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|
if not modules then modules = { } end modules ['lpdf-epd'] = {
version = 1.001,
comment = "companion to lpdf-epa.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- This is an experimental layer around the epdf library. The reason for this layer is that
-- I want to be independent of the library (which implements a selection of what a file
-- provides) and also because I want an interface closer to Lua's table model while the API
-- stays close to the original xpdf library. Of course, after prototyping a solution, we can
-- optimize it using the low level epdf accessors. However, not all are accessible (this will
-- be fixed).
--
-- It will be handy when we have a __length and __next that can trigger the resolve till then
-- we will provide .n as #; maybe in Lua 5.3 or later.
--
-- As there can be references to the parent we cannot expand a tree. I played with some
-- expansion variants but it does not pay off; adding extra checks is not worth the trouble.
--
-- The document stays open. In order to free memory one has to explicitly unload the loaded
-- document.
--
-- We have much more checking then needed in the prepare functions because occasionally
-- we run into bugs in poppler or the epdf interface. It took us a while to realize that
-- there was a long standing gc issue the on long runs with including many pages could
-- crash the analyzer.
--
-- Normally a value is fetched by key, as in foo.Title but as it can be in pdfdoc encoding
-- a safer bet is foo("Title") which will return a decoded string (or the original if it
-- already was unicode).
local setmetatable, rawset, rawget, type, next = setmetatable, rawset, rawget, type, next
local tostring, tonumber, unpack = tostring, tonumber, unpack
local lower, match, char, byte, find = string.lower, string.match, string.char, string.byte, string.find
local abs = math.abs
local concat = table.concat
local toutf, toeight, utfchar = string.toutf, utf.toeight, utf.char
local setmetatableindex = table.setmetatableindex
local lpegmatch, lpegpatterns = lpeg.match, lpeg.patterns
local P, C, S, R, Ct, Cc, V, Carg, Cs, Cf, Cg = lpeg.P, lpeg.C, lpeg.S, lpeg.R, lpeg.Ct, lpeg.Cc, lpeg.V, lpeg.Carg, lpeg.Cs, lpeg.Cf, lpeg.Cg
local epdf = epdf
lpdf = lpdf or { }
local lpdf = lpdf
local lpdf_epdf = { }
lpdf.epdf = lpdf_epdf
-- local getDict, getArray, getReal, getNum, getString, getBool, getName, getRef, getRefNum
-- local getType, getTypeName
-- local dictGetLength, dictGetVal, dictGetValNF, dictGetKey
-- local arrayGetLength, arrayGetNF, arrayGet
-- local streamReset, streamGetDict, streamGetChar
-- We use as little as possible and also not an object interface. After all, we
-- don't know how the library (and its api) evolves so we better can be prepared
-- for wrappers.
local registry = debug.getregistry()
local object = registry["epdf.Object"]
local dictionary = registry["epdf.Dict"]
local array = registry["epdf.Array"]
local xref = registry["epdf.XRef"]
local catalog = registry["epdf.Catalog"]
local pdfdoc = registry["epdf.PDFDoc"]
if not (object and dictionary and array and xref and catalog and pdfdoc) then
logs.report("fatal error","invalid pdf inclusion library (%s)",1)
os.exit()
end
local openPDF = epdf.open
local getMajorVersion = pdfdoc.getPDFMajorVersion
local getMinorVersion = pdfdoc.getPDFMinorVersion
local getXRef = pdfdoc.getXRef
local getRawCatalog = pdfdoc.getCatalog
if not (openPDF and getMajorVersion and getMinorVersion and getXRef and getRawCatalog) then
logs.report("fatal error","invalid pdf inclusion library (%s)",2)
os.exit()
end
local getDict = object.getDict
local getArray = object.getArray
local getReal = object.getReal
local getInt = object.getInt
local getString = object.getString
local getBool = object.getBool
local getName = object.getName
local getRef = object.getRef
local getRefNum = object.getRefNum
local getType = object.getType
if not (getDict and getArray and getReal and getInt and getString and getBool and getName and getRef and getRefNum and getType) then
logs.report("fatal error","invalid pdf inclusion library (%s)",3)
os.exit()
end
local streamReset = object.streamReset
local streamGetDict = object.streamGetDict
local streamGetChar = object.streamGetChar
local streamGetAll = object.streamGetAll
