265 lines
10 KiB
OCaml
265 lines
10 KiB
OCaml
open Pdfutil
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(* Raised when syntax is ok, but endpage is too low. Caught by validator.
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Caught and reraised as normal failure by parse_pagespec. *)
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exception PageSpecUnknownPage of int
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(* There would be no pages *)
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exception PageSpecWouldBeNoPages
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(* Raised when syntax is wrong. Caught and reraised by parse_pagespec and
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validator. *)
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exception PageSpecBadSyntax
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(* Parsing range specifications *)
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let rec splitat_commas toks =
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match cleavewhile (neq (Pdfgenlex.LexName ",")) toks with
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| [], [] -> []
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| [], _ -> raise PageSpecBadSyntax
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| some, [] -> [some]
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| _::_ as before, _::rest -> before::splitat_commas rest
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let is_dimension pdf comparison {Pdfpage.mediabox = box} =
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let minx, miny, maxx, maxy = Pdf.parse_rectangle pdf box in
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comparison (maxx -. minx) (maxy -. miny)
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let select_dimensions comparison pdf candidates =
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let pages = Pdfpage.pages_of_pagetree pdf in
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let pagenums, kept_pages =
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split
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(option_map
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(fun (index, page) ->
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if mem index candidates then Some (index, page) else None)
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(combine (indx pages) pages))
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in
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option_map2
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(fun pagenum page ->
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if is_dimension pdf comparison page then Some pagenum else None)
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pagenums
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kept_pages
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let select_portrait = select_dimensions ( < )
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let select_landscape = select_dimensions ( > )
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let rec mk_numbers pdf endpage lexemes =
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match lexemes with
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| [Pdfgenlex.LexInt n] -> [n]
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| [Pdfgenlex.LexName "end"] -> [endpage]
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| [Pdfgenlex.LexInt n; Pdfgenlex.LexName "-"; Pdfgenlex.LexInt n'] ->
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if n > n' then rev (ilist n' n) else ilist n n'
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| [Pdfgenlex.LexName "end"; Pdfgenlex.LexName "-"; Pdfgenlex.LexInt n] ->
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if n <= endpage
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then rev (ilist n endpage)
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else raise (PageSpecUnknownPage n)
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| [Pdfgenlex.LexInt n; Pdfgenlex.LexName "-"; Pdfgenlex.LexName "end"] ->
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if n <= endpage
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then ilist n endpage
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else raise (PageSpecUnknownPage n)
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| [Pdfgenlex.LexName "end"; Pdfgenlex.LexName "-"; Pdfgenlex.LexName "end"] ->
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[endpage]
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| [Pdfgenlex.LexName "even"] ->
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drop_odds (ilist 1 endpage)
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| [Pdfgenlex.LexName "portrait"] ->
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select_portrait pdf (ilist 1 endpage)
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| [Pdfgenlex.LexName "landscape"] ->
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select_landscape pdf (ilist 1 endpage)
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| [Pdfgenlex.LexName "odd"] ->
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really_drop_evens (ilist 1 endpage)
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| [Pdfgenlex.LexName "all"] ->
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ilist 1 endpage
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| [Pdfgenlex.LexName "reverse"] ->
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rev (ilist 1 endpage)
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| toks ->
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let ranges = splitat_commas toks in
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if ranges = [toks] then raise PageSpecBadSyntax else
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flatten (map (mk_numbers pdf endpage) ranges)
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(* Space dashes and commas *)
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let rec add_spaces = function
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| [] -> []
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| ('-' | ',') as h::t -> ' '::h::' '::add_spaces t
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| h::t -> h::add_spaces t
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let space_string s =
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implode (add_spaces (explode s))
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let fixup_negatives endpage = function
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| Pdfgenlex.LexName s when String.length s > 1 && s.[0] = '~' ->
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Pdfgenlex.LexInt (endpage + 1 + ~-(int_of_string (implode (tl (explode s)))))
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| x -> x
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let invert_range endpage r =
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option_map (fun p -> if mem p r then None else Some p) (ilist 1 endpage)
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let duplicate_range n r =
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flatten (map (fun x -> many x n) r)
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(* e.g [1] -> 1, [iii] -> x, [/]] -> ] etc. *)
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let resolve_pagelabels pdf spec =
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let labels =
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let labs = Pdfpagelabels.read pdf in
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map
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(fun pnum -> (begin try Pdfpagelabels.pagelabeltext_of_pagenumber pnum labs with Not_found -> "" end, pnum))
