New unit Quick.Compression.LZO

Author: exilon

Quick.Compression.LZO.pas

@@ -0,0 +1,141 @@
+{ ***************************************************************************
+
+  Copyright (c) 2016-2019 Kike Pérez
+
+  Unit        : Quick.Compression.LZO
+  Description : LZO Compressor
+  Author      : Kike Pérez
+  Version     : 1.8
+  Created     : 15/09/2019
+  Modified    : 22/09/2019
+
+  This file is part of QuickLib: https://github.com/exilon/QuickLib
+
+ ***************************************************************************
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+ *************************************************************************** }
+
+unit Quick.Compression.LZO;
+
+{$i QuickLib.inc}
+
+interface
+
+uses
+  SysUtils;
+
+const
+
+  {$IFDEF MSWINDOWS}
+  LIBPATH = '.\lzo.dll';
+  {$ELSE}
+  LIBPATH = './lzo.so';
+  {$ENDIF}
+
+type
+
+  TLZOCompressor = class
+  private
+    fWorkMemory : Pointer;
+  public
+    constructor Create;
+    destructor Destroy; override;
+    function Version : string;
+    function VersionDate : string;
+    function Compress(const aUncompressed : string) : string;
+    function Decompress(const aCompressed : string) : string;
+  end;
+
+  ELZOCompressor = class(Exception);
+
+implementation
+
+function __lzo_init3 : Integer; stdcall; external LIBPATH;
+function lzo_version_string : PChar; stdcall; external LIBPATH;
+function lzo_version_date : PChar; stdcall; external LIBPATH;
+function lzo1x_1_compress(src : Pointer; src_len : LongWord; dest : Pointer; var dest_len : LongWord; wrkmem : Pointer) : Integer; stdcall; external LIBPATH;
+function lzo1x_decompress(src : Pointer; src_len : LongWord; dest : Pointer; var dest_len : LongWord; wrkmem : Pointer) : Integer; stdcall; external LIBPATH;
+
+
+{ TLZOCompressor }
+
+function TLZOCompressor.Compress(const aUncompressed: string): string;
+var
+  srclen : Integer;
+  outlen : LongWord;
+  uncompressed : TBytes;
+  compressed : TBytes;
+  byteslen : array[1.. sizeof(integer)] of byte;
+begin
+  outlen := 0;
+  try
+    SetLength(compressed, Round(aUncompressed.Length + aUncompressed.Length / 64 + 16 + 3 + 4));
+    uncompressed := TEncoding.UTF8.GetBytes(aUncompressed);
+    lzo1x_1_compress(uncompressed, High(uncompressed)+1, compressed, outlen, fWorkMemory);
+    Finalize(uncompressed);
+    srclen := aUncompressed.Length;
+    Move(srclen,byteslen[1], SizeOf(Integer));
+    SetLength(compressed,outlen + 4);
+    Move(byteslen,compressed[outlen],4);
+    Result := TEncoding.ANSI.GetString(compressed,0,outlen + 4);
+  except
+    on E : Exception do raise ELZOCompressor.CreateFmt('LZO Compression error: %s',[e.Message]);
+  end;
+end;
+
+constructor TLZOCompressor.Create;
+begin
+  if __lzo_init3 <> 0 then raise Exception.Create('Initialization LZO-Compressor failed');
+  GetMem(fWorkMemory,16384 * 4);
+end;
+
+function TLZOCompressor.Decompress(const aCompressed: string): string;
+var
+  srclen : LongWord;
+  dstlen : LongWord;
+  uncompressed : TBytes;
+  compressed : TBytes;
+  i : Integer;
+begin
+  try
+    compressed := TEncoding.ANSI.GetBytes(aCompressed);
+    //get src length
+    srclen := PLongInt(@compressed[High(compressed)-3])^;
+    SetLength(uncompressed,srclen);
+    dstlen := 0;
+    lzo1x_decompress(compressed, High(compressed) - 4, uncompressed, dstlen, fWorkMemory);
+    Result := TEncoding.UTF8.GetString(uncompressed,0,dstlen);
+  except
+    on E : Exception do raise ELZOCompressor.CreateFmt('LZO Descompression error: %s',[e.Message]);
+  end;
+end;
+
+destructor TLZOCompressor.Destroy;
+begin
+  FreeMem(fWorkMemory);
+  inherited;
+end;
+
+function TLZOCompressor.Version: string;
+begin
+  Result := string(lzo_version_string);
+end;
+
+function TLZOCompressor.VersionDate: string;
+begin
+  Result := string(lzo_version_date^);
+end;
+
+end.