Re: [gentoo-dev] Re: Finding relative path between two dirs

[Jeremy Huddleston]

Thanks for all the responses.  I've got a mostly-bash solution based on
Georgi's response.  I had to clean it up a bit to handle .. and .
properly.  I'd like to figure out a way to use bash for the .., but for
now it's just using sed.

Thanks again guys.

# Helper function for create_ml_includes
create_ml_includes-relative_between() {
        local src="$(create_ml_includes-tidy_path ${1})"
        local dst="$(create_ml_includes-tidy_path ${2})"

        src=(${src//\// })
        dst=(${dst//\// })

        local i
        for ((i=0; i<${#src[*]}; i++)); do
                [ "${dst[i]}" != "${src[i]}" ] && break
        done

        local common=$i

        for ((i=${#src[*]}; i>common; i--)); do
                echo -n ../
        done

        for ((i=common; i<${#dst[*]}-1; i++)); do
                echo -n ${dst[i]}/
        done

        echo -n ${dst[i]}
}

# Helper function for create_ml_includes
create_ml_includes-tidy_path() {
        local removed="${1}"

        if [ -n "${1}" ]; then
                # Remove multiple slashes
                while [ "${removed}" != "${removed/\/\//\/}" ]; do
                        removed=${removed/\/\//\/}
                done

                # Remove . directories
                while [ "${removed}" != "${removed//\/.\//\/}" ]; do
                        removed=${removed//\/.\//\/}
                done
                [ "${removed##*/}" = "." ] && removed=${removed%/*}

                # Removed .. directories
                # I wonder if there's a non-trivial bashism for this one...
                while [ "${removed}" !=  "$(echo ${removed} | sed -e
's:[^/]*/\.\./::')" ]; do
                        removed=$(echo ${removed} | sed -e 's:[^/]*/\.\./::')
                done

                # Remove trailing ..
                removed=$(echo ${removed} | sed -e 's:/[^/]*/\.\.$::')

                # Remove trailing /
                [ "${removed##*/}" = "" ] && removed=${removed%/*}
                
                echo ${removed}
        fi
}

signature.asc
Description: This is a digitally signed message part