if not (streamReset and streamGetDict and streamGetChar) then
logs.report("fatal error","invalid pdf inclusion library (%s)",3)
os.exit()
end
local dictGetLength = dictionary.getLength
local dictGetVal = dictionary.getVal
local dictGetValNF = dictionary.getValNF
local dictGetKey = dictionary.getKey
if not (dictGetLength and dictGetVal and dictGetValNF and dictGetKey) then
logs.report("fatal error","invalid pdf inclusion library (%s)",4)
os.exit()
end
local arrayGetLength = array.getLength
local arrayGetNF = array.getNF
local arrayGet = array.get
if not (arrayGetLength and arrayGetNF and arrayGet) then
logs.report("fatal error","invalid pdf inclusion library (%s)",5)
os.exit()
end
-- these are kind of weird as they can't be accessed by (root) object
local getNumPages = catalog.getNumPages
local getPageRef = catalog.getPageRef
local fetch = xref.fetch
local getCatalog = xref.getCatalog
local getDocInfo = xref.getDocInfo
if not (getNumPages and getPageRef and fetch and getCatalog and getDocInfo) then
logs.report("fatal error","invalid pdf inclusion library (%s)",6)
os.exit()
end
-- we're done with library shortcuts
local typenames = { [0] =
"boolean",
"integer",
"real",
"string",
"name",
"null",
"array",
"dictionary",
"stream",
"ref",
"cmd",
"error",
"eof",
"none",
"integer64",
}
local typenumbers = table.swapped(typenames)
local null_object_code = typenumbers.null
local ref_object_code = typenumbers.ref
local report_epdf = logs.reporter("epdf")
local function fatal_error(...)
report_epdf(...)
report_epdf("aborting job in order to avoid crash")
os.exit()
end
-- epdf is the built-in library
function epdf.type(o)
local t = lower(match(tostring(o),"[^ :]+"))
return t or "?"
end
local checked_access
-- dictionaries (can be optimized: ... resolve and redefine when all locals set)
local frompdfdoc = lpdf.frompdfdoc
local get_flagged
if lpdf.dictionary then
local pdfdictionary = lpdf.dictionary
local pdfarray = lpdf.array
local pdfconstant = lpdf.constant
local pdfstring = lpdf.string
local pdfunicode = lpdf.unicode
get_flagged = function(t,f,k)
local tk = t[k] -- triggers resolve
local fk = f[k]
if not fk then
return tk
elseif fk == "name" then
return pdfconstant(tk)
elseif fk == "array" then
return pdfarray(tk)
elseif fk == "dictionary" then
return pdfarray(tk)
elseif fk == "rawtext" then
return pdfstring(tk)
elseif fk == "unicode" then
return pdfunicode(tk)
else
return tk
end
end
else
get_flagged = function(t,f,k)
local tk = t[k] -- triggers resolve
local fk = f[k]
if not fk then
return tk
elseif fk == "rawtext" then
return frompdfdoc(tk)
else
return tk
end
end
end
local function prepare(document,d,t,n,k,mt,flags)
for i=1,n do
local v = dictGetVal(d,i)
if v then
local r = dictGetValNF(d,i)
local kind = getType(v)
if kind == null_object_code then
-- ignore
elseif kind then
local key = dictGetKey(d,i)
if r and getType(r) == ref_object_code then
local objnum = getRefNum(r)
local cached = document.__cache__[objnum]
if not cached then
cached = checked_access[kind](v,document,objnum,mt)
if cached then
document.__cache__[objnum] = cached
document.__xrefs__[cached] = objnum
end
end
t[key] = cached
else
local v, flag = checked_access[kind](v,document)
t[key] = v
if flag and flags then
flags[key] = flag -- flags
end
end
else
report_epdf("warning: nil value for key %a in dictionary",key)
end
else
fatal_error("error: invalid value at index %a in dictionary of %a",i,document.filename)
end
end
if mt then
setmetatable(t,mt)
else
getmetatable(t).__index = nil
end
return t[k]
end
-- local function prepare(document,d,t,n,k,mt,flags)
-- for i=1,n do
-- local v = dictGetValNF(d,i)
-- if v then
-- local key = dictGetKey(d,i)
-- local kind = getType(v)
-- if kind == ref_object_code then
-- local objnum = getRefNum(v)
-- local cached = document.__cache__[objnum]
-- if not cached then
-- local v = dictGetVal(d,i)
-- local kind = getType(v)
-- cached = checked_access[kind](v,document,objnum,mt)
-- if cached then
-- document.__cache__[objnum] = cached
-- document.__xrefs__[cached] = objnum
-- end
-- end
-- t[key] = cached
-- else
-- local v, flag = checked_access[kind](v,document)
-- t[key] = v
-- if flag and flags then
-- flags[key] = flag -- flags
-- end
-- end
-- end
-- end
-- if mt then
-- setmetatable(t,mt)
-- else
-- getmetatable(t).__index = nil
-- end
-- return t[k]
-- end
