git init

1 files changed, 40 insertions, 0 deletions

diff --git a/src/arena.c b/src/arena.c
new file mode 100644
index 0000000..f45d11b
--- /dev/null
+++ b/src/arena.c
@@ -0,0 +1,40 @@
+#include "arena.h"
+
+#include <stdlib.h>
+
+void init_arena(arena_t *r, int blocksz) {
+    if (blocksz < 4096) blocksz = 4096;
+    r->head = (struct memblock){NULL, 0, blocksz};
+    r->head.buf = malloc(blocksz);
+    r->current = &(r->head);
+    r->blocksz = blocksz;
+}
+
+void destroy_arena(arena_t *r) {
+    free(r->head.buf);
+    struct memblock *cur = r->head.next;
+    while (cur != NULL) {
+        struct memblock *prev = cur;
+        cur = cur->next;
+        free(prev->buf);
+        free(prev);
+    }
+}
+
+void *arena_alloc(arena_t *r, int sz) {
+    int remain = r->current->cap - r->current->sz;
+    if (remain >= sz) {
+        void *ptr = r->current->buf + r->current->sz;
+        r->current->sz += sz;
+        return ptr;
+    }
+    int blocksz = sz > blocksz ? sz : blocksz;
+    struct memblock *nextblock = malloc(sizeof(struct memblock));
+    void *ptr = malloc(blocksz);
+    nextblock->buf = ptr;
+    nextblock->cap = blocksz;
+    nextblock->sz = sz;
+    r->current->next = nextblock;
+    r->current = nextblock;
+    return ptr;
+}