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(ilist 1 (Pdfpage.endpage pdf))
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in
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(*iter (fun (s, l) -> Printf.printf "%s = %i\n" s l) labels;*)
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let rec readuntilclose a t =
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match t with
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| ']'::t -> rev a, t
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| '\\'::('[' | ']' as c)::t -> readuntilclose (c::a) t
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| '['::t -> raise PageSpecBadSyntax
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| x::t -> readuntilclose (x::a) t
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| [] -> rev a, []
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in
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let rec resolve_pagelabels_inner = function
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| '['::t ->
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let pagelabel, rest = readuntilclose [] t in
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let resolved =
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explode (string_of_int (begin match lookup (implode pagelabel) labels with Some x -> x | None -> raise PageSpecBadSyntax end))
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in
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resolved @ resolve_pagelabels_inner rest
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| '\\'::('[' | ']' as c)::t -> c::resolve_pagelabels_inner t
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| ']'::t -> raise PageSpecBadSyntax
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| h::t -> h::resolve_pagelabels_inner t
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| [] -> []
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in
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resolve_pagelabels_inner spec
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let rec parse_pagespec_inner endpage pdf spec =
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let spec = if spec = "" then "all" else spec in
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let spec = implode (resolve_pagelabels pdf (explode spec)) in
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let spec = space_string spec in
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if endpage < 1 then raise (Pdf.PDFError "This PDF file has no pages and is therefore malformed") else
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let numbers =
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try
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match explode spec with
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| 'N'::'O'::'T'::r ->
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invert_range endpage (parse_pagespec_inner endpage pdf (implode r))
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| x::'D'::'U'::'P'::r ->
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duplicate_range (int_of_string (implode [x])) (parse_pagespec_inner endpage pdf (implode r))
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| x::y::'D'::'U'::'P'::r ->
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duplicate_range (int_of_string (implode [x; y])) (parse_pagespec_inner endpage pdf (implode r))
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| x::y::z::'D'::'U'::'P'::r ->
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duplicate_range (int_of_string (implode [x; y; z])) (parse_pagespec_inner endpage pdf (implode r))
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| x::y::z::a::'D'::'U'::'P'::r ->
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duplicate_range (int_of_string (implode [x; y; z; a])) (parse_pagespec_inner endpage pdf (implode r))
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| x::y::z::a::b::'D'::'U'::'P'::r ->
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duplicate_range (int_of_string (implode [x; y; z; a; b])) (parse_pagespec_inner endpage pdf (implode r))
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| x::y::z::a::b::c::'D'::'U'::'P'::r ->
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duplicate_range (int_of_string (implode [x; y; z; a; b; c])) (parse_pagespec_inner endpage pdf (implode r))
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| _ ->
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match rev (explode spec) with
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| ['n'; 'e'; 'v'; 'e'] ->
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keep even (ilist 1 endpage)
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| ['d'; 'd'; 'o'] ->
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keep odd (ilist 1 endpage)
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| ['t'; 'i'; 'a'; 'r'; 't'; 'r'; 'o'; 'p'] ->
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select_portrait pdf (ilist 1 endpage)
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| ['e'; 'p'; 'a'; 'c'; 's'; 'd'; 'n'; 'a'; 'l'] ->
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select_landscape pdf (ilist 1 endpage)
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| 't'::'i'::'a'::'r'::'t'::'r'::'o'::'p'::more ->
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select_portrait
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pdf
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(mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
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| 'e'::'p'::'a'::'c'::'s'::'d'::'n'::'a'::'l'::more ->
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select_landscape
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pdf
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(mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
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| 'd'::'d'::'o'::more ->
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keep
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odd
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(mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
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| 'n'::'e'::'v'::'e'::more ->
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keep
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even
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(mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string (implode (rev more)))))
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| _ ->
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mk_numbers pdf endpage (map (fixup_negatives endpage) (Pdfgenlex.lex_string spec))
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with
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e -> raise PageSpecBadSyntax
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in
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if numbers = [] then raise PageSpecWouldBeNoPages else
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iter
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(fun n ->
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if n <= 0 || n > endpage then raise (PageSpecUnknownPage n))
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numbers;
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numbers
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let parse_pagespec pdf spec =
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try parse_pagespec_inner (Pdfpage.endpage pdf) pdf spec with
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| PageSpecUnknownPage n ->
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raise (Pdf.PDFError ("Page " ^ string_of_int n ^ " does not exist."))
