Compression VB.NET WinRT Reference Documentation

Compression

Data compression component implementing the PPMD, Bzip2, Deflate, and LZW compression algorithms. .NET, ActiveX, and C++ implementations provide progress monitoring and abort capabilities. Provides a unified API for all supported compression algorithms.

Object Creation

Dim obj As New Chilkat.Compression()

Properties

Algorithm As String

The compression algorithm to be used. Should be set to either "ppmd", "deflate", "zlib", "bzip2", or "lzw".

Note: The PPMD compression algorithm is only available for 32-bit builds. It is not available for 64-bit implementations. Also, this PPMD implementation is the "J" variant.

Charset As String

Only applies to methods that compress or decompress strings. This specifies the character encoding that the string should be converted to before compression. Many programming languages use Unicode (2 bytes per char) for representing characters. This property allows for the string to be converted to a 1-byte per char encoding prior to compression.

DebugLogFilePath As String

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

EncodingMode As String

Controls the encoding expected by methods ending in "ENC", such as CompressBytesENC. Valid values are "base64", "hex", "url", and "quoted-printable". Compression methods ending in ENC return the binary compressed data as an encoded string using this encoding. Decompress methods expect the input string to be this encoding.

HeartbeatMs As Integer

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

LastErrorHtml As String (ReadOnly)

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

LastErrorText As String (ReadOnly)

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

LastErrorXml As String (ReadOnly)

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

LastMethodSuccess As Boolean

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

VerboseLogging As Boolean

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version As String (ReadOnly)

Version of the component/library, such as "9.5.0.63"

Methods

<Awaitable> Function BeginCompressBytesAsync(ByVal data As Byte()) As IAsyncOperation(Of Byte())

Large amounts of binary byte data may be compressed in chunks by first calling BeginCompressBytes, followed by 0 or more calls to MoreCompressedBytes, and ending with a final call to EndCompressBytes. Each call returns 0 or more bytes of compressed data which may be output to a compressed data stream (such as a file, socket, etc.).

Returns an empty byte array on failure

Compress Large Binary File in Blocks

<Awaitable> Function BeginCompressBytesENCAsync(ByVal data As Byte()) As IAsyncOperation(Of String)

Large amounts of binary byte data may be compressed in chunks by first calling BeginCompressBytesENC, followed by 0 or more calls to MoreCompressedBytesENC, and ending with a final call to EndCompressBytesENC. Each call returns 0 or more characters of compressed data (encoded as a string according to the EncodingMode property setting) which may be output to a compressed data stream (such as a file, socket, etc.).

Returns Nothing on failure

<Awaitable> Function BeginCompressStringAsync(ByVal str As String) As IAsyncOperation(Of Byte())

Large amounts of string data may be compressed in chunks by first calling BeginCompressString, followed by 0 or more calls to MoreCompressedString, and ending with a final call to EndCompressString. Each call returns 0 or more bytes of compressed data which may be output to a compressed data stream (such as a file, socket, etc.).

Returns an empty byte array on failure

Compress Text Feed to Binary

<Awaitable> Function BeginCompressStringENCAsync(ByVal str As String) As IAsyncOperation(Of String)

Large amounts of string data may be compressed in chunks by first calling BeginCompressStringENC, followed by 0 or more calls to MoreCompressedStringENC, and ending with a final call to EndCompressStringENC. Each call returns 0 or more characters of compressed data (encoded as a string according to the EncodingMode property setting) which may be output to a compressed data stream (such as a file, socket, etc.).

Returns Nothing on failure

Compress String Feed to Base64

<Awaitable> Function BeginDecompressBytesAsync(ByVal data As Byte()) As IAsyncOperation(Of Byte())

A compressed data stream may be decompressed in chunks by first calling BeginDecompressBytes, followed by 0 or more calls to MoreDecompressedBytes, and ending with a final call to EndDecompressBytes. Each call returns 0 or more bytes of decompressed data.

Returns an empty byte array on failure

Decompress Large Binary File in Blocks

<Awaitable> Function BeginDecompressBytesENCAsync(ByVal str As String) As IAsyncOperation(Of Byte())

The input to this method is an encoded string containing compressed data. The EncodingMode property should be set prior to calling this method. The input string is decoded according to the EncodingMode (hex, base64, etc.) and then decompressed.

A compressed data stream may be decompressed in chunks by first calling BeginDecompressBytesENC, followed by 0 or more calls to MoreDecompressedBytesENC, and ending with a final call to EndDecompressBytesENC. Each call returns 0 or more bytes of decompressed data.

Returns an empty byte array on failure

<Awaitable> Function BeginDecompressStringAsync(ByVal data As Byte()) As IAsyncOperation(Of String)

A compressed data stream may be decompressed in chunks by first calling BeginDecompressString, followed by 0 or more calls to MoreDecompressedString, and ending with a final call to EndDecompressString. Each call returns 0 or more characters of decompressed text.

