git/mem-pool.c
René Scharfe 116affac3f mem-pool: drop trailing semicolon from macro definition
Allow BLOCK_GROWTH_SIZE to be used like an integer literal by removing
the trailing semicolon from its definition.  Also wrap the expression in
parentheses, to allow it to be used with operators without leading to
unexpected results.  It doesn't matter for the current use site, but
make it follow standard macro rules anyway to avoid future surprises.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-17 10:20:16 -07:00

159 lines
3.5 KiB
C

/*
* Memory Pool implementation logic.
*/
#include "cache.h"
#include "mem-pool.h"
#define BLOCK_GROWTH_SIZE (1024 * 1024 - sizeof(struct mp_block))
/*
* Allocate a new mp_block and insert it after the block specified in
* `insert_after`. If `insert_after` is NULL, then insert block at the
* head of the linked list.
*/
static struct mp_block *mem_pool_alloc_block(struct mem_pool *pool,
size_t block_alloc,
struct mp_block *insert_after)
{
struct mp_block *p;
pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
p->next_free = (char *)p->space;
p->end = p->next_free + block_alloc;
if (insert_after) {
p->next_block = insert_after->next_block;
insert_after->next_block = p;
} else {
p->next_block = pool->mp_block;
pool->mp_block = p;
}
return p;
}
void mem_pool_init(struct mem_pool *pool, size_t initial_size)
{
memset(pool, 0, sizeof(*pool));
pool->block_alloc = BLOCK_GROWTH_SIZE;
if (initial_size > 0)
mem_pool_alloc_block(pool, initial_size, NULL);
}
void mem_pool_discard(struct mem_pool *pool, int invalidate_memory)
{
struct mp_block *block, *block_to_free;
block = pool->mp_block;
while (block)
{
block_to_free = block;
block = block->next_block;
if (invalidate_memory)
memset(block_to_free->space, 0xDD, ((char *)block_to_free->end) - ((char *)block_to_free->space));
free(block_to_free);
}
pool->mp_block = NULL;
pool->pool_alloc = 0;
}
void *mem_pool_alloc(struct mem_pool *pool, size_t len)
{
struct mp_block *p = NULL;
void *r;
/* round up to a 'uintmax_t' alignment */
if (len & (sizeof(uintmax_t) - 1))
len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
if (pool->mp_block &&
pool->mp_block->end - pool->mp_block->next_free >= len)
p = pool->mp_block;
if (!p) {
if (len >= (pool->block_alloc / 2))
return mem_pool_alloc_block(pool, len, pool->mp_block);
p = mem_pool_alloc_block(pool, pool->block_alloc, NULL);
}
r = p->next_free;
p->next_free += len;
return r;
}
void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size)
{
size_t len = st_mult(count, size);
void *r = mem_pool_alloc(pool, len);
memset(r, 0, len);
return r;
}
char *mem_pool_strdup(struct mem_pool *pool, const char *str)
{
size_t len = strlen(str) + 1;
char *ret = mem_pool_alloc(pool, len);
return memcpy(ret, str, len);
}
char *mem_pool_strndup(struct mem_pool *pool, const char *str, size_t len)
{
char *p = memchr(str, '\0', len);
size_t actual_len = (p ? p - str : len);
char *ret = mem_pool_alloc(pool, actual_len+1);
ret[actual_len] = '\0';
return memcpy(ret, str, actual_len);
}
int mem_pool_contains(struct mem_pool *pool, void *mem)
{
struct mp_block *p;
/* Check if memory is allocated in a block */
for (p = pool->mp_block; p; p = p->next_block)
if ((mem >= ((void *)p->space)) &&
(mem < ((void *)p->end)))
return 1;
return 0;
}
void mem_pool_combine(struct mem_pool *dst, struct mem_pool *src)
{
struct mp_block *p;
/* Append the blocks from src to dst */
if (dst->mp_block && src->mp_block) {
/*
* src and dst have blocks, append
* blocks from src to dst.
*/
p = dst->mp_block;
while (p->next_block)
p = p->next_block;
p->next_block = src->mp_block;
} else if (src->mp_block) {
/*
* src has blocks, dst is empty.
*/
dst->mp_block = src->mp_block;
} else {
/* src is empty, nothing to do. */
}
dst->pool_alloc += src->pool_alloc;
src->pool_alloc = 0;
src->mp_block = NULL;
}