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(Xojo Plugin) Compress Large Binary File in BlocksCompresses a large binary file in blocks. Note: This example requires Chilkat v11.0.0 or greater.
Dim success As Boolean success = False // This example assumes the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. Dim facSrc As New Chilkat.FileAccess Dim facDest As New Chilkat.FileAccess // Open a large binary file for reading. success = facSrc.OpenForRead("qa_data/bmp/big.bmp") If (success = False) Then System.DebugLog(facSrc.LastErrorText) Return End If // If we compress in 64K chunks, find out how many blocks there will be. Dim blockSize As Int32 blockSize = 65536 Dim numBlocks As Int32 numBlocks = facSrc.GetNumBlocks(blockSize) // Open an output file for the compressed data. success = facDest.OpenForWrite("c:/temp/qa_output/compressedBmp.dat") If (success = False) Then System.DebugLog(facDest.LastErrorText) Return End If Dim compress As New Chilkat.Compression compress.Algorithm = "deflate" Dim fileBytes As MemoryBlock Dim compressedBytes As MemoryBlock // Assuming numBlocks > 1 compress.FirstChunk = True compress.LastChunk = False Dim i As Int32 i = 0 While i < numBlocks fileBytes = facSrc.ReadBlock(i,blockSize) compressedBytes = compress.CompressBytes(fileBytes) success = facDest.FileWrite(compressedBytes) i = i + 1 compress.FirstChunk = False If (i = (numBlocks - 1)) Then compress.LastChunk = True End If Wend facSrc.FileClose facDest.FileClose System.DebugLog("Finished compressing file.") |
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