local function some_dictionary(d,document)
local n = d and dictGetLength(d) or 0
if n > 0 then
local t = { }
local f = { }
setmetatable(t, {
__index = function(t,k)
return prepare(document,d,t,n,k,_,_,f)
end,
__call = function(t,k)
return get_flagged(t,f,k)
end,
-- __kind = function(k)
-- return f[k] or type(t[k])
-- end,
} )
return t, "dictionary"
end
end
local function get_dictionary(object,document,r,mt)
local d = getDict(object)
local n = d and dictGetLength(d) or 0
if n > 0 then
local t = { }
local f = { }
setmetatable(t, {
__index = function(t,k)
return prepare(document,d,t,n,k,mt,f)
end,
__call = function(t,k)
return get_flagged(t,f,k)
end,
-- __kind = function(k)
-- return f[k] or type(t[k])
-- end,
} )
return t, "dictionary"
end
end
-- arrays (can be optimized: ... resolve and redefine when all locals set)
local function prepare(document,a,t,n,k)
for i=1,n do
local v = arrayGet(a,i)
if v then
local kind = getType(v)
if kind == null_object_code then
-- ignore
elseif kind then
local r = arrayGetNF(a,i)
if r and getType(r) == ref_object_code then
local objnum = getRefNum(r)
local cached = document.__cache__[objnum]
if not cached then
cached = checked_access[kind](v,document,objnum)
document.__cache__[objnum] = cached
document.__xrefs__[cached] = objnum
end
t[i] = cached
else
t[i] = checked_access[kind](v,document)
end
else
report_epdf("warning: nil value for index %a in array",i)
end
else
fatal_error("error: invalid value at index %a in array of %a",i,document.filename)
end
end
local m = getmetatable(t)
if m then
m.__index = nil
m.__len = nil
end
if k then
return t[k]
end
end
-- local function prepare(document,a,t,n,k)
-- for i=1,n do
-- local v = arrayGetNF(a,i)
-- if v then
-- local kind = getType(v)
-- if kind == ref_object_code then
-- local objnum = getRefNum(v)
-- local cached = document.__cache__[objnum]
-- if not cached then
-- local v = arrayGet(a,i)
-- local kind = getType(v)
-- cached = checked_access[kind](v,document,objnum)
-- document.__cache__[objnum] = cached
-- document.__xrefs__[cached] = objnum
-- end
-- t[i] = cached
-- else
-- t[i] = checked_access[kind](v,document)
-- end
-- end
-- end
-- local m = getmetatable(t)
-- if m then
-- m.__index = nil
-- m.__len = nil
-- end
-- if k then
-- return t[k]
-- end
-- end
local function some_array(a,document)
local n = a and arrayGetLength(a) or 0
if n > 0 then
local t = { n = n }
setmetatable(t, {
__index = function(t,k)
return prepare(document,a,t,n,k,_,_,f)
end,
__len = function(t)
prepare(document,a,t,n,_,_,f)
return n
end,
__call = function(t,k)
return get_flagged(t,f,k)
end,
-- __kind = function(k)
-- return f[k] or type(t[k])
-- end,
} )
return t, "array"
end
end
local function get_array(object,document)
local a = getArray(object)
local n = a and arrayGetLength(a) or 0
if n > 0 then
local t = { n = n }
local f = { }
setmetatable(t, {
__index = function(t,k)
return prepare(document,a,t,n,k,_,_,f)
end,
__len = function(t)
prepare(document,a,t,n,_,_,f)
return n
end,
__call = function(t,k)
return get_flagged(t,f,k)
end,
-- __kind = function(k)
-- return f[k] or type(t[k])
-- end,
} )
return t, "array"
end
end
-- todo: collect chunks
-- local function streamaccess(s,_,what)
-- if not what or what == "all" or what == "*all" then
-- local t, n = { }, 0
-- streamReset(s)
-- while true do
-- local c = streamGetChar(s)
-- if c < 0 then
-- break
-- else
-- n = n + 1
-- t[n] = char(c)
-- end
-- end
-- return concat(t,"",1,n)
-- end
-- end
local function getstream(s)
streamReset(s)
if streamGetAll then
return streamGetAll(s)
else
local t, b, n = { }, { }, 0
while true do
local c = streamGetChar(s)
if c < 0 then
break
else
n = n + 1
b[n] = c
end
if n == 2000 then
t[#t+1] = char(unpack(b,1,n))
n = 1
end
end
t[#t+1] = char(unpack(b,1,n))
return concat(t)
end
end
local function streamaccess(s,_,what)
if not what or what == "all" or what == "*all" then
return getstream(s)
end
end
local function get_stream(d,document)
if d then
streamReset(d)
local s = some_dictionary(streamGetDict(d),document)
getmetatable(s).__call = function(...) return streamaccess(d,...) end
return s
end
end
-- We need to convert the string from utf16 although there is no way to
-- check if we have a regular string starting with a bom. So, we have
-- na dilemma here: a pdf doc encoded string can be invalid utf.
