paszlib
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paszlib is a Pascal conversion of the standard zlib library: you don't need any external dependencies. It was implemented by Jacques Nomssi Nzali (his old homepage is dead, see a continuation of the project here). It is used in the FCL to implement the TCompressionStream class.
This class lets you compress and decompress .zip files.
The main unit of this package is paszlib. There are other, auxiliary units, but the only unit that needs to be included in a typical program is this one.
TZipper
TZipper implements support for compressing and decompressing .zip files, but does not support all zip compression methods.
Documentation
See official FPC documentation for Zipper.
Examples
Zip files
Create a zip file named as first parameter. Treats all other parameters as filenames to add, so you can specify e.g.
zipper newzip.zip autoexec.bat config.sys
uses
Zipper;
var
OurZipper: TZipper;
I: Integer;
begin
OurZipper := TZipper.Create;
try
// Define the file name of the zip file to be created
OurZipper.FileName := ParamStr(1);
for I := 2 to ParamCount do
// Specify the names of the files to be included in the zip as first argument
// The second argument is the name of the file as it appears in the zip and
// later in the file system after unzipping
OurZipper.Entries.AddFileEntry(ParamStr(I), ParamStr(I));
// Execute the zipping operation and write the zip file.
OurZipper.ZipAllFiles;
finally
OurZipper.Free;
end;
end.
Please note that the names of the files to be zipped are assumed to contain only characters of the old IBM PC character set (code page 437). For extended characters (UTF-8), see the section below.
Unzip files
Unzip all files in archive c:\test.zip into directory c:\windows\temp\
uses
Zipper;
var
UnZipper: TUnZipper;
begin
UnZipper := TUnZipper.Create;
try
UnZipper.FileName := 'c:\test.zip';
UnZipper.OutputPath := 'c:\windows\temp';
UnZipper.Examine;
UnZipper.UnZipAllFiles;
finally
UnZipper.Free;
end;
end.
Zip files with encoding filenames
As already noted, the zip file format originally was written to support only code page 437 of the IBM PC. In modern operating systems, however, the encoding of file names is much more general.
If your FPC is version 3.2 or newer you can take advantage of the boolean property UseLanguageEncoding. When set to true, file names are assumed to have the default encoding of FPC, in case of Lazarus programs this is UTF-8. Here any file name can be passed to the zipper (except for restrictions of the OS, of course).
In the following practical routine for FPC 3.2, a zip file is created from the files in a given directory so that file names are considered correctly:
uses
FileUtil, zipper;
function PackFiles(AZipFilename, ADirectory, AMask: String;
IncludingSubDirs: Boolean): Boolean;
var
OurZipper: TZipper;
list: TStringList;
i: Integer;
diskFileName, archiveFileName: String;
begin
Result := false;
ADirectory := IncludeTrailingPathDelimiter(ADirectory);
if DirectoryExists(ADirectory) then
begin
OurZipper := TZipper.Create;
try
// Set the name of the zip file to be created
OurZipper.FileName := AZipFileName;
// Read names of the files contained in ADirectory to a stringlist
list := TStringList.Create;
try
// FindAllFiles adds all file names matching the mask (e.g. '*.*')
// found in the given directory to the provided list.
// When IncludingSubDirs is true the search continues recursively in
// the subdirectories.
FindAllFiles(list, ADirectory, AMask, IncludingSubDirs);
for i := 0 to list.Count - 1 do
begin
// diskfilename is the name of the file to be zipped on the disk
diskFileName := list[i];
// archivefilename is the name of the file to be zipped as it appears
// in the zip. We remove the deirectory from the
archiveFileName := StringReplace(diskFileName, ADirectory, '', []);
// Store these filenames for the zipper
OurZipper.Entries.AddFileEntry(diskFileName, archiveFileName);
end;
finally
list.Free;
end;
// By default zipper writes file names in encoding of the IBM PC, CP437.
// UTF8 encoding is written when UseLanguageEncoding is true.
OurZipper.UseLanguageEncoding := true; // Requires FPC 3.2+
// create and write the zip file
OurZipper.ZipAllFiles;
Result := true;
finally
OurZipper.Free;
end;
end else
Result := false;
end;
If your FPC is older than v3.2 you must convert the ArchiveFileName argument to CP437 - of course, this is not possible for all characters, and thus you must be very careful with zipper in this case. Note also that the DiskFileName must have the encoding required by the operating system, otherwise the file will not be found for zipping; in case of FPC before 3.0 this may require another code page conversion.
