From 17bd51d1975c45fd68479a41dfee6cf6331846fc Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Fri, 20 Aug 2021 16:51:23 +0200
Subject: [PATCH] abacus: bignum: add equality comparisons

---
 src/bignum/bignum.cc | 11 +++++++++++
 src/bignum/bignum.hh | 10 ++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/bignum/bignum.cc b/src/bignum/bignum.cc
index e47c9b8..4f0c810 100644
--- a/src/bignum/bignum.cc
+++ b/src/bignum/bignum.cc
@@ -27,6 +27,17 @@ BigNum::BigNum(std::int64_t number) {
     assert(is_canonicalized());
 }
 
+bool BigNum::equal(BigNum const& rhs) const {
+    assert(is_canonicalized());
+    assert(rhs.is_canonicalized());
+
+    if (sign_ != rhs.sign_) {
+        return false;
+    }
+
+    return digits_ == rhs.digits_;
+}
+
 void BigNum::canonicalize() {
     auto const it = std::find_if(digits_.rbegin(), digits_.rend(),
                                  [](auto v) { return v != 0; });
diff --git a/src/bignum/bignum.hh b/src/bignum/bignum.hh
index c814e75..e1b13c4 100644
--- a/src/bignum/bignum.hh
+++ b/src/bignum/bignum.hh
@@ -10,7 +10,17 @@ class BigNum {
 public:
     explicit BigNum(std::int64_t number);
 
+    friend bool operator==(BigNum const& lhs, BigNum const& rhs) {
+        return lhs.equal(rhs);
+    }
+
+    friend bool operator!=(BigNum const& lhs, BigNum const& rhs) {
+        return !(lhs == rhs);
+    }
+
 private:
+    bool equal(BigNum const& rhs) const;
+
     void canonicalize();
     bool is_canonicalized() const;