-- <hex encoded> : implicit 0 appended if odd
-- (byte encoded) : \( \) \\ escaped
--
-- <FE><FF> : utf16be
--
-- \r \r \t \b \f \( \) \\ \NNN and \<newline> : append next line
--
-- the getString function gives back bytes so we don't need to worry about
-- the hex aspect.
local u_pattern = lpeg.patterns.utfbom_16_be * lpeg.patterns.utf16_to_utf8_be
----- b_pattern = lpeg.patterns.hextobytes
local function get_string(v)
-- the toutf function only converts a utf16 string and leaves the original
-- untouched otherwise; one might want to apply lpdf.frompdfdoc to a
-- non-unicode string
local s = getString(v)
if not s or s == "" then
return ""
end
local u = lpegmatch(u_pattern,s)
if u then
return u, "unicode"
end
-- this is too tricky and fails on e.g. reload of url www.pragma-ade.com)
-- local b = lpegmatch(b_pattern,s)
-- if b then
-- return b, "rawtext"
-- end
return s, "rawtext"
end
local function get_name(v)
return getName(v), "name"
end
local function get_null()
return nil
end
-- we have dual access: by typenumber and by typename
local function invalidaccess(k,document)
local fullname = type(document) == "table" and document.fullname
if fullname then
fatal_error("error, asking for key %a in checker of %a",k,fullname)
else
fatal_error("error, asking for key %a in checker",k)
end
end
checked_access = setmetatableindex(function(t,k)
return function(v,document)
invalidaccess(k,document)
end
end)
checked_access[typenumbers.boolean] = getBool
checked_access[typenumbers.integer] = getInt
checked_access[typenumbers.real] = getReal
checked_access[typenumbers.string] = get_string -- getString
checked_access[typenumbers.name] = get_name
checked_access[typenumbers.null] = get_null
checked_access[typenumbers.array] = get_array -- d,document,r
checked_access[typenumbers.dictionary] = get_dictionary -- d,document,r
checked_access[typenumbers.stream] = get_stream
checked_access[typenumbers.ref] = getRef
for i=0,#typenames do
local checker = checked_access[i]
if not checker then
checker = function()
return function(v,document)
invalidaccess(i,document)
end
end
checked_access[i] = checker
end
checked_access[typenames[i]] = checker
end
local function getnames(document,n,target) -- direct
if n then
local Names = n.Names
if Names then
if not target then
target = { }
end
for i=1,Names.n,2 do
target[Names[i]] = Names[i+1]
end
else
local Kids = n.Kids
if Kids then
for i=1,Kids.n do
target = getnames(document,Kids[i],target)
end
end
end
return target
end
end
local function getkids(document,n,target) -- direct
if n then
local Kids = n.Kids
if Kids then
for i=1,Kids.n do
target = getkids(document,Kids[i],target)
end
elseif target then
target[#target+1] = n
else
target = { n }
end
return target
end
end
-- /OCProperties <<
-- /OCGs [ 15 0 R 17 0 R 19 0 R 21 0 R 23 0 R 25 0 R 27 0 R ]
-- /D <<
-- /Order [ 15 0 R 17 0 R 19 0 R 21 0 R 23 0 R 25 0 R 27 0 R ]
-- /ON [ 15 0 R 17 0 R 19 0 R 21 0 R 23 0 R 25 0 R 27 0 R ]
-- /OFF [ ]
-- >>
-- >>
local function getlayers(document)
local properties = document.Catalog.OCProperties
if properties then
local layers = properties.OCGs
if layers then
local t = { }
local n = layers.n
for i=1,n do
local layer = layers[i]
t[i] = layer.Name
end
t.n = n
return t
end
end
end
local function getstructure(document)
-- this might become a tree
return document.Catalog.StructTreeRoot
end
-- This is the only messy helper. We can't access the root as any object (it seems)
-- so we need a few low level acessors. It's anyway sort of simple enough to deal
-- with but it won't win a beauty contest.
