Fix the Size trailer entry in hand written PDFs.

Change-Id: Ib84cc570c2ffaf9fdd49d32bc12c7e6197e130c1
Reviewed-on: https://pdfium-review.googlesource.com/6850
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

33 files changed, 105 insertions, 153 deletions

diff --git a/testing/resources/annotiter.in b/testing/resources/annotiter.in
index 4dc2a4ee2e..21e7b45e17 100644
--- a/testing/resources/annotiter.in
+++ b/testing/resources/annotiter.in
@@ -122,8 +122,6 @@ endobj
 >>
 endobj
 {{xref}}
-trailer <<
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/annotiter.pdf b/testing/resources/annotiter.pdf
index 2cb6d395d0..feb7909768 100644
--- a/testing/resources/annotiter.pdf
+++ b/testing/resources/annotiter.pdf
@@ -150,9 +150,7 @@ xref
 0000001160 00000 n 
 0000001288 00000 n 
 0000001415 00000 n 
-trailer <<
-  /Root 1 0 R
->>
+trailer<< /Root 1 0 R /Size 26 >>
 startxref
 1546
 %%EOF
diff --git a/testing/resources/bookmarks.in b/testing/resources/bookmarks.in
index dfa6e1426f..793f6ae542 100644
--- a/testing/resources/bookmarks.in
+++ b/testing/resources/bookmarks.in
@@ -90,9 +90,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/bookmarks.pdf b/testing/resources/bookmarks.pdf
index 824ce78db7..8c2eb5ac7b 100644
--- a/testing/resources/bookmarks.pdf
+++ b/testing/resources/bookmarks.pdf
@@ -115,10 +115,7 @@ xref
 0000000000 65535 f 
 0000000924 00000 n 
 0000001034 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+trailer<< /Root 1 0 R /Size 23 >>
 startxref
 1122
 %%EOF
diff --git a/testing/resources/bookmarks_circular.in b/testing/resources/bookmarks_circular.in
index 48a5695e17..1b05f36a1e 100644
--- a/testing/resources/bookmarks_circular.in
+++ b/testing/resources/bookmarks_circular.in
@@ -90,9 +90,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/bookmarks_circular.pdf b/testing/resources/bookmarks_circular.pdf
index e7eb624781..0e4ef86e69 100644
--- a/testing/resources/bookmarks_circular.pdf
+++ b/testing/resources/bookmarks_circular.pdf
@@ -115,10 +115,7 @@ xref
 0000000000 65535 f 
 0000000924 00000 n 
 0000001034 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+trailer<< /Root 1 0 R /Size 23 >>
 startxref
 1122
 %%EOF
diff --git a/testing/resources/circular_viewer_ref.in b/testing/resources/circular_viewer_ref.in
index f791607e91..0ce7808154 100644
--- a/testing/resources/circular_viewer_ref.in
+++ b/testing/resources/circular_viewer_ref.in
@@ -19,6 +19,6 @@ endobj
 endobj
 
