From 8ed3e8c79b5cbccfeccee865e555b68025ee2c1f Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Mon, 25 Jan 2021 08:05:43 -0500
Subject: NNTree: rework iterators to be more memory efficient

Keep a std::pair internal to the iterators so that operator* can
return a reference and operator-> can work, and each can work without
copying pairs of objects around.
---
 include/qpdf/QPDFNameTreeObjectHelper.hh   | 8 +++++---
 include/qpdf/QPDFNumberTreeObjectHelper.hh | 8 +++++---
 2 files changed, 10 insertions(+), 6 deletions(-)

(limited to 'include')

diff --git a/include/qpdf/QPDFNameTreeObjectHelper.hh b/include/qpdf/QPDFNameTreeObjectHelper.hh
index aa1955ed..18156768 100644
--- a/include/qpdf/QPDFNameTreeObjectHelper.hh
+++ b/include/qpdf/QPDFNameTreeObjectHelper.hh
@@ -75,9 +75,6 @@ class QPDFNameTreeObjectHelper: public QPDFObjectHelper
 
     class iterator: public std::iterator<
         std::bidirectional_iterator_tag,
-        std::pair<std::string, QPDFObjectHandle>,
-        void,
-        std::pair<std::string, QPDFObjectHandle>*,
         std::pair<std::string, QPDFObjectHandle>>
     {
         friend class QPDFNameTreeObjectHelper;
@@ -105,6 +102,8 @@ class QPDFNameTreeObjectHelper: public QPDFObjectHelper
         QPDF_DLL
         reference operator*();
         QPDF_DLL
+        pointer operator->();
+        QPDF_DLL
         bool operator==(iterator const& other) const;
         QPDF_DLL
         bool operator!=(iterator const& other) const
@@ -131,8 +130,11 @@ class QPDFNameTreeObjectHelper: public QPDFObjectHelper
         void remove();
 
       private:
+        void updateIValue();
+
         iterator(std::shared_ptr<NNTreeIterator> const&);
         std::shared_ptr<NNTreeIterator> impl;
+        value_type ivalue;
     };
 
     // The iterator looks like map iterator, so i.first is a string
diff --git a/include/qpdf/QPDFNumberTreeObjectHelper.hh b/include/qpdf/QPDFNumberTreeObjectHelper.hh
index 70695327..7343978b 100644
--- a/include/qpdf/QPDFNumberTreeObjectHelper.hh
+++ b/include/qpdf/QPDFNumberTreeObjectHelper.hh
@@ -94,9 +94,6 @@ class QPDFNumberTreeObjectHelper: public QPDFObjectHelper
 
     class iterator: public std::iterator<
         std::bidirectional_iterator_tag,
-        std::pair<numtree_number, QPDFObjectHandle>,
-        void,
-        std::pair<numtree_number, QPDFObjectHandle>*,
         std::pair<numtree_number, QPDFObjectHandle>>
     {
         friend class QPDFNumberTreeObjectHelper;
@@ -124,6 +121,8 @@ class QPDFNumberTreeObjectHelper: public QPDFObjectHelper
         QPDF_DLL
         reference operator*();
         QPDF_DLL
+        pointer operator->();
+        QPDF_DLL
         bool operator==(iterator const& other) const;
         QPDF_DLL
         bool operator!=(iterator const& other) const
@@ -150,8 +149,11 @@ class QPDFNumberTreeObjectHelper: public QPDFObjectHelper
         void remove();
 
       private:
+        void updateIValue();
+
         iterator(std::shared_ptr<NNTreeIterator> const&);
         std::shared_ptr<NNTreeIterator> impl;
+        value_type ivalue;
     };
 
     // The iterator looks like map iterator, so i.first is a string
-- 
cgit v1.2.3-70-g09d2