88 lines
2.3 KiB
Lua
88 lines
2.3 KiB
Lua
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local format = string.format
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local gsub = string.gsub
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local byte = string.byte
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local pack = string.pack
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local error = error
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local pairs = pairs
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local setmetatable = setmetatable
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local assigned = {}
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local function stream(pdf, num, dict, content)
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if not num then num = pdf:getobj() end
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if pdf[num] ~= assigned then
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error[[Invalid object]]
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end
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pdf[num] = {offset = pdf.file:seek()}
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pdf.file:write(format('%i 0 obj\n<<%s/Length %i>>stream\n', num, dict, #content))
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pdf.file:write(content)
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pdf.file:write'\nendstream\nendobj\n'
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return num
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end
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local function indirect(pdf, num, content)
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if not num then num = pdf:getobj() end
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if pdf[num] ~= assigned then
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error[[Invalid object]]
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end
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pdf[num] = {offset = pdf.file:seek()}
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pdf.file:write(format('%i 0 obj\n', num))
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pdf.file:write(content)
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pdf.file:write'\nendobj\n'
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return num
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end
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local function getid(pdf)
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local id = pdf[0] + 1
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pdf[0] = id
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pdf[id] = assigned
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return id
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end
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local function trailer(pdf)
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local nextid = getid(pdf)
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local myoff = pdf.file:seek()
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pdf[nextid] = {offset = myoff}
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local linked = 0
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local offsets = {}
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for i=1,nextid do
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local off = pdf[i].offset
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if off then
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offsets[i+1] = pack(">I1I3I1", 1, off, 0)
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else
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offsets[linked+1] = pack(">I1I3I1", 0, i, 255)
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linked = i
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end
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end
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offsets[linked+1] = '\0\0\0\0\255'
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pdf[nextid] = assigned
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-- TODO: Add an /ID according to 14.4
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stream(pdf, nextid, format([[/Type/XRef/Size %i/W[1 3 1]/Root %i 0 R]], nextid+1, pdf.root), table.concat(offsets))
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pdf.file:write('startxref\n', myoff, '\n%%EOF')
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end
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local function close(pdf)
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trailer(pdf)
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if #pdf.version ~= 3 then
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error[[Invalid PDF version]]
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end
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pdf.file:seek('set', 5)
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pdf.file:write(pdf.version)
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pdf.file:close()
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end
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local pagetree = require'luametalatex-pdf-pagetree'
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local pdfmeta = {
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close = close,
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getobj = getid,
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indirect = indirect,
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stream = stream,
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newpage = pagetree.newpage,
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writepages = pagetree.write,
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-- delayed = delayed,
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-- delayedstream = delayedstream,
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-- reference
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}
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pdfmeta.__index = pdfmeta
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local function open(filename)
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local file = io.open(filename, 'w')
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file:write"%PDF-X.X\n%🖋\n"
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return setmetatable({file = file, version = '1.7', [0] = 0, pages = {}}, pdfmeta)
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end
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return {
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open = open,
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}
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