ZipCrc PureBasic Reference Documentation

ZipCrc

Current Version: 10.1.0

Requires Chilkat Bundle License

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

Object Creation

obj.i = CkZipCrc::ckCreate()

; Make sure to dispose of the object when finished like this:
CkZipCrc::ckDispose(obj);

Properties

DebugLogFilePath

Declare.s ckDebugLogFilePath(obj.i)
Declare setCkDebugLogFilePath(obj.i, value.s)

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:

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

More Information and Examples

Example showing how to use DebugLogFilePath.

LastErrorHtml

Declare.s ckLastErrorHtml(obj.i) ; (read-only)

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

Declare.s ckLastErrorText(obj.i) ; (read-only)

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.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

LastErrorXml

Declare.s ckLastErrorXml(obj.i) ; (read-only)

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

Declare.i ckLastMethodSuccess(obj.i)
Declare setCkLastMethodSuccess(obj.i, value.i)

Indicate whether the last method call succeeded or failed. A value of 1 indicates success, a value of 0 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 = 1 and failure = 0.
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 1. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

VerboseLogging

Declare.i ckVerboseLogging(obj.i)
Declare setCkVerboseLogging(obj.i, value.i)

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version

Declare.s ckVersion(obj.i) ; (read-only)

Version of the component/library, such as "9.5.0.94"

More Information and Examples

How to get the Chilkat version at runtime.

Methods

BeginStream

Declare ckBeginStream(obj.i)

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.

CrcBd

Declare.i ckCrcBd(obj.i, bd.i)

Introduced in version 9.5.0.75

Calculates a CRC32 for the bytes contained in bd.

CrcSb

Declare.i ckCrcSb(obj.i, sb.i, charset.s)

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.

CrcString

Declare.i ckCrcString(obj.i, str.s, charset.s)

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.

EndStream

Declare.i ckEndStream(obj.i)

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

FileCrc

Declare.i ckFileCrc(obj.i, path.s)

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

Compute CRC32 of a File

FileCrcAsync ⁽¹⁾

Declare.i ckFileCrcAsync(obj.i, path.s)

Creates an asynchronous task to call the FileCrc method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns 0 on failure

LoadTaskCaller

Declare.i ckLoadTaskCaller(obj.i, task.i)

Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns 1 for success, 0 for failure.

ToHex

Declare.s ckToHex(obj.i, crc.l)

Converts a 32-bit integer to a hex string.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.