(* example.c -- usage example of the zlib compression library

 * Copyright (C) 1995-2003 Jean-loup Gailly.

 * For conditions of distribution and use, see copyright notice in zlib.h

 *

 * Pascal translation

 * Copyright (C) 1998 by Jacques Nomssi Nzali.

 * For conditions of distribution and use, see copyright notice in readme.txt

 *

 * Adaptation to the zlibpas interface

 * Copyright (C) 2003 by Cosmin Truta.

 * For conditions of distribution and use, see copyright notice in readme.txt

 *)

program example;

{$DEFINE TEST_COMPRESS}

{DO NOT $DEFINE TEST_GZIO}

{$DEFINE TEST_DEFLATE}

{$DEFINE TEST_INFLATE}

{$DEFINE TEST_FLUSH}

{$DEFINE TEST_SYNC}

{$DEFINE TEST_DICT}

uses SysUtils, zlibpas;

const TESTFILE = 'foo.gz';

(* "hello world" would be more standard, but the repeated "hello"

 * stresses the compression code better, sorry...

 *)

const hello: PChar = 'hello, hello!';

const dictionary: PChar = 'hello';

var dictId: LongInt; (* Adler32 value of the dictionary *)

procedure CHECK_ERR(err: Integer; msg: String);

begin

  if err <> Z_OK then

  begin

    WriteLn(msg, ' error: ', err);

    Halt(1);

  end;

end;

procedure EXIT_ERR(const msg: String);

begin

  WriteLn('Error: ', msg);

  Halt(1);

end;

(* ===========================================================================

 * Test compress and uncompress

 *)

{$IFDEF TEST_COMPRESS}

procedure test_compress(compr: Pointer; comprLen: LongInt;

                        uncompr: Pointer; uncomprLen: LongInt);

var err: Integer;

    len: LongInt;

begin

  len := StrLen(hello)+1;

  err := compress(compr, comprLen, hello, len);

  CHECK_ERR(err, 'compress');

  StrCopy(PChar(uncompr), 'garbage');

  err := uncompress(uncompr, uncomprLen, compr, comprLen);

  CHECK_ERR(err, 'uncompress');

  if StrComp(PChar(uncompr), hello) <> 0 then

    EXIT_ERR('bad uncompress')

  else

    WriteLn('uncompress(): ', PChar(uncompr));

end;

{$ENDIF}

(* ===========================================================================

 * Test read/write of .gz files

 *)

{$IFDEF TEST_GZIO}

procedure test_gzio(const fname: PChar; (* compressed file name *)

                    uncompr: Pointer;

                    uncomprLen: LongInt);

var err: Integer;

    len: Integer;

    zfile: gzFile;

    pos: LongInt;

begin

  len := StrLen(hello)+1;

  zfile := gzopen(fname, 'wb');

  if zfile = NIL then

  begin

    WriteLn('gzopen error');

    Halt(1);

  end;

  gzputc(zfile, 'h');

  if gzputs(zfile, 'ello') <> 4 then

  begin

    WriteLn('gzputs err: ', gzerror(zfile, err));

    Halt(1);

  end;

  {$IFDEF GZ_FORMAT_STRING}

  if gzprintf(zfile, ', %s!', 'hello') <> 8 then

  begin

    WriteLn('gzprintf err: ', gzerror(zfile, err));

    Halt(1);

  end;

  {$ELSE}

  if gzputs(zfile, ', hello!') <> 8 then

  begin

    WriteLn('gzputs err: ', gzerror(zfile, err));

    Halt(1);

  end;

  {$ENDIF}

  gzseek(zfile, 1, SEEK_CUR); (* add one zero byte *)

  gzclose(zfile);

  zfile := gzopen(fname, 'rb');

  if zfile = NIL then

  begin

    WriteLn('gzopen error');

    Halt(1);

  end;

  StrCopy(PChar(uncompr), 'garbage');

  if gzread(zfile, uncompr, uncomprLen) <> len then

  begin

    WriteLn('gzread err: ', gzerror(zfile, err));

    Halt(1);

  end;

  if StrComp(PChar(uncompr), hello) <> 0 then

  begin

    WriteLn('bad gzread: ', PChar(uncompr));

