ZipCrc Tcl Reference Documentation
ZipCrc
Current Version: 11.5.0
Chilkat.ZipCrc
Use
Use
Use
Use
Call
Use Calculate ZIP-compatible CRC32 values for files, bytes, strings, and streamed data.
Chilkat.ZipCrc calculates the 32-bit CRC value used in ZIP file
headers. It can compute CRC32 values for in-memory byte arrays,
BinData, StringBuilder content, strings using a
specified character encoding, and entire files. It also supports streaming
CRC calculation, allowing applications to process large or incremental data
in chunks without holding the full input in memory.
CRC32 for byte data
CalculateCrc to calculate a ZIP-style CRC32 value for
an in-memory byte array.
BinData support
CrcBd when the input bytes are already stored in a
Chilkat.BinData object.
String CRCs
CrcString or CrcSb to calculate CRC32 for
text using a specific charset such as utf-8,
utf-16, or windows-1252.
File CRCs
FileCrc to calculate the CRC32 of a file while streaming
the file contents to keep memory usage small and constant.
Streaming calculation
BeginStream, add chunks with MoreData, and
finish with EndStream when data arrives incrementally.
Hex formatting
ToHex to convert a 32-bit CRC integer into a readable
hexadecimal string.
FileCrc for files, CalculateCrc or
CrcBd for binary data already in memory, and
CrcString or CrcSb for text where the byte
representation depends on a charset. For large or chunked input, initialize
the CRC with BeginStream, feed each block with
MoreData, and call EndStream to obtain the final
CRC32 value.
Object Creation
# 'this' is not a keyword in Tcl. It can freely be used as a variable name. set this [new CkZipCrc]
Properties
DebugLogFilePath
# ckStr is a CkString
CkZipCrc_get_DebugLogFilePath $this $ckStr
set strVal [CkZipCrc_get_debugLogFilePath $this]
CkZipCrc_put_DebugLogFilePath $this $strVal
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.
LastErrorHtml
# ckStr is a CkString
CkZipCrc_get_LastErrorHtml $this $ckStr
set strVal [CkZipCrc_get_lastErrorHtml $this]
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.
topLastErrorText
# ckStr is a CkString
CkZipCrc_get_LastErrorText $this $ckStr
set strVal [CkZipCrc_get_lastErrorText $this]
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.
LastErrorXml
# ckStr is a CkString
CkZipCrc_get_LastErrorXml $this $ckStr
set strVal [CkZipCrc_get_lastErrorXml $this]
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.
topLastMethodSuccess
set boolVal [CkZipCrc_get_LastMethodSuccess $this]
CkZipCrc_put_LastMethodSuccess $this $boolVal
Indicates the success or failure of the most recent method call: 1 means success, 0 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. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
Utf8
set boolVal [CkZipCrc_get_Utf8 $this]
CkZipCrc_put_Utf8 $this $boolVal
When set to 1, all string arguments and return values are interpreted as UTF-8 strings. When set to 0, they are interpreted as ANSI strings.
In Chilkat v11.0.0 and later, the default value is 1. Before v11.0.0, it was 0.
VerboseLogging
set boolVal [CkZipCrc_get_VerboseLogging $this]
CkZipCrc_put_VerboseLogging $this $boolVal
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
# ckStr is a CkString
CkZipCrc_get_Version $this $ckStr
set strVal [CkZipCrc_get_version $this]
Methods
BeginStream
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.
topCrcBd
set retInt [CkZipCrc_CrcBd $this $bd]
Calculates a CRC32 for the bytes contained in bd.
CrcSb
# charset is a string
set retInt [CkZipCrc_CrcSb $this $sb $charset]
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
# charset is a string
set retInt [CkZipCrc_CrcString $this $str $charset]
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
Finalizes and returns the Zip CRC value calculated by calling BeginStream followed by multiple calls to MoreData.
topFileCrc
set retInt [CkZipCrc_FileCrc $this $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.
FileCrcAsync (1)
# path is a string
set ret_task [CkZipCrc_FileCrcAsync $this $path]
Creates an asynchronous task to call the FileCrc method with the arguments provided.
Returns NULL on failure
LoadTaskCaller
set status [CkZipCrc_LoadTaskCaller $this $task]
ToHex
# outStr is a CkString (output)
set status [CkZipCrc_ToHex $this $crc $outStr]
set retStr [CkZipCrc_toHex $this $crc]
Deprecated
CalculateCrc Deprecated
set retInt [CkZipCrc_CalculateCrc $this $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.
MoreData Deprecated
CkZipCrc_MoreData $this $data
Adds additional data to the CRC currently being calculated. (See BeginStream for more information.)
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