ZipCrc Delphi DLL Reference Documentation

ZipCrc

Current Version: 9.5.0.75

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, 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.

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

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.

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

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.

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

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.

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

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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 "9.5.0.63"

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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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CalculateCrc
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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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. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns nil on failure

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MoreData
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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SaveLastError
function CkZipCrc_SaveLastError(objHandle: HCkZipCrc;
    path: PWideChar): wordbool; stdcall;

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns True for success, False for failure.

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

Converts a 32-bit integer to a hex string.

Returns True for success, False for failure.

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