ZIP_SOURCE_FUNCTION(3)					     Library Functions Manual					    ZIP_SOURCE_FUNCTION(3)

NAME

       zip_source_function - create data source from function

LIBRARY

       libzip (-lzip)

SYNOPSIS

       #include <zip.h>

       struct zip_source * zip_source_function(struct zip *archive, zip_source_callback fn, void *userdata);

DESCRIPTION

       The  function  zip_source_function  creates  a  zip source from the user-provided function fn, which must be of the following type: typedef
       zip_int64_t (*zip_source_callback)(void *state,
	   void *data, zip_uint64_t len, enum zip_source_cmd cmd);

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

	      ZIP_SOURCE_OPEN	   Prepare for reading.  Return 0 on success, -1 on error.

	      ZIP_SOURCE_READ	   Read data into the buffer data of size len.	Return the number of bytes placed into	data  on  success,  -1	on
				   error.

	      ZIP_SOURCE_CLOSE	   Reading is done.  Return 0.

	      ZIP_SOURCE_STAT	   Get	meta  information  for	the  input  data.   data points to an initialized which should be filled in.  (See
				   zip_stat_init(3). ) 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, -1 on error.

	      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.  Return return(2 * sizeof(int)).

	      ZIP_SOURCE_FREE	   Clean up and free all resources.  Return 0.

       The  library  will always issue ZIP_SOURCE_OPEN before issuing ZIP_SOURCE_READ.	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_STAT can be issued at any time.  ZIP_SOURCE_ERROR will only be issued in response to the function returning -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.

RETURN VALUES

       Upon successful completion, the created source is returned.  Otherwise, NULL is returned and the error code in archive is set  to  indicate
       the error.

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_buffer(3),	zip_source_file(3),    zip_source_filep(3),    zip_source_free(3),
       zip_source_zip(3), zip_stat_init(3)

AUTHORS

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

NiH								  March 30, 2009					    ZIP_SOURCE_FUNCTION(3)