local function getpages(document,Catalog)
local __data__ = document.__data__
local __xrefs__ = document.__xrefs__
local __cache__ = document.__cache__
local __xref__ = document.__xref__
--
local rawcatalog = getRawCatalog(__data__)
local nofpages = getNumPages(rawcatalog)
--
local majorversion = getMajorVersion(__data__)
local minorversion = getMinorVersion(__data__)
--
local pages = { }
local metatable = { __index = Catalog.Pages } -- somewhat empty
--
for pagenumber=1,nofpages do
local pagereference = getPageRef(rawcatalog,pagenumber).num
local pageobject = fetch(__xref__,pagereference,0)
local pagedata = get_dictionary(pageobject,document,pagereference,metatable)
if pagedata then
-- rawset(pagedata,"number",pagenumber)
pagedata.number = pagenumber
pagedata.object = pageobject
pages[pagenumber] = pagedata
__xrefs__[pagedata] = pagereference
__cache__[pagereference] = pagedata
else
report_epdf("missing pagedata at slot %i",i)
end
end
--
pages.n = nofpages
--
document.pages = pages
document.majorversion = majorversion
document.minorversion = minorversion
--
return pages
end
local function resolve(document,k)
local entry = nil
local Catalog = document.Catalog
local Names = Catalog.Names
if k == "pages" then
entry = getpages(document,Catalog)
elseif k == "destinations" then
entry = getnames(document,Names and Names.Dests)
elseif k == "javascripts" then
entry = getnames(document,Names and Names.JS)
elseif k == "widgets" then
entry = getnames(document,Names and Names.AcroForm)
elseif k == "embeddedfiles" then
entry = getnames(document,Names and Names.EmbeddedFiles)
elseif k == "layers" then
entry = getlayers(document)
elseif k == "structure" then
entry = getstructure(document)
end
document[k] = entry
return entry
end
local loaded = { }
function lpdf_epdf.load(filename)
local document = loaded[filename]
if not document then
statistics.starttiming(lpdf_epdf)
local __data__ = openPDF(filename) -- maybe resolvers.find_file
if __data__ then
local __xref__ = getXRef(__data__)
document = {
filename = filename,
__cache__ = { },
__xrefs__ = { },
__fonts__ = { },
__data__ = __data__,
__xref__ = __xref__
}
document.Catalog = some_dictionary(getDict(getCatalog(__xref__)),document)
document.Info = some_dictionary(getDict(getDocInfo(__xref__)),document)
setmetatableindex(document,resolve)
--
document.nofpages = getNumPages(getRawCatalog(__data__))
else
document = false
end
loaded[filename] = document
loaded[document] = document
statistics.stoptiming(lpdf_epdf)
-- print(statistics.elapsedtime(lpdf_epdf))
end
return document or nil
end
function lpdf_epdf.unload(filename)
local document = loaded[filename]
if document then
loaded[document] = nil
loaded[filename] = nil
end
end
-- for k, v in next, expand(t) do
local function expand(t)
if type(t) == "table" then
local dummy = t.dummy
end
return t
end
-- for k, v in expanded(t) do
local function expanded(t)
if type(t) == "table" then
local dummy = t.dummy
end
return next, t
end
lpdf_epdf.expand = expand
lpdf_epdf.expanded = expanded
-- we could resolve the text stream in one pass if we directly handle the
-- font but why should we complicate things
local hexdigit = R("09","AF")
local numchar = ( P("\\") * ( (R("09")^3/tonumber) + C(1) ) ) + C(1)
local number = lpegpatterns.number / tonumber
local spaces = lpegpatterns.whitespace^1
local optspaces = lpegpatterns.whitespace^0
local keyword = P("/") * C(R("AZ","az","09")^1)
local operator = C((R("AZ","az")+P("'")+P('"'))^1)
local grammar = P { "start",
start = (keyword + number + V("dictionary") + V("unicode") + V("string") + V("unicode")+ V("array") + spaces)^1,
-- keyvalue = (keyword * spaces * V("start") + spaces)^1,
keyvalue = optspaces * Cf(Ct("") * Cg(keyword * optspaces * V("start") * optspaces)^1,rawset),
