#! /bin/bash

# Version compare based on
# http://stackoverflow.com/questions/4023830/bash-how-compare-two-strings-in-version-format
vercomp() {
    if [[ $1 == $2 ]]
    then
        return 0
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            return 1
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            return 2
        fi
    done
    return 0
}

vertest() {
    local ver1=($1) op=($2) ver2=($3)
    vercomp $ver1 $ver2
    case $op in
        '=')
            [ $? -eq 0 ] && return 0 || return 1
            ;;
        '!=')
            [ $? -ne 0 ] && return 0 || return 1
            ;;
        '<')
            [ $? -eq 2 ] && return 0 || return 1
            ;;
        '<=')
            [ $? -eq 2 -o $? -eq 0 ] && return 0 || return 1
            ;;
        '>')
            [ $? -eq 1 ] && return 0 || return 1
            ;;
        '>=')
            [ $? -eq 1 -o $? -eq 0 ] && return 0 || return 1
            ;;
    esac
    return -1
}