1 files changed, 19 insertions, 2 deletions

diff --git a/lib/arena.c b/lib/arena.c
index dd12d0c..8cd1748 100644
--- a/lib/arena.c
+++ b/lib/arena.c
@@ -10,12 +10,18 @@ region *new_region(size_t cap) {
   return r;
 }
 
+arena arena_init_cap(size_t cap) {
+  arena a = {0};
+  a.region_cap = cap;
+  return a;
+}
+
 void *arena_alloc(arena *a, size_t size_bytes) {
   size_t size = (size_bytes + sizeof(uintptr_t)-1)/sizeof(uintptr_t);
 
   if (a->end == NULL) {
 	assert(a->beg == NULL);
-	size_t capacity = ARENA_REGION_DEFAULT_CAPACITY;
+	size_t capacity = a->region_cap ? a->region_cap : ARENA_REGION_DEFAULT_CAPACITY;
 	if (capacity < size) capacity = size;
 	a->beg = new_region(capacity);
 	a->end = a->beg;
@@ -26,7 +32,7 @@ void *arena_alloc(arena *a, size_t size_bytes) {
   }
 
   if (a->end->len + size > a->end->cap) {
-	size_t capacity = ARENA_REGION_DEFAULT_CAPACITY;
+	size_t capacity = a->region_cap ? a->region_cap : ARENA_REGION_DEFAULT_CAPACITY;
 	if (capacity < size) capacity = size;
 	a->beg = new_region(capacity);
 	a->end->next = new_region(capacity);
@@ -47,6 +53,17 @@ void arena_free(arena *a) {
   }
 }
 
+void *arena_realloc(arena *a, void *oldptr, size_t oldsz, size_t newsz) {
+  if (newsz <= oldsz) return oldptr;
+  void *newptr = arena_alloc(a, newsz);
+  char *newptr_char = (char*)newptr;
+  char *oldptr_char = (char*)oldptr;
+  for (size_t i = 0; i < oldsz; ++i) {
+    newptr_char[i] = oldptr_char[i];
+  }
+  return newptr;
+}
+
 void grow_da(void *slice, size_t size, arena *arena) {
   struct {
 	void *data;