Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
ZIP_SOURCE_FUNCTION(3)	 BSD Library Functions Manual	ZIP_SOURCE_FUNCTION(3)

NAME
     zip_source_function -- create data	source from function

LIBRARY
     libzip (-lzip)

SYNOPSIS
     #include <zip.h>

     zip_source_t *
     zip_source_function(zip_t *archive, zip_source_callback fn,
	 void *userdata);

     zip_source_t *
     zip_source_function_create(zip_source_callback fn,	void *userdata,
	 zip_error_t *error);

DESCRIPTION
     The functions zip_source_function() and zip_source_function_create() cre-
     ates a zip	source from the	user-provided function fn, which must be of
     the following type:

     typedef zip_int64_t (*zip_source_callback)(void *userdata,	void *data,
     zip_uint64_t len, zip_source_cmd_t	cmd)

     archive or	error are used for reporting errors and	can be NULL.

     When called by the	library, the first argument is the userdata argument
     supplied to the function.	The next two arguments are a buffer data of
     size len when data	is passed in or	expected to be returned, or else NULL
     and 0.  The last argument,	cmd, specifies which action the	function
     should perform.

     Depending on the uses, there are three useful sets	of commands to be sup-
     ported by a zip_source_callback():

     read source	     Providing streamed	data (for file data added to
			     archives).	 Must support ZIP_SOURCE_OPEN,
			     ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE,
			     ZIP_SOURCE_STAT, and ZIP_SOURCE_ERROR.

     seekable read source    Same as previous, but from	a source allowing
			     reading from arbitrary offsets (also for read-
			     only zip archive).	 Must additionally support
			     ZIP_SOURCE_SEEK, ZIP_SOURCE_TELL, and
			     ZIP_SOURCE_SUPPORTS.

     read/write	source	     Same as previous, but additionally	allowing writ-
			     ing (also for writable zip	archives).  Must addi-
			     tionally support ZIP_SOURCE_BEGIN_WRITE,
			     ZIP_SOURCE_COMMIT_WRITE,
			     ZIP_SOURCE_ROLLBACK_WRITE,	ZIP_SOURCE_SEEK_WRITE,
			     ZIP_SOURCE_TELL_WRITE, and	ZIP_SOURCE_REMOVE.

   ZIP_SOURCE_BEGIN_WRITE
     Prepare the source	for writing.  Use this to create any temporary
     file(s).

   ZIP_SOURCE_CLOSE
     Reading is	done.

   ZIP_SOURCE_COMMIT_WRITE
     Finish writing to the source.  Replace the	original data with the newly
     written data.  Clean up temporary files or	internal buffers.  Subse-
     quently opening and reading from the source should	return the newly writ-
     ten data.

   ZIP_SOURCE_ERROR
     Get error information.  data points to an array of	two ints, which	should
     be	filled with the	libzip error code and the corresponding	system error
     code for the error	that occurred.	See zip_errors(3) for details on the
     error codes.  If the source stores	error information in a zip_error_t,
     use zip_error_to_data(3) and return its return value.  Otherwise, return
     2 * sizeof(int).

   ZIP_SOURCE_FREE
     Clean up and free all resources, including	state.	The callback function
     will not be called	again.

   ZIP_SOURCE_OPEN
     Prepare for reading.

   ZIP_SOURCE_READ
     Read data into the	buffer data of size len.  Return the number of bytes
     placed into data on success.

   ZIP_SOURCE_REMOVE
     Remove the	underlying file.  This is called if a zip archive is empty
     when closed.

   ZIP_SOURCE_ROLLBACK_WRITE
     Abort writing to the source.  Discard written data.  Clean	up temporary
     files or internal buffers.	 Subsequently opening and reading from the
     source should return the original data.

   ZIP_SOURCE_SEEK
     Specify position to read next byte	from, like fseek(3).  Use
     ZIP_SOURCE_GET_ARGS(3) to decode the arguments into the following struct:

     struct zip_source_args_seek {
	 zip_int64_t offset;
	 int whence;
     };

     If	the size of the	source's data is known,	use
     zip_source_seek_compute_offset(3) to validate the arguments and compute
     the new offset.

   ZIP_SOURCE_SEEK_WRITE
     Specify position to write next byte to, like fseek(3).  See
     ZIP_SOURCE_SEEK for details.

   ZIP_SOURCE_STAT
     Get meta information for the input	data.  data points to an allocated
     struct zip_stat, which should be initialized using	zip_stat_init(3) and
     then filled in.  Information only available after the source has been
     read (e.g.	size) can be omitted in	an earlier call.  Return sizeof(struct
     zip_stat) on success.  NOTE: zip_source_function()	may be called with
     this argument even	after being called with	ZIP_SOURCE_CLOSE.

   ZIP_SOURCE_SUPPORTS
     Return bitmap specifying which commands are supported.  Use
     zip_source_make_command_bitmap(3).	 If this command is not	implemented,
     the source	is assumed to be a read	source without seek support.

   ZIP_SOURCE_TELL
     Return the	current	read offset in the source, like	ftell(3).

   ZIP_SOURCE_TELL_WRITE
     Return the	current	write offset in	the source, like ftell(3).

   ZIP_SOURCE_WRITE
     Write data	to the source.	Return number of bytes written.

   Return Values
     Commands should return -1 on error.  ZIP_SOURCE_ERROR will	be called to
     retrieve the error	code.  On success, commands return 0, unless specified
     otherwise in the description above.

   Calling Conventions
     The library will always issue ZIP_SOURCE_OPEN before issuing
     ZIP_SOURCE_READ, ZIP_SOURCE_SEEK, or ZIP_SOURCE_TELL.  When it no longer
     wishes to read from this source, it will issue ZIP_SOURCE_CLOSE.  If the
     library wishes to read the	data again, it will issue ZIP_SOURCE_OPEN a
     second time.  If the function is unable to	provide	the data again,	it
     should return -1.

     ZIP_SOURCE_BEGIN_WRITE will be called before ZIP_SOURCE_WRITE,
     ZIP_SOURCE_SEEK_WRITE, or ZIP_SOURCE_TELL_WRITE.  When writing is com-
     plete, either ZIP_SOURCE_COMMIT_WRITE or ZIP_SOURCE_ROLLBACK_WRITE	will
     be	called.

     ZIP_SOURCE_STAT can be issued at any time.

     ZIP_SOURCE_ERROR will only	be issued in response to the function return-
     ing -1.

     ZIP_SOURCE_FREE will be the last command issued; if ZIP_SOURCE_OPEN was
     called and	succeeded, ZIP_SOURCE_CLOSE will be called before
     ZIP_SOURCE_FREE, and similarly for	ZIP_SOURCE_BEGIN_WRITE and
     ZIP_SOURCE_COMMIT_WRITE or	ZIP_SOURCE_ROLLBACK_WRITE.

RETURN VALUES
     Upon successful completion, the created source is returned.  Otherwise,
     NULL is returned and the error code in archive or error is	set to indi-
     cate the error (unless it is NULL).

ERRORS
     zip_source_function() fails if:

     [ZIP_ER_MEMORY]	Required memory	could not be allocated.

SEE ALSO
     libzip(3),	zip_add(3), zip_replace(3), zip_source(3), zip_stat_init(3)

AUTHORS
     Dieter Baron <dillo@nih.at> and Thomas Klausner <tk@giga.or.at>

BSD			       November	13, 2014			   BSD

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=zip_source_function&sektion=3&manpath=FreeBSD+12.0-RELEASE+and+Ports>

home | help