fpc/packages/paszlib/examples/minigzip.pas
marco 2ff48d2576 * len now longint.
git-svn-id: trunk@12432 -
2008-12-24 15:37:31 +00:00

248 lines
5.6 KiB
ObjectPascal

program minigzip;
{
minigzip.c -- simulate gzip using the zlib compression library
Copyright (C) 1995-1998 Jean-loup Gailly.
minigzip is a minimal implementation of the gzip utility. This is
only an example of using zlib and isn't meant to replace the
full-featured gzip. No attempt is made to deal with file systems
limiting names to 14 or 8+3 characters, etc... Error checking is
very limited. So use minigzip only for testing; use gzip for the
real thing. On MSDOS, use only on file names without extension
or in pipe mode.
Pascal tranlastion based on code contributed by Francisco Javier Crespo
Copyright (C) 1998 by Jacques Nomssi Nzali
For conditions of distribution and use, see copyright notice in readme.txt
}
uses
gzio;
const
BUFLEN = 16384 ;
GZ_SUFFIX = '.gz' ;
{$DEFINE MAXSEF_64K}
var
buf : packed array [0..BUFLEN-1] of byte; { Global uses BSS instead of stack }
prog : string;
{ ERROR =====================================================================
Display error message and exit
============================================================================}
procedure error (msg:string);
begin
writeln (prog,': ',msg);
halt(1);
end;
{ GZ_COMPRESS ===============================================================
Compress input to output then close both files
============================================================================}
procedure gz_compress (var infile:file; outfile:gzFile);
var
len : cardinal;
ioerr : integer;
err : integer;
begin
while true do begin
{$I-}
blockread (infile, buf, BUFLEN, len);
{$I+}
ioerr := IOResult;
if (ioerr <> 0) then begin
writeln ('read error: ',ioerr);
halt(1);
end;
if (len = 0) then break;
if (gzwrite (outfile, @buf, len) <> len)
then error (gzerror (outfile, err));
end; {WHILE}
close (infile);
if (gzclose (outfile) <> 0{Z_OK})
then error ('gzclose error');
end;
{ GZ_UNCOMPRESS =============================================================
Uncompress input to output then close both files
============================================================================}
procedure gz_uncompress (infile:gzFile; var outfile:file);
var
len : longint;
written : cardinal;
ioerr : integer;
err : integer;
begin
while true do begin
len := gzread (infile, @buf, BUFLEN);
if (len < 0)
then error (gzerror (infile, err));
if (len = 0)
then break;
{$I-}
blockwrite (outfile, buf, len, written);
{$I+}
if (written <> len)
then error ('write error');
end; {WHILE}
{$I-}
close (outfile);
{$I+}
ioerr := IOResult;
if (ioerr <> 0) then begin
writeln ('close error: ',ioerr);
halt(1);
end;
if (gzclose (infile) <> 0{Z_OK})
then error ('gzclose error');
end;
{ FILE_COMPRESS =============================================================
Compress the given file:
create a corresponding .gz file and remove the original
============================================================================}
procedure file_compress (filename:string; mode:string);
var
infile : file;
outfile : gzFile;
ioerr : integer;
outname : string;
begin
Assign (infile, filename);
{$I-}
Reset (infile,1);
{$I+}
ioerr := IOResult;
if (ioerr <> 0) then begin
writeln ('open error: ',ioerr);
halt(1);
end;
outname := filename + GZ_SUFFIX;
outfile := gzopen (outname, mode);
if (outfile = NIL) then begin
writeln (prog,': can''t gzopen ',outname);
halt(1);
end;
gz_compress(infile, outfile);
erase (infile);
end;
{ FILE_UNCOMPRESS ===========================================================
Uncompress the given file and remove the original
============================================================================}
procedure file_uncompress (filename:string);
var
inname : string;
outname : string;
infile : gzFile;
outfile : file;
ioerr : integer;
len : integer;
begin
len := Length(filename);
if (copy(filename,len-2,3) = GZ_SUFFIX) then begin
inname := filename;
outname := copy(filename,0,len-3);
end
else begin
inname := filename + GZ_SUFFIX;
outname := filename;
end;
infile := gzopen (inname, 'r');
if (infile = NIL) then begin
writeln (prog,': can''t gzopen ',inname);
halt(1);
end;
Assign (outfile, outname);
{$I-}
Rewrite (outfile,1);
{$I+}
ioerr := IOResult;
if (ioerr <> 0) then begin
writeln ('open error: ',ioerr);
halt(1);
end;
gz_uncompress (infile, outfile);
{ erase (infile); }
end;
{ MINIGZIP =================================================================}
var
uncompr : boolean;
outmode : string[20];
i : integer;
option : string;
begin
uncompr := false;
outmode := 'w6 ';
prog := ParamStr(0);
if (ParamCount = 0) then begin
writeln ('Error: STDIO/STDOUT not supported yet');
writeln;
writeln ('Usage: minigzip [-d] [-f] [-h] [-1 to -9] <file>');
writeln (' -d : decompress');
writeln (' -f : compress with Z_FILTERED');
writeln (' -h : compress with Z_HUFFMAN_ONLY');
writeln (' -1 to -9 : compression level');
exit;
end;
for i:=1 to ParamCount do begin
option := ParamStr(i);
if (option = '-d') then uncompr := true;
if (option = '-f') then outmode[3] := 'f';
if (option = '-h') then outmode[3] := 'h';
if (option[1] = '-') and (option[2] >= '1') and (option[2] <= '9')
then outmode[2] := option[2];
end;
if (uncompr = true)
then file_uncompress (ParamStr(ParamCount))
else file_compress (ParamStr(ParamCount), outmode);
end.