{*******************************************************************}
{                                                                   }
{       Almediadev Visual Component Library                         }
{       BusinessSkinForm                                            }
{       Version 6.15                                                }
{                                                                   }
{       Copyright (c) 2000-2008 Almediadev                          }
{       ALL RIGHTS RESERVED                                         }
{                                                                   }
{       Home:  http://www.almdev.com                                }
{       Support: support@almdev.com                                 }
{                                                                   }
{*******************************************************************}

unit bszlibcompress;

{$WARNINGS OFF}
{$HINTS OFF}


interface

uses Sysutils, Classes, bszlib;

const
  BufSize = 4096;
   
type
  TAlloc = function (AppData: Pointer; Items, Size: Integer): Pointer;
  TFree = procedure (AppData, Block: Pointer);
  TZStreamRec = z_stream;

  TCustomZlibStream = class(TStream)
  private
    FStrm: TStream;
    FStrmPos: Integer;
    FOnProgress: TNotifyEvent;
    FZRec: TZStreamRec;
    FBuffer: array [0..BufSize - 1] of Char;
  protected
    procedure Progress(Sender: TObject); dynamic;
    property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;
    constructor Create(Strm: TStream);
  end;

  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 = 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;

const
  zlib_version = '1.1.4';

type
  EZlibError = class(Exception);
  ECompressionError = class(EZlibError);
  EDecompressionError = class(EZlibError);

procedure CompressStream(Stream, SaveStream: TStream);
procedure DeCompressStream(Stream, CompressedStream: TStream);

implementation

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_DEFAULT_STRATEGY    = 0;

  Z_BINARY   = 0;
  Z_ASCII    = 1;
  Z_UNKNOWN  = 2;

  Z_DEFLATED = 8;

  _z_errmsg: array[0..9] of PChar = (
    'need dictionary',      // Z_NEED_DICT      (2)
    'stream end',           // Z_STREAM_END     (1)
    '',                     // Z_OK             (0)
    'file error',           // Z_ERRNO          (-1)
    'stream error',         // Z_STREAM_ERROR   (-2)
    'data error',           // Z_DATA_ERROR     (-3)
    'insufficient memory',  // Z_MEM_ERROR      (-4)
    'buffer error',         // Z_BUF_ERROR      (-5)
    'incompatible version', // Z_VERSION_ERROR  (-6)
    ''
  );

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;

function zcalloc(AppData: Pointer; Items, Size: Integer): Pointer;
begin
  GetMem(Result, Items*Size);
end;

procedure zcfree(AppData, Block: Pointer);
begin
  FreeMem(Block);
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('compression error');
end;

constructor TCustomZLibStream.Create(Strm: TStream);
begin
  inherited Create;
  FStrm := Strm;
  FStrmPos := Strm.Position;
end;

procedure TCustomZLibStream.Progress(Sender: TObject);
begin
  if Assigned(FOnProgress) then FOnProgress(Sender);
end;

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.Create('Invalid stream operation');
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.Create('Invalid stream operation');
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;

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
  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 - Longint(FZRec.avail_out);
          Exit;
        end;
      FZRec.next_in := @FBuffer;
      FStrmPos := FStrm.Position;
      Progress(Self);
    end;
    DCheck(inflate(FZRec, 0));
  end;
  Result := Count;
end;

function TDecompressionStream.Write(const Buffer; Count: Longint): Longint;
begin
  raise EDecompressionError.Create('Invalid stream operation');
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.Create('Invalid stream operation');
  Result := FZRec.total_out;
end;

procedure CompressStream(Stream, SaveStream: TStream);
var
  CompStrm: TCompressionStream;
begin
  CompStrm := TCompressionStream.Create(clMax, SaveStream);
  try
    Stream.Seek(0, 0);
    CompStrm.CopyFrom(Stream, 0);
  finally
    CompStrm.Free;
  end;
end;

procedure DeCompressStream(Stream, CompressedStream: TStream);
var
  Size: LongInt;
  DecompStrm: TDecompressionStream;
  Buf: array[0..BufSize - 1] of Byte;
begin
  CompressedStream.Seek(0, 0);
  DeCompStrm := TDecompressionStream.Create(CompressedStream);
  try
    while True do
    begin
      Size := DecompStrm.Read(Buf, BufSize);
      if Size <> 0 then Stream.WriteBuffer(Buf, Size) else Break;
    end;
  finally
    DecompStrm.Free;
  end;
end;

end.