# Directory Structure Image (DSI) File Format.

# Lines starting with hash ('#') characteres are comments.
# Hash characters inline are comments
# Support for characters in filenames is limited to ASCII (not extended ASCII)

The general format of data lines (i.e. non-commment lines) is:

<DirectiveOrElement> <Data>

where <DirectiveOrElement> is one of a fixed set of values, and <Data> depends on <DirectiveOrElement>.

<DirectiveOrElement> can be one of i, d, D, f, s.

The format of <Data> for element and directives types is:

i <PkgTag> <PkgMajorVersion> <PkgMajorVersionShort> <PkgMinorVersion> <PkgDescription>
  The 'i' Info entry contains package metadata provided by the user upon DSI creation.
  There can be only one 'i' entry per DSI file, and it must be the first entry.
  <PkgTag> alphanumeric+dash+underbar, e.g. fgs for Friendly Greeting System product..
  <PkgMajorVersion> alphanumeric+dash+underbar, the major version identifier, e.g. 2020.1.
  <PkgMajorVersion> alphanumeric+dash+underbar, a short form of the major version identifier, e.g. r20.1, or 'none'.
  <PkgMinorVersion> positive integer, typically a Perforce Helix changelist number of a product build.
  <PkgDesscription> ASCII string (can have spaces, but not extended ASCII)

d <RelPath> <Owner>:<Group> <Perms> <Timestamp>
  The 'd' is a directory element.
  <RelPath> is the relative path to the directory from the package root
  <Owner>:<Group> are the owner/group settings as used by the `chown` command.
  <Perms> are the file permissions as used by the `chmod` command.
  <Timestamp> is the file timestamp as reported by the `ls -l` command.

D <RelPath> <Owner>:<Group> <RecusrivePerms>
f <RelPath> <Owner>:<Group> <Perms> <Timestamp> <MD5Checksum>
s <RelPath> <Target> <TargetMD5Checksum>

<PkgTag> is the tag name for a product, e.g. 'fgs' for the Friendly Greeting System product.

The <Owner>:<Group> defines the Operating System owner and group, wit

<Perms> contains permission data, of the form <OwnerPerms>:<GroupPerms>:<OtherPerms>

# Sample Friendly Greeting System file format, with tag 'fgs':
i fgs 2020.1 r20.1 26937 Friendly Greeting System
d src unset:unset 750 20201123080422
f src/hello.h unset:unset 640 20201123080422
f src/hello.c unset:unset 640
f src/Makefile unset:unset 640
f src/build.sh unset:unset 750