array = P("[") * Ct(V("start")^1) * P("]"),
dictionary = P("<<") * V("keyvalue") * P(">>"),
unicode = P("<") * Ct(Cc("hex") * C((1-P(">"))^1)) * P(">"),
string = P("(") * Ct(Cc("dec") * C((V("string")+numchar)^1)) * P(")"), -- untested
}
local operation = Ct(grammar^1 * operator)
local parser = Ct((operation + P(1))^1)
-- beginbfrange : <start> <stop> <firstcode>
-- <start> <stop> [ <firstsequence> <firstsequence> <firstsequence> ]
-- beginbfchar : <code> <newcodes>
local fromsixteen = lpdf.fromsixteen -- maybe inline the lpeg ... but not worth it
local function f_bfchar(t,a,b)
t[tonumber(a,16)] = fromsixteen(b)
end
local function f_bfrange_1(t,a,b,c)
print("todo 1",a,b,c)
-- c is string
-- todo t[tonumber(a,16)] = fromsixteen(b)
end
local function f_bfrange_2(t,a,b,c)
print("todo 2",a,b,c)
-- c is table
-- todo t[tonumber(a,16)] = fromsixteen(b)
end
local optionals = spaces^0
local hexstring = optionals * P("<") * C((1-P(">"))^1) * P(">")
local bfchar = Carg(1) * hexstring * hexstring / f_bfchar
local bfrange = Carg(1) * hexstring * hexstring * hexstring / f_bfrange_1
+ Carg(1) * hexstring * hexstring * optionals * P("[") * Ct(hexstring^1) * optionals * P("]") / f_bfrange_2
local fromunicode = (
P("beginbfchar" ) * bfchar ^1 * optionals * P("endbfchar" ) +
P("beginbfrange") * bfrange^1 * optionals * P("endbfrange") +
spaces +
P(1)
)^1 * Carg(1)
local function analyzefonts(document,resources) -- unfinished, see mtx-pdf for better code
local fonts = document.__fonts__
if resources then
local fontlist = resources.Font
if fontlist then
for id, data in expanded(fontlist) do
if not fonts[id] then
-- a quick hack ... I will look into it more detail if I find a real
-- -application for it
local tounicode = data.ToUnicode()
if tounicode then
tounicode = lpegmatch(fromunicode,tounicode,1,{})
end
fonts[id] = {
tounicode = type(tounicode) == "table" and tounicode or { }
}
setmetatableindex(fonts[id],"self")
end
end
end
end
return fonts
end
local more = 0
local unic = nil -- cheaper than passing each time as Carg(1)
local p_hex_to_utf = 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 unic[now] or utfchar(now)
elseif now >= 0xD800 and now <= 0xDBFF then
more = now
-- return ""
else
return unic[now] or utfchar(now)
end
end
local p_dec_to_utf = C(1) / function(s) -- needs checking !
local now = byte(s)
return unic[now] or utfchar(now)
end
local p_hex_to_utf = P(true) / function() more = 0 end * Cs(p_hex_to_utf^1)
local p_dec_to_utf = P(true) / function() more = 0 end * Cs(p_dec_to_utf^1)
function lpdf_epdf.getpagecontent(document,pagenumber)
local page = document.pages[pagenumber]
if not page then
return
end
local fonts = analyzefonts(document,page.Resources)
local content = page.Contents() or ""
local list = lpegmatch(parser,content)
local font = nil
-- local unic = nil
for i=1,#list do
local entry = list[i]
local size = #entry
local operator = entry[size]
if operator == "Tf" then
font = fonts[entry[1]]
unic = font.tounicode
elseif operator == "TJ" then -- { array, TJ }
local list = entry[1]
for i=1,#list do
local li = list[i]
if type(li) == "table" then
if li[1] == "hex" then
list[i] = lpegmatch(p_hex_to_utf,li[2])
else
list[i] = lpegmatch(p_dec_to_utf,li[2])
end
else
-- kern
end
end
elseif operator == "Tj" or operator == "'" or operator == '"' then -- { string, Tj } { string, ' } { n, m, string, " }
local list = entry[size-1]
if list[1] == "hex" then
list[2] = lpegmatch(p_hex_to_utf,li[2])
else
list[2] = lpegmatch(p_dec_to_utf,li[2])
end
end
end
unic = nil -- can be collected
return list
end
-- This is also an experiment. When I really need it I can improve it, for instance
-- with proper position calculating. It might be usefull for some search or so.
