v1.1.0 - New helper functions: arena_copy(), arena_strdup()

arena.h

@@ -1,4 +1,4 @@
-// arena.h - v1.0.3 - MIT License - https://github.com/seajee/arena.h
+// arena.h - v1.1.0 - MIT License
 // single header library for region-based memory management.
 //
 // [License and changelog]
@@ -23,10 +23,10 @@
 //
 //     #define ARENA_NO_ASSERT
 //
-//         This macro disables assertions that happen when a reallocation
-//         fails. The disabled assertions will be replaced with a simple
-//         condition that returns NULL when it fails. Note that ARENA_ASSERT
-//         is only used in arena_alloc().
+//         This macro disables assertions that happen when allocations fail.
+//         The disabled assertions will be replaced with a simple condition
+//         that returns NULL when it fails. This macro affects every function
+//         that returns a pointer.
 //
 //     #define ARENA_REGION_CAPACITY new_region_capacity_in_bytes (4096)
 //
@@ -34,9 +34,8 @@
 //
 //     #define ARENA_ASSERT my_assert
 //
-//         This macro defines an alternative function for assertions. In this
-//         library, ARENA_ASSERT is only used when arena_alloc() fails. Will
-//         be overwritten if ARENA_NO_ASSERT is defined.
+//         This macro defines an alternative function for assertions. This has
+//         no effect when ARENA_NO_ASSERT is defined.
 //
 //     #define ARENA_REALLOC my_realloc
 //     #define ARENA_FREE my_free
@@ -53,16 +52,25 @@
 //
 //     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).
+// This function is optional (see [Example] section): initializes an arena
+// with a specified region capacity. It will override the default
+// ARENA_REGION_CAPACITY. 
 //
 //     void *arena_alloc(Arena *a, size_t size)
 //
 // This function allocates a buffer of <size> bytes into the specified arena
 // and returns it's pointer.
 //
+//     void *arena_copy(Arena *a, const void *src, size_t size);
+//
+// This function allocates a buffer of <size> bytes into the arena and copies
+// the contents of <src>.
+//
+//     char *arena_strdup(Arena *a, const char *s);
+//
+// This functions acts like the strdup() function but it instead allocates on
+// the specified arena. It duplicates a string in the arena.
+//
 //     void arena_free(Arena *a)
 //
 // This function frees all of the regions allocated in the specified arena
@@ -77,7 +85,7 @@
 // Warning: this functions may cause fragmentation, consider setting an
 // appropriate region capacity.
 //
-// [Note]
+// [Notes]
 //
 // This library is not Thread-safe.
 //
@@ -105,6 +113,7 @@ int main(void)
 
 #include <stddef.h>
 #include <stdint.h>
+#include <string.h>
 
 #ifndef ARENA_REGION_CAPACITY
 #    define ARENA_REGION_CAPACITY (8*1024)
@@ -150,6 +159,8 @@ typedef struct Arena {
 
 Arena arena_create(size_t region_capacity);
 void *arena_alloc(Arena *a, size_t size);
+void *arena_copy(Arena *a, const void *src, size_t size);
+char *arena_strdup(Arena *a, const char *s);
 void arena_free(Arena *a);
 void arena_reset(Arena *a);
 
@@ -167,7 +178,8 @@ extern "C" { // Prevent name mangling of functions
 
 Arena arena_create(size_t region_capacity)
 {
-    Arena a = {0};
+    Arena a;
+    memset(&a, 0, sizeof(a));
     a.region_capacity = region_capacity;
     return a;
 }
@@ -175,7 +187,7 @@ Arena arena_create(size_t region_capacity)
 void *arena_alloc(Arena *a, size_t size)
 {
     if (a == NULL || size == 0) {
-        ARENA_ASSERT(false && "Invalid, parameters");
+        ARENA_ASSERT(false && "Invalid parameters");
         return NULL;
     }
 
@@ -233,6 +245,30 @@ void *arena_alloc(Arena *a, size_t size)
     return a->tail->data + a->tail->count - size;
 }
 
+void *arena_copy(Arena *a, const void *src, size_t size)
+{
+    if (a == NULL || src == NULL) {
+        ARENA_ASSERT(false && "Invalid parameters");
+        return NULL;
+    }
+
+    void *copy = arena_alloc(a, size);
+    memcpy(copy, src, size);
+
+    return copy;
+}
+
+char *arena_strdup(Arena *a, const char *s)
+{
+    if (a == NULL || s == NULL) {
+        ARENA_ASSERT(false && "Invalid parameters");
+        return NULL;
+    }
+
+    return (char*)arena_copy(a, s, strlen(s) + 1);
+}
+
+
 void arena_free(Arena *a)
 {
     if (a == NULL) {
@@ -273,6 +309,7 @@ void arena_reset(Arena *a)
 /*
  * Revision history:
  *
+ *     1.1.0 (2025-11-18) New helper functions: arena_copy(), arena_strdup()
  *     1.0.3 (2025-09-10) Renamed parameter bytes to size in arena_alloc()
  *     1.0.2 (2025-09-06) Bug fixes; new ARENA_NO_ASSERT macro
  *     1.0.1 (2025-08-02) Prevent name mangling of functions; don't reset