(Visual FoxPro) Compress and Decompress Base64

Imagine we have data represented as a base64 string. This example demonstrates how to decode, compress, and re-encode to smaller base64 representing the compressed data.

Note: This example requires Chilkat v9.5.0.66 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL lnSuccess
LOCAL lcStrBase64
LOCAL loCompress
LOCAL loBinDat
LOCAL lcCompressedBase64
LOCAL lcDecompressedBase64

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

lcStrBase64 = "VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NClRoZSBxdWljayBicm93biBmb3gganVtcGVkIG92ZXIgdGhlIGxhenkgZG9nLg0KVGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NCg0K"

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Compression')
loCompress = CreateObject('Chilkat.Compression')
loCompress.Algorithm = "deflate"

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.BinData')
loBinDat = CreateObject('Chilkat.BinData')
* Load the base64 data into a BinData object.
* This decodes the base64. The decoded bytes will be contained in the BinData.
loBinDat.AppendEncoded(lcStrBase64,"base64")

* Compress the BinData.
loCompress.CompressBd(loBinDat)

* Get the compressed data in base64 format:
lcCompressedBase64 = loBinDat.GetEncoded("base64")
? "compressed base64:"
? lcCompressedBase64

* The compressed base64 is: C8lIVSgszUzOVkgqyi/PU0jLr1DIKs0tSE1RyC9LLVIoAcrnJFZVKqTkp+vxcoUMYeW8XAA=

* Now decompress:
loBinDat.Clear()
loBinDat.AppendEncoded(lcCompressedBase64,"base64")
loCompress.DecompressBd(loBinDat)

lcDecompressedBase64 = loBinDat.GetEncoded("base64")
? "decompressed base64:"
? lcDecompressedBase64

* The output is the original data:
* VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NClRoZSBxdWljayBicm93biBmb3gganVtcGVkIG92ZXIgdGhlIGxhenkgZG9nLg0KVGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NCg0K

RELEASE loCompress
RELEASE loBinDat