///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2013 - License: GNU GPLv3      //
//  Please see: http://www.gnu.org/licenses/gpl.html for legal details,  //
//  rights of fair usage, the disclaimer and warranty conditions.        //
///////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2013 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueGet(string var, string kvp) {
    list dVars = llParseString2List(kvp, ["&"], []);
    do {
        list data = llParseString2List(llList2String(dVars, 0), ["="], []);
        string k = llList2String(data, 0);
        if(k != var) jump continue;
        return llList2String(data, 1);
@continue;
        dVars = llDeleteSubList(dVars, 0, 0);
    } while(llGetListLength(dVars));
    return "";
}

///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2013 Wizardry and Steamworks - License: GNU GPLv3    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueSet(string var, string val, string kvp) {
    list dVars = llParseString2List(kvp, ["&"], []);
    if(llGetListLength(dVars) == 0) return var + "=" + val;
    list result = [];
    do {
        list data = llParseString2List(llList2String(dVars, 0), ["="], []);
        string k = llList2String(data, 0);
        if(k == "") jump continue;
        if(k == var && val == "") jump continue;
        if(k == var) {
            result += k + "=" + val;
            val = "";
            jump continue;
        }
        string v = llList2String(data, 1);
        if(v == "") jump continue;
        result += k + "=" + v;
@continue;
        dVars = llDeleteSubList(dVars, 0, 0);
    } while(llGetListLength(dVars));
    if(val != "") result += var + "=" + val;
    return llDumpList2String(result, "&");
}

default {
    touch_start(integer num) {
        integer page = (integer)wasKeyValueGet("page", llGetObjectDesc());
        vector p = llDetectedTouchST(0);
        if(p.y > .5) jump back;
        if(page+1 > llGetInventoryNumber(INVENTORY_TEXTURE)-1) return;
        llSetTexture(llGetInventoryName(INVENTORY_TEXTURE, ++page), 0);
        llSetObjectDesc(wasKeyValueSet("page", (string)page, llGetObjectDesc()));
        return;
@back;
        if(page-1 < 0) return;
        llSetTexture(llGetInventoryName(INVENTORY_TEXTURE, --page), 0);
        llSetObjectDesc(wasKeyValueSet("page", (string)page, llGetObjectDesc()));
    }
}