resta corregida + un par de asserts

diff --git a/src/number.h b/src/number.h
index 71705cc9512a61b0430d7fb69b43a48094d438ff..27d19a848d027b2d59f9d783dcaf8b7b328f7eca 100644 (file)
--- a/src/number.h
+++ b/src/number.h
@@ -132,19 +132,18 @@ struct number
        // borrow)
        void borrow(size_type i)
        {
-               if (chunk.size() >= i)
+               // para poder pedir prestado debo tener uno a la izquierda
+               assert (chunk.size() >= i);
+               
+               if (chunk[i] == 0)
                {
-                       if (chunk[i] == 0)
-                       {
-                               borrow(i+1); // Overflow, pido prestado
-                               chunk[i] = ~((N)0); //quedo con el valor máximo
-                       }
-                       else
-                       {
-                               --chunk[i]; //tengo para dar, pero pierdo uno yo
-                       }
+                       borrow(i+1); // Overflow, pido prestado
+                       chunk[i] = ~((N)0); //quedo con el valor máximo
+               }
+               else
+               {
+                       --chunk[i]; //tengo para dar, pero pierdo uno yo
                }
-               //else ERROR, están haciendo a-b con a>b
        }
        // Verifica si es un número par
        bool es_impar() const
@@ -326,11 +325,17 @@ number< N, E >& number< N, E >::operator-= (const number< N, E >& n)
                // si no alcanza para restar pido prestado
                if ((minuend.chunk[i] < subtrahend.chunk[i]))
                {
-                       minuend.borrow(i);
+                       // no puedo pedir si soy el más significativo ...
+                       assert (i != fin);
+
+                       // le pido uno al que me sigue
+                       minuend.borrow(i+1);
                }
                
-               // resto el chunk i-ésimo
-               minuend.chunk[i] -= subtrahend.chunk[i];
+               // es como hacer 24-5: el 4 pide prestado al 2 (borrow(i+1)) y después
+               // se hace 4 + (9-5) + 1
+
+               minuend.chunk[i] += (~((N)0) - subtrahend.chunk[i]) + 1; 
        }
 
        //retorno el minuendo ya restado
@@ -397,17 +402,17 @@ number< N, E > operator<< (const number< N, E >& n, typename number< N, E >::siz
        return tmp;
 }
 
-template < typename N, typename E >
-std::ostream& operator<< (std::ostream& os, const number< N, E >& n)
+template < typename NN, typename EE >
+std::ostream& operator<< (std::ostream& os, const number< NN, EE >& n)
 {
        // FIXME sacar una salida bonita en ASCII =)
        if (n.sign == positive)
                os << "+ ";
        else
                os << "- ";
-       for (typename number< N, E >::const_reverse_iterator i = n.chunk.rbegin();
+       for (typename number< NN, EE >::const_reverse_iterator i = n.chunk.rbegin();
                        i != n.chunk.rend(); ++i)
-               os << std::setfill('0') << std::setw(sizeof(N) * 2) << std::hex
+               os << std::setfill('0') << std::setw(sizeof(NN) * 2) << std::hex
                        << *i << " ";
        return os;
 }

diff --git a/tests/number.cpp b/tests/number.cpp
index fc74c5501d832ac03fe3877850cac78f86c6eae2..3b9d1b591e0a428617532cdc597644741a55f21f 100644 (file)
--- a/tests/number.cpp
+++ b/tests/number.cpp
@@ -4,7 +4,7 @@
 int main()
 {
 #if 0
-       unsigned buf[5] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0 };
+       unsigned long buf[5] = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff, 0 };
        //unsigned buf[3] = { 0xffffffff, 0x1, 0 };
        number<> nu(buf, 4);
        //number< unsigned > nu2(nu);
@@ -18,18 +18,25 @@ int main()
 
 #if 0
        number< unsigned > nu = 0xffffffff;
-       std::cout << "nu = " << nu << "\n\n";
+       std::cout << "nu = " << nu ;
 
        nu << 5;
-       std::cout << "nu = " << nu << "\n\n";
+       std::cout << "nu = " << nu ;
 
-       number<> n1 = 0x00000000;
-       number<> n2 = 0x00000000;
+       number<> n1 = 0xFFFFFFFF;
+       number<> n2 = 0xFFFFFFFF;
 
-       n2 += 1;
+       n1 += 1;
 
-       n1 <<= 1;
-       n2 <<= 1;
+/*     for (int k = 0; k < 100; k++)
+       {
+               n1 += (unsigned) rand() * k;
+               n2 += (unsigned) rand() * k;
+       }
+*/
+       
+//     n1 <<= 1;
+//     n2 <<= 1;
 
        if (n1 < n2)
                std::cout << "n1 es menor que n2\n";
@@ -54,12 +61,47 @@ int main()
        std::cout << "n1-n2: " << n1 ;
 #endif
 
+#if 1
        uint32_t buf[] = { 0x00000040, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000 };
-       number<> nu(buf, 8);
+       number<> nu(buf, 8, negative);
        number<> nu2 = 0x2;
-       std::cout << "nu = " << nu << "\n\n";
-       std::cout << "nu2 = " << nu2 << "\n\n";
-       std::cout << "nu * nu2 = "  << naif(nu, nu2) << "\n\n";
+       std::cout << "nu = " << nu ;
+       std::cout << "\n";
+       std::cout << "nu2 = " << nu2 ;
+       std::cout << "\n";
+       std::cout << "nu * nu2 = "  << naif(nu, nu2) ;
+       std::cout << "\n";
+       std::cout << "nu + nu2 = "  << nu + nu2 ;
+       std::cout << "\n";
+       std::cout << "nu - nu2 = "  << nu - nu2 ;
+
+#endif
+
+       number<> h = 0x10000000;
+       h<<=1;
+       h += 0xfffffffc;
+       h<<=1;
+       h += 0xffffffff;
+       h<<=1;
+       h += 0x00000002;
+       number<> d = 0;
+       number<> m = 0xfffffffe;
+       m<<=1;
+       m += 0xffffffff;
+       m<<=1;
+       m += 0x00000001;
+
+       std::cout << "h: " << h ;
+       std::cout << "\n";
+       std::cout << "d: " << d ;
+       std::cout << "\n";
+       std::cout << "m: " << m ;
+       std::cout << "\n";
+
+       number<> a = h - d - m;
+
+       std::cout << "h-d-m: " << a ;
+
 
        return 0;
 }