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{*******************************************************}

{                                                       }

{       Borland Delphi Supplemental Components          }

{       ZLIB Data Compression Interface Unit            }

{                                                       }

{       Copyright (c) 1997,99 Borland Corporation       }

{                                                       }

{*******************************************************}

{ Updated for zlib 1.2.x by Cosmin Truta <cosmint@cs.ubbcluj.ro> }

unit ZLib;

interface

uses SysUtils, Classes;

type

  TAlloc = function (AppData: Pointer; Items, Size: Integer): Pointer; cdecl;

  TFree = procedure (AppData, Block: Pointer); cdecl;

  // Internal structure.  Ignore.

  TZStreamRec = packed record

    next_in: PChar;       // next input byte

    avail_in: Integer;    // number of bytes available at next_in

    total_in: Longint;    // total nb of input bytes read so far

    next_out: PChar;      // next output byte should be put here

    avail_out: Integer;   // remaining free space at next_out

    total_out: Longint;   // total nb of bytes output so far

    msg: PChar;           // last error message, NULL if no error

    internal: Pointer;    // not visible by applications

    zalloc: TAlloc;       // used to allocate the internal state

    zfree: TFree;         // used to free the internal state

    AppData: Pointer;     // private data object passed to zalloc and zfree

    data_type: Integer;   // best guess about the data type: ascii or binary

    adler: Longint;       // adler32 value of the uncompressed data

    reserved: Longint;    // reserved for future use

  end;

  // Abstract ancestor class

  TCustomZlibStream = class(TStream)

  private

    FStrm: TStream;

    FStrmPos: Integer;

    FOnProgress: TNotifyEvent;

    FZRec: TZStreamRec;

    FBuffer: array [Word] of Char;

  protected

    procedure Progress(Sender: TObject); dynamic;

    property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;

    constructor Create(Strm: TStream);

  end;

{ TCompressionStream compresses data on the fly as data is written to it, and

  stores the compressed data to another stream.

  TCompressionStream is write-only and strictly sequential. Reading from the

  stream will raise an exception. Using Seek to move the stream pointer

  will raise an exception.

  Output data is cached internally, written to the output stream only when

  the internal output buffer is full.  All pending output data is flushed

  when the stream is destroyed.

  The Position property returns the number of uncompressed bytes of

  data that have been written to the stream so far.

  CompressionRate returns the on-the-fly percentage by which the original

  data has been compressed:  (1 - (CompressedBytes / UncompressedBytes)) * 100

  If raw data size = 100 and compressed data size = 25, the CompressionRate

  is 75%

  The OnProgress event is called each time the output buffer is filled and

  written to the output stream.  This is useful for updating a progress

  indicator when you are writing a large chunk of data to the compression

  stream in a single call.}

  TCompressionLevel = (clNone, clFastest, clDefault, clMax);

  TCompressionStream = class(TCustomZlibStream)

  private

    function GetCompressionRate: Single;

  public

    constructor Create(CompressionLevel: TCompressionLevel; Dest: TStream);

    destructor Destroy; override;

    function Read(var Buffer; Count: Longint): Longint; override;

    function Write(const Buffer; Count: Longint): Longint; override;

    function Seek(Offset: Longint; Origin: Word): Longint; override;

    property CompressionRate: Single read GetCompressionRate;

    property OnProgress;

  end;

{ TDecompressionStream decompresses data on the fly as data is read from it.

  Compressed data comes from a separate source stream.  TDecompressionStream

  is read-only and unidirectional; you can seek forward in the stream, but not

  backwards.  The special case of setting the stream position to zero is

  allowed.  Seeking forward decompresses data until the requested position in

  the uncompressed data has been reached.  Seeking backwards, seeking relative

  to the end of the stream, requesting the size of the stream, and writing to

  the stream will raise an exception.

  The Position property returns the number of bytes of uncompressed data that

  have been read from the stream so far.

  The OnProgress event is called each time the internal input buffer of

  compressed data is exhausted and the next block is read from the input stream.

  This is useful for updating a progress indicator when you are reading a

  large chunk of data from the decompression stream in a single call.}

  TDecompressionStream = class(TCustomZlibStream)

  public

    constructor Create(Source: TStream);

    destructor Destroy; override;

    function Read(var Buffer; Count: Longint): Longint; override;

    function Write(const Buffer; Count: Longint): Longint; override;

    function Seek(Offset: Longint; Origin: Word): Longint; override;

    property OnProgress;

  end;

{ CompressBuf compresses data, buffer to buffer, in one call.

