From fa2862fa648cca9a181184a849444409d07e9fb2 Mon Sep 17 00:00:00 2001
From: EuAndreh <eu@euandre.org>
Date: Fri, 31 May 2024 11:48:58 -0300
Subject: src/math.h: Add "add_size()"

---
 src/math.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

(limited to 'src/math.c')

diff --git a/src/math.c b/src/math.c
index 366bd5e..4e9fee0 100644
--- a/src/math.c
+++ b/src/math.c
@@ -1,6 +1,7 @@
 #include "config.h"
 
 #include <assert.h>
+#include <errno.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -8,9 +9,24 @@
 #include "math.h"
 
 
+int
+add_size(const size_t x, const size_t y, size_t *const out) {
+	int rc = EOVERFLOW;
+
+	const bool overflows = (SIZE_MAX - x) < y;
+	if (overflows) {
+		goto out;
+	}
+
+	*out = x + y;
+	rc = 0;
+out:
+	return rc;
+}
+
 int
 mul_size(const size_t x, const size_t y, size_t *const out) {
-	int rc = -1;
+	int rc = EOVERFLOW;
 
 	assert(x != 0U);
 	assert(y != 0U);
-- 
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