ZipCrc SQL Server Reference Documentation
ZipCrc
Current Version: 11.6.0
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
DECLARE @hr int
DECLARE @zipCrc int
EXEC @hr = sp_OACreate 'Chilkat.ZipCrc', @zipCrc OUT
IF @hr <> 0
BEGIN
PRINT 'Failed to create ActiveX component'
RETURN
END
-- ... use @zipCrc ...
EXEC @hr = sp_OADestroy @zipCrcT-SQL uses the Chilkat ActiveX through the OLE Automation stored procedures. They must be enabled once on the server (EXEC sp_configure 'Ole Automation Procedures', 1; RECONFIGURE;), and the Chilkat ActiveX registered must match the bitness of the SQL Server instance (64-bit for a 64-bit SQL Server). To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as sp_OACreate 'Chilkat.ZipCrc.11' for Chilkat v11.*.*.
sp_OACreate returns an object token (an int) that is passed as the first argument of every sp_OAMethod, sp_OAGetProperty and sp_OASetProperty call, and released with sp_OADestroy. Objects returned by methods (such as an HttpResponse or JsonObject) are also tokens received through an int OUT parameter; they must likewise be destroyed, and the OUT parameter is NULL when the method fails to return an object. Objects passed as arguments are passed by their token. When an OLE Automation procedure itself fails (non-zero @hr), sp_OAGetErrorInfo describes the error.
Data types: strings are nvarchar(4000); integers, booleans (1 or 0) and object tokens are int; dates are datetime. In the signatures on this page, @success, @iResult, @sResult and the like are the OUT variables receiving a method's return value, @iValue / @sValue receive or supply a property value, and the remaining @ variables are the method's arguments in order.
A string returned through an OUT parameter is limited to 4000 characters. For longer values, retrieve the result as a result set into a table variable instead of an OUT parameter, for example DECLARE @tmp TABLE (outputLine ntext) followed by INSERT INTO @tmp EXEC sp_OAGetProperty @zipCrc, 'LastErrorText'. See string length limitations for strings returned by sp_OAMethod calls.
Methods that pass or return raw byte arrays are not shown on this page, because varbinary(max) values cannot be exchanged through sp_OAMethod (see varbinary(max) limitation). Use the BinData-based alternatives (methods ending in Bd) or the base64 / hex string-encoded variants instead. Binary properties (such as LastBinaryResult) can be retrieved as a result set into a table variable, as shown in their signatures. Asynchronous (*Async) methods and event callbacks are not available from SQL Server.
Properties
DebugLogFilePath
EXEC sp_OASetProperty @zipCrc, 'DebugLogFilePath', @sValue
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.
LastBinaryResult
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 1. 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.
LastErrorHtml
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
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
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
EXEC sp_OASetProperty @zipCrc, 'LastMethodSuccess', @iValue
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.
LastStringResult
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.
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topVerboseLogging
EXEC sp_OASetProperty @zipCrc, 'VerboseLogging', @iValue
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
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
Calculates a CRC32 for the bytes contained in bd.
CrcSb
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
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
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.