   In: InBuf = ptr to compressed data

       InBytes = number of bytes in InBuf

  Out: OutBuf = ptr to newly allocated buffer containing decompressed data

       OutBytes = number of bytes in OutBuf   }

procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;

                      out OutBuf: Pointer; out OutBytes: Integer);

{ DecompressBuf decompresses data, buffer to buffer, in one call.

   In: InBuf = ptr to compressed data

       InBytes = number of bytes in InBuf

       OutEstimate = zero, or est. size of the decompressed data

  Out: OutBuf = ptr to newly allocated buffer containing decompressed data

       OutBytes = number of bytes in OutBuf   }

procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;

 OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer);

{ DecompressToUserBuf decompresses data, buffer to buffer, in one call.

   In: InBuf = ptr to compressed data

       InBytes = number of bytes in InBuf

  Out: OutBuf = ptr to user-allocated buffer to contain decompressed data

       BufSize = number of bytes in OutBuf   }

procedure DecompressToUserBuf(const InBuf: Pointer; InBytes: Integer;

  const OutBuf: Pointer; BufSize: Integer);

const

  zlib_version = '1.2.3';

type

  EZlibError = class(Exception);

  ECompressionError = class(EZlibError);

  EDecompressionError = class(EZlibError);

implementation

uses ZLibConst;

const

  Z_NO_FLUSH      = 0;

  Z_PARTIAL_FLUSH = 1;

  Z_SYNC_FLUSH    = 2;

  Z_FULL_FLUSH    = 3;

  Z_FINISH        = 4;

  Z_OK            = 0;

  Z_STREAM_END    = 1;

  Z_NEED_DICT     = 2;

  Z_ERRNO         = (-1);

  Z_STREAM_ERROR  = (-2);

  Z_DATA_ERROR    = (-3);

  Z_MEM_ERROR     = (-4);

  Z_BUF_ERROR     = (-5);

  Z_VERSION_ERROR = (-6);

  Z_NO_COMPRESSION       =   0;

  Z_BEST_SPEED           =   1;

  Z_BEST_COMPRESSION     =   9;

  Z_DEFAULT_COMPRESSION  = (-1);

  Z_FILTERED            = 1;

  Z_HUFFMAN_ONLY        = 2;

  Z_RLE                 = 3;

  Z_DEFAULT_STRATEGY    = 0;

  Z_BINARY   = 0;

  Z_ASCII    = 1;

  Z_UNKNOWN  = 2;

  Z_DEFLATED = 8;

{$L adler32.obj}

{$L compress.obj}

{$L crc32.obj}

{$L deflate.obj}

{$L infback.obj}

{$L inffast.obj}

{$L inflate.obj}

{$L inftrees.obj}

{$L trees.obj}

{$L uncompr.obj}

{$L zutil.obj}

procedure adler32; external;

procedure compressBound; external;

procedure crc32; external;

procedure deflateInit2_; external;

procedure deflateParams; external;

function _malloc(Size: Integer): Pointer; cdecl;

begin

  Result := AllocMem(Size);

end;

procedure _free(Block: Pointer); cdecl;

begin

  FreeMem(Block);

end;

procedure _memset(P: Pointer; B: Byte; count: Integer); cdecl;

begin

  FillChar(P^, count, B);

end;

procedure _memcpy(dest, source: Pointer; count: Integer); cdecl;

begin

  Move(source^, dest^, count);

end;

// deflate compresses data

function deflateInit_(var strm: TZStreamRec; level: Integer; version: PChar;

  recsize: Integer): Integer; external;

function deflate(var strm: TZStreamRec; flush: Integer): Integer; external;

function deflateEnd(var strm: TZStreamRec): Integer; external;

// inflate decompresses data

function inflateInit_(var strm: TZStreamRec; version: PChar;

  recsize: Integer): Integer; external;

function inflate(var strm: TZStreamRec; flush: Integer): Integer; external;

function inflateEnd(var strm: TZStreamRec): Integer; external;

function inflateReset(var strm: TZStreamRec): Integer; external;

function zlibAllocMem(AppData: Pointer; Items, Size: Integer): Pointer; cdecl;

begin

//  GetMem(Result, Items*Size);

  Result := AllocMem(Items * Size);

end;

procedure zlibFreeMem(AppData, Block: Pointer); cdecl;

begin

  FreeMem(Block);

end;

{function zlibCheck(code: Integer): Integer;

begin

  Result := code;

  if code < 0 then

    raise EZlibError.Create('error');    //!!

