Attachment 136832 Details for Bug 104565 – GfxFontDict: merge reference generation from xpdf 4.00

[patch] GfxFontDict: merge reference generation from xpdf 4.00

GfxFontDict-merge-reference-generation-from-xpdf-4.patch (text/plain), 4.41 KB, created by Jason Crain on 2018-01-18 18:02:05 UTC

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Creator: Jason Crain

Created: 2018-01-18 18:02:05 UTC

Size: 4.41 KB

patch

obsolete

>From 5d7dae4cac91b2d983a2dc07cec26295da9eb6f6 Mon Sep 17 00:00:00 2001
>From: Jason Crain <jason@inspiresomeone.us>
>Date: Thu, 18 Jan 2018 11:57:33 -0600
>Subject: [PATCH] GfxFontDict: merge reference generation from xpdf 4.00
>
>The GfxFontDict constructor generates a fake indirect reference if the
>font dictionary doesn't have a real indirect reference.  It sometimes
>assigns the same reference to two different fonts leading to a wrong
>font being used.  XPDF 4.00 fixes this by using the hash of the font
>data to create the fake reference.
>
>https://bugs.freedesktop.org/show_bug.cgi?id=104565
>---
> poppler/GfxFont.cc | 125 +++++++++++++++++++++++++++++++++++++++++++++++++----
> poppler/GfxFont.h  |   4 ++
> 2 files changed, 120 insertions(+), 9 deletions(-)
>
>diff --git a/poppler/GfxFont.cc b/poppler/GfxFont.cc
>index 27be71d0..9ef26234 100644
>--- a/poppler/GfxFont.cc
>+++ b/poppler/GfxFont.cc
>@@ -2443,16 +2443,16 @@ GfxFontDict::GfxFontDict(XRef *xref, Ref *fontDictRef, Dict *fontDict) {
>     if (obj2.isDict()) {
>       if (obj1.isRef()) {
> 	r = obj1.getRef();
>-      } else {
>-	// no indirect reference for this font, so invent a unique one
>-	// (legal generation numbers are five digits, so any 6-digit
>-	// number would be safe)
>+      } else if (fontDictRef) {
>+	// legal generation numbers are five digits, so we use a
>+	// 6-digit number here
>+	r.gen = 100000 + fontDictRef->num;
> 	r.num = i;
>-	if (fontDictRef) {
>-	  r.gen = 100000 + fontDictRef->num;
>-	} else {
>-	  r.gen = 999999;
>-	}
>+      } else {
>+	// no indirect reference for this font, or for the containing
>+	// font dict, so hash the font and use that
>+	r.gen = 100000;
>+	r.num = hashFontObject(&obj2);
>       }
>       fonts[i] = GfxFont::makeFont(xref, fontDict->getKey(i),
> 				   r, obj2.getDict());
>@@ -2492,3 +2492,110 @@ GfxFont *GfxFontDict::lookup(char *tag) {
>   }
>   return nullptr;
> }
>+
>+// FNV-1a hash
>+class FNVHash {
>+public:
>+
>+  FNVHash() {
>+    h = 2166136261U;
>+  }
>+
>+  void hash(char c) {
>+    h ^= c & 0xff;
>+    h *= 16777619;
>+  }
>+
>+  void hash(char *p, int n) {
>+    int i;
>+    for (i = 0; i < n; ++i) {
>+      hash(p[i]);
>+    }
>+  }
>+
>+  int get31() {
>+    return (h ^ (h >> 31)) & 0x7fffffff;
>+  }
>+
>+private:
>+
>+  Guint h;
>+};
>+
>+int GfxFontDict::hashFontObject(Object *obj) {
>+  FNVHash h;
>+
>+  hashFontObject1(obj, &h);
>+  return h.get31();
>+}
>+
>+void GfxFontDict::hashFontObject1(Object *obj, FNVHash *h) {
>+  Object obj2;
>+  GooString *s;
>+  char *p;
>+  double r;
>+  int n, i;
>+
>+  switch (obj->getType()) {
>+  case objBool:
>+    h->hash('b');
>+    h->hash(obj->getBool() ? 1 : 0);
>+    break;
>+  case objInt:
>+    h->hash('i');
>+    n = obj->getInt();
>+    h->hash((char *)&n, sizeof(int));
>+    break;
>+  case objReal:
>+    h->hash('r');
>+    r = obj->getReal();
>+    h->hash((char *)&r, sizeof(double));
>+    break;
>+  case objString:
>+    h->hash('s');
>+    s = obj->getString();
>+    h->hash(s->getCString(), s->getLength());
>+    break;
>+  case objName:
>+    h->hash('n');
>+    p = obj->getName();
>+    h->hash(p, (int)strlen(p));
>+    break;
>+  case objNull:
>+    h->hash('z');
>+    break;
>+  case objArray:
>+    h->hash('a');
>+    n = obj->arrayGetLength();
>+    h->hash((char *)&n, sizeof(int));
>+    for (i = 0; i < n; ++i) {
>+      obj2 = obj->arrayGetNF(i);
>+      hashFontObject1(&obj2, h);
>+    }
>+    break;
>+  case objDict:
>+    h->hash('d');
>+    n = obj->dictGetLength();
>+    h->hash((char *)&n, sizeof(int));
>+    for (i = 0; i < n; ++i) {
>+      p = obj->dictGetKey(i);
>+      h->hash(p, (int)strlen(p));
>+      obj2 = obj->dictGetValNF(i);
>+      hashFontObject1(&obj2, h);
>+    }
>+    break;
>+  case objStream:
>+    // this should never happen - streams must be indirect refs
>+    break;
>+  case objRef:
>+    h->hash('f');
>+    n = obj->getRefNum();
>+    h->hash((char *)&n, sizeof(int));
>+    n = obj->getRefGen();
>+    h->hash((char *)&n, sizeof(int));
>+    break;
>+  default:
>+    h->hash('u');
>+    break;
>+  }
>+}
>diff --git a/poppler/GfxFont.h b/poppler/GfxFont.h
>index 00df389a..e082cdde 100644
>--- a/poppler/GfxFont.h
>+++ b/poppler/GfxFont.h
>@@ -48,6 +48,7 @@ class FoFiTrueType;
> class PSOutputDev;
> struct GfxFontCIDWidths;
> struct Base14FontMapEntry;
>+class FNVHash;
> 
> //------------------------------------------------------------------------
> // GfxFontType
>@@ -458,6 +459,9 @@ public:
> 
> private:
> 
>+  int hashFontObject(Object *obj);
>+  void hashFontObject1(Object *obj, FNVHash *h);
>+
>   GfxFont **fonts;		// list of fonts
>   int numFonts;			// number of fonts
> };
>-- 
>2.15.1

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Attachments on bug 104565: 136640 | 136641 | 136642 | 136832

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