From 476c5fda5d1bfb496cff9de7eb691dea312ff5a5 Mon Sep 17 00:00:00 2001
From: John Whitington <john@coherentgraphics.co.uk>
Date: Mon, 1 Jul 2019 15:35:17 +0100
Subject: [PATCH] Added -pad-mutliple-before

---
 cpdf.ml        |  5 +++--
 cpdfcommand.ml | 13 ++++++++++++-
 cpdfmanual.tex |  1 +
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/cpdf.ml b/cpdf.ml
index fa5bd6d..191a426 100644
--- a/cpdf.ml
+++ b/cpdf.ml
@@ -2156,6 +2156,7 @@ let padbefore ?padwith range pdf =
     pad padwith (map pred range) pdf true
 
 let padmultiple n pdf =
+  let neg, n = n < 0, if n < 0 then -n else n in
   let pages = Pdfpage.pages_of_pagetree pdf in
     let len = length pages in
       let pages_to_add = if len / n * n = len then 0 else n - (len mod n) in
@@ -2166,11 +2167,11 @@ let padmultiple n pdf =
                Pdfpage.mediabox = (select len pages).Pdfpage.mediabox;
                Pdfpage.resources = Pdf.Dictionary [];
                Pdfpage.rotate = (select len pages).Pdfpage.rotate;
-               Pdfpage.rest = (select len pages).Pdfpage.rest}
+               Pdfpage.rest = Pdf.Dictionary []}
               pages_to_add
           in
             let changes = map (fun x -> (x, x)) (ilist 1 (length pages)) in
-              Pdfpage.change_pages ~changes true pdf (pages @ blankpages)
+              Pdfpage.change_pages ~changes true pdf (if neg then blankpages @ pages else pages @ blankpages)
         else
           pdf
 
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 9f1e06c..f3756ce 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -92,6 +92,7 @@ type op =
   | PadAfter
   | PadEvery of int
   | PadMultiple of int
+  | PadMultipleBefore of int
   | Shift
   | Scale
   | ScaleToFit
@@ -205,6 +206,7 @@ let string_of_op = function
   | PadAfter -> "PadAfter"
   | PadEvery _ -> "PadEvery"
   | PadMultiple _ -> "PadMultiple"
+  | PadMultipleBefore _ -> "PadMultipleBefore"
   | Shift -> "Shift"
   | Scale -> "Scale"
   | ScaleToFit -> "ScaleToFit"
@@ -636,7 +638,7 @@ let banned banlist = function
   | Decrypt | Encrypt | CombinePages _ -> true (* Never allowed *)
   (* ISO says Noextract no longer relevent, due to accessibility concerns *)
   (*| ExtractText | ExtractImages | ExtractFontFile -> mem Pdfcrypt.NoExtract banlist*)
-  | AddBookmarks _ | PadBefore | PadAfter | PadEvery _ | PadMultiple _
+  | AddBookmarks _ | PadBefore | PadAfter | PadEvery _ | PadMultiple _ | PadMultipleBefore _
   | Merge | Split | SplitOnBookmarks _ | RotateContents _ | Rotate _
   | Rotateby _ | Upright | VFlip | HFlip | SetPageLayout _
   | SetPageMode _ | HideToolbar _ | HideMenubar _ | HideWindowUI _
@@ -1433,6 +1435,9 @@ let setpadwith filename =
 let setpadmultiple i =
   args.op <- Some (PadMultiple i)
 
+let setpadmultiplebefore i =
+  args.op <- Some (PadMultipleBefore i)
+
 let setfast () =
   args.fast <- true
 
@@ -1971,6 +1976,9 @@ and specs =
    ("-pad-multiple",
       Arg.Int setpadmultiple,
       " Pad the document to a multiple of n pages");
+   ("-pad-multiple-before",
+      Arg.Int setpadmultiplebefore,
+      " Pad the document at beginning to a multiple of n pages");
    ("-list-annotations",
       Arg.Unit (setop ListAnnotations),
       " List annotations");
@@ -3980,6 +3988,9 @@ let go () =
   | Some (PadMultiple n) ->
       let pdf = get_single_pdf args.op false in
         write_pdf false (Cpdf.padmultiple n pdf)
+  | Some (PadMultipleBefore n) ->
+      let pdf = get_single_pdf args.op false in
+        write_pdf false (Cpdf.padmultiple (-n) pdf)
   | Some Draft ->
       let pdf = get_single_pdf args.op false in
         let range = parse_pagespec pdf (get_pagespec ()) in
diff --git a/cpdfmanual.tex b/cpdfmanual.tex
index b72a22f..47531f0 100644
--- a/cpdfmanual.tex
+++ b/cpdfmanual.tex
@@ -15,6 +15,7 @@
 %FIXME: Document new -create-metadata
 %FIXME: Document -remove-clipping
 %FIXME: Document new -list-spot-colours
+%FIXME: Document new -pad-multiple-before
 
 \documentclass{book}
 \usepackage{palatino}