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/*
* FRR ID Number Allocator
* Copyright (C) 2018 Amazon.com, Inc. or its affiliates
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _ZEBRA_ID_ALLOC_H
#define _ZEBRA_ID_ALLOC_H
#include <strings.h>
#include <limits.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
#define IDALLOC_INVALID 0
#define IDALLOC_DIR_BITS 8
#define IDALLOC_SUBDIR_BITS 7
#define IDALLOC_PAGE_BITS 7
#define IDALLOC_WORD_BITS 5
#define IDALLOC_OFFSET_BITS 5
#define IDALLOC_DIR_COUNT (1 << IDALLOC_DIR_BITS)
#define IDALLOC_SUBDIR_COUNT (1 << IDALLOC_SUBDIR_BITS)
#define IDALLOC_PAGE_COUNT (1 << IDALLOC_PAGE_BITS)
#define IDALLOC_WORD_COUNT (1 << IDALLOC_WORD_BITS)
struct id_alloc_page {
/* Bitmask of allocations. 1s indicates the ID is already allocated. */
uint32_t allocated_mask[IDALLOC_WORD_COUNT];
/* Bitmask for free space in allocated_mask. 1s indicate whole 32 bit
* section is full.
*/
uint32_t full_word_mask;
/* The ID that bit 0 in allocated_mask corresponds to. */
uint32_t base_value;
struct id_alloc_page
*next_has_free; /* Next page with at least one bit open */
};
struct id_alloc_subdir {
struct id_alloc_page *sublevels[IDALLOC_PAGE_COUNT];
};
struct id_alloc_dir {
struct id_alloc_subdir *sublevels[IDALLOC_SUBDIR_COUNT];
};
struct id_alloc {
struct id_alloc_dir *sublevels[IDALLOC_DIR_COUNT];
struct id_alloc_page *has_free;
char *name;
uint32_t allocated, capacity;
};
struct id_alloc_pool {
struct id_alloc_pool *next;
uint32_t id;
};
void idalloc_free(struct id_alloc *alloc, uint32_t id);
void idalloc_free_to_pool(struct id_alloc_pool **pool_ptr, uint32_t id);
void idalloc_drain_pool(struct id_alloc *alloc,
struct id_alloc_pool **pool_ptr);
uint32_t idalloc_allocate(struct id_alloc *alloc);
uint32_t idalloc_allocate_prefer_pool(struct id_alloc *alloc,
struct id_alloc_pool **pool_ptr);
uint32_t idalloc_reserve(struct id_alloc *alloc, uint32_t id);
struct id_alloc *idalloc_new(const char *name);
void idalloc_destroy(struct id_alloc *alloc);
#ifdef __cplusplus
}
#endif
#endif
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