end;}

function CCheck(code: Integer): Integer;

begin

  Result := code;

  if code < 0 then

    raise ECompressionError.Create('error'); //!!

end;

function DCheck(code: Integer): Integer;

begin

  Result := code;

  if code < 0 then

    raise EDecompressionError.Create('error');  //!!

end;

procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;

                      out OutBuf: Pointer; out OutBytes: Integer);

var

  strm: TZStreamRec;

  P: Pointer;

begin

  FillChar(strm, sizeof(strm), 0);

  strm.zalloc := zlibAllocMem;

  strm.zfree := zlibFreeMem;

  OutBytes := ((InBytes + (InBytes div 10) + 12) + 255) and not 255;

  GetMem(OutBuf, OutBytes);

  try

    strm.next_in := InBuf;

    strm.avail_in := InBytes;

    strm.next_out := OutBuf;

    strm.avail_out := OutBytes;

    CCheck(deflateInit_(strm, Z_BEST_COMPRESSION, zlib_version, sizeof(strm)));

    try

      while CCheck(deflate(strm, Z_FINISH)) <> Z_STREAM_END do

      begin

        P := OutBuf;

        Inc(OutBytes, 256);

        ReallocMem(OutBuf, OutBytes);

        strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));

        strm.avail_out := 256;

      end;

    finally

      CCheck(deflateEnd(strm));

    end;

    ReallocMem(OutBuf, strm.total_out);

    OutBytes := strm.total_out;

  except

    FreeMem(OutBuf);

    raise

  end;

end;

procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;

  OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer);

var

  strm: TZStreamRec;

  P: Pointer;

  BufInc: Integer;

begin

  FillChar(strm, sizeof(strm), 0);

  strm.zalloc := zlibAllocMem;

  strm.zfree := zlibFreeMem;

  BufInc := (InBytes + 255) and not 255;

  if OutEstimate = 0 then

    OutBytes := BufInc

  else

    OutBytes := OutEstimate;

  GetMem(OutBuf, OutBytes);

  try

    strm.next_in := InBuf;

    strm.avail_in := InBytes;

    strm.next_out := OutBuf;

    strm.avail_out := OutBytes;

    DCheck(inflateInit_(strm, zlib_version, sizeof(strm)));

    try

      while DCheck(inflate(strm, Z_NO_FLUSH)) <> Z_STREAM_END do

      begin

        P := OutBuf;

        Inc(OutBytes, BufInc);

        ReallocMem(OutBuf, OutBytes);

        strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));

        strm.avail_out := BufInc;

      end;

    finally

      DCheck(inflateEnd(strm));

    end;

    ReallocMem(OutBuf, strm.total_out);

    OutBytes := strm.total_out;

  except

    FreeMem(OutBuf);

    raise

  end;

end;

procedure DecompressToUserBuf(const InBuf: Pointer; InBytes: Integer;

  const OutBuf: Pointer; BufSize: Integer);

var

  strm: TZStreamRec;

begin

  FillChar(strm, sizeof(strm), 0);

  strm.zalloc := zlibAllocMem;

  strm.zfree := zlibFreeMem;

  strm.next_in := InBuf;

  strm.avail_in := InBytes;

  strm.next_out := OutBuf;

  strm.avail_out := BufSize;

  DCheck(inflateInit_(strm, zlib_version, sizeof(strm)));

  try

    if DCheck(inflate(strm, Z_FINISH)) <> Z_STREAM_END then

      raise EZlibError.CreateRes(@sTargetBufferTooSmall);

  finally

    DCheck(inflateEnd(strm));

  end;

end;

// TCustomZlibStream

constructor TCustomZLibStream.Create(Strm: TStream);

begin

  inherited Create;

  FStrm := Strm;

  FStrmPos := Strm.Position;

  FZRec.zalloc := zlibAllocMem;

  FZRec.zfree := zlibFreeMem;

end;

procedure TCustomZLibStream.Progress(Sender: TObject);

begin

  if Assigned(FOnProgress) then FOnProgress(Sender);

end;

// TCompressionStream

constructor TCompressionStream.Create(CompressionLevel: TCompressionLevel;

  Dest: TStream);

const

  Levels: array [TCompressionLevel] of ShortInt =

    (Z_NO_COMPRESSION, Z_BEST_SPEED, Z_DEFAULT_COMPRESSION, Z_BEST_COMPRESSION);

begin

  inherited Create(Dest);

  FZRec.next_out := FBuffer;

