From bfda94151950c9dfd930e1d780d6f16b2dfd4501 Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Thu, 2 Apr 2020 20:10:31 -0400
Subject: Use an unordered map for SparseOHArray for efficiency

This was added in C++11.
---
 libqpdf/SparseOHArray.cc      | 16 ++++++----------
 libqpdf/qpdf/SparseOHArray.hh |  6 +++---
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/libqpdf/SparseOHArray.cc b/libqpdf/SparseOHArray.cc
index 05b44ee0..48ddce0f 100644
--- a/libqpdf/SparseOHArray.cc
+++ b/libqpdf/SparseOHArray.cc
@@ -30,8 +30,7 @@ SparseOHArray::at(size_t idx) const
 	throw std::logic_error(
 	    "INTERNAL ERROR: bounds error accessing SparseOHArray element");
     }
-    std::map<size_t, QPDFObjectHandle>::const_iterator iter =
-        this->elements.find(idx);
+    auto iter = this->elements.find(idx);
     if (iter == this->elements.end())
     {
         return QPDFObjectHandle::newNull();
@@ -58,8 +57,7 @@ SparseOHArray::remove_last()
 void
 SparseOHArray::releaseResolved()
 {
-    for (std::map<size_t, QPDFObjectHandle>::iterator iter =
-             this->elements.begin();
+    for (auto iter = this->elements.begin();
 	 iter != this->elements.end(); ++iter)
     {
 	QPDFObjectHandle::ReleaseResolver::releaseResolved((*iter).second);
@@ -90,9 +88,8 @@ SparseOHArray::erase(size_t idx)
     {
 	throw std::logic_error("bounds error erasing item from SparseOHArray");
     }
-    std::map<size_t, QPDFObjectHandle> dest;
-    for (std::map<size_t, QPDFObjectHandle>::iterator iter =
-             this->elements.begin();
+    decltype(this->elements) dest;
+    for (auto iter = this->elements.begin();
 	 iter != this->elements.end(); ++iter)
     {
         if ((*iter).first < idx)
@@ -122,9 +119,8 @@ SparseOHArray::insert(size_t idx, QPDFObjectHandle oh)
     }
     else
     {
-        std::map<size_t, QPDFObjectHandle> dest;
-        for (std::map<size_t, QPDFObjectHandle>::iterator iter =
-                 this->elements.begin();
+        decltype(this->elements) dest;
+        for (auto iter = this->elements.begin();
              iter != this->elements.end(); ++iter)
         {
             if ((*iter).first < idx)
diff --git a/libqpdf/qpdf/SparseOHArray.hh b/libqpdf/qpdf/SparseOHArray.hh
index 6cd30ece..f23a871b 100644
--- a/libqpdf/qpdf/SparseOHArray.hh
+++ b/libqpdf/qpdf/SparseOHArray.hh
@@ -2,7 +2,7 @@
 #define QPDF_SPARSEOHARRAY_HH
 
 #include <qpdf/QPDFObjectHandle.hh>
-#include <map>
+#include <unordered_map>
 
 class SparseOHArray
 {
@@ -26,14 +26,14 @@ class SparseOHArray
     QPDF_DLL
     void insert(size_t idx, QPDFObjectHandle oh);
 
-    typedef std::map<size_t, QPDFObjectHandle>::const_iterator const_iterator;
+    typedef std::unordered_map<size_t, QPDFObjectHandle>::const_iterator const_iterator;
     QPDF_DLL
     const_iterator begin() const;
     QPDF_DLL
     const_iterator end() const;
 
   private:
-    std::map<size_t, QPDFObjectHandle> elements;
+    std::unordered_map<size_t, QPDFObjectHandle> elements;
     size_t n_elements;
 };
 
-- 
cgit v1.2.3-54-g00ecf