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if not modules then modules = { } end modules ['lpdf-aux'] = {
version = 1.001,
comment = "companion to lpdf-ini.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
local tonumber = tonumber
local format, concat = string.format, table.concat
local utfchar, utfbyte, char = utf.char, utf.byte, string.char
local lpegmatch, lpegpatterns = lpeg.match, lpeg.patterns
local P, C, R, S, Cc, Cs, V = lpeg.P, lpeg.C, lpeg.R, lpeg.S, lpeg.Cc, lpeg.Cs, lpeg.V
local rshift = bit32.rshift
lpdf = lpdf or { }
-- tosixteen --
local cache = table.setmetatableindex(function(t,k) -- can be made weak
local v = utfbyte(k)
if v < 0x10000 then
v = format("%04x",v)
else
v = format("%04x%04x",rshift(v,10),v%1024+0xDC00)
end
t[k] = v
return v
end)
local unified = Cs(Cc("<feff") * (lpegpatterns.utf8character/cache)^1 * Cc(">"))
function lpdf.tosixteen(str) -- an lpeg might be faster (no table)
if not str or str == "" then
return "<feff>" -- not () as we want an indication that it's unicode
else
return lpegmatch(unified,str)
end
end
-- fromsixteen --
-- local zero = S(" \n\r\t") + P("\\ ")
-- local one = C(4)
-- local two = P("d") * R("89","af") * C(2) * C(4)
--
-- local pattern = P { "start",
-- start = V("wrapped") + V("unwrapped") + V("original"),
-- original = Cs(P(1)^0),
-- wrapped = P("<") * V("unwrapped") * P(">") * P(-1),
-- unwrapped = P("feff")
-- * Cs( (
-- zero / ""
-- + two / function(a,b)
-- a = (tonumber(a,16) - 0xD800) * 1024
-- b = (tonumber(b,16) - 0xDC00)
-- return utfchar(a+b)
-- end
-- + one / function(a)
-- return utfchar(tonumber(a,16))
-- end
-- )^1 ) * P(-1)
-- }
--
-- function lpdf.fromsixteen(s)
-- return lpegmatch(pattern,s) or s
-- end
local more = 0
local pattern = C(4) / function(s) -- needs checking !
local now = tonumber(s,16)
if more > 0 then
now = (more-0xD800)*0x400 + (now-0xDC00) + 0x10000 -- the 0x10000 smells wrong
more = 0
return utfchar(now)
elseif now >= 0xD800 and now <= 0xDBFF then
more = now
return "" -- else the c's end up in the stream
else
return utfchar(now)
end
end
local pattern = P(true) / function() more = 0 end * Cs(pattern^0)
function lpdf.fromsixteen(str)
if not str or str == "" then
return ""
else
return lpegmatch(pattern,str)
end
end
-- frombytes --
local b_pattern = Cs((P("\\")/"" * (
S("()")
+ S("nrtbf")/ { n = "\n", r = "\r", t = "\t", b = "\b", f = "\f" }
+ lpegpatterns.octdigit^-3 / function(s) return char(tonumber(s,8)) end)
+ P(1))^0)
local u_pattern = lpegpatterns.utfbom_16_be * lpegpatterns.utf16_to_utf8_be -- official
+ lpegpatterns.utfbom_16_le * lpegpatterns.utf16_to_utf8_le -- we've seen these
local h_pattern = lpegpatterns.hextobytes
local zero = S(" \n\r\t") + P("\\ ")
local one = C(4)
local two = P("d") * R("89","af") * C(2) * C(4)
local x_pattern = P { "start",
start = V("wrapped") + V("unwrapped") + V("original"),
original = Cs(P(1)^0),
wrapped = P("<") * V("unwrapped") * P(">") * P(-1),
unwrapped = P("feff")
* Cs( (
zero / ""
+ two / function(a,b)
a = (tonumber(a,16) - 0xD800) * 1024
b = (tonumber(b,16) - 0xDC00)
return utfchar(a+b)
end
+ one / function(a)
return utfchar(tonumber(a,16))
end
)^1 ) * P(-1)
}
function lpdf.frombytes(s,hex)
if not s or s == "" then
return ""
end
if hex then
local x = lpegmatch(x_pattern,s)
if x then
return x
end
local h = lpegmatch(h_pattern,s)
if h then
return h
end
else
local u = lpegmatch(u_pattern,s)
if u then
return u
end
end
return lpegmatch(b_pattern,s)
end
-- done --
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