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| PageSpecWouldBeNoPages ->
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raise (Pdf.PDFError ("Page range specifies no pages"))
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| e ->
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raise
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(Pdf.PDFError
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("Bad page specification " ^ spec ^
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". Raw error was " ^ Printexc.to_string e ^
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". Last page was " ^ string_of_int (Pdfpage.endpage pdf)))
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(* To validate a pagespec as being syntactically correct without the PDF in
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question. This is nasty, since the parser above includes checking based on the
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endpage of the PDF (which we don't have). Pass 100 as the endpage, doubling on
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page range exception, bailng out above 500000. *)
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let rec validate_pagespec_inner n spec =
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try
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ignore (parse_pagespec_inner n (Pdf.empty ()) spec); true
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with
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| PageSpecUnknownPage _ -> if n < 500000 then validate_pagespec_inner (n * 2) spec else false
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| PageSpecBadSyntax | _ -> false
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let validate_pagespec spec =
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validate_pagespec_inner 100 spec
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let rec parse_pagespec_without_pdf_inner n spec =
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try
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parse_pagespec_inner n (Pdf.empty ()) spec
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with
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PageSpecUnknownPage _ ->
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if n < 500000
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then parse_pagespec_without_pdf_inner (n * 2) spec
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else raise (Pdf.PDFError "PageSpecUnknownPage")
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let parse_pagespec_without_pdf spec =
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parse_pagespec_without_pdf_inner 100 spec
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(* Convert an integer list representing a set to a page specification, in order. *)
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let string_of_pagespec pdf = function
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| [] -> ""
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| is ->
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let iseven len is =
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drop_odds (ilist 1 len) = is
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in let isodd len is =
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really_drop_evens (ilist 1 len) = is
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in let isall len is =
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ilist 1 len = is
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in let is = sort compare is
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in let len = Pdfpage.endpage pdf in
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let rec mkranges prev = function
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| [] -> map extremes (rev (map rev prev))
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| h::t ->
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match prev with
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| (ph::pht)::pt when h = ph + 1 -> mkranges ((h::ph::pht)::pt) t
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| (_::_)::_ -> mkranges ([h]::prev) t
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| []::_ -> assert false
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| [] -> mkranges [[h]] t
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in
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if iseven len is && len > 3 then "even" else
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if isodd len is && len > 2 then "odd" else
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if isall len is then "all" else
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let ranges = mkranges [] is in
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let rangestrings =
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map
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(function (s, e) ->
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if s = e
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then string_of_int s
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else string_of_int s ^ "-" ^ string_of_int e)
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ranges
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in
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fold_left ( ^ ) "" (interleave "," rangestrings)
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let string_of_range r =
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fold_left (fun a b -> a ^ " " ^ b) "" (map string_of_int r)
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