nSharedGroups doesn't need to be a class member

And also mark some variables as const to make it easier to see they don't change
diff --git a/poppler/Hints.cc b/poppler/Hints.cc
index ad670c8..7f11304 100644
--- a/poppler/Hints.cc
+++ b/poppler/Hints.cc
@@ -141,7 +141,6 @@
   memset(numSharedObject, 0, nPages * sizeof(Guint));
   memset(pageObjectNum, 0, nPages * sizeof(int));
 
-  nSharedGroups = 0;
   groupLength = NULL;
   groupOffset = NULL;
   groupHasSignature = NULL;
@@ -351,34 +350,30 @@
 {
   StreamBitReader sbr(str);
 
-  Guint firstSharedObjectNumber = sbr.readBits(32);
+  const Guint firstSharedObjectNumber = sbr.readBits(32);
 
-  Guint firstSharedObjectOffset = sbr.readBits(32);
-  firstSharedObjectOffset += hintsLength;
+  const Guint firstSharedObjectOffset = sbr.readBits(32) + hintsLength;
 
-  Guint nSharedGroupsFirst = sbr.readBits(32);
+  const Guint nSharedGroupsFirst = sbr.readBits(32);
 
-  Guint nSharedGroups = sbr.readBits(32);
+  const Guint nSharedGroups = sbr.readBits(32);
 
-  Guint nBitsNumObjects = sbr.readBits(16);
+  const Guint nBitsNumObjects = sbr.readBits(16);
 
-  Guint groupLengthLeast = sbr.readBits(32);
+  const Guint groupLengthLeast = sbr.readBits(32);
 
-  Guint nBitsDiffGroupLength = sbr.readBits(16);
+  const Guint nBitsDiffGroupLength = sbr.readBits(16);
 
   if ((!nSharedGroups) || (nSharedGroups >= INT_MAX / (int)sizeof(Guint))) {
      error(errSyntaxWarning, -1, "Invalid number of shared object groups");
-     nSharedGroups = 0;
      return gFalse;
   }
   if ((!nSharedGroupsFirst) || (nSharedGroupsFirst > nSharedGroups)) {
      error(errSyntaxWarning, -1, "Invalid number of first page shared object groups");
-     nSharedGroups = 0;
      return gFalse;
   }
   if (nBitsNumObjects > 32 || nBitsDiffGroupLength > 32) {
      error(errSyntaxWarning, -1, "Invalid shared object groups bit length");
-     nSharedGroups = 0;
      return gFalse;
   }
 
@@ -390,7 +385,6 @@
   if (!groupLength || !groupOffset || !groupHasSignature ||
       !groupNumObjects || !groupXRefOffset) {
      error(errSyntaxWarning, -1, "Failed to allocate memory for shared object groups");
-     nSharedGroups = 0;
      return gFalse;
   }
 
diff --git a/poppler/Hints.h b/poppler/Hints.h
index d0a2e7d..f9d05da 100644
--- a/poppler/Hints.h
+++ b/poppler/Hints.h
@@ -79,7 +79,6 @@
   Guint *numSharedObject;
   Guint **sharedObjectId;
 
-  Guint nSharedGroups;
   Guint *groupLength;
   Guint *groupOffset;
   Guint *groupHasSignature;