NAME

write_data -- create unit to write data to file(s)

PROTOTYPE

unitptr write_data( char *pcFileName, char *pcFmtStr, char *pcHeader, unitptr uHost)

ARGUMENTS

char *pcFileName
file name for output file. Specify a trailing '+'-mark (separated by a blank from the file name) to append data to an existing file.
char *pcFmtStr
format string
char *pcHeader
header to be prepended
unitptr uHost
host unit

RETURN VALUE:

A pointer to the created unit or NULL in the case of an error.

INTERFACE OF CREATED UNIT:

in_0..n-1:
nr and type of input fields depends on specifications in format string pcFmtStr (see below).
CTL_in[1]:
(control field)
X_out[1]:
(output field 0) nr of last record written. A value of -1 indicates that not yet any record has been written since the unit was created.

EXECUTION OF CREATED UNIT:

INITIALIZATION:

DESCRIPTION:

The created unit writes records to file pcFileName according to the format specification in pcFmt. Records are separated by the newline character. Each record can consist of a number of items or fields. The format string specifies which fields shall be written as one record. This is indicated by a number of control tokens of the form %c, where c is a letter that indicates the type of the field (vector, image or string). Additional numbers between the % and the c may give additional specification about, e.g., the size of the field. Currently, the recognized control tokens include: - %df write vector item of dimension d [normal input field] - %dF write vector item of dimension d [packed input field] - %dV write vector with dimension prefix [packed output field] - %dv write vector with dimension prefix [normal output field] - %x:yM write Mono image of size x*y - %M Creates a single input field with one pin. This variant without arguments x:y is provided to suppress the writing of the image data in case that these data are already available in a file /path/basename#.pgm. In this case, the index # of this file should be given at the single pin of the input field that was created by the %M format field. The /path/basename and pgm - part must be specified in front of the format field (cf. below). - %x:yC write color image of size x*y [3 packed output fields] - %C analogous to %M-format field, but for .ppm-file. - %n write record separator For each control field, the unit will have an input field (three for the %x:yC control field) at which the data values to be written must be provided. The input field will be packed, if the control token ends with a capital letter, or if a negative vector dimension was specified, normal otherwise.

NOTE:

Image data are not directly written into the file pcFileName. Instead, for each %x:yM or %x:yC control token, the associated image data are written as a sequence of separate files with a common path, base name and suffix, but a monotonously increasing additional number index. For each %M or %C control token, the specification of the path, basename and file suffix is simply made by writing this information in front of the control token (any spaces or superfluous characters are ignored). The path, basename and suffix for each sequence are written into the header part of the created data file, the images themselves then appear in the records of this file only by their number index. The compagnon routine read_data can read this format and access the image data by this referencing mechanism. The writing of the image data can be suppressed by omitting the size specification x:y. In this case, the created unit will have a single unpacked input field with one pin for the index of an filename of an already existing file containing the image data. In this case, the writing of a new file will be suppressed, and the provided index (together with the path and basename specified before the format field) will be used to embed suitable referencing information in the written file.

CONTROL MODES:


   NST_I_CLOSE: close current file
   NST_RESET:
   NST_I_OPEN: append, if file exists, otherwise create new
                 and prepend header.

EXAMPLES:

The format %-10v%10v /mypath/myimage.pgm %80:80M%n will write records that consist of two 10-dimensional vectors and one 80x80-image. The image data for the #-th record will be in file /mypath/myimage#.pgm. The #-th record itself will just consist of two vectors, followed by the integer +#. The file path /mypath, the basename myimage and the type suffix .pgm will be written into the file header.

STATUS:

Preliminary.

SEE ALSO:

write_file, read_data

FILE

/local/homes/rhaschke/nst7/man/../o.linx86//../foldersrc/nst_file.c