X-Git-Url: https://ginac.de/ginac.git//ginac.git?a=blobdiff_plain;f=ginac%2Fex.h;h=af5cac31d7cecc73b0f6012260a02dae3f8dbb96;hb=09f37bdbd46f469b3a8a902a43d0f795c41a89bf;hp=c76290ff1ceb0a04a2dbdc21597d1e49ecffa8ca;hpb=cfea748404dec5fb2f2e3310d36eeb6640f13824;p=ginac.git

diff --git a/ginac/ex.h b/ginac/ex.h
index c76290ff..af5cac31 100644
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -3,7 +3,7 @@
  *  Interface to GiNaC's light-weight expression handles. */
 
 /*
- *  GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2002 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -23,11 +23,11 @@
 #ifndef __GINAC_EX_H__
 #define __GINAC_EX_H__
 
-#include "basic.h"
-#include "operators.h"
-
+#include <iosfwd>
 #include <functional>
 
+#include "basic.h"
+
 namespace GiNaC {
 
 /** Helper class to initialize the library.  There must be one static object
@@ -96,7 +96,19 @@ public:
 	
 	// non-virtual functions in this class
 public:
-	void swap(ex & other);
+	/** Efficiently swap the contents of two expressions. */
+	void swap(ex & other)
+	{
+		GINAC_ASSERT(bp!=0);
+		GINAC_ASSERT(bp->flags & status_flags::dynallocated);
+		GINAC_ASSERT(other.bp!=0);
+		GINAC_ASSERT(other.bp->flags & status_flags::dynallocated);
+	
+		basic * tmpbp = bp;
+		bp = other.bp;
+		other.bp = tmpbp;
+	}
+
 	void print(const print_context & c, unsigned level = 0) const;
 	void printtree(std::ostream & os) const;
 	void dbgprint(void) const;
@@ -195,9 +207,10 @@ protected:
 
 // member variables
 
-public:
-	basic *bp;      ///< pointer to basic object managed by this, direct manipulation deprecated
+private:
+	basic *bp;      ///< pointer to basic object managed by this
 #ifdef OBSCURE_CINT_HACK
+public:
 	static basic * last_created_or_assigned_bp;
 	static basic * dummy_bp;
 	static long last_created_or_assigned_exp;
@@ -343,6 +356,11 @@ bool ex::is_equal(const ex & other) const
 
 
 // utility functions
+
+/** Compare two objects of class quickly without doing a deep tree traversal.
+ *  @return "true" if they are equal
+ *          "false" if equality cannot be established quickly (e1 and e2 may
+ *          still be equal, in this case. */
 inline bool are_ex_trivially_equal(const ex &e1, const ex &e2)
 {
 	return e1.bp == e2.bp;
@@ -451,6 +469,10 @@ inline bool is_zero(const ex & thisex)
 inline void swap(ex & e1, ex & e2)
 { e1.swap(e2); }
 
+// This makes STL algorithms use the more efficient swap operation for ex objects
+inline void iter_swap(std::vector<ex>::iterator i1, std::vector<ex>::iterator i2)
+{ i1->swap(*i2); }
+
 
 /* Function objects for STL sort() etc. */
 struct ex_is_less : public std::binary_function<ex, ex, bool> {