v1.0.0 - Initial release

README.md

@@ -12,10 +12,11 @@ in C using a linked list approach.
 
 int main(void)
 {
-    Arena a = {0}; // or arena_create(...) to specify the region capacity
+    Arena a = {0}; // or arena_create(...) to specify a custom region
+                   // capacity just for this arena
 
-    int *x = arena_alloc(&a, sizeof(*x) * 69);
+    int *x = arena_alloc(&a, sizeof(*x) * 32);
-    float *y = arena_alloc(&a, sizeof(*y) * 420);
+    float *y = arena_alloc(&a, sizeof(*y) * 512);
 
     arena_free(&a);
     return 0;

arena.h

@@ -1,3 +1,81 @@
+// arena.h - v1.0.0 - MIT License - https://github.com/seajee/arena.h
+// single header library for region-based memory management.
+//
+// License and changelog:
+//
+//     See end of file.
+//
+// Compile-time options:
+//
+//     Note: every compile-time option listed here should be configured before
+//     the definition of the ARENA_IMPLEMENTATION macro.
+//
+//     #define ARENA_REGION_CAPACITY new_region_capacity_in_bytes (4096)
+//
+//         This macro defines the default capacity for arena regions.
+//
+//     #define ARENA_ASSERT my_assert
+//
+//         This macro defines an alternative function for assertions. In this
+//         library, ARENA_ASSERT is only used when ARENA_REALLOC fails.
+//
+//     #define ARENA_REALLOC my_realloc
+//     #define ARENA_FREE my_free
+//
+//         These macros define alternative functions for dynamic allocation
+//         and deallocation on the heap. They are only used for managing
+//         Arena_Region structures.
+//
+// Function documentation:
+//
+// In this library, arenas are implemented as linked lists of regions. Each
+// region will contain the allocated buffers. The following are all of the
+// functions
+//
+//     Arena arena_create(size_t region_capacity)
+//
+// This function initializes an arena with a specified region capacity. By
+// default the region capacity is ARENA_REGION_CAPACITY, which can be
+// configured by redefining it before including the header file. This function
+// is not strictly necessary for initializing an arena (see example).
+//
+//     void *arena_alloc(Arena *a,
+//                       size_t bytes)
+//
+// This function allocates a buffer of size <bytes> into the specified arena
+// and returns it's pointer.
+//
+//     void arena_free(Arena *a)
+//
+// This function frees all of the regions allocated in the specified arena
+// which invalidates all the pointers associated with the arena.
+//
+//     void arena_reset(Arena *a)
+//
+// This function resets an arena by keeping all of the regions allocated but
+// invalidates all of the pointers associated with the specified arena.
+// Warning: this functions may cause fragmentation, consider setting an
+// appropriate region capacity.
+//
+// Example:
+/*
+#define ARENA_IMPLEMENTATION
+#include "arena.h"
+
+int main(void)
+{
+    Arena a = {0}; // or arena_create(...) to specify a custom region
+                   // capacity just for this arena
+
+    int *x = arena_alloc(&a, sizeof(*x) * 32);
+    float *y = arena_alloc(&a, sizeof(*y) * 512);
+
+    arena_free(&a);
+    return 0;
+}
+
+*/
+
 #ifndef ARENA_H_
 #define ARENA_H_
 
@@ -38,7 +116,7 @@ typedef struct Arena {
     size_t region_capacity;
 } Arena;
 
-Arena arena_create(size_t min_capacity);
+Arena arena_create(size_t region_capacity);
 void *arena_alloc(Arena *a, size_t bytes);
 void arena_free(Arena *a);
 void arena_reset(Arena *a);
@@ -135,3 +213,33 @@ void arena_reset(Arena *a)
 }
 
 #endif // ARENA_IMPLEMENTATION
+
+/*
+ * Revision history:
+ *
+ *     1.0.0 (2025-07-24) Initial release
+ */
+
+/*
+ * MIT License
+ *
+ * Copyright (c) 2025 seajee
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */