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+Semicode for Cyber RCOPY Reader; Frozen at "detailed semicode" stage, Jan 84.
+
+
+# rcopy tape descriptor
+
+struct rcopy {
+
+ real data_min # minimum data value
+ real data_max # maximum data value
+ int nrows # number of rows in ipps raster
+ int ncols # number of columns in ipps raster
+ int data_type # number of bits per pixel in the ipps raster
+ int pru_eor # pru position of level zero eor
+ int wrds_per_row # number of 60-bit words per row; each row
+ # occupies an integral number of 64word pru's.
+ int pru_row_one # relative pru ordinal of the first row of raster.
+ char ipps_id # id string of the ipps raster
+}
+
+procedure t_rrcopy (rcopy_file, raster_list, iraf_file)
+
+
+begin
+ # get input filename and open tape drive
+ rcopy_fd = open (rcopy_file)
+
+ # get output filename if it will be needed
+ if (make_image = yes)
+ outfile = fetch root name of output file
+
+ # expand list of rasters to be read from tape
+ if (decode_ranges (raster_list, range, MAX_RANGES, nfiles) == ERR)
+ call error (0, "Illegal raster number list")
+
+ raster_number = 0
+ tape_pos = 1
+ while (get_next_number (range, raster_number, != EOF) {
+ # position tape to first record of raster_number
+ if (tape_pos != raster_number) {
+ iferr {
+ stat = position_rcopy (rcopy_fd, tape_pos ,raster_number)
+ if (stat = EOF)
+ return
+ } then
+ call ERRACT (EA_FATAL)
+ }
+ iraffile = generate output filename from root
+ iferr {
+ (stat = read_rcopy(rcopy_fd, iraffile, tape_pos))
+ if (stat = EOF)
+ return
+ } then {
+ call ERRACT (EA_WARN)
+ skip over rcopy raster
+ }
+ }
+
+end
+
+int procedure position_rcopy (rcopy_fd, tape_pos, raster_number)
+
+begin
+
+ nrasters_skip = raster_number - tape_pos
+ for (i=1; i<=nrasters_skip; i=i+1) {
+ stat = read_header (rcopy_fd, rcopy)
+ if (stat = EOF)
+ return (EOF)
+ call read_header (rcopy_fd, rcopy)
+ call skip_image (rcopy_fd, rcopy)
+ }
+end
+
+int procedure read_rcopy (rcopy_fd, iraffile, tape_pos)
+
+begin
+
+ # Read ipps raster header from rcopy tape
+ stat = read_header (rcopy_fd, rcopy)
+ if (stat = EOF)
+ return (EOF)
+
+ # Print header information from rcopy tape
+ if (print_header)
+ call print_header (rcopy)
+
+ # read image data if desired
+ if (make_image)
+ call read_image(rcopy_fd, iraffile, rcopy)
+
+ # skip image if not to be read
+ else
+ call skip_image (rcopy_fd, rcopy)
+
+ # increment tape position marker
+ tape_pos = tape_pos + 1
+
+
+end
+
+int procedure read_header(rcopy_fd, rcopy)
+
+begin
+ # structure rcopy contains decoded header
+ # Read ipps header (64 60-bit words = 240 chars) as a
+ # bit stream into temp.
+ NBITS_CHAR = SZB_CHAR * NBITS_BYTE
+ NBITS_CYBER_WORD = 60
+ NWORDS_CYBER_PRU = 64
+ SZ_HEADER = 240
+ stat = read_tape (rcopy_fd, raw_header, SZ_HEADER)
+ if (stat = EOF))
+ return (EOF)
+
+ # Unpack bit stream and fill structure rcopy
+ call unpack_header (raw_header, rcopy)
+
+ # skip to first row of raster
+ if (rcopy.pru_row_one not equal to 1) {
+ nchars_to_skip = (rcopy.pru_row_one - 1) * NWORDS_CYBER_PRU
+ * NBITS_CYBER_WORD / NBITS_CHAR
+ call skip_chars (rcopy_fd, nchars_to_skip)
+ }
+end
+
+procedure read_image (rcopy_fd, iraffile, rcopy)
+
+begin
+
+ # map new iraf image and set up image header
+ im = immap (iraffile, NEW_IMAGE)
+ im.im_len[1] = rcopy.ncols
+ im.im_len[2] = rcopy.nrows
+ im.im_title = rcopy.ipps_id
+ im.im_min = rcopy.data_min
+ im.im_max = rcopy.data_max
+
+ if (user hasn's supplied data type) {
+ switch (rcopy.data_type) {
+ case 12 :
+ im.im_pixtype = short
+ case 20 :
+ im.im_pixtype = real
+ case 30 :
+ im.im_pixtype = real
+ default:
+ call error (0, "error in data_type")
+ }
+ }
+
+ # Calculate number of chars per row; this will always be an
+ # integral number of chars because rcopy.words_per_row
+ # is always divisible by 64.
+ NBITS_CHAR = SZB_CHAR * NBITS_BYTE
+ NBITS_CYBER_WORD = 60
+ NWORDS_CYBER_PRU = 64
+ num_chars_per_row = rcopy.wrds_per_row * NBITS_CYBER_WORD / NBITS_CHAR
+
+ # Loop to read rcopy raster line by line into buf1, then
+ # convert ipps pixels to iraf pixels.
