Added a faster yet still simple memory pool

diff --git a/kmempool.c b/kmempool.c
new file mode 100644 (file)
index 0000000..8154112
--- /dev/null
+++ b/kmempool.c
@@ -0,0 +1,73 @@
+#include <stdint.h>
+#include <stdlib.h>
+#include "kmempool.h"
+
+#define Malloc(type, cnt)       ((type*)malloc((cnt) * sizeof(type)))
+#define Calloc(type, cnt)       ((type*)calloc((cnt), sizeof(type)))
+#define Realloc(type, ptr, cnt) ((type*)realloc((ptr), (cnt) * sizeof(type)))
+
+typedef struct {
+       uint32_t sz; // size of an entry
+       uint32_t chunk_size; // number of entries in a chunk
+       uint32_t n_chunk; // number of chunks
+       uint8_t *p; // pointing to an entry that can be allocated from a chunk
+       uint8_t *p_end; // end of the current chunk
+       uint8_t **chunk; // list of chunks
+       uint32_t n_buf, m_buf; // number/max number of buffered free entries
+       void **buf; // list of pointers to free entries
+} kmempool_t;
+
+static void kmp_add_chunk(kmempool_t *mp) // add a new chunk
+{
+       uint64_t x = (uint64_t)mp->sz * mp->chunk_size;
+       mp->chunk = Realloc(uint8_t*, mp->chunk, mp->n_chunk + 1);
+       mp->p = mp->chunk[mp->n_chunk++] = Calloc(uint8_t, x);
+       mp->p_end = mp->p + x;
+}
+
+void *kmp_init2(unsigned sz, unsigned chunk_size)
+{
+       kmempool_t *mp;
+       mp = Calloc(kmempool_t, 1);
+       mp->sz = sz, mp->chunk_size = chunk_size;
+       kmp_add_chunk(mp);
+       return mp;
+}
+
+void *kmp_init(unsigned sz) // fixed chunk size
+{
+       return kmp_init2(sz, 0x10000);
+}
+
+void kmp_destroy(void *mp_)
+{
+       kmempool_t *mp = (kmempool_t*)mp_;
+       uint32_t i;
+       for (i = 0; i < mp->n_chunk; ++i) // free all chunks
+               free(mp->chunk[i]);
+       free(mp->chunk); free(mp->buf); free(mp);
+}
+
+void *kmp_alloc(void *mp_)
+{
+       kmempool_t *mp = (kmempool_t*)mp_;
+       void *ret;
+       if (mp->n_buf > 0) { // there are buffered free entries
+               ret = mp->buf[--mp->n_buf];
+       } else { // need to "allocate" from chunks
+               if (mp->p == mp->p_end) kmp_add_chunk(mp); // chunk full; add a new one
+               ret = (void*)mp->p;
+               mp->p += mp->sz;
+       }
+       return ret;
+}
+
+void kmp_free(void *mp_, void *p)
+{
+       kmempool_t *mp = (kmempool_t*)mp_;
+       if (mp->n_buf == mp->m_buf) { // then enlarge the buffer
+               mp->m_buf += (mp->m_buf>>1) + 16;
+               mp->buf = Realloc(void*, mp->buf, mp->m_buf);
+       }
+       mp->buf[mp->n_buf++] = p;
+}

diff --git a/kmempool.h b/kmempool.h
new file mode 100644 (file)
index 0000000..fcbda8e
--- /dev/null
+++ b/kmempool.h
@@ -0,0 +1,17 @@
+#ifndef AC_KMEMPOOL_H
+#define AC_KMEMPOOL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void *kmp_init(unsigned sz);
+void kmp_destroy(void *mp);
+void *kmp_alloc(void *mp);
+void kmp_free(void *mp, void *p);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif