# ============================================================================
# Environment File for ksh
# Literatur : [1] The Kornshell Morris I.Bolski / David G.Korn
# Martin Zahn 30.9.91
# ============================================================================

#
# Define Aliases
#
alias   fn="typeset +f"       # Show all build in ksh Function Names
alias   fun="typeset -f"      # Show all build in ksh Function Definitions
alias   h="fc -l"             # Show history file
alias	kk="ls -la | more"
alias   ll="ls -la"

# Settings for JOB-CONTROL

stty tostop        # Background Jobs stops when using stdin, stdout stderr
stty susp        # Suspend Foreground Jobs with CTRL Z

# Reduce the time that it takes ksh to do a pathname search
# for a command. ksh defines a tracked alias for a command name 
# when the command is first encountered. (see alias -t)

set -o trackall

# Do not store function definitions in the history file
# (Not supportet in this release of ksh)
set -o nolog

# Allow to overwrite files with I/O Redirection ">"
unset noclobber

# No Pathname expansion for better performance
# set -o noglob

#
# Enhanced cd Interface:
# Redfine build in Command ([1] Page 71)
#
unalias cd
alias cd=_cd

#
# Enhanced cd Interface:
# Global Variables in Korn Shell should have an underscore to be
# different from any other variables
#
integer _stack_max_index=${CDSTACK-32}    # _push_max_index : max Index in the Directory-Stack Array
integer _stack_index=_stack_max_index     # _stack_index : current Index in the Directory-Stack Array
_directory_stack[_stack_index]=\~         # _directory_stack[] : this is the Directory-Stack Array
_host=`uname -n`                          # _host : Host-Name of this system

# ------------------------------------------------
# Display current directory and directories in the
# directory-stack in one column.
# ------------------------------------------------
function sd
{
        # Display all items in the Directory-Stack preceded by a number
        # with the select statement. select prints the PS3 prompt at
        # the end of the list, so redefine PS3 to nothing

        PS3=
        select i in "${_directory_stack[@]}"
        do
                :   # Do nothing with the items, just show them
        done < /dev/null
}

# ------------------------------------------------
# Manipulate Directory-Stack
# ------------------------------------------------
function _cd
{
        #
        # Local Variables, known only within this function
        #
	integer MAXPROMPTLEN=0   # Max Length of prompt calulated from COLUMNS
        typeset dir=             # Current Directory        
        integer n=0              # Index for Directory Stack Array
        typeset integer type=4   # Defines the kind of cd
                                 # type=1 : cd - : cd back to the previous Directory
                                 # type=2 : cd i : cd to Directory shown with sd
                                 # type=3 : Move Directories in Stack one Step down
                                 # type=4 : cd directory : Fill the Directory-Stack

        #
        # Set $1 to $HOME if cd has no arguments
        #
        set ${1:-$HOME}

        #
        # Set "type" and "n" depending what kind of cd user typed
        # "n" is just a dummy variable for the Directory-Stack Index
        #
        case $1 in                    # check first argument of cd

        -|-1)                         # cd - : cd back to the previous directory
                n=_stack_index+1
                type=1
                ;;

        [1-9]|[1-9][0-9])             # cd i : cd to the Directory shown with sd
                n=_stack_index+${1}-1
                type=2
                ;;

        *)                            # check if Directory-Stack is full
                if ((_stack_index <= 0))
                then
                        type=3
                        n=_stack_max_index
                fi
                ;;
        esac

        #
        # Check the range of the Directory-Stack when user choose cd i   
        #
        if ((type < 3))
        then
                if ((n > _stack_max_index))
                then
                        print - "cd: Directory stack not that deep, out of range problem"
                        return 1
                else
                        dir=${_directory_stack[n]} # Read the Directory-Stack for cd i
                fi
        fi

        #
        # Replace "~" with $HOME if dir is "~/subdir"
        # This is necessary for cd - if the last directory 
        # is "~/subdir" in the Directory-Stack
        #
        case $dir in
                ~*) dir=$HOME${dir#~}
                    ;;
        esac

        #
        # cd to $dir if set, else to argument of cd
        # return if cd is not possible
        #
        \cd "${dir:-$@}" > /dev/null || return 1

        #
        # Replace HOME with "~" for Prompt PS1
        #
        # Extract HOME/ from HOME/subdir/subdir --> subdir/subdir
        # PWD does not include HOME/ : dir=PWD
        # PWD does include HOME/ : Cut including Part of HOME/ from PWD and set dir=Rest of HOME
        #
        #
        dir=${PWD#$HOME/}

        case $dir in
        $HOME)
                dir=\~
                ;;
        /*)
                ;;
        *)
                dir=\~/$dir
                ;;
        esac

        #
        # Manipulate Directory-Stack
        #
        case $type in

        1)      # cd - : swap first two elements

                typeset temp=${_directory_stack[_stack_index]}
                _directory_stack[_stack_index]=$dir
                _directory_stack[n]=$temp
                ;;

        2|3)    # Directory-Stack is full or cd i, so
                # put $dir on top and shift down by one all other Directories
                # The least recently referenced directory is removed from the list

                integer i=_stack_index

                for x in "$dir" "${_directory_stack[@]}"
                do
                        ((i > _stack_max_index)) && break
                        _directory_stack[i]=$x
                        i=i+1
                done
                ;;

        4)      # cd argument : Fill Directory-Stack until _stack_index is 0
                # This case is only true when Directory-Stack is not jet full
                # this happens when you login in and start working

                _stack_index=_stack_index-1
                _directory_stack[_stack_index]=$dir
                ;;
        esac

        #
        # Show Prompt
        #
	COLUMNS=${COLUMNS:-80}
	MAXPROMPTLEN=COLUMNS/5

	if ((${#dir} > $MAXPROMPTLEN))
	then
		dir=$(print $dir | awk ' { print substr($0, length($0)-"'$MAXPROMPTLEN'", length($0)) } ')
		dir="...$dir"
	fi
        # PS1="$_host:$LOGNAME:$dir> "
        PS1="`tput smso`$LOGNAME:$dir>`tput rmso` "
        export PS1
}

function uncd
{
        unalias cd
        PS1="$_host:$LOGNAME:> "
}

#
# export functions
#
typeset -xf _cd
typeset -xf sd

#
# debug function with option typeset -ft
#
# typeset -ft _cd
# typeset -ft sd