    Halt(1);

  end

  else

    WriteLn('gzread(): ', PChar(uncompr));

  pos := gzseek(zfile, -8, SEEK_CUR);

  if (pos <> 6) or (gztell(zfile) <> pos) then

  begin

    WriteLn('gzseek error, pos=', pos, ', gztell=', gztell(zfile));

    Halt(1);

  end;

  if gzgetc(zfile) <> ' ' then

  begin

    WriteLn('gzgetc error');

    Halt(1);

  end;

  if gzungetc(' ', zfile) <> ' ' then

  begin

    WriteLn('gzungetc error');

    Halt(1);

  end;

  gzgets(zfile, PChar(uncompr), uncomprLen);

  uncomprLen := StrLen(PChar(uncompr));

  if uncomprLen <> 7 then (* " hello!" *)

  begin

    WriteLn('gzgets err after gzseek: ', gzerror(zfile, err));

    Halt(1);

  end;

  if StrComp(PChar(uncompr), hello + 6) <> 0 then

  begin

    WriteLn('bad gzgets after gzseek');

    Halt(1);

  end

  else

    WriteLn('gzgets() after gzseek: ', PChar(uncompr));

  gzclose(zfile);

end;

{$ENDIF}

(* ===========================================================================

 * Test deflate with small buffers

 *)

{$IFDEF TEST_DEFLATE}

procedure test_deflate(compr: Pointer; comprLen: LongInt);

var c_stream: z_stream; (* compression stream *)

    err: Integer;

    len: LongInt;

begin

  len := StrLen(hello)+1;

  c_stream.zalloc := NIL;

  c_stream.zfree := NIL;

  c_stream.opaque := NIL;

  err := deflateInit(c_stream, Z_DEFAULT_COMPRESSION);

  CHECK_ERR(err, 'deflateInit');

  c_stream.next_in := hello;

  c_stream.next_out := compr;

  while (c_stream.total_in <> len) and

        (c_stream.total_out < comprLen) do

  begin

    c_stream.avail_out := 1; { force small buffers }

    c_stream.avail_in := 1;

    err := deflate(c_stream, Z_NO_FLUSH);

    CHECK_ERR(err, 'deflate');

  end;

  (* Finish the stream, still forcing small buffers: *)

  while TRUE do

  begin

    c_stream.avail_out := 1;

    err := deflate(c_stream, Z_FINISH);

    if err = Z_STREAM_END then

      break;

    CHECK_ERR(err, 'deflate');

  end;

  err := deflateEnd(c_stream);

  CHECK_ERR(err, 'deflateEnd');

end;

{$ENDIF}

(* ===========================================================================

 * Test inflate with small buffers

 *)

{$IFDEF TEST_INFLATE}

procedure test_inflate(compr: Pointer; comprLen : LongInt;

                       uncompr: Pointer; uncomprLen : LongInt);

var err: Integer;

    d_stream: z_stream; (* decompression stream *)

begin

  StrCopy(PChar(uncompr), 'garbage');

  d_stream.zalloc := NIL;

  d_stream.zfree := NIL;

  d_stream.opaque := NIL;

  d_stream.next_in := compr;

  d_stream.avail_in := 0;

  d_stream.next_out := uncompr;

  err := inflateInit(d_stream);

  CHECK_ERR(err, 'inflateInit');

  while (d_stream.total_out < uncomprLen) and

        (d_stream.total_in < comprLen) do

  begin

    d_stream.avail_out := 1; (* force small buffers *)

    d_stream.avail_in := 1;

    err := inflate(d_stream, Z_NO_FLUSH);

    if err = Z_STREAM_END then

      break;

    CHECK_ERR(err, 'inflate');

  end;

  err := inflateEnd(d_stream);

  CHECK_ERR(err, 'inflateEnd');

  if StrComp(PChar(uncompr), hello) <> 0 then

    EXIT_ERR('bad inflate')

  else

    WriteLn('inflate(): ', PChar(uncompr));

end;

{$ENDIF}

(* ===========================================================================

 * Test deflate with large buffers and dynamic change of compression level

 *)

{$IFDEF TEST_DEFLATE}

procedure test_large_deflate(compr: Pointer; comprLen: LongInt;

