Added the left-shift computation

Signed-off-by: Olivier Gayot <og@satcom1.com>

2 files changed, 50 insertions, 0 deletions

diff --git a/number.cpp b/number.cpp
index d16f37f..497cf64 100644
--- a/number.cpp
+++ b/number.cpp
@@ -106,6 +106,33 @@ number::operator*(const number &n) const
     return result;
 }
 
+number
+number::operator<<(std::uint32_t shift) const
+{
+    if (shift > 32) {
+        /* TODO */
+        throw std::out_of_range("> 32");
+    }
+
+    number result(*this);
+
+    std::uint32_t carry = 0;
+
+    for (auto &operand: result._operands) {
+        std::uint32_t tmp = ((1ull * operand) << shift) + carry;
+
+        carry = ((1ull * operand) >> (32 - shift));
+
+        operand = tmp;
+    }
+
+    if (carry) {
+        result._operands.push_back(carry);
+    }
+
+    return result;
+}
+
 /* }}} */
 /* Comparison operators {{{ */
 
@@ -174,6 +201,14 @@ number::operator+=(const number &n)
 }
 
 number &
+number::operator<<=(std::uint32_t n)
+{
+    *this = *this << n;
+
+    return *this;
+}
+
+number &
 number::operator++()
 {
     *this = *this + 1;
diff --git a/number.h b/number.h
index d93ed70..16fcea6 100644
--- a/number.h
+++ b/number.h
@@ -49,6 +49,14 @@ public:
     number operator*(const number &) const;
 
     /**
+     * \brief Return a number equals to this number where n bits have been
+     * shifted to the left.
+     *
+     * \param n Number of bits to shift.
+     */
+    number operator<<(std::uint32_t n) const;
+
+    /**
      * \brief Tells whether the number passed as parameter is strictly less
      * than this number.
      *
@@ -104,6 +112,13 @@ public:
     number &operator+=(const number &n);
 
     /**
+     * \brief Shift the number n bits to the left.
+     *
+     * \param n Number of bits to shift.
+     */
+    number &operator<<=(std::uint32_t);
+
+    /**
      * \brief Increment this number.
      */
     number &operator++();