 {{xref}}
-trailer <</Root 1 0 R>>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/circular_viewer_ref.pdf b/testing/resources/circular_viewer_ref.pdf
index 2e5c4dd8ab..f97d068a06 100644
--- a/testing/resources/circular_viewer_ref.pdf
+++ b/testing/resources/circular_viewer_ref.pdf
@@ -29,7 +29,7 @@ xref
 0000000000 65535 f 
 0000000000 65535 f 
 0000000195 00000 n 
-trailer <</Root 1 0 R>>
+trailer<< /Root 1 0 R /Size 8 >>
 startxref
 291
 %%EOF
diff --git a/testing/resources/combobox_form.in b/testing/resources/combobox_form.in
index c64f329f22..6c9f914023 100644
--- a/testing/resources/combobox_form.in
+++ b/testing/resources/combobox_form.in
@@ -31,6 +31,7 @@ endobj
   /Subtype /Type1
   /BaseFont /Helvetica
 >>
+endobj
 {{object 7 0}}
 << /Length 51 >>
 stream
@@ -66,6 +67,7 @@ endobj
   /Opt [(Apple) (Banana) (Cherry)]
   /V (Banana)
 >>
+endobj
 {{object 10 0}}
 <<
   /Type /Annot
@@ -79,6 +81,6 @@ endobj
 >>
 endobj
 {{xref}}
-trailer<< /Size 10 /Root 1 0 R >>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/combobox_form.pdf b/testing/resources/combobox_form.pdf
index d543737606..5249276b62 100644
--- a/testing/resources/combobox_form.pdf
+++ b/testing/resources/combobox_form.pdf
@@ -32,6 +32,7 @@ endobj
   /Subtype /Type1
   /BaseFont /Helvetica
 >>
+endobj
 7 0 obj
 << /Length 51 >>
 stream
@@ -67,6 +68,7 @@ endobj
   /Opt [(Apple) (Banana) (Cherry)]
   /V (Banana)
 >>
+endobj
 10 0 obj
 <<
   /Type /Annot
@@ -88,11 +90,11 @@ xref
 0000000335 00000 n 
 0000000368 00000 n 
 0000000399 00000 n 
-0000000468 00000 n 
-0000000568 00000 n 
-0000000772 00000 n 
-0000000961 00000 n 
-trailer<< /Size 10 /Root 1 0 R >>
+0000000475 00000 n 
+0000000575 00000 n 
+0000000779 00000 n 
+0000000975 00000 n 
+trailer<< /Root 1 0 R /Size 11 >>
 startxref
-1150
+1164
 %%EOF
diff --git a/testing/resources/hello_world.in b/testing/resources/hello_world.in
index 19fce0ce33..d3cf265c35 100644
--- a/testing/resources/hello_world.in
+++ b/testing/resources/hello_world.in
@@ -3,6 +3,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 {{object 2 0}} <<
   /Type /Pages
   /MediaBox [ 0 0 200 200 ]
@@ -48,9 +49,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/hello_world.pdf b/testing/resources/hello_world.pdf
index bb4f0a88e7..dcde8f7655 100644
--- a/testing/resources/hello_world.pdf
+++ b/testing/resources/hello_world.pdf
@@ -4,6 +4,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 2 0 obj <<
   /Type /Pages
   /MediaBox [ 0 0 200 200 ]
@@ -52,15 +53,12 @@ xref
 0 7
 0000000000 65535 f 
 0000000015 00000 n 
-0000000061 00000 n 
-0000000154 00000 n 
-0000000296 00000 n 
-0000000374 00000 n 
-0000000450 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+0000000068 00000 n 
+0000000161 00000 n 
+0000000303 00000 n 
+0000000381 00000 n 
+0000000457 00000 n 
+trailer<< /Root 1 0 R /Size 7 >>
 startxref
-571
+578
 %%EOF
diff --git a/testing/resources/launch_action.in b/testing/resources/launch_action.in
index c98539f5ea..00569e4489 100644
--- a/testing/resources/launch_action.in
+++ b/testing/resources/launch_action.in
@@ -3,6 +3,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 {{object 2 0}} <<
   /Type /Pages
   /MediaBox [ 0 0 200 200 ]
@@ -40,15 +41,13 @@ endobj
   /F 6 0 R
   /S /Launch
 >>
+endobj
 {{object 6 0}} <<
   /F (test.pdf)
   /Type / Filespec
 >>
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/launch_action.pdf b/testing/resources/launch_action.pdf
index 99a42923de..327c863c7a 100644
--- a/testing/resources/launch_action.pdf
+++ b/testing/resources/launch_action.pdf
@@ -4,6 +4,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 2 0 obj <<
   /Type /Pages
   /MediaBox [ 0 0 200 200 ]
@@ -41,6 +42,7 @@ endobj
   /F 6 0 R
   /S /Launch
 >>
+endobj
 6 0 obj <<
   /F (test.pdf)
   /Type / Filespec
@@ -50,15 +52,12 @@ xref
 0 7
 0000000000 65535 f 
 0000000015 00000 n 
-0000000061 00000 n 
-0000000154 00000 n 
-0000000223 00000 n 
-0000000489 00000 n 
-0000000527 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+0000000068 00000 n 
+0000000161 00000 n 
+0000000230 00000 n 
+0000000496 00000 n 
+0000000541 00000 n 
+trailer<< /Root 1 0 R /Size 7 >>
 startxref
-583
+597
 %%EOF
diff --git a/testing/resources/named_dests.in b/testing/resources/named_dests.in
index 5309ee23aa..a97aebe8bf 100644
--- a/testing/resources/named_dests.in
+++ b/testing/resources/named_dests.in
@@ -101,9 +101,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/named_dests.pdf b/testing/resources/named_dests.pdf
index 2e0e5ce71d..b99cead4ce 100644
--- a/testing/resources/named_dests.pdf
+++ b/testing/resources/named_dests.pdf
@@ -126,10 +126,7 @@ xref
 0000000000 65535 f 
 0000001283 00000 n 
 0000001393 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+trailer<< /Root 1 0 R /Size 23 >>
 startxref
 1481
 %%EOF
diff --git a/testing/resources/repeat_viewer_ref.in b/testing/resources/repeat_viewer_ref.in
index 6b436e535f..09a17f522d 100644
--- a/testing/resources/repeat_viewer_ref.in
+++ b/testing/resources/repeat_viewer_ref.in
@@ -14,6 +14,6 @@ endobj
 endobj
 
