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(Delphi ActiveX) Compress Large Binary File in BlocksCompresses a large binary file in blocks. Note: This example requires Chilkat v11.0.0 or greater.
uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB; ... procedure TForm1.Button1Click(Sender: TObject); var success: Integer; facSrc: TCkFileAccess; facDest: TCkFileAccess; blockSize: Integer; numBlocks: Integer; compress: TChilkatCompression; fileBytes: Array of Byte; compressedBytes: Array of Byte; i: Integer; begin success := 0; // This example assumes the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. facSrc := TCkFileAccess.Create(Self); facDest := TCkFileAccess.Create(Self); // Open a large binary file for reading. success := facSrc.OpenForRead('qa_data/bmp/big.bmp'); if (success = 0) then begin Memo1.Lines.Add(facSrc.LastErrorText); Exit; end; // If we compress in 64K chunks, find out how many blocks there will be. blockSize := 65536; numBlocks := facSrc.GetNumBlocks(blockSize); // Open an output file for the compressed data. success := facDest.OpenForWrite('c:/temp/qa_output/compressedBmp.dat'); if (success = 0) then begin Memo1.Lines.Add(facDest.LastErrorText); Exit; end; compress := TChilkatCompression.Create(Self); compress.Algorithm := 'deflate'; // Assuming numBlocks > 1 compress.FirstChunk := 1; compress.LastChunk := 0; i := 0; while i < numBlocks do begin fileBytes := facSrc.ReadBlock(i,blockSize); compressedBytes := compress.CompressBytes(fileBytes); facDest.FileWrite(compressedBytes); i := i + 1; compress.FirstChunk := 0; if (i = (numBlocks - 1)) then begin compress.LastChunk := 1; end; end; facSrc.FileClose(); facDest.FileClose(); Memo1.Lines.Add('Finished compressing file.'); end; |
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