wxFFileInputStream(_T("test.zip")));
wxTempFileOutputStream out(_T("test.zip"));
wxZipInputStream inzip(in);
wxZipInputStream inzip(*in);
wxZipOutputStream outzip(out);
// 'smart pointer' type created with wxDEFINE_SCOPED_PTR_TYPE
wxZipEntryPtr entry;
// transfer any meta-data for the archive as a whole (the zip comment
@ -127,7 +140,22 @@ For example to delete all entries matching the pattern "*.txt":
if (!outzip.CopyEntry(entry.release(), inzip))
break;
bool success = inzip.Eof() && outzip.Close();
// close the input stream by releasing the pointer to it, do this
// before closing the output stream so that the file can be replaced
in.reset();
// you can check for success as follows
bool success = inzip.Eof() && outzip.Close() && out.Commit();
\end{verbatim}
The \helpref{smart pointer}{wxscopedptr} types {\em wxZipEntryPtr}
and {\em wxFFileInputStreamPtr} can be created like this:
\begin{verbatim}
#include <wx/ptr_scpd.h>
wxDEFINE_SCOPED_PTR_TYPE(wxZipEntry);
wxDEFINE_SCOPED_PTR_TYPE(wxFFileInputStream);
\end{verbatim}
@ -159,7 +187,7 @@ it is better to convert the local name to the archive's internal format
and search for that:
\begin{verbatim}
wxDEFINE_SCOPED_PTR_TYPE(wxZipEntry);
// 'smart pointer' type created with wxDEFINE_SCOPED_PTR_TYPE
wxZipEntryPtr entry;
// convert the local name we are looking for into the internal format
@ -251,7 +279,8 @@ So there is a class factory for each archive type, derived from
\helpref{wxArchiveClassFactory}{wxarchiveclassfactory}, which can create
the other classes.
For example, given {\it wxArchiveClassFactory* factory}:
For example, given {\it wxArchiveClassFactory* factory}, streams and
entries can be created like this:
\begin{verbatim}
// create streams without knowing their type
@ -263,6 +292,18 @@ For example, given {\it wxArchiveClassFactory* factory}:
\end{verbatim}
The \helpref{smart pointer}{wxscopedptr} types {\em wxArchiveInputStreamPtr},
{\em wxArchiveOutputStreamPtr} and {\em wxArchiveEntryPtr} would need to
have already have been defined, which could be done like this:
\begin{verbatim}
#include <wx/ptr_scpd.h>
wxDEFINE_SCOPED_PTR_TYPE(wxArchiveInputStream);
wxDEFINE_SCOPED_PTR_TYPE(wxArchiveOutputStream);
wxDEFINE_SCOPED_PTR_TYPE(wxArchiveEntry);
\end{verbatim}
The class factory itself can either be created explicitly:
\begin{verbatim}

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@ -502,6 +502,7 @@ libraries, and to provide enhanced functionality.
\twocolitem{\helpref{wxZlibInputStream}{wxzlibinputstream}}{Zlib (compression) input stream class}
\twocolitem{\helpref{wxZlibOutputStream}{wxzliboutputstream}}{Zlib (compression) output stream class}
\twocolitem{\helpref{wxZipInputStream}{wxzipinputstream}}{Input stream for reading from ZIP archives}
\twocolitem{\helpref{wxZipOutputStream}{wxzipoutputstream}}{Output stream for writing from ZIP archives}
\twocolitem{\helpref{wxSocketInputStream}{wxsocketinputstream}}{Socket input stream class}
\twocolitem{\helpref{wxSocketOutputStream}{wxsocketoutputstream}}{Socket output stream class}
\end{twocollist}

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@ -433,6 +433,9 @@ the wxZipInputStream then returns the entry's data. Eof() becomes true
after an attempt has been made to read past the end of the entry's data.
When there are no more entries, GetNextEntry() returns NULL and sets Eof().
Note that in general zip entries are not seekable, and
wxZipInputStream::SeekI() always returns wxInvalidOffset.
\wxheading{Derived from}
\helpref{wxArchiveInputStream}{wxarchiveinputstream}
@ -467,6 +470,10 @@ no effect on the stream's data.
Compatibility constructor.
When this constructor is used, an emulation of seeking is
switched on for compatibility with previous versions. Note however,
that it is deprecated.
\membersection{wxZipInputStream::CloseEntry}\label{wxzipinputstreamcloseentry}