CC_Json

local std=require "libraries/std"

function parse(source)

    local source,value = consumeValue(source)
    source=consumeWhiteSpace(source)

    if (string.len(source)>0) then error("invalid json input: " .. source) end

    return value;
end

function consumeValue(source)
    source = consumeWhiteSpace(source)
    local first = string.byte(source);
    if first == 123 then --'{'
        source = consumeWhiteSpace(string.sub(source, 2))

        local values={}
        while (string.byte(source) ~= 125) do --'}'
            local key, value
            source, key = consumeValue(source)
            source = consumeWhiteSpace(source);
            if string.byte(source) ~= 58 then error("invalid json input: " .. source) end --':'
            source = consumeWhiteSpace(string.sub(source, 2));
            source, value = consumeValue(source)
            source = consumeWhiteSpace(source);

            first=string.byte(source)
            if first ~= 44  and first~=125 then error("invalid json input: " .. source) end --',' ':'
            if first==44 then
                source = consumeWhiteSpace(string.sub(source,2));
            end

            values[key]=value
        end
        return string.sub(source,2,#source),values
    elseif first == 34 then --'"'
        local escaped = false
        local l = 2
        local value = ""

        while (true) do
            local s = string.sub(source, l, l)
            if (s == "\\") then
                escaped = true
            elseif not escaped and s == "\"" then
                break;
            else value = value .. s
            end
            l = l + 1;
        end
        return string.sub(source, l + 1), value
    elseif 48<=first and first<=57 then
        local l=1
        while(48<=first and first<=57) do
            first=string.byte(source,l)
            l=l+1
        end
        return string.sub(source,l-1),string.sub(source,1,l-2)
    else error("invalid json input: " .. source)
    end
end

function consumeWhiteSpace(source)
    local i = 1;
    while (string.len(source) >i-1) do
        local c = string.byte(source, i)
        if c == 32 or c == 10 or c == 13 then --' \n\r'
            i = i + 1;
        else break;
        end
    end
    return string.sub(source, i)
end

return {
    parse=parse
}