 {{xref}}
-trailer <</Root 1 0 R>>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/repeat_viewer_ref.pdf b/testing/resources/repeat_viewer_ref.pdf
index 3f4ee47724..72bd7e4847 100644
--- a/testing/resources/repeat_viewer_ref.pdf
+++ b/testing/resources/repeat_viewer_ref.pdf
@@ -24,7 +24,7 @@ xref
 0000000000 65535 f 
 0000000000 65535 f 
 0000000221 00000 n 
-trailer <</Root 1 0 R>>
+trailer<< /Root 1 0 R /Size 8 >>
 startxref
 317
 %%EOF
diff --git a/testing/resources/text_form.in b/testing/resources/text_form.in
index 4872986af1..c30f0bac4e 100644
--- a/testing/resources/text_form.in
+++ b/testing/resources/text_form.in
@@ -40,6 +40,7 @@ endobj
   /Subtype /Type1
   /BaseFont /Helvetica
 >>
+endobj
 {{object 8 0}}
 << /Length 51 >>
 stream
@@ -52,6 +53,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer<< /Size 8 /Root 1 0 R >>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/text_form.pdf b/testing/resources/text_form.pdf
index f72a73567b..1f3ab8571c 100644
--- a/testing/resources/text_form.pdf
+++ b/testing/resources/text_form.pdf
@@ -41,6 +41,7 @@ endobj
   /Subtype /Type1
   /BaseFont /Helvetica
 >>
+endobj
 8 0 obj
 << /Length 51 >>
 stream
@@ -62,8 +63,8 @@ xref
 0000000445 00000 n 
 0000000478 00000 n 
 0000000509 00000 n 
-0000000578 00000 n 
-trailer<< /Size 8 /Root 1 0 R >>
+0000000585 00000 n 
+trailer<< /Root 1 0 R /Size 9 >>
 startxref
-678
+685
 %%EOF
diff --git a/testing/resources/unsupported_feature.in b/testing/resources/unsupported_feature.in
index 3aa8632d14..d3080519bf 100644
--- a/testing/resources/unsupported_feature.in
+++ b/testing/resources/unsupported_feature.in
@@ -9,12 +9,12 @@ endobj
   /Type /Pages
   /Count 3
   /Kids [
-    10 0 R
+    3 0 R
   ]
 >>
 endobj
 % Page number 0.
-{{object 10 0}} <<
+{{object 3 0}} <<
   /Type /Page
   /Parent 2 0 R
   /Resources <<
@@ -25,8 +25,6 @@ endobj
 >>
 endobj
 {{xref}}
-trailer <<
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/unsupported_feature.pdf b/testing/resources/unsupported_feature.pdf
index f7091c5016..eb7ee08fa4 100644
--- a/testing/resources/unsupported_feature.pdf
+++ b/testing/resources/unsupported_feature.pdf
@@ -10,12 +10,12 @@ endobj
   /Type /Pages
   /Count 3
   /Kids [
-    10 0 R
+    3 0 R
   ]
 >>
 endobj
 % Page number 0.
-10 0 obj <<
+3 0 obj <<
   /Type /Page
   /Parent 2 0 R
   /Resources <<
@@ -26,21 +26,12 @@ endobj
 >>
 endobj
 xref
-0 11
+0 4
 0000000000 65535 f 
 0000000015 00000 n 
 0000000088 00000 n 
-0000000000 65535 f 
-0000000000 65535 f 
-0000000000 65535 f 
-0000000000 65535 f 
-0000000000 65535 f 
-0000000000 65535 f 
-0000000000 65535 f 
-0000000177 00000 n 
-trailer <<
-  /Root 1 0 R
->>
+0000000176 00000 n 
+trailer<< /Root 1 0 R /Size 4 >>
 startxref
-312
+310
 %%EOF
diff --git a/testing/resources/use_outlines.in b/testing/resources/use_outlines.in
index b344143f64..7b09ff9547 100644
--- a/testing/resources/use_outlines.in
+++ b/testing/resources/use_outlines.in
@@ -4,6 +4,7 @@
   /Pages 2 0 R
   /PageMode /UseOutlines
 >>
+endobj
 {{object 2 0}} <<
   /Type /Pages
   /MediaBox [ 0 0 200 200 ]
@@ -49,9 +50,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/use_outlines.pdf b/testing/resources/use_outlines.pdf
index 371ff4083c..81b01cabf6 100644
--- a/testing/resources/use_outlines.pdf
+++ b/testing/resources/use_outlines.pdf
@@ -5,6 +5,7 @@
   /Pages 2 0 R
   /PageMode /UseOutlines
 >>
+endobj
 2 0 obj <<
   /Type /Pages
   /MediaBox [ 0 0 200 200 ]
@@ -53,15 +54,12 @@ xref
 0 7
 0000000000 65535 f 
 0000000015 00000 n 
-0000000086 00000 n 
-0000000179 00000 n 
-0000000321 00000 n 
-0000000399 00000 n 
-0000000475 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+0000000093 00000 n 
+0000000186 00000 n 
+0000000328 00000 n 
+0000000406 00000 n 
+0000000482 00000 n 
+trailer<< /Root 1 0 R /Size 7 >>
 startxref
-596
+603
 %%EOF
