ZipCrc Delphi DLL Reference Documentation

ZipCrc

Current Version: 11.1.0

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

Create/Dispose

var
myObject: HCkZipCrc;

begin
myObject := CkZipCrc_Create();

// ...

CkZipCrc_Dispose(myObject);
end;
function CkZipCrc_Create: HCkZipCrc; stdcall;

Creates an instance of the HCkZipCrc object and returns a handle (i.e. a Pointer). The handle is passed in the 1st argument for the functions listed on this page.

procedure CkZipCrc_Dispose(handle: HCkZipCrc); stdcall;

Objects created by calling CkZipCrc_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.

Properties

DebugLogFilePath
procedure CkZipCrc_getDebugLogFilePath(objHandle: HCkZipCrc; outPropVal: HCkString); stdcall;
procedure CkZipCrc_putDebugLogFilePath(objHandle: HCkZipCrc; newPropVal: PWideChar); stdcall;
function CkZipCrc__debugLogFilePath(objHandle: HCkZipCrc): PWideChar; stdcall;

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.

See the notes about PWideChar memory ownership and validity.

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LastErrorHtml
procedure CkZipCrc_getLastErrorHtml(objHandle: HCkZipCrc; outPropVal: HCkString); stdcall;
function CkZipCrc__lastErrorHtml(objHandle: HCkZipCrc): PWideChar; stdcall;

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.

See the notes about PWideChar memory ownership and validity.

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LastErrorText
procedure CkZipCrc_getLastErrorText(objHandle: HCkZipCrc; outPropVal: HCkString); stdcall;
function CkZipCrc__lastErrorText(objHandle: HCkZipCrc): PWideChar; stdcall;

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.

See the notes about PWideChar memory ownership and validity.

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LastErrorXml
procedure CkZipCrc_getLastErrorXml(objHandle: HCkZipCrc; outPropVal: HCkString); stdcall;
function CkZipCrc__lastErrorXml(objHandle: HCkZipCrc): PWideChar; stdcall;

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.

See the notes about PWideChar memory ownership and validity.

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LastMethodSuccess
function CkZipCrc_getLastMethodSuccess(objHandle: HCkZipCrc): wordbool; stdcall;
procedure CkZipCrc_putLastMethodSuccess(objHandle: HCkZipCrc; newPropVal: wordbool); stdcall;

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.

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VerboseLogging
function CkZipCrc_getVerboseLogging(objHandle: HCkZipCrc): wordbool; stdcall;
procedure CkZipCrc_putVerboseLogging(objHandle: HCkZipCrc; newPropVal: wordbool); stdcall;

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.

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Version
procedure CkZipCrc_getVersion(objHandle: HCkZipCrc; outPropVal: HCkString); stdcall;
function CkZipCrc__version(objHandle: HCkZipCrc): PWideChar; stdcall;

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

See the notes about PWideChar memory ownership and validity.

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Methods

BeginStream
procedure CkZipCrc_BeginStream(objHandle: HCkZipCrc) stdcall;

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.

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CrcBd
function CkZipCrc_CrcBd(objHandle: HCkZipCrc;
    bd: HCkBinData): LongWord; stdcall;
Introduced in version 9.5.0.75

Calculates a CRC32 for the bytes contained in bd.

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CrcSb
function CkZipCrc_CrcSb(objHandle: HCkZipCrc;
    sb: HCkStringBuilder;
    charset: PWideChar): LongWord; stdcall;
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.

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CrcString
function CkZipCrc_CrcString(objHandle: HCkZipCrc;
    str: PWideChar;
    charset: PWideChar): LongWord; stdcall;
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.

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EndStream
function CkZipCrc_EndStream(objHandle: HCkZipCrc): LongWord; stdcall;

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

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FileCrc
function CkZipCrc_FileCrc(objHandle: HCkZipCrc;
    path: PWideChar): LongWord; stdcall;

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.

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FileCrcAsync (1)
function CkZipCrc_FileCrcAsync(objHandle: HCkZipCrc;
    path: PWideChar): HCkTask; stdcall;

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

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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LoadTaskCaller
function CkZipCrc_LoadTaskCaller(objHandle: HCkZipCrc;
    task: HCkTask): wordbool; stdcall;
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns True for success, False for failure.

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ToHex
function CkZipCrc_ToHex(objHandle: HCkZipCrc;
    crc: LongWord;
    outStr: HCkString): wordbool; stdcall;
function CkZipCrc__toHex(objHandle: HCkZipCrc;
    crc: LongWord): PWideChar; stdcall;

Converts a 32-bit integer to a hex string.

Returns True for success, False for failure.

See the notes about PWideChar memory ownership and validity.

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Events

AbortCheck
function MyAbortCheck(): Integer; cdecl;
Introduced in version 9.5.0.82

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second. Return True to abort; return False to continue (not abort)

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PercentDone
function MyPercentDone(pctDone: Integer): Integer; cdecl;
Introduced in version 9.5.0.82

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

Return True to abort; return False to continue (not abort)

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ProgressInfo
procedure MyProgressInfo(name: PWideChar; value: PWideChar) cdecl;
Introduced in version 9.5.0.82

This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

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TaskCompleted
procedure MyTaskCompleted(task: HCkTask) cdecl;
Introduced in version 9.5.0.82

Called from the background thread when an asynchronous task completes.

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Deprecated

CalculateCrc Deprecated
function CkZipCrc_CalculateCrc(objHandle: HCkZipCrc;
    data: HCkByteData): LongWord; stdcall;

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.

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MoreData Deprecated
procedure CkZipCrc_MoreData(objHandle: HCkZipCrc;
    data: HCkByteData) stdcall;

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

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