local intutil = {}

function intutil.fromle16(tab, idx)
    local n = tab[idx]
    n = n | tab[idx+1] << 8
    return n
end

function intutil.tole16(tab, idx, n)
    tab[idx] = n & 0xFF
    tab[idx+1] = (n >> 8) & 0xFF
end

function intutil.fromle32(tab, idx)
    local n = tab[idx]
    n = n | tab[idx+1] << 8
    n = n | tab[idx+2] << 16
    n = n | tab[idx+3] << 24
    return n
end

function intutil.tole32(tab, idx, n)
    tab[idx] = n & 0xFF
    tab[idx+1] = (n >>  8) & 0xFF
    tab[idx+2] = (n >> 16) & 0xFF
    tab[idx+3] = (n >> 24) & 0xFF
end

function intutil.fromle64(tab, idx)
    local n = tab[idx]
    n = n | tab[idx+1] << 8
    n = n | tab[idx+2] << 16
    n = n | tab[idx+3] << 24
    n = n | tab[idx+4] << 32
    n = n | tab[idx+5] << 40
    n = n | tab[idx+6] << 48
    n = n | tab[idx+7] << 56
    return n
end

function intutil.tole64(tab, idx, n)
    tab[idx] = n & 0xFF
    tab[idx+1] = (n >>  8) & 0xFF
    tab[idx+2] = (n >> 16) & 0xFF
    tab[idx+3] = (n >> 24) & 0xFF
    tab[idx+4] = (n >> 32) & 0xFF
    tab[idx+5] = (n >> 40) & 0xFF
    tab[idx+6] = (n >> 48) & 0xFF
    tab[idx+7] = (n >> 56) & 0xFF
end

function intutil.signexti32(n)
    if (n & 0x80000000) ~= 0 then
        n = n | 0xFFFFFFFF00000000
    end
    return n
end

function intutil.signexti16(n)
    if (n & 0x8000) ~= 0 then
        n = n | 0xFFFFFFFFFFFF0000
    end
    return n
end

function intutil.signexti8(n)
    if (n & 0x80) ~= 0 then
        n = n | 0xFFFFFFFFFFFFFF00
    end
    return n
end

function intutil.fromuleb128(tab, idx)
    local result = 0
    local shift = 0
    local len = 0
    repeat
        local byte = tab[idx+len]
        result = result | ((byte & 0x7F) << shift)
        shift = shift + 7
        len = len + 1
    until (byte & 0x80) == 0
    return len, result
end

function intutil.fromsleb128(tab, idx, bits)
    bits = bits or 64
    local result = 0
    local shift = 0
    local len = 0

    repeat
        local byte = tab[idx+len]
        result = result | ((byte & 0x7F) << shift)
        shift = shift + 7
        len = len + 1
    until (byte & 0x80) == 0

    if (shift < bits) and ((tab[idx+len-1] & 0x40) ~= 0) then
        result = result |  (((1 << bits) - 1) << shift)
    end
    return len, result & ((1 << bits) - 1)
end

return intutil