(Swift 2) Decompress Large Binary File in Blocks

Decompresses a large binary file in blocks. This example uses BeginDecompressBytes, MoreDecompressBytes, and EndDecompressBytes.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let facSrc = CkoFileAccess()
    let facDest = CkoFileAccess()

    // Open a previously compressed file for decompressing.
    // See Compress Large File in Blocks

    var success: Bool = facSrc.OpenForRead("qa_data/bmp/compressedBmp.dat")
    if success != true {
        print("\(facSrc.LastErrorText)")
        return
    }

    // If we compress in 32K chunks, find out how many blocks there will be.
    var blockSize: Int = 32768
    var numBlocks: Int = facSrc.GetNumBlocks(blockSize).intValue

    // Open an output file for the decompressed data.
    success = facDest.OpenForWrite("qa_output/decompressed.bmp")
    if success != true {
        print("\(facDest.LastErrorText)")
        return
    }

    let compress = CkoCompression()
    compress.Algorithm = "deflate"

    var decompressedBytes: NSData
    var compressedBytes: NSData

    var i: Int = 0
    while i < numBlocks {
        compressedBytes = facSrc.ReadBlock(i, blockSize: blockSize)
        if i == 0 {
            decompressedBytes = compress.BeginDecompressBytes(compressedBytes)
        }
        else {
            decompressedBytes = compress.MoreDecompressBytes(compressedBytes)
        }

        facDest.FileWrite(decompressedBytes)

        i = i + 1
    }

    // At the very end, flush any remaining decompressed bytes, if any.
    decompressedBytes = compress.EndDecompressBytes()
    facDest.FileWrite(decompressedBytes)

    facSrc.FileClose()
    facDest.FileClose()

    print("Finished decompressing file.")

}