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if not modules then modules = { } end modules ['l-number'] = {
version = 1.001,
comment = "companion to luat-lib.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- this module will be replaced when we have the bit library .. the number based sets
-- might go away
local tostring, tonumber = tostring, tonumber
local format, floor, match, rep = string.format, math.floor, string.match, string.rep
local concat, insert = table.concat, table.insert
local lpegmatch = lpeg.match
local floor = math.floor
number = number or { }
local number = number
if bit32 then -- I wonder if this is faster
local btest, bor = bit32.btest, bit32.bor
function number.bit(p)
return 2 ^ (p - 1) -- 1-based indexing
end
number.hasbit = btest
number.setbit = bor
function number.setbit(x,p) -- why not bor?
return btest(x,p) and x or x + p
end
function number.clearbit(x,p)
return btest(x,p) and x - p or x
end
else
-- http://ricilake.blogspot.com/2007/10/iterating-bits-in-lua.html
function number.bit(p)
return 2 ^ (p - 1) -- 1-based indexing
end
function number.hasbit(x, p) -- typical call: if hasbit(x, bit(3)) then ...
return x % (p + p) >= p
end
function number.setbit(x, p)
return (x % (p + p) >= p) and x or x + p
end
function number.clearbit(x, p)
return (x % (p + p) >= p) and x - p or x
end
end
-- print(number.tobitstring(8))
-- print(number.tobitstring(14))
-- print(number.tobitstring(66))
-- print(number.tobitstring(0x00))
-- print(number.tobitstring(0xFF))
-- print(number.tobitstring(46260767936,4))
if bit32 then
local bextract = bit32.extract
local t = {
"0", "0", "0", "0", "0", "0", "0", "0",
"0", "0", "0", "0", "0", "0", "0", "0",
"0", "0", "0", "0", "0", "0", "0", "0",
"0", "0", "0", "0", "0", "0", "0", "0",
}
function number.tobitstring(b,m)
-- if really needed we can speed this one up
-- because small numbers need less extraction
local n = 32
for i=0,31 do
local v = bextract(b,i)
local k = 32 - i
if v == 1 then
n = k
t[k] = "1"
else
t[k] = "0"
end
end
if m then
m = 33 - m * 8
if m < 1 then
m = 1
end
return concat(t,"",m)
elseif n < 8 then
return concat(t)
elseif n < 16 then
return concat(t,"",9)
elseif n < 24 then
return concat(t,"",17)
else
return concat(t,"",25)
end
end
else
function number.tobitstring(n,m)
if n > 0 then
local t = { }
while n > 0 do
insert(t,1,n % 2 > 0 and 1 or 0)
n = floor(n/2)
end
local nn = 8 - #t % 8
if nn > 0 and nn < 8 then
for i=1,nn do
insert(t,1,0)
end
end
if m then
m = m * 8 - #t
if m > 0 then
insert(t,1,rep("0",m))
end
end
return concat(t)
elseif m then
rep("00000000",m)
else
return "00000000"
end
end
end
function number.valid(str,default)
return tonumber(str) or default or nil
end
function number.toevenhex(n)
local s = format("%X",n)
if #s % 2 == 0 then
return s
else
return "0" .. s
end
end
-- a,b,c,d,e,f = number.toset(100101)
--
-- function number.toset(n)
-- return match(tostring(n),"(.?)(.?)(.?)(.?)(.?)(.?)(.?)(.?)")
-- end
--
-- -- the lpeg way is slower on 8 digits, but faster on 4 digits, some 7.5%
-- -- on
--
-- for i=1,1000000 do
-- local a,b,c,d,e,f,g,h = number.toset(12345678)
-- local a,b,c,d = number.toset(1234)
-- local a,b,c = number.toset(123)
-- local a,b,c = number.toset("123")
-- end
local one = lpeg.C(1-lpeg.S('')/tonumber)^1
function number.toset(n)
return lpegmatch(one,tostring(n))
end
-- function number.bits(n,zero)
-- local t, i = { }, (zero and 0) or 1
-- while n > 0 do
-- local m = n % 2
-- if m > 0 then
-- insert(t,1,i)
-- end
-- n = floor(n/2)
-- i = i + 1
-- end
-- return t
-- end
--
-- -- a bit faster
local function bits(n,i,...)
if n > 0 then
local m = n % 2
local n = floor(n/2)
if m > 0 then
return bits(n, i+1, i, ...)
else
return bits(n, i+1, ...)
end
else
return ...
end
end
function number.bits(n)
return { bits(n,1) }
end
function number.bytetodecimal(b)
local d = floor(b * 100 / 255 + 0.5)
if d > 100 then
return 100
elseif d < -100 then
return -100
else
return d
end
end
function number.decimaltobyte(d)
local b = floor(d * 255 / 100 + 0.5)
if b > 255 then
return 255
elseif b < -255 then
return -255
else
return b
end
end
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