From 59ce1a4a3fdac2a59b32e615ce68fb2ef310946f Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Fri, 10 Nov 2023 11:48:44 +0100
Subject: [PATCH] Fix the maxp table version in font to make it visible on
 Windows

---
 src/core/fonts.js             | 25 ++++++++++++++++++++++---
 test/pdfs/issue16839.pdf.link |  2 ++
 test/test_manifest.json       |  8 ++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)
 create mode 100644 test/pdfs/issue16839.pdf.link

diff --git a/src/core/fonts.js b/src/core/fonts.js
index 84e3dd131..2ec70e41d 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -292,6 +292,13 @@ function signedInt16(b0, b1) {
   return value & (1 << 15) ? value - 0x10000 : value;
 }
 
+function writeUint32(bytes, index, value) {
+  bytes[index + 3] = value & 0xff;
+  bytes[index + 2] = value >>> 8;
+  bytes[index + 1] = value >>> 16;
+  bytes[index] = value >>> 24;
+}
+
 function int32(b0, b1, b2, b3) {
   return (b0 << 24) + (b1 << 16) + (b2 << 8) + b3;
 }
@@ -2642,9 +2649,21 @@ class Font {
     }
 
     font.pos = (font.start || 0) + tables.maxp.offset;
-    const version = font.getInt32();
+    let version = font.getInt32();
     const numGlyphs = font.getUint16();
 
+    if (version !== 0x00010000 && version !== 0x00005000) {
+      // https://learn.microsoft.com/en-us/typography/opentype/spec/maxp
+      if (tables.maxp.length === 6) {
+        version = 0x0005000;
+      } else if (tables.maxp.length >= 32) {
+        version = 0x00010000;
+      } else {
+        throw new FormatError(`"maxp" table has a wrong version number`);
+      }
+      writeUint32(tables.maxp.data, 0, version);
+    }
+
     if (properties.scaleFactors?.length === numGlyphs && isTrueType) {
       const { scaleFactors } = properties;
       const isGlyphLocationsLong = int16(
@@ -2695,7 +2714,7 @@ class Font {
     }
     let maxFunctionDefs = 0;
     let maxSizeOfInstructions = 0;
-    if (version >= 0x00010000 && tables.maxp.length >= 22) {
+    if (version >= 0x00010000 && tables.maxp.length >= 32) {
       // maxZones can be invalid
       font.pos += 8;
       const maxZones = font.getUint16();
@@ -2761,7 +2780,7 @@ class Font {
 
       // Some fonts have incorrect maxSizeOfInstructions values, so we use
       // the computed value instead.
-      if (version >= 0x00010000 && tables.maxp.length >= 22) {
+      if (version >= 0x00010000 && tables.maxp.length >= 32) {
         tables.maxp.data[26] = glyphsInfo.maxSizeOfInstructions >> 8;
         tables.maxp.data[27] = glyphsInfo.maxSizeOfInstructions & 255;
       }
diff --git a/test/pdfs/issue16839.pdf.link b/test/pdfs/issue16839.pdf.link
new file mode 100644
index 000000000..1bc6dab87
--- /dev/null
+++ b/test/pdfs/issue16839.pdf.link
@@ -0,0 +1,2 @@
+https://github.com/mozilla/pdf.js/files/12356264/250125_010823.pdf
+
diff --git a/test/test_manifest.json b/test/test_manifest.json
index bd98b5f99..56c8ce8d3 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -8206,5 +8206,13 @@
       "link": true,
       "type": "eq",
       "annotations": true
+   },
+   {
+      "id": "issue16839",
+      "file": "pdfs/issue16839.pdf",
+      "md5": "413fceec0ac31e079dc487bf4c5e44d8",
+      "rounds": 1,
+      "link": true,
+      "type": "eq"
    }
 ]