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/*
* 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);
}
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