Here is the adaption of above example for an FPC version before 3.2:
uses
FileUtil, LConvEncoding, LazUTF8, Zipper;
function PackFiles(AZipFilename, ADirectory, AMask: String;
IncludingSubdirs: Boolean): Boolean;
var
OurZipper: TZipper;
list: TStringList;
i: Integer;
diskFileName, archiveFileName: String;
begin
Result := false;
if AMask = '' then AMask := '*.*';
ADirectory := IncludeTrailingPathDelimiter(ADirectory);
if DirectoryExists(ADirectory) then
begin
OurZipper := TZipper.Create;
try
OurZipper.FileName := AZipFileName;
list := TStringList.Create;
try
// List all files in ADirectory and, if required, its sub-directories.
FindAllFiles(list, ADirectory, AMask, IncludingSubDirs);
for i := 0 to list.Count-1 do
begin
// Name of the file to be zipped on disk
diskFileName := list[i];
{$IF FPC_FullVersion < 30000}
diskFileName := UTF8ToWinCP(diskFileName);
{$IFEND}
// Name of the file to be zipped in the archive: we remove the
// common path and thus make the files relative to the directory
// into which they will be unzipped later.
archiveFileName := StringReplace(list[i], ADirectory, '', []);
archiveFileName := UTF8ToCP437(archiveFileName);
OurZipper.Entries.AddFileEntry(diskFileName, archiveFileName);
end;
finally
list.Free;
end;
// Execute zipping action and create zip file
OurZipper.ZipAllFiles;
Result := true;
finally
OurZipper.Free;
end;
end;
end;
Another restriction is the path delimiter in the archived file name. Specification of the zip format requires that forward slashes ('/') are used even in case of Windows. This is important for the one-parameter overload of TZipper.Entries.AddFileEntry(DiskfileName) which simply assume the archived file name to be equal to the DiskFileName, without any adaptions. Therefore, such a zip file will contain backslashes on Windows. It will unzip correctly on Windows, but not on Linux where the backslash is considered to be a valid file name character. It is highly recommended to use the two-parameter version of TZipper.Entries.AFileEntry(DiskFileName, ArchiveFileName) with ArchivefileName = DiskFileName because this procedure automatically replaces the path delimiters as required.
Unzip files with encoding filenames
uses
Zipper, LConvEncoding;
...
function EndPathCP866ToUTF8(AText:string):string;
var
c,i:integer;
s,s1,s2,chr:string;
begin
s:='';
c:=UTF8Length(AText);
for i:=c downto 1 do
begin
chr:=UTF8Copy(AText,i,1);
if ((not(chr='/')) and (not(chr='\')))or(i=c) then
begin
s:=UTF8Copy(AText,i,1)+s;
end
else begin
s:=UTF8Copy(AText,i,1)+s;
break;
end;
end;
dec(i);
s1:=UTF8Copy(AText,1,i);
s2:=CP866ToUTF8(s);
Result:=s1+s2;
end;
function UnPackFiles(Filename, UnPackPath: String): Integer;
var
UnZipper :TUnZipper; //PasZLib
UnPackFileDir,
ADiskFileName,
ANewDiskFileName,
AArchiveFileName :String;
i :integer;
begin
Result:=-1;
if FileExists(Filename)and DirectoryExists(UnPackPath) then
begin
UnPackFileDir :=SysUtils.IncludeTrailingPathDelimiter(UnPackPath);
UnZipper :=TUnZipper.Create;
try
UnZipper.FileName := Filename;
UnZipper.OutputPath := UnPackPath;
UnZipper.Examine;
UnZipper.UnZipAllFiles;
for i:=UnZipper.Entries.Count-1 downto 0 do
begin
AArchiveFileName:=UnZipper.Entries.Entries[i].ArchiveFileName;
AArchiveFileName:=EndPathCP866ToUTF8(AArchiveFileName);
AArchiveFileName:=UTF8ToSys(AArchiveFileName);
ANewDiskFileName:=UnPackFileDir+AArchiveFileName;
ADiskFileName :=UnPackFileDir+UnZipper.Entries.Entries[i].DiskFileName;
if FileExists(ADiskFileName) then
begin
RenameFile(ADiskFileName, ANewDiskFileName);
end
else if DirectoryExists(ADiskFileName) then
begin
ADiskFileName :=SysUtils.IncludeTrailingPathDelimiter(ADiskFileName);
ANewDiskFileName :=SysUtils.IncludeTrailingPathDelimiter(ANewDiskFileName);
RenameFile(ADiskFileName, ANewDiskFileName);
end;
end;
Result:=1;
finally
UnZipper.Free;
end;
end;
end;
More examples can be found in the FPC source directory:
Unzip file to a stream
In Lazarus, drop a TMemo, TButton, TEdit and TFileNameEdit on a form. Clicking the button will read the zip file in FileNameEdit, extract the file specified in the Edit box, and display the content in Memo.