Returns Nothing on failure

Decompress Large Text File in Blocks

<Awaitable> Function BeginDecompressStringENCAsync(ByVal str As String) As IAsyncOperation(Of String)

The input to this method is an encoded string containing compressed data. The EncodingMode property should be set prior to calling this method. The input string is decoded according to the EncodingMode (hex, base64, etc.) and then decompressed.

A compressed data stream may be decompressed in chunks by first calling BeginDecompressStringENC, followed by 0 or more calls to MoreDecompressedStringENC, and ending with a final call to EndDecompressStringENC. Each call returns 0 or more characters of decompressed text.

Returns Nothing on failure

<Awaitable> Function CompressBdAsync(ByVal binData As BinData) As IAsyncOperation(Of Boolean)

Introduced in version 9.5.0.66

Compresses the data contained in a BinData object.

Returns True for success, False for failure.

Compress and Decompress Base64

Compress and Decompress Hex String

<Awaitable> Function CompressBytesAsync(ByVal data As Byte()) As IAsyncOperation(Of Byte())

Compresses byte data.

Returns an empty byte array on failure

Compress Bytes

<Awaitable> Function CompressBytesENCAsync(ByVal data As Byte()) As IAsyncOperation(Of String)

Compresses bytes and returns the compressed data encoded to a string. The encoding (hex, base64, etc.) is determined by the EncodingMode property setting.

Returns Nothing on failure

Compress Bytes to Base64 (or any other encoding)

<Awaitable> Function CompressFileAsync(ByVal srcPath As String, ByVal destPath As String) As IAsyncOperation(Of Boolean)

Performs file-to-file compression. Files of any size may be compressed because the file is compressed internally in streaming mode.

Returns True for success, False for failure.

Compress and Decompress a File

<Awaitable> Function CompressStreamAsync(ByVal strm As Stream) As IAsyncOperation(Of Boolean)

Introduced in version 9.5.0.56

Compresses a stream. Internally, the strm's source is read, compressed, and the compressed data written to the strm's sink. It does this in streaming fashion. Extremely large or even infinite streams can be compressed with stable ungrowing memory usage.

Returns True for success, False for failure.

Streaming Compression

<Awaitable> Function CompressStringAsync(ByVal str As String) As IAsyncOperation(Of Byte())

Compresses a string.

Returns an empty byte array on failure

Compress and Decompress a String

<Awaitable> Function CompressStringENCAsync(ByVal str As String) As IAsyncOperation(Of String)

Compresses a string and returns the compressed data encoded to a string. The output encoding (hex, base64, etc.) is determined by the EncodingMode property setting.

Returns Nothing on failure

Compress and Decompress a String

<Awaitable> Function DecompressBdAsync(ByVal binData As BinData) As IAsyncOperation(Of Boolean)

Introduced in version 9.5.0.66

Decompresses the data contained in a BinData object.

Returns True for success, False for failure.

Compress and Decompress Base64

Compress and Decompress Hex String

<Awaitable> Function DecompressBytesAsync(ByVal data As Byte()) As IAsyncOperation(Of Byte())

The opposite of CompressBytes.

Returns an empty byte array on failure

Decompress Bytes

<Awaitable> Function DecompressBytesENCAsync(ByVal encodedCompressedData As String) As IAsyncOperation(Of Byte())

The opposite of CompressBytesENC. encodedCompressedData contains the compressed data as an encoded string (hex, base64, etc) as specified by the EncodingMode property setting.

Returns an empty byte array on failure

Compress Bytes to Base64 (or any other encoding)

<Awaitable> Function DecompressFileAsync(ByVal srcPath As String, ByVal destPath As String) As IAsyncOperation(Of Boolean)

Performs file-to-file decompression (the opposite of CompressFile). Internally the file is decompressed in streaming mode which allows files of any size to be decompressed.

Returns True for success, False for failure.

Compress and Decompress a File

<Awaitable> Function DecompressStreamAsync(ByVal strm As Stream) As IAsyncOperation(Of Boolean)

Introduced in version 9.5.0.56

Decompresses a stream. Internally, the strm's source is read, decompressed, and the decompressed data written to the strm's sink. It does this in streaming fashion. Extremely large or even infinite streams can be decompressed with stable ungrowing memory usage.

Returns True for success, False for failure.

Streaming Compression

<Awaitable> Function DecompressStringAsync(ByVal data As Byte()) As IAsyncOperation(Of String)

Takes compressed bytes, decompresses, and returns the resulting string.

Returns Nothing on failure

Compress and Decompress a String

<Awaitable> Function DecompressStringENCAsync(ByVal encodedCompressedData As String) As IAsyncOperation(Of String)

The opposite of CompressStringENC. encodedCompressedData contains the compressed data as an encoded string (hex, base64, etc) as specified by the EncodingMode property setting.

Returns Nothing on failure

Compress and Decompress a String

<Awaitable> Function EndCompressBytesAsync() As IAsyncOperation(Of Byte())

Must be callled to finalize a compression stream. Returns any remaining (buffered) compressed data.

