---[[
-/*
- * Copyright (c) 2007 Tim Kelly/Dialectronics
- *
- * Permission is hereby granted, free of charge, to any person obtaining
- * a copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sublicense, and/or sell copies of the Software, and to permit
- * persons to whom the Software is furnished to do so, subject to the
- * following conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
- * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
- * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
- * OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
- * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-
- Modifications and documentation for LuCI made by
- Steven Barth <steven@midlink.org> and
- Jo-Philipp Wich <xm@leipzig.freifunk.net>
-
---]]
-
---- LuCI number conversion and bit manipulation functions.
-module("luci.bits", package.seeall);
-
-local hex2bin = {
- ["0"] = "0000",
- ["1"] = "0001",
- ["2"] = "0010",
- ["3"] = "0011",
- ["4"] = "0100",
- ["5"] = "0101",
- ["6"] = "0110",
- ["7"] = "0111",
- ["8"] = "1000",
- ["9"] = "1001",
- ["a"] = "1010",
- ["b"] = "1011",
- ["c"] = "1100",
- ["d"] = "1101",
- ["e"] = "1110",
- ["f"] = "1111"
-}
-
-local bin2hex = {
- ["0000"] = "0",
- ["0001"] = "1",
- ["0010"] = "2",
- ["0011"] = "3",
- ["0100"] = "4",
- ["0101"] = "5",
- ["0110"] = "6",
- ["0111"] = "7",
- ["1000"] = "8",
- ["1001"] = "9",
- ["1010"] = "A",
- ["1011"] = "B",
- ["1100"] = "C",
- ["1101"] = "D",
- ["1110"] = "E",
- ["1111"] = "F"
-}
-
---- Convert hexadecimal to binary number.
--- This function is big endian and can take up to 32 bits.
--- @param s String containing hex value
--- @return String containing binary value
-function Hex2Bin(s)
-
- local ret = ""
- local i = 0
-
-
- for i in string.gfind(s, ".") do
- i = string.lower(i)
-
- ret = ret..hex2bin[i]
-
- end
-
- return ret
-end
-
---- Convert binary to hexadecimal number.
--- This function is big endian and can take up to 32 bits.
--- @param s String containing binary value
--- @return String containing hex value
-function Bin2Hex(s)
-
- local l = 0
- local h = ""
- local b = ""
- local rem
-
- l = string.len(s)
- rem = l % 4
- l = l-1
- h = ""
-
- -- need to prepend zeros to eliminate mod 4
- if (rem > 0) then
- s = string.rep("0", 4 - rem)..s
- end
-
- for i = 1, l, 4 do
- b = string.sub(s, i, i+3)
- h = h..bin2hex[b]
- end
-
- return h
-
-end
-
---- Convert binary to decimal number.
--- This function is big endian and can take up to 32 bits.
--- @param s String containing binary value
--- @return String containing decimal value
-function Bin2Dec(s)
-
- local num = 0
- local ex = string.len(s) - 1
- local l = 0
-
- l = ex + 1
- for i = 1, l do
- b = string.sub(s, i, i)
- if b == "1" then
- num = num + 2^ex
- end
- ex = ex - 1
- end
-
- return string.format("%u", num)
-
-end
-
---- Convert decimal to binary number.
--- This function is big endian and can take up to 32 bits.
--- @param s String or number containing decimal value
--- @param num Pad binary number to num bits
--- @return String containing binary value
-function Dec2Bin(s, num)
-
- local n
-
- if (num == nil) then
- n = 0
- else
- n = num
- end
-
- s = string.format("%x", s)
-
- s = Hex2Bin(s)
-
- while string.len(s) < n do
- s = "0"..s
- end
-
- return s
-
-end
-
---- Convert hexadecimal to decimal number.
--- This function is big endian and can take up to 32 bits.
--- @param s String containing hex value
--- @return String containing decimal value
-function Hex2Dec(s)
-
- local s = Hex2Bin(s)
-
- return Bin2Dec(s)
-
-end
-
---- Convert decimal to hexadecimal number.
--- This function is big endian and can take up to 32 bits.
--- @param s String containing decimal value
--- @return String containing hex value
-function Dec2Hex(s)
-
- s = string.format("%x", s)
-
- return s
-
-end
-
-
---- Apply bitmask to value using bitwise And.
--- This function is big endian and will extend the values to 32 bits.
--- @param v String containing hex value to be masked
--- @param m String containing hex value of mask
--- @return String containing hex value of masked value
-function BMAnd(v, m)
-
- local bv = Hex2Bin(v)
- local bm = Hex2Bin(m)
-
- local i = 0
- local s = ""
-
- while (string.len(bv) < 32) do
- bv = "0000"..bv
- end
-
- while (string.len(bm) < 32) do
- bm = "0000"..bm
- end
-
-
- for i = 1, 32 do
- cv = string.sub(bv, i, i)
- cm = string.sub(bm, i, i)
- if cv == cm then
- if cv == "1" then
- s = s.."1"
- else
- s = s.."0"
- end
- else
- s = s.."0"
-
- end
- end
-
- return Bin2Hex(s)
-
-end
-
---- Apply bitmask to value using bitwise Nand.
