(Android™) Compress Large Binary File in Blocks

Compresses a large binary file in blocks. This example uses BeginCompressBytes, MoreCompressBytes, and EndCompressBytes.

Chilkat Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkFileAccess facSrc = new CkFileAccess();
    CkFileAccess facDest = new CkFileAccess();

    // Open a large binary file for reading.
    boolean success = facSrc.OpenForRead("qa_data/bmp/big.bmp");
    if (success != true) {
        Log.i(TAG, facSrc.lastErrorText());
        return;
        }

    // If we compress in 64K chunks, find out how many blocks there will be.
    int blockSize = 65536;
    int numBlocks = facSrc.GetNumBlocks(blockSize);

    // Open an output file for the compressed data.
    success = facDest.OpenForWrite("qa_data/bmp/compressedBmp.dat");
    if (success != true) {
        Log.i(TAG, facDest.lastErrorText());
        return;
        }

    CkCompression compress = new CkCompression();
    compress.put_Algorithm("deflate");

    CkByteData fileBytes = new CkByteData();
    CkByteData compressedBytes = new CkByteData();

    int i = 0;
    while (i < numBlocks) {
        success = facSrc.ReadBlock(i,blockSize,fileBytes);
        if (i == 0) {
            success = compress.BeginCompressBytes(fileBytes,compressedBytes);
            }
        else {
            success = compress.MoreCompressBytes(fileBytes,compressedBytes);
            }

        facDest.FileWrite(compressedBytes);

        i = i + 1;
        }

    // At the very end, flush any remaining compressed bytes, if any.
    success = compress.EndCompressBytes(compressedBytes);
    facDest.FileWrite(compressedBytes);

    facSrc.FileClose();
    facDest.FileClose();

    Log.i(TAG, "Finished compressing file.");

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}