Assume "Adobe-Identity" for character collection

When 'CIDSystemInfo' dictionary is absent or
has invalid content, instead of aborting the font
because we cannot read the character collection,
let's assume in that case character collection
to be "Adobe-Identity".

Fixes #1465 - Does not show text of Apple-edited PDFs

1 files changed, 13 insertions, 9 deletions

diff --git a/poppler/GfxFont.cc b/poppler/GfxFont.cc
index 156d4fb6..811a4878 100644
--- a/poppler/GfxFont.cc
+++ b/poppler/GfxFont.cc
@@ -1770,17 +1770,21 @@ GfxCIDFont::GfxCIDFont(XRef *xref, const char *tagA, Ref idA, std::optional<std:
 
     // char collection
     obj1 = desFontDict->lookup("CIDSystemInfo");
-    if (!obj1.isDict()) {
+    if (obj1.isDict()) {
+        obj2 = obj1.dictLookup("Registry");
+        obj3 = obj1.dictLookup("Ordering");
+        if (!obj2.isString() || !obj3.isString()) {
+            error(errSyntaxError, -1, "Invalid CIDSystemInfo dictionary in Type 0 descendant font");
+            error(errSyntaxError, -1, "Assuming Adobe-Identity for character collection");
+            obj2 = Object(new GooString("Adobe"));
+            obj3 = Object(new GooString("Identity"));
+        }
+        collection = obj2.getString()->copy()->append('-')->append(obj3.getString());
+    } else {
         error(errSyntaxError, -1, "Missing CIDSystemInfo dictionary in Type 0 descendant font");
-        return;
-    }
-    obj2 = obj1.dictLookup("Registry");
-    obj3 = obj1.dictLookup("Ordering");
-    if (!obj2.isString() || !obj3.isString()) {
-        error(errSyntaxError, -1, "Invalid CIDSystemInfo dictionary in Type 0 descendant font");
-        return;
+        error(errSyntaxError, -1, "Assuming Adobe-Identity for character collection");
+        collection = new GooString("Adobe-Identity");
     }
-    collection = obj2.getString()->copy()->append('-')->append(obj3.getString());
 
     // look for a ToUnicode CMap
     if (!(ctu = readToUnicodeCMap(fontDict, 16, nullptr))) {