1 files changed, 115 insertions, 0 deletions
diff --git a/alloc.c b/alloc.c
new file mode 100644
index 000000000..12afadfac
--- /dev/null
+++ b/alloc.c
@@ -0,0 +1,115 @@
+/*
+ * alloc.c  - specialized allocator for internal objects
+ *
+ * Copyright (C) 2006 Linus Torvalds
+ *
+ * The standard malloc/free wastes too much space for objects, partly because
+ * it maintains all the allocation infrastructure (which isn't needed, since
+ * we never free an object descriptor anyway), but even more because it ends
+ * up with maximal alignment because it doesn't know what the object alignment
+ * for the new allocation is.
+ */
+#include "cache.h"
+#include "object.h"
+#include "blob.h"
+#include "tree.h"
+#include "commit.h"
+#include "tag.h"
+
+#define BLOCKING 1024
+
+union any_object {
+	struct object object;
+	struct blob blob;
+	struct tree tree;
+	struct commit commit;
+	struct tag tag;
+};
+
+struct alloc_state {
+	int count; /* total number of nodes allocated */
+	int nr;    /* number of nodes left in current allocation */
+	void *p;   /* first free node in current allocation */
+};
+
+static inline void *alloc_node(struct alloc_state *s, size_t node_size)
+{
+	void *ret;
+
+	if (!s->nr) {
+		s->nr = BLOCKING;
+		s->p = xmalloc(BLOCKING * node_size);
+	}
+	s->nr--;
+	s->count++;
+	ret = s->p;
+	s->p = (char *)s->p + node_size;
+	memset(ret, 0, node_size);
+	return ret;
+}
+
+static struct alloc_state blob_state;
+void *alloc_blob_node(void)
+{
+	struct blob *b = alloc_node(&blob_state, sizeof(struct blob));
+	b->object.type = OBJ_BLOB;
+	return b;
+}
+
+static struct alloc_state tree_state;
+void *alloc_tree_node(void)
+{
+	struct tree *t = alloc_node(&tree_state, sizeof(struct tree));
+	t->object.type = OBJ_TREE;
+	return t;
+}
+
+static struct alloc_state tag_state;
+void *alloc_tag_node(void)
+{
+	struct tag *t = alloc_node(&tag_state, sizeof(struct tag));
+	t->object.type = OBJ_TAG;
+	return t;
+}
+
+static struct alloc_state object_state;
+void *alloc_object_node(void)
+{
+	struct object *obj = alloc_node(&object_state, sizeof(union any_object));
+	obj->type = OBJ_NONE;
+	return obj;
+}
+
+static struct alloc_state commit_state;
+
+unsigned int alloc_commit_index(void)
+{
+	static unsigned int count;
+	return count++;
+}
+
+void *alloc_commit_node(void)
+{
+	struct commit *c = alloc_node(&commit_state, sizeof(struct commit));
+	c->object.type = OBJ_COMMIT;
+	c->index = alloc_commit_index();
+	return c;
+}
+
+static void report(const char *name, unsigned int count, size_t size)
+{
+	fprintf(stderr, "%10s: %8u (%"PRIuMAX" kB)\n",
+			name, count, (uintmax_t) size);
+}
+
+#define REPORT(name, type)	\
+    report(#name, name##_state.count, name##_state.count * sizeof(type) >> 10)
+
+void alloc_report(void)
+{
+	REPORT(blob, struct blob);
+	REPORT(tree, struct tree);
+	REPORT(commit, struct commit);
+	REPORT(tag, struct tag);
+	REPORT(object, union any_object);
+}