diff --git a/testing/resources/viewer_ref.in b/testing/resources/viewer_ref.in
index 62ae372dfe..704e9d3a46 100644
--- a/testing/resources/viewer_ref.in
+++ b/testing/resources/viewer_ref.in
@@ -49,9 +49,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/viewer_ref.pdf b/testing/resources/viewer_ref.pdf
index fb72107b5b..851ea273e7 100644
--- a/testing/resources/viewer_ref.pdf
+++ b/testing/resources/viewer_ref.pdf
@@ -73,10 +73,7 @@ xref
 0000000000 65535 f 
 0000000000 65535 f 
 0000000537 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+trailer<< /Root 1 0 R /Size 22 >>
 startxref
 625
 %%EOF
diff --git a/testing/resources/weblinks.in b/testing/resources/weblinks.in
index ed20b2e642..818e676e90 100644
--- a/testing/resources/weblinks.in
+++ b/testing/resources/weblinks.in
@@ -3,6 +3,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 {{object 2 0}} <<
   /Type /Pages
   /MediaBox [ 0 0 600 600 ]
@@ -58,9 +59,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/weblinks.pdf b/testing/resources/weblinks.pdf
index 0d201a45aa..2639be85dc 100644
--- a/testing/resources/weblinks.pdf
+++ b/testing/resources/weblinks.pdf
@@ -4,6 +4,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 2 0 obj <<
   /Type /Pages
   /MediaBox [ 0 0 600 600 ]
@@ -62,15 +63,12 @@ xref
 0 7
 0000000000 65535 f 
 0000000015 00000 n 
-0000000061 00000 n 
-0000000154 00000 n 
-0000000374 00000 n 
+0000000068 00000 n 
+0000000161 00000 n 
+0000000381 00000 n 
 0000000000 65535 f 
-0000000450 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+0000000457 00000 n 
+trailer<< /Root 1 0 R /Size 7 >>
 startxref
-963
+970
 %%EOF
diff --git a/testing/resources/weblinks_across_lines.in b/testing/resources/weblinks_across_lines.in
index bb04b5e9cf..5771534913 100644
--- a/testing/resources/weblinks_across_lines.in
+++ b/testing/resources/weblinks_across_lines.in
@@ -3,6 +3,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 {{object 2 0}} <<
   /Type /Pages
   /MediaBox [ 0 0 600 600 ]
@@ -66,9 +67,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/weblinks_across_lines.pdf b/testing/resources/weblinks_across_lines.pdf
index e9327c4b34..b70910d629 100644
--- a/testing/resources/weblinks_across_lines.pdf
+++ b/testing/resources/weblinks_across_lines.pdf
@@ -4,6 +4,7 @@
   /Type /Catalog
   /Pages 2 0 R
 >>
+endobj
 2 0 obj <<
   /Type /Pages
   /MediaBox [ 0 0 600 600 ]
@@ -70,15 +71,12 @@ xref
 0 7
 0000000000 65535 f 
 0000000015 00000 n 
-0000000061 00000 n 
-0000000154 00000 n 
-0000000296 00000 n 
-0000000374 00000 n 
-0000000450 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+0000000068 00000 n 
+0000000161 00000 n 
+0000000303 00000 n 
+0000000381 00000 n 
+0000000457 00000 n 
+trailer<< /Root 1 0 R /Size 7 >>
 startxref
-921
+928
 %%EOF
diff --git a/testing/resources/zero_length_stream.in b/testing/resources/zero_length_stream.in
index 5b258d4d74..e7203437cc 100644
--- a/testing/resources/zero_length_stream.in
+++ b/testing/resources/zero_length_stream.in
@@ -55,9 +55,6 @@ ET
 endstream
 endobj
 {{xref}}
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+{{trailer}}
 {{startxref}}
 %%EOF
diff --git a/testing/resources/zero_length_stream.pdf b/testing/resources/zero_length_stream.pdf
index 90fae5be7f..1317c3f98a 100644
--- a/testing/resources/zero_length_stream.pdf
+++ b/testing/resources/zero_length_stream.pdf
@@ -65,10 +65,7 @@ xref
 0000000382 00000 n 
 0000000458 00000 n 
 0000000531 00000 n 
-trailer <<
-  /Size 6
-  /Root 1 0 R
->>
+trailer<< /Root 1 0 R /Size 8 >>
 startxref
 652
 %%EOF
diff --git a/testing/tools/fixup_pdf_template.py b/testing/tools/fixup_pdf_template.py
index 80a712f6e8..10ca241242 100755
--- a/testing/tools/fixup_pdf_template.py
+++ b/testing/tools/fixup_pdf_template.py
@@ -10,8 +10,10 @@ script replaces {{name}}-style variables in the input with calculated results
 