                             uncompr: Pointer; uncomprLen: LongInt);

var c_stream: z_stream; (* compression stream *)

    err: Integer;

begin

  c_stream.zalloc := NIL;

  c_stream.zfree := NIL;

  c_stream.opaque := NIL;

  err := deflateInit(c_stream, Z_BEST_SPEED);

  CHECK_ERR(err, 'deflateInit');

  c_stream.next_out := compr;

  c_stream.avail_out := Integer(comprLen);

  (* At this point, uncompr is still mostly zeroes, so it should compress

   * very well:

   *)

  c_stream.next_in := uncompr;

  c_stream.avail_in := Integer(uncomprLen);

  err := deflate(c_stream, Z_NO_FLUSH);

  CHECK_ERR(err, 'deflate');

  if c_stream.avail_in <> 0 then

    EXIT_ERR('deflate not greedy');

  (* Feed in already compressed data and switch to no compression: *)

  deflateParams(c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY);

  c_stream.next_in := compr;

  c_stream.avail_in := Integer(comprLen div 2);

  err := deflate(c_stream, Z_NO_FLUSH);

  CHECK_ERR(err, 'deflate');

  (* Switch back to compressing mode: *)

  deflateParams(c_stream, Z_BEST_COMPRESSION, Z_FILTERED);

  c_stream.next_in := uncompr;

  c_stream.avail_in := Integer(uncomprLen);

  err := deflate(c_stream, Z_NO_FLUSH);

  CHECK_ERR(err, 'deflate');

  err := deflate(c_stream, Z_FINISH);

  if err <> Z_STREAM_END then

    EXIT_ERR('deflate should report Z_STREAM_END');

  err := deflateEnd(c_stream);

  CHECK_ERR(err, 'deflateEnd');

end;

{$ENDIF}

(* ===========================================================================

 * Test inflate with large buffers

 *)

{$IFDEF TEST_INFLATE}

procedure test_large_inflate(compr: Pointer; comprLen: LongInt;

                             uncompr: Pointer; uncomprLen: LongInt);

var err: Integer;

    d_stream: z_stream; (* decompression stream *)

begin

  StrCopy(PChar(uncompr), 'garbage');

  d_stream.zalloc := NIL;

  d_stream.zfree := NIL;

  d_stream.opaque := NIL;

  d_stream.next_in := compr;

  d_stream.avail_in := Integer(comprLen);

  err := inflateInit(d_stream);

  CHECK_ERR(err, 'inflateInit');

  while TRUE do

  begin

    d_stream.next_out := uncompr;            (* discard the output *)

    d_stream.avail_out := Integer(uncomprLen);

    err := inflate(d_stream, Z_NO_FLUSH);

    if err = Z_STREAM_END then

      break;

    CHECK_ERR(err, 'large inflate');

  end;

  err := inflateEnd(d_stream);

  CHECK_ERR(err, 'inflateEnd');

  if d_stream.total_out <> 2 * uncomprLen + comprLen div 2 then

  begin

    WriteLn('bad large inflate: ', d_stream.total_out);

    Halt(1);

  end

  else

    WriteLn('large_inflate(): OK');

end;

{$ENDIF}

(* ===========================================================================

 * Test deflate with full flush

 *)

{$IFDEF TEST_FLUSH}

procedure test_flush(compr: Pointer; var comprLen : LongInt);

var c_stream: z_stream; (* compression stream *)

    err: Integer;

    len: Integer;

begin

  len := StrLen(hello)+1;

  c_stream.zalloc := NIL;

  c_stream.zfree := NIL;

  c_stream.opaque := NIL;

  err := deflateInit(c_stream, Z_DEFAULT_COMPRESSION);

  CHECK_ERR(err, 'deflateInit');

  c_stream.next_in := hello;

  c_stream.next_out := compr;

  c_stream.avail_in := 3;

  c_stream.avail_out := Integer(comprLen);

  err := deflate(c_stream, Z_FULL_FLUSH);

  CHECK_ERR(err, 'deflate');

  Inc(PByteArray(compr)^[3]); (* force an error in first compressed block *)

  c_stream.avail_in := len - 3;

  err := deflate(c_stream, Z_FINISH);

  if err <> Z_STREAM_END then

    CHECK_ERR(err, 'deflate');

  err := deflateEnd(c_stream);

  CHECK_ERR(err, 'deflateEnd');

  comprLen := c_stream.total_out;

end;

