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-rw-r--r--mem-pool.c145
1 files changed, 145 insertions, 0 deletions
diff --git a/mem-pool.c b/mem-pool.c
new file mode 100644
index 0000000000..a2841a4a9a
--- /dev/null
+++ b/mem-pool.c
@@ -0,0 +1,145 @@
+/*
+ * 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 *mem_pool, size_t block_alloc, struct mp_block *insert_after)
+{
+ struct mp_block *p;
+
+ mem_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 = mem_pool->mp_block;
+ mem_pool->mp_block = p;
+ }
+
+ return p;
+}
+
+void mem_pool_init(struct mem_pool **mem_pool, size_t initial_size)
+{
+ struct mem_pool *pool;
+
+ if (*mem_pool)
+ return;
+
+ pool = xcalloc(1, sizeof(*pool));
+
+ pool->block_alloc = BLOCK_GROWTH_SIZE;
+
+ if (initial_size > 0)
+ mem_pool_alloc_block(pool, initial_size, NULL);
+
+ *mem_pool = pool;
+}
+
+void mem_pool_discard(struct mem_pool *mem_pool, int invalidate_memory)
+{
+ struct mp_block *block, *block_to_free;
+
+ block = mem_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);
+ }
+
+ free(mem_pool);
+}
+
+void *mem_pool_alloc(struct mem_pool *mem_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 (mem_pool->mp_block &&
+ mem_pool->mp_block->end - mem_pool->mp_block->next_free >= len)
+ p = mem_pool->mp_block;
+
+ if (!p) {
+ if (len >= (mem_pool->block_alloc / 2))
+ return mem_pool_alloc_block(mem_pool, len, mem_pool->mp_block);
+
+ p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc, NULL);
+ }
+
+ r = p->next_free;
+ p->next_free += len;
+ return r;
+}
+
+void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
+{
+ size_t len = st_mult(count, size);
+ void *r = mem_pool_alloc(mem_pool, len);
+ memset(r, 0, len);
+ return r;
+}
+
+int mem_pool_contains(struct mem_pool *mem_pool, void *mem)
+{
+ struct mp_block *p;
+
+ /* Check if memory is allocated in a block */
+ for (p = mem_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;
+}