vdcomp(1) MachTen Programmer’s Manual vdcomp(1)
vdcomp - decompress a compressed PDS image
vdcomp [ infile ] [ outfile ] [ format-code ]
The vdcomp program reads a variable length compressed PDS
image and outputs a fixed length uncompressed image file
in PDS format with labels, image histogram, engineering
table, line header table and an image with PDS, FITS,
VICAR or no labels.
If used on a non-byte-swapped
machine the image histogram
Vdcomp will prompt for any options that are not supplied
on the command-line.
The name of compressed image file.
The name of uncompressed image file.
Select from the following list:
1 - SFDU/PDS format [default]
2 - FITS format
3 - VICAR format
4 - unlabelled binary array
This program has been tested on a VAX 780 (VMS 4.6), SUN
Workstation (UNIX 4.2, release 3.4), an IBM PC (MICROSOFT
5.1 compiler) and Macintosh IIx using Lightspeed C version
3.0. When converting to other systems, check for porta-
This program uses Kris Becker’s subroutine DECOMP.C (which
is included in this program in a shortened version).
firstname.lastname@example.org 06-23-94 ansi-fied program
email@example.com, 11-15-91 added
recognition of - as std-
out for output filename; disabled various messages;
directed messages to stderr; added exit status
DEC89 Modified program to handle
both Voyager and Viking
OCT89 Converted Voyager
decompression program to handle
Viking compressed images. Changed obuf to ’unsigned’ to
simplify computation of checksum.
AUG89 Added code to get command
line arguments for file-
names and output format; routines to free memory used by
the Huffman tree); fixed the SFDU label output length; and
modified the I/O routines so that the open for Host type 2
uses binary I/O.
JUN89 Fixed READVAR, to get
length on 16-bit unswapped
JUL88 C driver to decompress
standard Voyager Compressed
images by Mike Martin 1989/12/02.