local softhyphen = utfchar(0xAD) .. "$"
local linefactor = 1.3
function lpdf_epdf.contenttotext(document,list) -- maybe signal fonts
local last_y = 0
local last_f = 0
local text = { }
local last = 0
for i=1,#list do
local entry = list[i]
local size = #entry
local operator = entry[size]
if operator == "Tf" then
last_f = entry[2]
elseif operator == "TJ" then
local list = entry[1]
for i=1,#list do
local li = list[i]
if type(li) == "string" then
last = last + 1
text[last] = li
elseif li < -50 then
last = last + 1
text[last] = " "
end
end
line = concat(list)
elseif operator == "Tj" then
last = last + 1
text[last] = entry[size-1]
elseif operator == "cm" or operator == "Tm" then
local ty = entry[6]
local dy = abs(last_y - ty)
if dy > linefactor*last_f then
if last > 0 then
if find(text[last],softhyphen,1,true) then
-- ignore
else
last = last + 1
text[last] = "\n"
end
end
end
last_y = ty
end
end
return concat(text)
end
function lpdf_epdf.getstructure(document,list) -- just a test
local depth = 0
for i=1,#list do
local entry = list[i]
local size = #entry
local operator = entry[size]
if operator == "BDC" then
report_epdf("%w%s : %s",depth,entry[1] or "?",entry[2].MCID or "?")
depth = depth + 1
elseif operator == "EMC" then
depth = depth - 1
elseif operator == "TJ" then
local list = entry[1]
for i=1,#list do
local li = list[i]
if type(li) == "string" then
report_epdf("%w > %s",depth,li)
elseif li < -50 then
report_epdf("%w >",depth,li)
end
end
elseif operator == "Tj" then
report_epdf("%w > %s",depth,entry[size-1])
end
end
end
-- document.Catalog.StructTreeRoot.ParentTree.Nums[2][1].A.P[1])
-- helpers
-- function lpdf_epdf.getdestinationpage(document,name)
-- local destination = document.__data__:findDest(name)
-- return destination and destination.number
-- end
-- This is experimental code that we need for testing the transition from
-- poppler to a new lightweight library. Don't rely on this code to remain
-- as it is now. Interesting is that performance of this variant is the same
-- as the natural page includer.
if img then do
local copydictionary = nil
local copyarray = nil
local ref_object_code = typenumbers.ref
local boolean_object_code = typenumbers.boolean
local integer_object_code = typenumbers.integer
local real_object_code = typenumbers.real
local string_object_code = typenumbers.string
local name_object_code = typenumbers.name
local null_object_code = typenumbers.null
local array_object_code = typenumbers.array
local dictionary_object_code = typenumbers.dictionary
local stream_object_code = typenumbers.stream
local cmd_object_code = typenumbers.cmd
local pdfreserveobject = lpdf.reserveobject
local pdfflushobject = lpdf.flushobject
local pdfflushstreamobject = lpdf.flushstreamobject
local pdfreference = lpdf.reference
local pdfconstant = lpdf.constant
local pdfarray = lpdf.array
local pdfdictionary = lpdf.dictionary
local pdfunicode = lpdf.unicode
local pdfstring = lpdf.string
local pdfnull = lpdf.null
local report = logs.reporter("backend","xobjects")
local factor = 65536 / (7200/7227) -- 1/number.dimenfactors.bp
local createimage = images.create
local function scaledbbox(b)
return { b[1]*factor, b[2]*factor, b[3]*factor, b[4]*factor }
end
local function copyobject(xref,copied,kind,r,v)
if kind == null_object_code then
return pdfnull()
elseif r and getType(r) == ref_object_code then
local objnum = getRefNum(r)
local r = copied[objnum]
if r then
-- report("%s object %i is reused",kind,objnum)
else
local o
r = pdfreserveobject()
copied[objnum] = r
if kind == array_object_code then
local a = copyarray(xref,copied,fetch(xref,objnum,0))
pdfflushobject(r,tostring(a))
elseif kind == dictionary_object_code then
local d = copydictionary(xref,copied,fetch(xref,objnum,0))
pdfflushobject(r,tostring(d))
elseif kind == stream_object_code then
local f = fetch(xref,objnum,0)
local d = copydictionary(xref,copied,false,streamGetDict(f))
local s = getstream(f)
--
d.Filter = nil
d.Length = nil
d.DecodeParms = nil
d.DL = nil
--
pdfflushstreamobject(s,d,true,r)
else
report("reference not done: %s", kind)
end
end
return pdfreference(r)
elseif kind == array_object_code then
return copyarray(xref,copied,v)
elseif kind == dictionary_object_code then
return copydictionary(xref,copied,v)
elseif kind == integer_object_code then
return getInt(v)
elseif kind == real_object_code then
return getReal(v)
elseif kind == name_object_code then
return pdfconstant(getName(v))
elseif kind == string_object_code then
local s = getString(v)
if not s or s == "" then
return ""
end
local u = lpegmatch(u_pattern,s)
if u then
return pdfunicode(s)
end
return pdfstring(s)
elseif kind == boolean_object_code then
return getBool(v)
elseif kind == stream_object_code then
-- hm ...
