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/*
* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
*
* This file is released under the LGPL.
*/
#include "lib.h"
#include "pool.h"
#include "lvm-types.h"
struct chunk {
char *begin, *end;
struct chunk *prev;
};
struct pool {
struct chunk *chunk, *spare_chunk; /* spare_chunk is a one entry free
list to stop 'bobbling' */
size_t chunk_size;
size_t object_len;
unsigned object_alignment;
};
void _align_chunk(struct chunk *c, unsigned alignment);
struct chunk *_new_chunk(struct pool *p, size_t s);
/* by default things come out aligned for doubles */
#define DEFAULT_ALIGNMENT __alignof__ (double)
struct pool *pool_create(size_t chunk_hint)
{
size_t new_size = 1024;
struct pool *p = dbg_malloc(sizeof(*p));
if (!p) {
log_error("Couldn't create memory pool (size %" PRIuPTR ")",
sizeof(*p));
return 0;
}
memset(p, 0, sizeof(*p));
/* round chunk_hint up to the next power of 2 */
p->chunk_size = chunk_hint + sizeof(struct chunk);
while (new_size < p->chunk_size)
new_size <<= 1;
p->chunk_size = new_size;
return p;
}
void pool_destroy(struct pool *p)
{
struct chunk *c, *pr;
dbg_free(p->spare_chunk);
c = p->chunk;
while (c) {
pr = c->prev;
dbg_free(c);
c = pr;
}
dbg_free(p);
}
void *pool_alloc(struct pool *p, size_t s)
{
return pool_alloc_aligned(p, s, DEFAULT_ALIGNMENT);
}
void *pool_alloc_aligned(struct pool *p, size_t s, unsigned alignment)
{
struct chunk *c = p->chunk;
void *r;
/* realign begin */
if (c)
_align_chunk(c, alignment);
/* have we got room ? */
if (!c || (c->begin > c->end) || (c->end - c->begin < s)) {
/* allocate new chunk */
int needed = s + alignment + sizeof(struct chunk);
c = _new_chunk(p, (needed > p->chunk_size) ?
needed : p->chunk_size);
if (!c)
return NULL;
_align_chunk(c, alignment);
}
r = c->begin;
c->begin += s;
return r;
}
void pool_empty(struct pool *p)
{
struct chunk *c;
for (c = p->chunk; c && c->prev; c = c->prev)
;
if (p->chunk)
pool_free(p, (char *) (p->chunk + 1));
}
void pool_free(struct pool *p, void *ptr)
{
struct chunk *c = p->chunk;
while (c) {
if (((char *) c < (char *) ptr) &&
((char *) c->end > (char *) ptr)) {
c->begin = ptr;
break;
}
if (p->spare_chunk)
dbg_free(p->spare_chunk);
p->spare_chunk = c;
c = c->prev;
}
if (!c)
log_error("Internal error: pool_free asked to free pointer "
"not in pool");
else
p->chunk = c;
}
int pool_begin_object(struct pool *p, size_t hint)
{
struct chunk *c = p->chunk;
const size_t align = DEFAULT_ALIGNMENT;
p->object_len = 0;
p->object_alignment = align;
if (c)
_align_chunk(c, align);
if (!c || (c->begin > c->end) || (c->end - c->begin < hint)) {
/* allocate a new chunk */
c = _new_chunk(p,
hint > (p->chunk_size - sizeof(struct chunk)) ?
hint + sizeof(struct chunk) + align :
p->chunk_size);
if (!c)
return 0;
_align_chunk(c, align);
}
return 1;
}
int pool_grow_object(struct pool *p, const void *extra, size_t n)
{
struct chunk *c = p->chunk, *nc;
if (c->end - (c->begin + p->object_len) < n) {
/* move into a new chunk */
if (p->object_len + n > (p->chunk_size / 2))
nc = _new_chunk(p, (p->object_len + n) * 2);
else
nc = _new_chunk(p, p->chunk_size);
if (!nc)
return 0;
_align_chunk(p->chunk, p->object_alignment);
memcpy(p->chunk->begin, c->begin, p->object_len);
c = p->chunk;
}
memcpy(c->begin + p->object_len, extra, n);
p->object_len += n;
return 1;
}
void *pool_end_object(struct pool *p)
{
struct chunk *c = p->chunk;
void *r = c->begin;
c->begin += p->object_len;
p->object_len = 0u;
p->object_alignment = DEFAULT_ALIGNMENT;
return r;
}
void pool_abandon_object(struct pool *p)
{
p->object_len = 0;
p->object_alignment = DEFAULT_ALIGNMENT;
}
char *pool_strdup(struct pool *p, const char *str)
{
char *ret = pool_alloc(p, strlen(str) + 1);
if (ret)
strcpy(ret, str);
return ret;
}
void _align_chunk(struct chunk *c, unsigned alignment)
{
c->begin += alignment - ((unsigned long) c->begin & (alignment - 1));
}
struct chunk *_new_chunk(struct pool *p, size_t s)
{
struct chunk *c;
if (p->spare_chunk &&
((p->spare_chunk->end - (char *) p->spare_chunk) >= s)) {
/* reuse old chunk */
c = p->spare_chunk;
p->spare_chunk = 0;
} else {
if (!(c = dbg_malloc(s))) {
log_err("Out of memory. Requested %" PRIuPTR " bytes.",
s);
return NULL;
}
c->end = (char *) c + s;
}
c->prev = p->chunk;
c->begin = (char *) (c + 1);
p->chunk = c;
return c;
}
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