resolving merge conflicts

pholser · May 30, 2012 · 98ea0df · 98ea0df
2 parents 81afe3b + 891f43e
commit 98ea0df
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Showing 3 changed files with 32 additions and 12 deletions.
diff --git a/Bignum.cpp b/Bignum.cpp
@@ -133,16 +133,15 @@ Bignum operator+(const Bignum& left, const Bignum& right) {
 }
 
 const Bignum& Bignum::operator+=(const Bignum& other) {
-    if (other.sign == 0) {
+    if (other.sign == 0)
         return *this;
-    }
 
     Bignum this_abs = abs();
     Bignum other_abs = other.abs();
 
-    if (sign == other.sign) {
+    if (sign == other.sign)
         store = add(this_abs.store, other_abs.store);
-    } else {
+    else {
         if (this_abs > other_abs)
             store = subtract(this_abs.store, other_abs.store);
         else {
@@ -161,16 +160,15 @@ Bignum operator-(const Bignum& left, const Bignum& right) {
 }
 
 const Bignum& Bignum::operator-=(const Bignum& other) {
-    if (other.sign == 0) {
+    if (other.sign == 0)
         return *this;
-    }
 
     Bignum this_abs = abs();
     Bignum other_abs = other.abs();
 
-    if (sign != other.sign) {
+    if (sign != other.sign)
         store = add(this_abs.store, other_abs.store);
-    } else {
+    else {
         if (this_abs > other_abs)
             store = subtract(this_abs.store, other_abs.store);
         else {
@@ -189,7 +187,15 @@ Bignum operator>>(const Bignum& b, unsigned int n) {
 }
 
 const Bignum& Bignum::operator>>=(unsigned int n) {
-    store[0] >>= n;
+    uint32_t leading(0);
+    uint32_t trailing(0);
+
+    for (std::vector<uint32_t>::reverse_iterator i = store.rbegin(); i != store.rend(); ++i) {
+        trailing = *i & ((1 << n) - 1);
+        *i >>= n;
+        *i |= leading;
+        leading = trailing << (sizeof(uint32_t) * CHAR_BIT - n);
+    }
 
     reconcile_sign_of_zero();
 

diff --git a/Bignum.h b/Bignum.h
@@ -17,11 +17,11 @@ class Bignum {
         const Bignum& operator+=(const Bignum& other);
         const Bignum& operator-=(const Bignum& other);
         const Bignum& operator>>=(unsigned int n);
-        bool equal(const Bignum& other) const;
-        bool less(const Bignum& other) const;
         Bignum operator-() const;
         Bignum abs() const;
 
+        bool equal(const Bignum& other) const;
+        bool less(const Bignum& other) const;
         int signum() const;
 
         friend std::ostream& operator<<(std::ostream& out, const Bignum& n);

diff --git a/Bignum_unittest.cpp b/Bignum_unittest.cpp
@@ -464,7 +464,6 @@ TEST(BignumTest, RightShiftNegativeOneByOne) {
     ASSERT_EQ(Bignum(d(1, 0x0U), 0), n);
 }
 
-
 TEST(BignumTest, RightShiftNegativeOneByOneWithAssignment) {
     Bignum m(d(1, 0x1U), -1);
     m >>= 1;
@@ -485,3 +484,18 @@ TEST(BignumTest, RightShiftByFifteenWithAssignment) {
 
     ASSERT_EQ(Bignum(d(1, 0x00011312U), 1), m);
 }
+
+TEST(BignumTest, RightShiftMultipleDigits) {
+    Bignum m(d(3, 0x01234567U, 0x89ABCDEFU, 0x78784949U), 1);
+    Bignum n(m >> 7);
+
+    ASSERT_EQ(Bignum(d(3, 0xDE02468AU, 0x9313579BU, 0x00F0F092U), 1), n);
+}
+
+TEST(BignumTest, RightShiftMultipleDigitsWithAssignment) {
+    Bignum m(d(3, 0x00000034U, 0xC08905EAU, 0x4892BEADU), 1);
+    m >>= 23;
+
+    ASSERT_EQ(Bignum(d(3, 0x120BD400U, 0x257D5B81U, 0x00000091U), 1), m);
+}
+