From 9a6fa39923e407f55f205c9f35e86b066d591ba9 Mon Sep 17 00:00:00 2001
From: Sebastian Limbach <slimbach@mpi-inf.mpg.de>
Date: Thu, 15 Mar 2007 13:04:32 +0000
Subject: [PATCH] New file for construct_binary functions, containing the new
 general function.

---
 .gitattributes                                |   1 +
 .../Algebraic_kernel_d/construct_binary.h     | 132 ++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/construct_binary.h

diff --git a/.gitattributes b/.gitattributes
index 732d741e08b..13a1d93c124 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -27,6 +27,7 @@ Algebraic_kernel_GBRS/test/Gbrs_polynomial/parsers.h -text
 Algebraic_kernel_d/doc_tex/Algebraic_kernel_d_ref/figures/cpvl.eps -text svneol=unset#application/postscript
 Algebraic_kernel_d/doc_tex/Algebraic_kernel_d_ref/figures/cpvl.fig -text svneol=unset#application/octet-stream
 Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/Descartes.h -text
+Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/construct_binary.h -text
 Algebraic_kernel_d/test/Algebraic_kernel_d/Descartes.cpp -text
 Algebraic_kernel_d/test/Algebraic_kernel_d/include/CGAL/_test_real_root_isolator.h -text
 Alpha_shapes_2/demo/Alpha_shapes_2/alpha_shapes_2.vcproj eol=crlf
diff --git a/Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/construct_binary.h b/Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/construct_binary.h
new file mode 100644
index 00000000000..c59e24a235f
--- /dev/null
+++ b/Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/construct_binary.h
@@ -0,0 +1,132 @@
+// TODO: Add licence
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL:$
+// $Id: $
+// 
+//
+// Author(s)     :  
+//
+// ============================================================================
+
+#ifndef CGAL_ALGEBRAIC_KERNEL_D_CONSTRUCT_BINARY_H
+#define CGAL_ALGEBRAIC_KERNEL_D_CONSTRUCT_BINARY_H
+
+#include <CGAL/basic.h>
+#include <CGAL/Polynomial/ipower.h>
+
+#ifdef CGAL_USE_LEDA
+#include <CGAL/leda_integer.h>
+#include <CGAL/leda_rational.h>
+#endif
+#ifdef CGAL_USE_CORE
+#include <CGAL/CORE_BigInt.h>
+#include <CGAL/CORE_BigRat.h>
+#endif
+
+#include <limits>
+
+CGAL_BEGIN_NAMESPACE
+
+namespace CGALi {
+
+// Generic construct_binary function, using ipower 
+template< class Integer >
+inline void construct_binary( const Integer& e, Integer& x ) {
+    CGAL_precondition( e >= 0 );
+    Integer exponent(e);
+    x = Integer(1);
+    
+    const Integer max_ipower = (exponent > Integer(std::numeric_limits<int>::max())) ?
+                INTERN_POLYNOMIAL::ipower( Integer(2), std::numeric_limits<int>::max() ) : 
+                Integer(0);
+    
+    while( exponent > Integer(std::numeric_limits<int>::max()) ) {
+        x *= max_ipower;
+        exponent -= Integer(std::numeric_limits<int>::max());    
+    }
+    
+    x *= INTERN_POLYNOMIAL::ipower( Integer(2), (int)CGAL::to_double(exponent) );    
+}
+
+template< class Integer, class Rational >
+inline void construct_binary( const Integer& m, const Integer& e, Rational& x ) {
+       Integer den(1), num;
+       if(e>0) {
+          construct_binary( e, num );
+          num *= m;          
+       }
+       else {
+          num = m;
+          construct_binary( -e, den );
+       }
+       x = Rational(num, den);
+}
+
+// Specialization for LEDA
+    
+#ifdef CGAL_USE_LEDA
+    
+    // Constructs 2^e from an integer e. Needed in Descartes
+    inline void construct_binary(const ::leda::integer& e, ::leda::integer& x) {
+       typedef ::leda::integer  Integer;
+       x = Integer(1) << e.to_long();
+    }
+    
+    // Constructs m*2^e from two integers m,e. Needed in Descartes
+    inline void construct_binary(const ::leda::integer& m, const ::leda::integer& e,
+                  ::leda::rational& x) {
+                    
+       typedef ::leda::integer  Integer;
+       typedef ::leda::rational Rational;
+    
+       Integer den(1);
+       Integer num(m);
+       if(e>0) {
+          num <<= e.to_long();
+       }
+       else {
+          den <<= (-e).to_long();
+       }
+       x = Rational(num, den);
+    }
+
+#endif // CGAL_USE_LEDA
+
+// Specialization for CORE
+
+#ifdef CGAL_USE_CORE
+    
+    // Constructs 2^e from an integer e. Needed in Descartes
+    inline void construct_binary(const ::CORE::BigInt& e, ::CORE::BigInt& x) {
+       typedef ::CORE::BigInt Integer;
+       x = Integer(1) << ::CORE::ulongValue(e);
+    }
+    
+    // Constructs m*2^e from two integers m,e. Needed in Descardes
+    inline void construct_binary(const ::CORE::BigInt& m, const ::CORE::BigInt& e, 
+                  ::CORE::BigRat& x) {
+       typedef ::CORE::BigInt Integer;
+       typedef ::CORE::BigRat Rational;
+      
+       Integer den(1);
+       Integer num(m);
+       if(e>0) {
+          num <<= ::CORE::ulongValue(e);
+       }
+       else {
+          den <<= ::CORE::ulongValue(-e);
+       }
+       x = Rational(num, den);
+    }
+    
+#endif // CGAL_USE_CORE
+
+} // namespace CGALi
+
+CGAL_END_NAMESPACE
+
+
+#endif // CGAL_ALGEBRAIC_KERNEL_D_CONSTRUCT_BINARY_H