1 files changed, 50 insertions, 0 deletions
diff --git a/src/arena.c b/src/arena.c
new file mode 100644
index 0000000..2221616
--- /dev/null
+++ b/src/arena.c
@@ -0,0 +1,50 @@
+#include "arena.h"
+
+struct block {
+    size_t size;
+    size_t used;
+    struct block *next;
+    char data_start[];
+};
+
+static const size_t min_block_room = 16 * 1024 - sizeof(struct block);
+
+static void add_block(struct arena* a, size_t room_wanted)
+{
+    if (room_wanted < min_block_room) {
+        room_wanted = min_block_room;
+    }
+    struct block *new_block = malloc(sizeof(struct block) + room_wanted);
+    new_block->size = room_wanted;
+    new_block->used = 0;
+    new_block->next = a->cur_block;
+    a->cur_block = new_block;
+}
+
+void arena_init(struct arena *a)
+{
+    a->cur_block = NULL;
+}
+
+void* arena_malloc(struct arena *a, size_t amount)
+{
+    struct block* b = a->cur_block;
+    if (b == NULL || b->size - b->used < amount) {
+        add_block(a, amount);
+        b = a->cur_block;
+    }
+    void* result = &b->data_start[b->used];
+    b->used += amount;
+    return result;
+}
+
+void arena_free(struct arena *a)
+{
+    struct block* b = a->cur_block;
+    while (b != NULL) {
+        struct block* next = b->next;
+        free(b);
+        b = next;
+    }
+    a->cur_block = NULL;
+}