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binand/countermanager.sh

Created October 23, 2016 15:01
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  1. binand created this gist Oct 23, 2016.
    55 changes: 55 additions & 0 deletions countermanager.sh
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,55 @@
    #!/bin/bash

    # Initializes the counter to 0 (uses filename in arg #1 for state). Returns 0 on success.
    function init_counter() {
    local _f=$1
    if [ ! -f $_f ]; then
    local _t=$( mktemp $( dirname $_f )/b.XXXXXXXX )
    echo 0 > $_t
    mv -f $_t $_f
    fi
    export COUNTER_FILE=$_f
    return 0
    }

    # Get the counter's value. Returns value.
    function get_counter() {
    local _f=$COUNTER_FILE
    local _v=
    if [ -z "$_f" -o \! -f "$_f" ]; then
    return $(( 2 ** 31 ))
    fi
    _v=$( < $_f )
    echo $_v
    return $_v
    }

    # Set the counter's value to arg #1. Returns new value.
    function set_counter() {
    local _f=$COUNTER_FILE
    local _new=$1
    if [ -z "$_f" -o \! -f "$_f" ]; then
    return $(( 2 ** 31 ))
    fi
    local _t=$( mktemp $( dirname $_f )/b.XXXXXXXX )
    echo $_new > $_t
    mv -f $_t $_f
    echo $_new
    return $_new
    }

    # Increment the counter's value by arg #1. Returns new value.
    function inc_counter() {
    local _inc=$1
    local _cur=$( get_counter )
    local _r=$( set_counter $(( $_cur + $_inc )) )
    echo $_r
    return $_r
    }

    # Add 1 to the counter's value. Returns new value.
    function add_counter() {
    local _r=$( inc_counter 1 )
    echo $_r
    return $_r
    }