return getStream(v)
else
report("object not done: %s", kind)
end
end
copyarray = function (xref,copied,object)
local a = getArray(object)
local n = a and arrayGetLength(a) or 0
if n > 0 then
local target = pdfarray()
for i=1,n do
local v = arrayGet(a,i)
if v then
local kind = getType(v)
local r = arrayGetNF(a,i)
target[i] = copyobject(xref,copied,kind,r,v)
end
end
return target
end
end
copydictionary = function (xref,copied,object,d)
local d = d or getDict(object)
local n = d and dictGetLength(d) or 0
if n > 0 then
local target = pdfdictionary()
for i=1,n do
local v = dictGetVal(d,i)
if v then
local kind = getType(v)
local key = dictGetKey(d,i)
local r = dictGetValNF(d,i)
target[key] = copyobject(xref,copied,kind,r,v)
end
end
return target
end
end
local function copy_resources(pdfdoc,xref,copied,pagedata)
local object = pagedata.object
if object then
local d = getDict(object)
local n = d and dictGetLength(d) or 0
for i=1,n do
local k = dictGetKey(d,i)
if v and k == "Resources" then
local v = dictGetVal(d,i)
local kind = getType(v)
local r = dictGetValNF(d,i)
return copyobject(xref,copied,kind,r,v)
end
end
end
end
local function openpdf(filename)
local pdfdoc = lpdf_epdf.load(filename)
if pdfdoc then
pdfdoc.__copied__ = pdfdoc.__copied__ or { }
pdfdoc.filename = filename
return pdfdoc
end
end
local function closepdf(pdfdoc)
if pdfdoc then
lpdf_epdf.unload(pdfdoc.filename)
end
end
local function querypdf(pdfdoc,pagenumber)
if pdfdoc then
if not pagenumber then
pagenumber = 1
end
local root = pdfdoc.Catalog
local page = pdfdoc.pages[pagenumber]
if page then
local mediabox = page.MediaBox or { 0, 0, 0, 0 }
local cropbox = page.CropBox or mediabox
return {
filename = pdfdoc.filename,
pagenumber = pagenumber,
nofpages = pdfdoc.nofpages,
boundingbox = scaledbbox(cropbox),
cropbox = cropbox,
mediabox = mediabox,
bleedbox = page.BleedBox or cropbox,
trimbox = page.TrimBox or cropbox,
artbox = page.ArtBox or cropbox,
}
end
end
end
local function copypage(pdfdoc,pagenumber,attributes)
if pdfdoc then
local root = pdfdoc.Catalog
local page = pdfdoc.pages[pagenumber or 1]
local pageinfo = querypdf(pdfdoc,pagenumber)
local contents = page.Contents
local xref = pdfdoc.__xref__
local copied = pdfdoc.__copied__
--
local xobject = pdfdictionary {
Type = pdfconstant("XObject"),
Subtype = pdfconstant("Form"),
-- image attributes
FormType = 1,
BBox = pageinfo.cropbox,
-- Metadata = copy(xref,copied,root,"Metadata"),
-- Group = copy(xref,copied,page,"Group"),
-- LastModified = copy(xref,copied,page,"LastModified"),
-- Metadata = copy(xref,copied,page,"Metadata"),
-- PieceInfo = copy(xref,copied,page,"PieceInfo"),
Resources = copy_resources(pdfdoc,xref,copied,page),
-- SeparationInfo = copy(xref,copied,page,"SeparationInfo"),
}
if attributes then
for k, v in next, expand(attributes) do
page[k] = v -- maybe nested
end
end
return createimage {
bbox = pageinfo.boundingbox,
stream = contents(),
attr = xobject(),
}
end
end
-- todo: codeinjections
lpdf_epdf.image = {
open = openpdf,
close = closepdf,
query = querypdf,
copy = copypage,
}
end end
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