ZipCrc DataFlex Reference Documentation

ZipCrc

Current Version: 10.1.2

Calculate a Zip CRC checksum for a file or in-memory data.

Object Creation

// (Dataflex programs use the 32-bit Chilkat ActiveX)
Handle hoZipCrc
Get Create(RefClass(cComChilkatZipCrc)) to hoZipCrc

Properties

DebugLogFilePath
Function ComDebugLogFilePath Returns String
Procedure Set ComDebugLogFilePath String value

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
top
LastBinaryResult
Function ComLastBinaryResult Returns Variant

This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to True. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.

top
LastErrorHtml
Function ComLastErrorHtml Returns String

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

top
LastErrorText
Function ComLastErrorText Returns String

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

top
LastErrorXml
Function ComLastErrorXml Returns String

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

top
LastMethodSuccess
Function ComLastMethodSuccess Returns Boolean
Procedure Set ComLastMethodSuccess Boolean value

Indicates the success or failure of the most recent method call: True means success, False means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.

top
LastStringResult
Function ComLastStringResult Returns String

In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.

top
LastStringResultLen
Function ComLastStringResultLen Returns Integer

The length, in characters, of the string contained in the LastStringResult property.

top
VerboseLogging
Function ComVerboseLogging Returns Boolean
Procedure Set ComVerboseLogging Boolean value

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.

top
Version
Function ComVersion Returns String

Version of the component/library, such as "10.1.0"

More Information and Examples
top

Methods

BeginStream
Procedure ComBeginStream

Provides a way to calculate a CRC by streaming the data a chunk at a time. An application would start by calling BeginStream. Then it would add data by calling MoreData for each additional chunk. After the last chunk has been processed, the EndStream method is called to return the CRC.

top
CalculateCrc
Function ComCalculateCrc Variant data

Calculates a 32-bit CRC for in-memory byte data. This is the 32-bit CRC that would be found in a Zip file header if a file containing the data was added to a zip archive. Returns the CRC32 of the data.

top
CrcBd
Function ComCrcBd cComChilkatBinData bd
Introduced in version 9.5.0.75

Calculates a CRC32 for the bytes contained in bd.

top
CrcSb
Function ComCrcSb cComChilkatStringBuilder sb String charset
Introduced in version 9.5.0.75

Calculates a CRC32 for the string contained in sb. The charset is the byte representation to be used for the sb when calculating the CRC32. It can be utf-8, utf-16, windows-1252, iso-8859-1, or any of the character encodings (charsets) listed at the link below.

top
CrcString
Function ComCrcString String str String charset
Introduced in version 9.5.0.75

Calculates a CRC32 for a string. The charset is the byte representation to be used for the str when calculating the CRC32. It can be utf-8, utf-16, windows-1252, iso-8859-1, or any of the character encodings (charsets) listed at the link below.

top
EndStream
Function ComEndStream

Finalizes and returns the Zip CRC value calculated by calling BeginStream followed by multiple calls to MoreData.

top
FileCrc
Function ComFileCrc String path

Calculates the CRC32 of a file. The data contained in the file is streamed for the calculation to keep the memory footprint small and constant. Returns the CRC32 of the file.

More Information and Examples
top
FileCrcAsync (1)
Function ComFileCrcAsync String path Returns cComChilkatTask

Creates an asynchronous task to call the FileCrc method with the arguments provided.

Returns null on failure

top
LoadTaskCaller
Function ComLoadTaskCaller cComChilkatTask task Returns Boolean
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

top
MoreData
Procedure ComMoreData Variant data

Adds additional data to the CRC currently being calculated. (See BeginStream for more information.)

top
ToHex
Function ComToHex Variant crc Returns String

Converts a 32-bit integer to a hex string.

Returns null on failure

top