1 files changed, 158 insertions, 0 deletions
diff --git a/hicn-light/src/hicn/base/pool.c b/hicn-light/src/hicn/base/pool.c
new file mode 100644
index 000000000..ba2a14c5f
--- /dev/null
+++ b/hicn-light/src/hicn/base/pool.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2021 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * \file pool.c
+ * \brief Implementation of fixed-size pool allocator.
+ *
+ * NOTE:
+ *  - Ideally, we should have a single realloc per resize, that would encompass
+ *  both the free indices vector and bitmap, by nesting data structures. Because
+ *  of the added complexity, and by lack of evidence of the need for this, we
+ *  currently rely on a simpler implementation.
+ */
+
+#include <assert.h>
+#include <stdlib.h>  // calloc
+
+#include "common.h"
+#include "pool.h"
+
+#include <stdio.h>  // XXX
+
+void _pool_init(void** pool_ptr, size_t elt_size, size_t init_size,
+                size_t max_size) {
+  assert(pool_ptr);
+  assert(elt_size);
+
+  init_size = next_pow2(init_size);
+
+  if (max_size && init_size > max_size) goto ERR_MAX_SIZE;
+
+  /* The initial pool size is rounded to the next power of two */
+  size_t alloc_size = next_pow2(init_size);
+
+  pool_hdr_t* ph = calloc(POOL_HDRLEN + alloc_size * elt_size, 1);
+  if (!ph) goto ERR_MALLOC;
+
+  ph->elt_size = elt_size;
+  ph->alloc_size = alloc_size;
+  ph->max_size = max_size;
+
+  /* Free indices */
+  off_t* free_indices;
+  vector_init(free_indices, init_size, max_size);
+  for (unsigned i = 0; i < init_size; i++)
+    free_indices[i] = (init_size - 1) - i;
+  vector_len(free_indices) = init_size;
+  ph->free_indices = free_indices;
+
+  /* Free bitmap */
+  uint_fast32_t* fb = ph->free_bitmap;
+  bitmap_init(fb, init_size, max_size);
+  bitmap_set_to(fb, init_size);
+  ph->free_bitmap = fb;
+
+  *pool_ptr = (uint8_t*)ph + POOL_HDRLEN;
+
+  return;
+
+ERR_MALLOC:
+ERR_MAX_SIZE:
+  *pool_ptr = NULL;
+  return;
+}
+
+void _pool_free(void** pool_ptr) {
+  pool_hdr_t* ph = pool_hdr(*pool_ptr);
+  vector_free(ph->free_indices);
+  bitmap_free(ph->free_bitmap);
+
+  free(pool_hdr(*pool_ptr));
+  *pool_ptr = NULL;
+}
+
+bool _pool_validate_id(void** pool_ptr, off_t id) {
+  pool_hdr_t* ph = pool_hdr(*pool_ptr);
+  size_t pool_size = pool_get_alloc_size(*pool_ptr);
+  if (id >= pool_size || !bitmap_is_unset(ph->free_bitmap, id)) return false;
+
+  return true;
+}
+
+void _pool_resize(void** pool_ptr, size_t elt_size) {
+  pool_hdr_t* ph = pool_hdr(*pool_ptr);
+  size_t old_size = ph->alloc_size;
+  size_t new_size = old_size * 2;
+
+  TRACE("pool_resize to %lu", new_size);
+
+  if (ph->max_size && new_size > ph->max_size) goto ERR_MAX_SIZE;
+
+  /* Double pool storage */
+  ph = realloc(ph, POOL_HDRLEN + new_size * elt_size);
+  if (!ph) goto ERR_REALLOC;
+  ph->elt_size = elt_size;
+  ph->alloc_size = new_size;
+
+  /*
+   * After resize, the pool will have new free indices, ranging from
+   * old_size to (new_size - 1)
+   */
+  vector_ensure_pos(ph->free_indices, old_size);
+  for (unsigned i = 0; i < old_size; i++)
+    ph->free_indices[i] = new_size - 1 - i;
+  vector_len(ph->free_indices) = old_size;
+
+  /* We also need to update the bitmap */
+  bitmap_ensure_pos(&(ph->free_bitmap), new_size - 1);
+  bitmap_set_range(ph->free_bitmap, old_size, new_size - 1);
+
+  /* Reassign pool pointer */
+  *pool_ptr = (uint8_t*)ph + POOL_HDRLEN;
+
+  return;
+
+ERR_REALLOC:
+ERR_MAX_SIZE:
+  *pool_ptr = NULL;
+  return;
+}
+
+off_t _pool_get(void** pool_ptr, void** elt, size_t elt_size) {
+  pool_hdr_t* ph = pool_hdr(*pool_ptr);
+  uint64_t l = vector_len(ph->free_indices);
+  if (l == 0) {
+    _pool_resize(pool_ptr, elt_size);
+    ph = pool_hdr(*pool_ptr);
+    l = vector_len(ph->free_indices);
+  }
+  off_t free_id = ph->free_indices[l - 1];
+  vector_len(ph->free_indices)--;
+  bitmap_unset(ph->free_bitmap, free_id);
+  *elt = *pool_ptr + free_id * elt_size;
+  memset(*elt, 0, elt_size);
+  return free_id;
+}
+
+void _pool_put(void** pool_ptr, void** elt, size_t elt_size) {
+  pool_hdr_t* ph = pool_hdr(*pool_ptr);
+  uint64_t l = vector_len(ph->free_indices);
+  vector_ensure_pos(ph->free_indices, l);
+  off_t freed_id = (*elt - *pool_ptr) / elt_size;
+  ph->free_indices[l] = freed_id;
+  vector_len(ph->free_indices)++;
+  bitmap_set(ph->free_bitmap, freed_id);
+}