{$ENDIF}

(* ===========================================================================

 * Test inflateSync()

 *)

{$IFDEF TEST_SYNC}

procedure test_sync(compr: Pointer; comprLen: LongInt;

                    uncompr: Pointer; uncomprLen : LongInt);

var err: Integer;

    d_stream: z_stream; (* decompression stream *)

begin

  StrCopy(PChar(uncompr), 'garbage');

  d_stream.zalloc := NIL;

  d_stream.zfree := NIL;

  d_stream.opaque := NIL;

  d_stream.next_in := compr;

  d_stream.avail_in := 2; (* just read the zlib header *)

  err := inflateInit(d_stream);

  CHECK_ERR(err, 'inflateInit');

  d_stream.next_out := uncompr;

  d_stream.avail_out := Integer(uncomprLen);

  inflate(d_stream, Z_NO_FLUSH);

  CHECK_ERR(err, 'inflate');

  d_stream.avail_in := Integer(comprLen-2);   (* read all compressed data *)

  err := inflateSync(d_stream);               (* but skip the damaged part *)

  CHECK_ERR(err, 'inflateSync');

  err := inflate(d_stream, Z_FINISH);

  if err <> Z_DATA_ERROR then

    EXIT_ERR('inflate should report DATA_ERROR');

    (* Because of incorrect adler32 *)

  err := inflateEnd(d_stream);

  CHECK_ERR(err, 'inflateEnd');

  WriteLn('after inflateSync(): hel', PChar(uncompr));

end;

{$ENDIF}

(* ===========================================================================

 * Test deflate with preset dictionary

 *)

{$IFDEF TEST_DICT}

procedure test_dict_deflate(compr: Pointer; comprLen: LongInt);

var c_stream: z_stream; (* compression stream *)

    err: Integer;

begin

  c_stream.zalloc := NIL;

  c_stream.zfree := NIL;

  c_stream.opaque := NIL;

  err := deflateInit(c_stream, Z_BEST_COMPRESSION);

  CHECK_ERR(err, 'deflateInit');

  err := deflateSetDictionary(c_stream, dictionary, StrLen(dictionary));

  CHECK_ERR(err, 'deflateSetDictionary');

  dictId := c_stream.adler;

  c_stream.next_out := compr;

  c_stream.avail_out := Integer(comprLen);

  c_stream.next_in := hello;

  c_stream.avail_in := StrLen(hello)+1;

  err := deflate(c_stream, Z_FINISH);

  if err <> Z_STREAM_END then

    EXIT_ERR('deflate should report Z_STREAM_END');

  err := deflateEnd(c_stream);

  CHECK_ERR(err, 'deflateEnd');

end;

{$ENDIF}

(* ===========================================================================

 * Test inflate with a preset dictionary

 *)

{$IFDEF TEST_DICT}

procedure test_dict_inflate(compr: Pointer; comprLen: LongInt;

                            uncompr: Pointer; uncomprLen: LongInt);

var err: Integer;

    d_stream: z_stream; (* decompression stream *)

begin

  StrCopy(PChar(uncompr), 'garbage');

  d_stream.zalloc := NIL;

  d_stream.zfree := NIL;

  d_stream.opaque := NIL;

  d_stream.next_in := compr;

  d_stream.avail_in := Integer(comprLen);

  err := inflateInit(d_stream);

  CHECK_ERR(err, 'inflateInit');

  d_stream.next_out := uncompr;

  d_stream.avail_out := Integer(uncomprLen);

  while TRUE do

  begin

    err := inflate(d_stream, Z_NO_FLUSH);

    if err = Z_STREAM_END then

      break;

    if err = Z_NEED_DICT then

    begin

      if d_stream.adler <> dictId then

        EXIT_ERR('unexpected dictionary');

      err := inflateSetDictionary(d_stream, dictionary, StrLen(dictionary));

    end;

    CHECK_ERR(err, 'inflate with dict');

  end;

  err := inflateEnd(d_stream);

  CHECK_ERR(err, 'inflateEnd');

  if StrComp(PChar(uncompr), hello) <> 0 then

    EXIT_ERR('bad inflate with dict')

  else

    WriteLn('inflate with dictionary: ', PChar(uncompr));

end;

{$ENDIF}

var compr, uncompr: Pointer;