uses
Zipper;
...
procedure TForm1.Button1Click(Sender: TObject);
begin
ExtractFileFromZip(FileNameEdit1.FileName,Edit1.Text);
end;
procedure TForm1.DoCreateOutZipStream(Sender: TObject; var AStream: TStream;
AItem: TFullZipFileEntry);
begin
AStream:=TMemorystream.Create;
end;
procedure TForm1.DoDoneOutZipStream(Sender: TObject; var AStream: TStream;
AItem: TFullZipFileEntry);
begin
AStream.Position:=0;
Memo1.lines.LoadFromStream(Astream);
Astream.Free;
end;
procedure TForm1.ExtractFileFromZip(ZipName, FileName: string);
var
ZipFile: TUnZipper;
sl:TStringList;
begin
sl:=TStringList.Create;
sl.Add(FileName);
ZipFile := TUnZipper.Create;
try
ZipFile.FileName := ZipName;
ZipFile.OnCreateStream := @DoCreateOutZipStream;
ZipFile.OnDoneStream:=@DoDoneOutZipStream;
ZipFile.UnZipFiles(sl);
finally
ZipFile.Free;
sl.Free;
end;
end;
Zipping a whole directory tree
- This will recursively add the contents of 'C:\MyFolder' to the 'myzipfile.zip'
- Note that the absolute path is stored in the zipfile
- Note that this requires the Lazarus fileutil unit (which you can probably work around)
Uses ...Zipper,FileUtil
var
AZipper: TZipper;
TheFileList:TStringList;
begin
MyDirectory:='C:\MyFolder';
AZipper := TZipper.Create;
AZipper.Filename := 'myzipfile.zip';
TheFileList:=TStringList.Create;
try
FindAllFiles(TheFileList, MyDirectory);
AZipper.Entries.AddFileEntries(TheFileList);
AZipper.ZipAllFiles;
finally
TheFileList.Free;
AZipper.Free;
end;
end;
Zipping a whole directory tree storing only a relative path
This is more complicated, but it can be done. Note that this requires the Lazarus FileUtil unit (which you can probably work around).
uses
..., Zipper, FileUtil, StrUtils;
var
AZipper: TZipper;
szPathEntry: String;
i: Integer;
ZEntries: TZipFileEntries;
TheFileList: TStringList;
RelativeDirectory: String;
begin
AZipper := TZipper.Create;
try
try
AZipper.Filename := 'myzipfile.zip';
RelativeDirectory:='C:\MyFolder\MyFolder\';
AZipper.Clear;
ZEntries := TZipFileEntries.Create(TZipFileEntry);
// Verify valid directory
If DirPathExists(RelativeDirectory) then
begin
// Construct the path to the directory BELOW RelativeDirectory
// If user specifies 'C:\MyFolder\Subfolder' it returns 'C:\MyFolder\'
// If user specifies 'C:\MyFolder' it returns 'C:\'
// If user specifies 'C:\' it returns 'C:\'
i:=RPos(PathDelim,ChompPathDelim(RelativeDirectory));
szPathEntry:=LeftStr(RelativeDirectory,i);
// Use the FileUtils.FindAllFiles function to get everything (files and folders) recursively
TheFileList:=TstringList.Create;
try
FindAllFiles(TheFileList, RelativeDirectory);
for i:=0 to TheFileList.Count -1 do
begin
// Make sure the RelativeDirectory files are not in the root of the ZipFile
ZEntries.AddFileEntry(TheFileList[i],CreateRelativePath(TheFileList[i],szPathEntry));
end;
finally
TheFileList.Free;
end;
end;
if (ZEntries.Count > 0) then
AZipper.ZipFiles(ZEntries);
except
On E: EZipError do
E.CreateFmt('Zipfile could not be created%sReason: %s', [LineEnding, E.Message])
end;
result := True;
finally
FreeAndNil(ZEntries);
AZipper.Free;
end;
end;
Note that this example uses an overloaded version of AddFileEntry() (compared to simple examples). This version allows you to specify the directory structure inside the Zip file, and, then, of course, the directory structure when its all unzipped. You can, for example, specify only the file name with no directory structure and have all files returned in one flat output directory. Even if they came for all over the place.
ZEntries.AddFileEntry(FullDiskPathToFile, FileName);
See also
- official FPC documentation for Zipper
- Article demonstrating handling tar, bzip2, gzip, zip files and Blowfish encryption in FreePascal/Lazarus. A good introduction even though it was written some time ago (a lot of functionality has been improved).
- unzip
- FreePascalArchivePackage Abbrevia archive/zip library
- MIT licensed Delphi/Object Pascal library that includes zip file support.
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