  FZRec.avail_out := sizeof(FBuffer);

  CCheck(deflateInit_(FZRec, Levels[CompressionLevel], zlib_version, sizeof(FZRec)));

end;

destructor TCompressionStream.Destroy;

begin

  FZRec.next_in := nil;

  FZRec.avail_in := 0;

  try

    if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;

    while (CCheck(deflate(FZRec, Z_FINISH)) <> Z_STREAM_END)

      and (FZRec.avail_out = 0) do

    begin

      FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));

      FZRec.next_out := FBuffer;

      FZRec.avail_out := sizeof(FBuffer);

    end;

    if FZRec.avail_out < sizeof(FBuffer) then

      FStrm.WriteBuffer(FBuffer, sizeof(FBuffer) - FZRec.avail_out);

  finally

    deflateEnd(FZRec);

  end;

  inherited Destroy;

end;

function TCompressionStream.Read(var Buffer; Count: Longint): Longint;

begin

  raise ECompressionError.CreateRes(@sInvalidStreamOp);

end;

function TCompressionStream.Write(const Buffer; Count: Longint): Longint;

begin

  FZRec.next_in := @Buffer;

  FZRec.avail_in := Count;

  if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;

  while (FZRec.avail_in > 0) do

  begin

    CCheck(deflate(FZRec, 0));

    if FZRec.avail_out = 0 then

    begin

      FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));

      FZRec.next_out := FBuffer;

      FZRec.avail_out := sizeof(FBuffer);

      FStrmPos := FStrm.Position;

      Progress(Self);

    end;

  end;

  Result := Count;

end;

function TCompressionStream.Seek(Offset: Longint; Origin: Word): Longint;

begin

  if (Offset = 0) and (Origin = soFromCurrent) then

    Result := FZRec.total_in

  else

    raise ECompressionError.CreateRes(@sInvalidStreamOp);

end;

function TCompressionStream.GetCompressionRate: Single;

begin

  if FZRec.total_in = 0 then

    Result := 0

  else

    Result := (1.0 - (FZRec.total_out / FZRec.total_in)) * 100.0;

end;

// TDecompressionStream

constructor TDecompressionStream.Create(Source: TStream);

begin

  inherited Create(Source);

  FZRec.next_in := FBuffer;

  FZRec.avail_in := 0;

  DCheck(inflateInit_(FZRec, zlib_version, sizeof(FZRec)));

end;

destructor TDecompressionStream.Destroy;

begin

  FStrm.Seek(-FZRec.avail_in, 1);

  inflateEnd(FZRec);

  inherited Destroy;

end;

function TDecompressionStream.Read(var Buffer; Count: Longint): Longint;

begin

  FZRec.next_out := @Buffer;

  FZRec.avail_out := Count;

  if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;

  while (FZRec.avail_out > 0) do

  begin

    if FZRec.avail_in = 0 then

    begin

      FZRec.avail_in := FStrm.Read(FBuffer, sizeof(FBuffer));

      if FZRec.avail_in = 0 then

      begin

        Result := Count - FZRec.avail_out;

        Exit;

      end;

      FZRec.next_in := FBuffer;

      FStrmPos := FStrm.Position;

      Progress(Self);

    end;

    CCheck(inflate(FZRec, 0));

  end;

  Result := Count;

end;

function TDecompressionStream.Write(const Buffer; Count: Longint): Longint;

begin

  raise EDecompressionError.CreateRes(@sInvalidStreamOp);

end;

function TDecompressionStream.Seek(Offset: Longint; Origin: Word): Longint;

var

  I: Integer;

  Buf: array [0..4095] of Char;

begin

  if (Offset = 0) and (Origin = soFromBeginning) then

  begin

    DCheck(inflateReset(FZRec));

    FZRec.next_in := FBuffer;

    FZRec.avail_in := 0;

    FStrm.Position := 0;

    FStrmPos := 0;

  end

  else if ( (Offset >= 0) and (Origin = soFromCurrent)) or

          ( ((Offset - FZRec.total_out) > 0) and (Origin = soFromBeginning)) then

  begin

    if Origin = soFromBeginning then Dec(Offset, FZRec.total_out);

    if Offset > 0 then

    begin

      for I := 1 to Offset div sizeof(Buf) do

        ReadBuffer(Buf, sizeof(Buf));

      ReadBuffer(Buf, Offset mod sizeof(Buf));

    end;

  end

  else

    raise EDecompressionError.CreateRes(@sInvalidStreamOp);

  Result := FZRec.total_out;

end;

end.