From 404a78943d75dda7573d3324431a21918dbe526f Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Thu, 27 Nov 2025 12:14:59 +0100
Subject: [PATCH] - Somewhat faster BigInt output.

---
 lib/std/math/bigint.c3 | 45 ++++++++++++++++++++++++++++++++++++++----
 releasenotes.md        |  1 +
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/lib/std/math/bigint.c3 b/lib/std/math/bigint.c3
index a08e5d4a4..feb6b8b98 100644
--- a/lib/std/math/bigint.c3
+++ b/lib/std/math/bigint.c3
@@ -508,10 +508,47 @@ fn BigInt BigInt.abs(&self)
 
 fn usz? BigInt.to_format(&self, Formatter* format) @dynamic
 {
-	@stack_mem(4100; Allocator mem)
+	if (self.is_zero())
 	{
-	   return format.print(self.to_string_with_radix(10, mem));
-	};
+		format.print("0")!;
+		return 1;
+	}
+	BigInt a = *self;
+	bool negative = self.is_negative();
+	usz len;
+	if (negative)
+	{
+		format.out('-')!;
+		len++;
+		a.negate();
+	}
+	uint[280] chunks;
+	int chunk_count;
+
+	const BASE10_9 = 1000000000;
+	foreach_r(d : self.data)
+	{
+		ulong carry = d;
+		for (int i = 0; i < chunk_count; i++)
+		{
+			ulong v = chunks[i] * 4294967296ULL + carry;
+			carry = v / BASE10_9;
+			chunks[i] = (uint)(v - carry * BASE10_9);
+		}
+		if (carry)
+		{
+			ulong new_carry = carry / BASE10_9;
+			chunks[chunk_count++] = (uint)(carry - new_carry * BASE10_9);
+			if (new_carry) chunks[chunk_count++] = (uint)new_carry;
+		}
+	}
+	int ms = chunk_count - 1;
+	len += format.printf("%d", chunks[ms])!;
+	foreach_r (c : chunks[:ms])
+	{
+		len += format.printf("%09d", c)!;
+	}
+	return len;
 }
 
 fn String BigInt.to_string(&self, Allocator allocator) @dynamic
@@ -527,7 +564,7 @@ fn String BigInt.to_string_with_radix(&self, int radix, Allocator allocator)
 	if (self.is_zero()) return "0".copy(allocator);
 
 	const char[*] CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-	@stack_mem(4100; Allocator mem)
+	@stack_mem(4120; Allocator mem)
 	{
 		BigInt a = *self;
 		DString str;
diff --git a/releasenotes.md b/releasenotes.md
index 149d23d9f..d76791c5d 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -57,6 +57,7 @@
 - Make printing typeids give some helpful typeid data.
 - Add `NSApplicationTerminateReply` to ns module (macOS).
 - Add `registerClassPair` function to objc module (macOS).
+- Somewhat faster BigInt output.
 
 ## 0.7.7 Change list