From ee45da7befa4b5dcc28105df13b6248029dbf036 Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Fri, 22 Sep 2017 19:28:25 -0400
Subject: RAII for Power_Mod class

---
 src/lib/math/numbertheory/pow_mod.cpp | 33 +++++++++------------------------
 src/lib/math/numbertheory/pow_mod.h   |  4 ++--
 2 files changed, 11 insertions(+), 26 deletions(-)

(limited to 'src/lib/math')

diff --git a/src/lib/math/numbertheory/pow_mod.cpp b/src/lib/math/numbertheory/pow_mod.cpp
index e4fed9925..1a03767b8 100644
--- a/src/lib/math/numbertheory/pow_mod.cpp
+++ b/src/lib/math/numbertheory/pow_mod.cpp
@@ -15,7 +15,6 @@ namespace Botan {
 */
 Power_Mod::Power_Mod(const BigInt& n, Usage_Hints hints, bool disable_monty)
    {
-   m_core = nullptr;
    set_modulus(n, hints, disable_monty);
    }
 
@@ -24,9 +23,8 @@ Power_Mod::Power_Mod(const BigInt& n, Usage_Hints hints, bool disable_monty)
 */
 Power_Mod::Power_Mod(const Power_Mod& other)
    {
-   m_core = nullptr;
-   if(other.m_core)
-      m_core = other.m_core->copy();
+   if(other.m_core.get())
+      m_core.reset(other.m_core->copy());
    }
 
 /*
@@ -36,25 +34,14 @@ Power_Mod& Power_Mod::operator=(const Power_Mod& other)
    {
    if(this != &other)
       {
-      delete m_core;
-      m_core = nullptr;
       if(other.m_core)
-         {
-         m_core = other.m_core->copy();
-         }
+         m_core.reset(other.m_core->copy());
+      else
+         m_core.reset();
       }
    return (*this);
    }
 
-/*
-* Power_Mod Destructor
-*/
-Power_Mod::~Power_Mod()
-   {
-   delete m_core;
-   m_core = nullptr;
-   }
-
 /*
 * Set the modulus
 */
@@ -62,16 +49,14 @@ void Power_Mod::set_modulus(const BigInt& n, Usage_Hints hints, bool disable_mon
    {
    // Allow set_modulus(0) to mean "drop old state"
 
-   delete m_core;
-   m_core = nullptr;
+   m_core.reset();
 
    if(n != 0)
       {
       if(n.is_odd() && disable_monty == false)
-         m_core = new Montgomery_Exponentiator(n, hints);
-
-      if(!m_core)
-         m_core = new Fixed_Window_Exponentiator(n, hints);
+         m_core.reset(new Montgomery_Exponentiator(n, hints));
+      else
+         m_core.reset(new Fixed_Window_Exponentiator(n, hints));
       }
    }
 
diff --git a/src/lib/math/numbertheory/pow_mod.h b/src/lib/math/numbertheory/pow_mod.h
index 7613c2ddf..cca99b714 100644
--- a/src/lib/math/numbertheory/pow_mod.h
+++ b/src/lib/math/numbertheory/pow_mod.h
@@ -93,9 +93,9 @@ class BOTAN_PUBLIC_API(2,0) Power_Mod
                 Usage_Hints hints = NO_HINTS,
                 bool disable_montgomery_arith = false);
       Power_Mod(const Power_Mod&);
-      virtual ~Power_Mod();
+      virtual ~Power_Mod() {}
    private:
-      mutable Modular_Exponentiator* m_core;
+      mutable std::unique_ptr<Modular_Exponentiator> m_core;
    };
 
 /**
-- 
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