From 72fe8dd2d6d6a3a5592646950a4e43b9a79ed9b4 Mon Sep 17 00:00:00 2001
From: Steven Le Rouzic <steven.lerouzic@gmail.com>
Date: Mon, 2 Dec 2024 00:35:56 +0100
Subject: Start work on buffer

---
 asl/buffer.hpp | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 asl/buffer.hpp

(limited to 'asl/buffer.hpp')

diff --git a/asl/buffer.hpp b/asl/buffer.hpp
new file mode 100644
index 0000000..abf29fe
--- /dev/null
+++ b/asl/buffer.hpp
@@ -0,0 +1,46 @@
+#pragma once
+
+#include "asl/meta.hpp"
+#include "asl/allocator.hpp"
+#include "asl/annotations.hpp"
+
+namespace asl
+{
+
+template<is_object T, allocator Allocator = DefaultAllocator>
+class buffer
+{
+    
+    T*         m_data{};
+    isize_t    m_capacity{};
+
+    // bit 63       : 0 = on heap, 1 = inline
+    // bits [62:56] : size when inline
+    // bits [52:0]  : size when on heap
+    size_t     m_size_encoded{};
+
+    ASL_NO_UNIQUE_ADDRESS Allocator m_allocator;
+    
+    static_assert(align_of<T> <= align_of<T*>);
+    static_assert(align_of<T*> == align_of<isize_t>);
+    static_assert(align_of<T*> == align_of<size_t>);
+    
+public:
+
+    static constexpr isize_t kInlineCapacity = []() {
+        // 1 byte is used for size inline in m_size_encoded.
+        // This is enough because we have at most 24 bytes available,
+        // so 23 chars of capacity.
+        const isize_t available_size = size_of<T*> + size_of<isize_t> + size_of<size_t> - 1;
+        return available_size / size_of<T>;
+    }();
+
+    constexpr buffer() requires default_constructible<Allocator> = default;
+
+    explicit constexpr buffer(Allocator allocator)
+        : m_allocator{ASL_MOVE(allocator)}
+    {}
+};
+
+} // namespace asl
+
-- 
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