ash.xlib

#!/bin/busybox ash
#   Copyright 2021 bin jin
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

# Variable map.
#   env:
#       VARIABLE_MAP*_PREFIX_*
#
# Usage: __variable_map [[pool]] [option] [arguments]
#
# Options:
#    --put     [key] [value]      put the key and value in the map.
#    --append  [key] [value]      append the value to the value for KEY in the map.
#    --incrby  [key] [integer]    increment the value for KEY by INTEGER (atomic).
#    --get     [key]              print the value for KEY.
#    --remove  [key]              remove the value for KEY.
#    --size                       print the map size.
#    --clear                      clear the map.
#    --keys    [[key's prefix]]   list keys filtered by pool and key prefix.
#    --2keys   [[key's prefix]]   list pool*key pairs filtered by pool and key prefix.
__variable_map () {
    [ "$1" ] || return 1;
    __vmap_encode() {
        [ "${1//[0-9A-Za-z_]/}" == "" ] && { printf %s "$1"; return 0; }
        # One argument per character; an unquoted expansion drops the space key.
        local s=$1 idx=0; set --;
        while [ $idx -lt ${#s} ]; do set -- "$@" "'${s:$idx:1}"; idx=$((idx+1)); done;
        printf x%02x "$@"
    }

    local key pool value;
    [ "${1:0:2}" == "--" ] || { pool=`__vmap_encode "$1"`; shift; };
    key=`__vmap_encode "$2"` value="$3";
    case $1 in
        --put) [ "$value" ] && eval VARIABLE_MAP${pool}_PREFIX_$key=\"\$value\";;
        --incrby) [ "$value" ] && eval ": \$((VARIABLE_MAP${pool}_PREFIX_$key += $value))";;
        --append) [ "$value" ] && eval VARIABLE_MAP${pool}_PREFIX_$key=\"\$VARIABLE_MAP${pool}_PREFIX_$key\$value\";;
        --get) [ "$key" ] && eval printf %s \"\$VARIABLE_MAP${pool}_PREFIX_$key\";;
        --remove) [ "$key" ] && unset VARIABLE_MAP${pool}_PREFIX_$key;;
        --size) printf %d $(set | grep -c '^VARIABLE_MAP'${pool}_PREFIX_);;
        --clear) unset `set | awk -F '=' '/^VARIABLE_MAP'${pool}'_PREFIX_/{printf " " $1}'`;;
        # WARNING: a backquote eats a backslash before the command is parsed, so
        # [$(...)] is required here; decode the [xHH] pairs with 'printf %b'.
        --keys)
            local k;
            for k in $(set | awk -F '_PREFIX_|=' '/^VARIABLE_MAP'${pool//x2a/".*"}'_PREFIX_'${key//x2a/".*"}'/{if ($2 ~ /^(x[0-9a-f]{2})+$/) {s=$2; o=""; while (s != "") {o = o "\\" "x" substr(s, 2, 2); s = substr(s, 4)}; printf "%s\n", o} else {printf "%s\n", $2}}'); do
                printf '%b\n' "$k"
            done
        ;;
        --2keys)
            local k;
            for k in $(set | awk -F 'VARIABLE_MAP|_PREFIX_|=' '/^VARIABLE_MAP'${pool//x2a/".*"}'_PREFIX_'${key//x2a/".*"}'/{if ($2 ~ /^(x[0-9a-f]{2})+$/) {s=$2; o=""; while (s != "") {o = o "\\" "x" substr(s, 2, 2); s = substr(s, 4)}; printf "%s", o} else {printf "%s", $2}; printf "*"; if ($3 ~ /^(x[0-9a-f]{2})+$/) {s=$3; o=""; while (s != "") {o = o "\\" "x" substr(s, 2, 2); s = substr(s, 4)}; printf "%s", o} else {printf "%s", $3}; printf "\n"}'); do
                printf '%b\n' "$k"
            done
        ;;
        *) printf "%s\033[31m%s\033[0m%s\n" "[MAP:ERROR] invalid option: " "$1" >&2; return 1;;
    esac

}