From 9468d6381997dedaf3330f0c6e1b4290a9af1345 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Mon, 16 Dec 2019 10:17:43 -0500
Subject: allow comparison of any numeric types

---
 src/bigint.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'src/bigint.cpp')

diff --git a/src/bigint.cpp b/src/bigint.cpp
index 6c74b5f64a..1127033d02 100644
--- a/src/bigint.cpp
+++ b/src/bigint.cpp
@@ -1759,3 +1759,27 @@ void bigint_incr(BigInt *x) {
     bigint_add(x, &copy, &one);
 }
 
+void bigint_decr(BigInt *x) {
+    if (x->digit_count == 0) {
+        bigint_init_signed(x, -1);
+        return;
+    }
+
+    if (x->digit_count == 1) {
+        if (x->is_negative && x->data.digit != UINT64_MAX) {
+            x->data.digit += 1;
+            return;
+        } else if (!x->is_negative && x->data.digit != 0) {
+            x->data.digit -= 1;
+            return;
+        }
+    }
+
+    BigInt copy;
+    bigint_init_bigint(&copy, x);
+
+    BigInt neg_one;
+    bigint_init_signed(&neg_one, -1);
+
+    bigint_add(x, &copy, &neg_one);
+}
-- 
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