--- This function is big endian and will extend the values to 32 bits.
--- @param v String containing hex value to be masked
--- @param m String containing hex value of mask
--- @return String containing hex value of masked value
-function BMNAnd(v, m)
-
- local bv = Hex2Bin(v)
- local bm = Hex2Bin(m)
-
- local i = 0
- local s = ""
-
- while (string.len(bv) < 32) do
- bv = "0000"..bv
- end
-
- while (string.len(bm) < 32) do
- bm = "0000"..bm
- end
-
-
- for i = 1, 32 do
- cv = string.sub(bv, i, i)
- cm = string.sub(bm, i, i)
- if cv == cm then
- if cv == "1" then
- s = s.."0"
- else
- s = s.."1"
- end
- else
- s = s.."1"
-
- end
- end
-
- return Bin2Hex(s)
-
-end
-
---- Apply bitmask to value using bitwise Or.
--- This function is big endian and will extend the values to 32 bits.
--- @param v String containing hex value to be masked
--- @param m String containing hex value of mask
--- @return String containing hex value of masked value
-function BMOr(v, m)
-
- local bv = Hex2Bin(v)
- local bm = Hex2Bin(m)
-
- local i = 0
- local s = ""
-
- while (string.len(bv) < 32) do
- bv = "0000"..bv
- end
-
- while (string.len(bm) < 32) do
- bm = "0000"..bm
- end
-
-
- for i = 1, 32 do
- cv = string.sub(bv, i, i)
- cm = string.sub(bm, i, i)
- if cv == "1" then
- s = s.."1"
- elseif cm == "1" then
- s = s.."1"
- else
- s = s.."0"
- end
- end
-
- return Bin2Hex(s)
-
-end
-
---- Apply bitmask to value using bitwise Xor.
--- This function is big endian and will extend the values to 32 bits.
--- @param v String containing hex value to be masked
--- @param m String containing hex value of mask
--- @return String containing hex value of masked value
-function BMXOr(v, m)
-
- local bv = Hex2Bin(v)
- local bm = Hex2Bin(m)
-
- local i = 0
- local s = ""
-
- while (string.len(bv) < 32) do
- bv = "0000"..bv
- end
-
- while (string.len(bm) < 32) do
- bm = "0000"..bm
- end
-
-
- for i = 1, 32 do
- cv = string.sub(bv, i, i)
- cm = string.sub(bm, i, i)
- if cv == "1" then
- if cm == "0" then
- s = s.."1"
- else
- s = s.."0"
- end
- elseif cm == "1" then
- if cv == "0" then
- s = s.."1"
- else
- s = s.."0"
- end
- else
- -- cv and cm == "0"
- s = s.."0"
- end
- end
-
- return Bin2Hex(s)
-
-end
-
---- Apply bitmask to value using bitwise Not.
--- This function is big endian and will extend the values to 32 bits.
--- @param v String containing hex value to be masked
--- @param m String containing hex value of mask
--- @return String containing hex value of masked value
-function BMNot(v, m)
-
- local bv = Hex2Bin(v)
- local bm = Hex2Bin(m)
-
- local i = 0
- local s = ""
-
- while (string.len(bv) < 32) do
- bv = "0000"..bv
- end
-
- while (string.len(bm) < 32) do
- bm = "0000"..bm
- end
-
-
- for i = 1, 32 do
- cv = string.sub(bv, i, i)
- cm = string.sub(bm, i, i)
- if cm == "1" then
- if cv == "1" then
- -- turn off
- s = s.."0"
- else
- -- turn on
- s = s.."1"
- end
- else
- -- leave untouched
- s = s..cv
-
- end
- end
-
- return Bin2Hex(s)
-
-end
-
-
---- Perform righthand bit shifting on value.
--- This function pads the shifted value with zeroes and will extend to 32 bits.
--- @param v String containing hex value to be shifted
--- @param nb Number of bits to shift right
--- @return String containing hex value of shifted value
-function BShRight(v, nb)
-
- local s = Hex2Bin(v)
-
- while (string.len(s) < 32) do
- s = "0000"..s
- end
-
- s = string.sub(s, 1, 32 - nb)
-
- while (string.len(s) < 32) do
- s = "0"..s
- end
-
- return Bin2Hex(s)
-
-end
-
---- Perform lefthand bit shifting on value.
--- This function pads the shifted value with zeroes and extend to 32 bits.
--- @param v String containing hex value to be shifted
--- @param nb Number of bits to shift left
--- @return String containing hex value of shifted value
-function BShLeft(v, nb)
-
- local s = Hex2Bin(v)
-
- while (string.len(s) < 32) do
- s = "0000"..s
- end
-
- s = string.sub(s, nb + 1, 32)
-
- while (string.len(s) < 32) do
- s = s.."0"
- end
-
- return Bin2Hex(s)
-
-end
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