From d2e43c82f11a88b5e0fe717f378f882f1846d368 Mon Sep 17 00:00:00 2001
From: Emily Boudreaux <thomas@boudreauxmail.com>
Date: Wed, 14 Oct 2026 10:58:52 -0400
Subject: [PATCH] feat(discretization): added implementation of
 checked_block_size

tho see the note in the header, this could be made more general likeley
---
 .../discretization/blocks/system_layout.cpp   | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 src/lib/serif/discretization/blocks/system_layout.cpp

diff --git a/src/lib/serif/discretization/blocks/system_layout.cpp b/src/lib/serif/discretization/blocks/system_layout.cpp
new file mode 100644
index 00000000..3886ee93
--- /dev/null
+++ b/src/lib/serif/discretization/blocks/system_layout.cpp
@@ -0,0 +1,20 @@
+#include "serif/discretization/blocks/system_layout.hpp"
+
+#include <limits>
+#include <stdexcept>
+#include "serif/utils/error/errors.hpp"
+
+namespace serif::discretization::blocks
+{
+    std::size_t checked_block_size(const std::span<const std::size_t> sizes)
+    {
+        using namespace utils::errors;
+
+        std::size_t total = 0;
+        for (const std::size_t size : sizes) {
+            serif_ensure<SERiFErrorCode::INVALID_DOF_COUNT, std::overflow_error>(size <= std::numeric_limits<std::size_t>::max() - total, "The system's packed coefficient count overflows size_t. Check the individual coordinate sizes.");
+            total += size;
+        }
+        return total;
+    }
+} // namespace serif::discretization::blocks