LaTeX format for LuaMetaTeX
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local readfile = require'luametalatex-readfile'
local format = string.format
local byte = string.byte
local pack = string.pack
local error = error
local pairs = pairs
local setmetatable = setmetatable
local assigned = {}
local delayed = {}
local compress = xzip.compress
local pdfvariable = pdf.variable
local digest = sha2.digest256
-- slightly tricky interface: No/nil return means that the objects content
-- isn't known yet, while false indicates a delayed object.
local function written(pdf, num)
num = pdf[num]
if not num or num == assigned then return end
return num ~= delayed
end
-- raw: Pass on preencoded stream.
local function stream(pdf, num, dict, content, isfile, raw)
if not num then num = pdf:getobj() end
if pdf[num] ~= assigned then
error[[Invalid object]]
end
pdf[num] = {offset = pdf.file:seek()}
if isfile then
local file <close> = readfile('pdf_stream', content, nil)
content = file()
end
local level = not raw and pdfvariable.compresslevel or 0
local filter = ''
if level > 0 then
local compressed = compress(content, level)
if #compressed < #content + 19 then -- Filter has some overhead
filter = "/Filter/FlateDecode"
content = compressed
end
end
pdf.file:write(format('%i 0 obj\n<<%s%s/Length %i>>stream\n', num, dict, filter, #content))
pdf.file:write(content)
pdf.file:write'\nendstream\nendobj\n'
return num
end
local function delayedstream(pdf, num, dict, content, isfile, raw)
if not num then num = pdf:getobj() end
if pdf[num] ~= assigned then
error[[Invalid object]]
end
pdf[num] = delayed
pdf[-num] = {stream, dict, content, isfile, raw}
return num
end
local function indirect(pdf, num, content, isfile, objstream)
if not num then num = pdf:getobj() end
if pdf[num] ~= assigned then
error[[Invalid object]]
end
if isfile then
local file <close> = readfile('pdf_dict', content, nil)
content = file()
end
if objstream ~= false and pdfvariable.objcompresslevel ~= 0 then
objstream = objstream or true
local objstr = pdf.objstream[objstream]
if not objstr then
objstr = {objnum = pdf:getobj(), off = 0, {}}
pdf.objstream[objstream] = objstr
end
local i = #objstr
pdf[num] = {objstr = objstr.objnum, i = i-1}
objstr[1][i] = string.format("%i %i ", num, objstr.off)
objstr[i+1] = content
objstr.off = objstr.off + #content
else
pdf[num] = {offset = pdf.file:seek()}
pdf.file:write(format('%i 0 obj\n', num))
pdf.file:write(content)
pdf.file:write'\nendobj\n'
end
return num
end
local function delay(pdf, num, content, isfile)
if not num then num = pdf:getobj() end
if pdf[num] ~= assigned then
error[[Invalid object]]
end
pdf[num] = delayed
pdf[-num] = {indirect, content, isfile}
return num
end
local function reference(pdf, num)
local status = pdf[num]
if status == delayed then
local saved = pdf[-num]
pdf[-num] = nil
pdf[num] = assigned
return saved[1](pdf, num, table.unpack(saved, 2))
elseif status == assigned or not status then
error[[Invalid object]]
-- else -- Already written
end
end
local function getid(pdf)
local id = pdf[0] + 1
pdf[0] = id
pdf[id] = assigned
return id
end
local function trailer(pdf)
local linked = 0
for k,objstr in next, pdf.objstream do
objstr[1] = table.concat(objstr[1])
pdf:stream(objstr.objnum, string.format("/Type/ObjStm/N %i/First %i", #objstr-1, #objstr[1]), table.concat(objstr))
end
local nextid = getid(pdf)
local myoff = pdf.file:seek()
pdf[nextid] = {offset = myoff}
local offsets = {}
for i=1,nextid do
local off = pdf[i].offset
if off then
offsets[i+1] = pack(">I1I3I2", 1, off, 0)
else
local objstr = pdf[i].objstr
if objstr then
offsets[i+1] = pack(">I1I3I2", 2, objstr, pdf[i].i)
else
offsets[linked+1] = pack(">I1I3I2", 0, i, 255)
linked = i
end
end
end
offsets[linked+1] = '\0\0\0\0\255\255'
pdf[nextid] = assigned
-- TODO: Add an /ID according to 14.4
local info = pdf.info and string.format("/Info %i 0 R", pdf.info) or ""
stream(pdf, nextid, format([[/Type/XRef/Size %i/W[1 3 2]/Root %i 0 R%s]], nextid+1, pdf.root, info), table.concat(offsets))
pdf.file:write('startxref\n', myoff, '\n%%EOF')
end
local function close(pdf)
trailer(pdf)
local size = pdf.file:seek()
if #pdf.version ~= 3 then
error[[Invalid PDF version]]
end
pdf.file:seek('set', 5)
pdf.file:write(pdf.version)
pdf.file:close()
return size
end
local pagetree = require'luametalatex-pdf-pagetree'
local pdfmeta = {
close = close,
getobj = getid,
indirect = indirect,
stream = stream,
newpage = pagetree.newpage,
reservepage = pagetree.reservepage,
writepages = pagetree.write,
delayed = delay,
delayedstream = delayedstream,
reference = reference,
written = written,
}
pdfmeta.__index = pdfmeta
local function open(filename)
local file, msg = io.open(filename, 'wb')
if not file then
tex.error('Unable to open output file', string.format("Opening the output file %q failed. According to your system, the reason is: %q. If you continue, all output will be discarded.", filename, msg))
file = assert(io.tmpfile())
end
file:write"%PDF-X.X\n%\xC1\xAC\xC1\xB4\n"
return setmetatable({file = file, version = '1.7', [0] = 0, pages = {}, objstream = {}}, pdfmeta)
end
return {
open = open,
}