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+// Copyright 2021 David Robillard <d@drobilla.net>
+// SPDX-License-Identifier: ISC
+
+#ifndef ZIX_BUMP_ALLOCATOR_H
+#define ZIX_BUMP_ALLOCATOR_H
+
+#include "zix/allocator.h"
+#include "zix/attributes.h"
+
+#include <stddef.h>
+
+/**
+   A simple bump-pointer allocator that never frees.
+
+   This is about the simplest possible allocator that is useful in practice.
+   It uses a user-provided memory buffer with a fixed size, and allocates by
+   simply "bumping" the top offset like a stack.  This approach is simple,
+   extremely fast, and hard real-time safe, but at the cost of being limited to
+   narrow use cases since there is (almost) no support for deallocation.
+
+   Using this allocator requires knowing up-front the total amount of memory
+   that will be allocated (without reuse).  Typically this makes sense in short
+   scopes like a function call.
+
+   This allocator adheres to standard C semantics as much as possible, but is
+   much more restrictive.  Specifically:
+
+   - All allocations are aligned to sizeof(uintmax_t).
+
+   - Both free() and realloc() only work on the most recently allocated
+     pointer, essentially serving as a cheap pop and pop-push, respectively.
+
+   - Calling free() means that realloc() will fail and free() will do nothing
+     until the next allocation.  In other words, free() can not be used twice
+     in a row.
+
+   - There is no relocation: realloc() always returns either the input pointer,
+     or null.
+*/
+typedef struct {
+  ZixAllocator      base;     ///< Base allocator instance
+  void* ZIX_NONNULL buffer;   ///< User-owned memory buffer
+  size_t            last;     ///< Last allocation offset in bytes
+  size_t            top;      ///< Stack top/end offset in bytes
+  size_t            capacity; ///< Size of buffer in bytes (the maximum top)
+} ZixBumpAllocator;
+
+ZIX_API
+ZixBumpAllocator
+zix_bump_allocator(size_t capacity, void* ZIX_NONNULL buffer);
+
+#endif // ZIX_BUMP_ALLOCATOR_H