imported from https://holmeshe.me/understanding-memcached-source-code-I/

main@memcached.c

case 'I':
    buf = strdup(optarg);
    unit = buf[strlen(buf)-1];
    if (unit == 'k' || unit == 'm' ||
        unit == 'K' || unit == 'M') {
        buf[strlen(buf)-1] = '\0';
        size_max = atoi(buf);
        if (unit == 'k' || unit == 'K')
            size_max *= 1024;
        if (unit == 'm' || unit == 'M')
            size_max *= 1024 * 1024;
        settings.item_size_max = size_max;
    } else {
        settings.item_size_max = atoi(buf);
    }
    free(buf);
    if (settings.item_size_max < 1024) {
        fprintf(stderr, "Item max size cannot be less than 1024 bytes.\n");
        return 1;
    }
    if (settings.item_size_max > 1024 * 1024 * 128) {
        fprintf(stderr, "Cannot set item size limit higher than 128 mb.\n");
        return 1;
    }
    if (settings.item_size_max > 1024 * 1024) {
        fprintf(stderr, "WARNING: Setting item max size above 1MB is not"
            " recommended!\n"
            " Raising this limit increases the minimum memory requirements\n"
            " and will decrease your memory efficiency.\n"
        );
    }
    break;