(See BeginCompressBytes)

Returns an empty byte array on failure

Compress Large Binary File in Blocks

<Awaitable> Function EndCompressBytesENCAsync() As IAsyncOperation(Of String)

Must be callled to finalize a compression stream. Returns any remaining (buffered) compressed data.

(See BeginCompressBytesENC)

Returns Nothing on failure

<Awaitable> Function EndCompressStringAsync() As IAsyncOperation(Of Byte())

Must be callled to finalize a compression stream. Returns any remaining (buffered) compressed data.

(See BeginCompressString)

Returns an empty byte array on failure

Compress Text Feed to Binary

<Awaitable> Function EndCompressStringENCAsync() As IAsyncOperation(Of String)

Must be callled to finalize a compression stream. Returns any remaining (buffered) compressed data.

(See BeginCompressStringENC)

Returns Nothing on failure

Compress String Feed to Base64

<Awaitable> Function EndDecompressBytesAsync() As IAsyncOperation(Of Byte())

Called to finalize the decompression stream and return any remaining (buffered) decompressed data.

(See BeginDecompressBytes)

Returns an empty byte array on failure

Decompress Large Binary File in Blocks

<Awaitable> Function EndDecompressBytesENCAsync() As IAsyncOperation(Of Byte())

Called to finalize the decompression stream and return any remaining (buffered) decompressed data.

The input to this method is an encoded string containing compressed data. The EncodingMode property should be set prior to calling this method. The input string is decoded according to the EncodingMode (hex, base64, etc.) and then decompressed.

(See BeginDecompressBytesENC)

Returns an empty byte array on failure

<Awaitable> Function EndDecompressStringAsync() As IAsyncOperation(Of String)

Called to finalize the decompression stream and return any remaining (buffered) decompressed data.

(See BeginDecompressString)

Returns Nothing on failure

Decompress Large Text File in Blocks

<Awaitable> Function EndDecompressStringENCAsync() As IAsyncOperation(Of String)

Called to finalize the decompression stream and return any remaining (buffered) decompressed data.

The input to this method is an encoded string containing compressed data. The EncodingMode property should be set prior to calling this method. The input string is decoded according to the EncodingMode (hex, base64, etc.) and then decompressed.

(See BeginDecompressStringENC)

Returns Nothing on failure

<Awaitable> Function MoreCompressBytesAsync(ByVal data As Byte()) As IAsyncOperation(Of Byte())

(See BeginCompressBytes)

Returns an empty byte array on failure

Compress Large Binary File in Blocks

<Awaitable> Function MoreCompressBytesENCAsync(ByVal data As Byte()) As IAsyncOperation(Of String)

(See BeginCompressBytesENC)

Returns Nothing on failure

<Awaitable> Function MoreCompressStringAsync(ByVal str As String) As IAsyncOperation(Of Byte())

(See BeginCompressString)

Returns an empty byte array on failure

Compress Text Feed to Binary

<Awaitable> Function MoreCompressStringENCAsync(ByVal str As String) As IAsyncOperation(Of String)

(See BeginCompressStringENC)

Returns Nothing on failure

Compress String Feed to Base64

<Awaitable> Function MoreDecompressBytesAsync(ByVal data As Byte()) As IAsyncOperation(Of Byte())

(See BeginDecompressBytes)

Returns an empty byte array on failure

Decompress Large Binary File in Blocks

<Awaitable> Function MoreDecompressBytesENCAsync(ByVal str As String) As IAsyncOperation(Of Byte())

The input to this method is an encoded string containing compressed data. The EncodingMode property should be set prior to calling this method. The input string is decoded according to the EncodingMode (hex, base64, etc.) and then decompressed.

(See BeginDecompressBytesENC)

Returns an empty byte array on failure

<Awaitable> Function MoreDecompressStringAsync(ByVal data As Byte()) As IAsyncOperation(Of String)

(See BeginDecompressString)

Returns Nothing on failure

Decompress Large Text File in Blocks

<Awaitable> Function MoreDecompressStringENCAsync(ByVal str As String) As IAsyncOperation(Of String)

The input to this method is an encoded string containing compressed data. The EncodingMode property should be set prior to calling this method. The input string is decoded according to the EncodingMode (hex, base64, etc.) and then decompressed.

(See BeginDecompressStringENC)

Returns Nothing on failure

Function UnlockComponent(ByVal unlockCode As String) As Boolean

Unlocks the component allowing for the full functionality to be used. The component may be used fully-functional for the 1st 30-days after download by passing an arbitrary string to this method. If for some reason you do not receive the full 30-day trial, send email to support@chilkatsoft.com for a temporary unlock code w/ an explicit expiration date. Upon purchase, a purchased unlock code is provided which should replace the temporary/arbitrary string passed to this method.

Returns True for success, False for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Permanent Unlock Code

LastErrorText Standard Information

Events