Refactor provider_init() without sed chain

[KeiTomiy]

I experimented with rewriting provider_init() to avoid the long chained sed decoder. Behavior should be identical just less brittle and easier to audit. The current version works but is somewhat hard to read and debug. This version splits the hex into bytes and decodes them using a small awk map. Curious what upstream thinks of this?

provider_init() {
    provider_name=$1

    hex=$(printf '%s' "$resp" | sed -n "$2" | head -n1 | cut -d: -f2- | tr -cd '0-9a-fA-F')
    [ -z "$hex" ] && return

    provider_id=$(
        printf '%s\n' "$hex" |
        awk '
        BEGIN{
            map["79"]="A"; map["7a"]="B"; map["7b"]="C"; map["7c"]="D"; map["7d"]="E"; map["7e"]="F"; map["7f"]="G";
            map["70"]="H"; map["71"]="I"; map["72"]="J"; map["73"]="K"; map["74"]="L"; map["75"]="M"; map["76"]="N"; map["77"]="O";
            map["68"]="P"; map["69"]="Q"; map["6a"]="R"; map["6b"]="S"; map["6c"]="T"; map["6d"]="U"; map["6e"]="V"; map["6f"]="W";
            map["60"]="X"; map["61"]="Y"; map["62"]="Z";

            map["59"]="a"; map["5a"]="b"; map["5b"]="c"; map["5c"]="d"; map["5d"]="e"; map["5e"]="f"; map["5f"]="g";
            map["50"]="h"; map["51"]="i"; map["52"]="j"; map["53"]="k"; map["54"]="l"; map["55"]="m"; map["56"]="n"; map["57"]="o";
            map["48"]="p"; map["49"]="q"; map["4a"]="r"; map["4b"]="s"; map["4c"]="t"; map["4d"]="u"; map["4e"]="v"; map["4f"]="w";
            map["40"]="x"; map["41"]="y"; map["42"]="z";

            map["08"]="0"; map["09"]="1"; map["0a"]="2"; map["0b"]="3"; map["0c"]="4";
            map["0d"]="5"; map["0e"]="6"; map["0f"]="7"; map["00"]="8"; map["01"]="9";

            map["15"]="-"; map["16"]="."; map["67"]="_"; map["46"]="~";
            map["02"]=":"; map["17"]="/"; map["07"]="?"; map["1b"]="#";
            map["63"]="["; map["65"]="]"; map["78"]="@";
            map["19"]="!"; map["1c"]="$"; map["1e"]="&";
            map["10"]="("; map["11"]=")"; map["12"]="*"; map["13"]="+"; map["14"]=",";
            map["03"]=";"; map["05"]="="; map["1d"]="%";
        }
        {
            for(i=1;i<=length($0);i+=2){
                b=tolower(substr($0,i,2))
                printf "%s",(b in map ? map[b] : "")
            }
        }'
    )

    provider_id=${provider_id/\/clock/\/clock.json}
}

[CoolnsX]

1. Did not ask
2. The long chain is due to windows problem, if u don't know just search slow on windows (ref: Poor Performance on Windows After Commit #bd597...fff1be #1157)
3. Awk, we don't want to introduce new dependency and also Awk is slow

[port19x]

We literally have a CI check to make sure noone adds awk