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--[[
Eugeniy Mikhailov
1 June 2021
]]
------------ BITS TO DECIMAL ------------
function toNum(bits)
local n = 0; local m = 1 -- m represents power of 2
for i = 1, #bits do -- '#' indicates number of bits in variable
n = n + bits[i]*m
m = m*2
end
return n
end
------------ DECIMAL TO BIT ------------
-- ****NOTE: Suitable only for positive integer inputs****
-- continue to divide by two until quotient is zero
function toBits(num)
local t = {}
local cnt = 0
while num > 0 do
cnt = cnt + 1
remainder = num % 2 -- Basics of binary. If num is divisible by two, 0 in table. If not, 1 in table
t[cnt] = remainder -- defaults to #t+1 key
num = (num - remainder)/2
--num = math.floor((num - remainder)/2) -- carry out calculation
-- note math.floor used here to eliminate floating values
--we subtract the number with the binary bit found, then divide by two to find the next bit
end
return t
end
------------ BINARY SEPARATION TO STRING ------------
function bin2string(bTable, separator)
if nil == separator then separator="" end
local str=""
for i=#bTable,1,-1 do
if (i % 8) == 0 then str=str..separator end -- space between every 8 bits
if bTable[i] == 0 -- to take care of floats
then
str=str.."0"
else
str=str.."1" -- assumes only nonzeros are ones
-- if nonzeros/ones involved, will also be counted as ones here
end
end
return str
end
------------ TESTS FOR bin2string------------
if "11111110" ~= bin2string(toBits(254))
then
print("Error in bits conversion")
end
if 2376 ~= toNum(toBits(2376))
then
print("Error in bits conversion")
end
------------ SLICE STRING ------------
function bitSlice(bTable, low, high)
-- make sure that 1 <= low <= high
local slice={}
local cnt=1 --counter
for i=low,high
do
slice[cnt] = (bTable[i])
cnt = cnt+1
end
return slice
end
------------ TESTS FOR bitSlice ------------
if "345" ~= table.concat(bitSlice({1,2,3,4,5,6,7,8}, 3,5))
then
print("Error bitSlice is compromised")
end
------------ COPY TABLE ------------
-- issue with index naming in future table.
function copyTableArray(src)
local dst={}
for i=1,#src do
dst[i] = (src[i])
end
return dst
end
------------ COMBINE SLICES ------------
function tableReplace(bTable1, bTable2, low, high) -- low=first index, high=last index
local dest = copyTableArray(bTable1)
local cnt=1
for i=low,high do
dest[i]=(bTable2[cnt])
cnt = cnt + 1
end
return dest -- destination
end
------------ PAD ZEROS INTO EMPTY INDICES ------------
function pad2NumBitsInPlace(bTable, num)
for i= #bTable+1, num do
bTable[i]=0
end
return bTable
end
------------ TEST PAD ZEROS ------------
if "00010111" ~= bin2string(pad2NumBitsInPlace({1,1,1,0,1},8))
then
print("Error in pad2NumBitsInPlace")
end
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