   {{header}}     - expands to the header comment required for PDF files.
   {{xref}}       - expands to a generated xref table, noting the offset.
+  {{trailer}}    - expands to a standard trailer with "1 0 R" as the /Root.
   {{startxref}   - expands to a startxref directive followed by correct offset.
-  {{object x y}} - expands to |x y obj| declaration, noting the offset."""
+  {{object x y}} - expands to |x y obj| declaration, noting the offset.
+"""
 
 import optparse
 import os
@@ -19,15 +21,19 @@ import re
 import sys
 
 class TemplateProcessor:
-  HEADER_TOKEN =  '{{header}}'
+  HEADER_TOKEN = '{{header}}'
   HEADER_REPLACEMENT = '%PDF-1.7\n%\xa0\xf2\xa4\xf4'
 
   XREF_TOKEN = '{{xref}}'
   XREF_REPLACEMENT = 'xref\n%d %d\n'
 
-  # XREF rows must be exactly 20 bytes - space required.
   XREF_REPLACEMENT_N = '%010d %05d n \n'
   XREF_REPLACEMENT_F = '0000000000 65535 f \n'
+  # XREF rows must be exactly 20 bytes - space required.
+  assert(len(XREF_REPLACEMENT_F) == 20)
+
+  TRAILER_TOKEN = '{{trailer}}'
+  TRAILER_REPLACEMENT = 'trailer<< /Root 1 0 R /Size %d >>'
 
   STARTXREF_TOKEN= '{{startxref}}'
   STARTXREF_REPLACEMENT = 'startxref\n%d'
@@ -60,6 +66,9 @@ class TemplateProcessor:
     if self.XREF_TOKEN in line:
       self.xref_offset = self.offset
       line = self.generate_xref_table()
+    if self.TRAILER_TOKEN in line:
+      replacement = self.TRAILER_REPLACEMENT % (self.max_object_number + 1)
+      line = line.replace(self.TRAILER_TOKEN, replacement)
     if self.STARTXREF_TOKEN in line:
       replacement = self.STARTXREF_REPLACEMENT % self.xref_offset
       line = line.replace(self.STARTXREF_TOKEN, replacement)