+ for(i=1; i<=rcopy.nrows; i=i+1) {
+ stat = read a single row from the internal buffer
+ if (stat = EOF) {
+ close imagefile already accumulated
+ call error (0, "unexpected EOF at row# ")
+ }
+ call ipps_to_iraf (buf1, Memr[impl2r(im,i)], rcopy)
+ }
+
+ # Read until header of next raster into dummy buffer.
+ # Calculate offset in chars from present position to eor
+ nchars_to_skip = (((rcopy.eor - rcopy.pru_row_one) * NWORDS_CYBER_PRU
+ + (rcopy.words_per_row * rcopy.nrows)) * NBITS_CYBER_WORD + 48)
+ / NBITS_CHAR
+
+ call skip_chars (rcopy_fd, nchars_to_skip)
+end
+
+procedure ipps_to_iraf (buf1, buf2, rcopy)
+
+begin
+
+ # convert (rcopy.ncols * rcopy.data_type ) bits from buf1.
+ # This is the number of bits per row that actually represent
+ # pixels. buf1 contains pixels plus filler.
+
+ switch (rcopy.data_type) {
+ case 12:
+ call unpack12 (buf1, bit_offset, buf2, npix)
+ case 20:
+ call unpack20 (buf1, bit_offset, buf2, npix)
+ case 30:
+ call unpack30 (buf1, bit_offset, buf2, npix)
+ default:
+ call error (0, "illegal ipps #b/p")
+ }
+end
+
+procedure skip_image(rcopy_fd, rcopy)
+
+begin
+
+ # Calculate number of chars in image
+ nchars_to_skip = ((rcopy.eor - rcopy.pru_row_one ) * NWORDS_CYBER_PRU *
+ NBITS_CYBER_WORD + 48 ) / NBITS_CHAR
+ call skip_chars (rcopy_fd, nchars_to_skip)
+
+end
+
+procedure print_header (rcopy)
+
+begin
+ # print header information from rcopy tape
+ print, rcopy.ipps_id, rcopy.ncols, rcopy.nrows, rcopy.data_min,
+ rcopy.data_max, rcopy.ipps_data_type
+end
+
+procedure unpack_header (raw_header, rcopy)
+
+begin
+
+ get from raw_header: nrows, ncols, data_type, ipps_id, pru_eor,
+ wrds_per_row, pru_row_one, data_min, data_max
+
+ if (rcopy.data_type != 12, 20, or 30)
+ call error (0, "invalid ipps #b/p")
+ if (nrows or ncols or pru_row_one !> 0)
+ call error (0, "invalid ipps raster")
+ if (wrds_per_row not divisible by 64)
+ call error (0, "invalid ipps raster")
+
+end
+
+procedure skip_chars (rcopy_fd, nchars_to_skip)
+
+begin
+
+ # calculate the number of chars in a tape block = (512 * 60) / 16
+ # This is the number of chars to be read at one time.
+ SZ_TAPE_BLK = 1920
+
+ # calculate number of blocks to skip (type int)
+ nblks_read = nchars_to_skip / SZ_TAPE_BLK
+ nchars_remaining = mod (nchars_to_skip, SZ_TAPE_BLK)
+
+ # read chars into dummy buffer
+ for (i=1; i<=nblks_read; i=i+1)
+ stat = read_tape (rcopy_fd, dummy, SZ_TAPE_BLK)
+
+ stat = read_tape (rcopy_fd, dummy, nchars_remaining)
+
+ # confirm reaching eor
+ if (searching for eor) {
+ reread last 3 chars and compare with level zero eor marker
+ if (eor not confirmed)
+ call error (0, "attempted skip to eor unsuccessful")
+ }
+
+end
+
+
+.help rrcopy 2 "Program Structure"
+.sh
+RCOPY Structure Chart
+
+.nf
+procedure t_rrcopy ()
+# Returns when file list is satisfied or if EOT is encountered
+
+ int procedure read_header (rcopy_fd, rcopy)
+ #returns EOF, ERR or OK
+
+ int procedure read (rcopy_fd, raw_header, SZ_HEADER)
+ #returns EOF or OK
+
+ int procedure unpack_header (raw_header, rcopy)
+ #returns ERR or OK
+
+ int procedure skip_image (rcopy_fd, rcopy)
+ #returns ERR, EOF or OK
+
+ int procedure skip_chars (rcopy_fd, nchars_to_skip)
+ #returns EOF, ERR or OK
+
+ procedure read_rcopy (rcopy_fd, iraffile)
+ #aborts if output filename exists and noclobber is set
+
+ int procedure read_header (rcopy_fd, rcopy)
+ #returns EOF, ERR or OK
+
+ int procedure read (rcopy_fd, raw_header, SZ_HEADER)
+ #returns EOF or OK
+
+ int procedure unpack_header (raw_header, rcopy)
+ #returns ERR or OK
+
+ procedure print_header (rcopy)
+
+ procedure read_image (rcopy_rd, iraffile, rcopy)
+ #returns EOF, or OK
+
+ int procedure read (rcopy_rd, buf1, num_chars_per_row)
+ #returns EOF or OK
+
+ int procedure ipps_to_iraf
+ #returns ERR or OK
+
+ int procedure skip_image (rcopy_rd, rcopy)
+ #returns EOF, ERR or OK
+.endhelp
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