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regional.h revision 1.1.1.1.2.2 
      1 /*
      2  * regional.h -- region based memory allocator.
      3  *
      4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
      5  *
      6  * This software is open source.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * Redistributions of source code must retain the above copyright notice,
     13  * this list of conditions and the following disclaimer.
     14  *
     15  * Redistributions in binary form must reproduce the above copyright notice,
     16  * this list of conditions and the following disclaimer in the documentation
     17  * and/or other materials provided with the distribution.
     18  *
     19  * Neither the name of the NLNET LABS nor the names of its contributors may
     20  * be used to endorse or promote products derived from this software without
     21  * specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 /**
     37  * \file
     38  * Regional allocator. Allocates small portions of of larger chunks.
     39  * Based on region-allocator from NSD, but rewritten to be light.
     40  *
     41  * Different from (nsd) region-allocator.h
     42  * 	o does not have recycle bin
     43  * 	o does not collect stats; just enough to answer get_mem() in use.
     44  * 	o does not keep cleanup list
     45  * 	o does not have function pointers to setup
     46  * 	o allocs the regional struct inside the first block.
     47  * 	o can take a block to create regional from.
     48  * 	o blocks and large allocations are kept on singly linked lists.
     49  */
     50 
     51 #ifndef UTIL_REGIONAL_H_
     52 #define UTIL_REGIONAL_H_
     53 
     54 /**
     55  * the regional* is the first block*.
     56  * every block has a ptr to the next in first bytes.
     57  * and so does the regional struct, which is the first block.
     58  */
     59 struct regional
     60 {
     61 	/**
     62 	 * next chunk. NULL if first chunk is the only chunk.
     63 	 * first inside that chunk is the char* next pointer.
     64 	 * When regional_free_all() has been called this value is NULL.
     65 	 */
     66 	char* next;
     67 	/** first large object, cast to char** to obtain next ptr */
     68 	char* large_list;
     69 	/** total large size */
     70 	size_t total_large;
     71 	/** initial chunk size */
     72 	size_t first_size;
     73 	/** number of bytes available in the current chunk. */
     74 	size_t available;
     75 	/** current chunk data position. */
     76 	char* data;
     77 };
     78 
     79 /**
     80  * Create a new regional.
     81  * @return: newly allocated regional.
     82  */
     83 struct regional* regional_create(void);
     84 
     85 /**
     86  * Create a new region, with custom settings.
     87  * @param size: length of first block.
     88  * @return: newly allocated regional.
     89  */
     90 struct regional* regional_create_custom(size_t size);
     91 
     92 /**
     93  * Free all memory associated with regional. Only keeps the first block with
     94  * the regional inside it.
     95  * @param r: the region.
     96  */
     97 void regional_free_all(struct regional *r);
     98 
     99 /**
    100  * Destroy regional.  All memory associated with regional is freed as if
    101  * regional_free_all was called, as well as destroying the regional struct.
    102  * @param r: to delete.
    103  */
    104 void regional_destroy(struct regional *r);
    105 
    106 /**
    107  * Allocate size bytes of memory inside regional.  The memory is
    108  * deallocated when region_free_all is called for this region.
    109  * @param r: the region.
    110  * @param size: number of bytes.
    111  * @return: pointer to memory allocated.
    112  */
    113 void *regional_alloc(struct regional *r, size_t size);
    114 
    115 /**
    116  * Allocate size bytes of memory inside regional and copy INIT into it.
    117  * The memory is deallocated when region_free_all is called for this
    118  * region.
    119  * @param r: the region.
    120  * @param init: to copy.
    121  * @param size: number of bytes.
    122  * @return: pointer to memory allocated.
    123  */
    124 void *regional_alloc_init(struct regional* r, const void *init, size_t size);
    125 
    126 /**
    127  * Allocate size bytes of memory inside regional that are initialized to
    128  * 0.  The memory is deallocated when region_free_all is called for
    129  * this region.
    130  * @param r: the region.
    131  * @param size: number of bytes.
    132  * @return: pointer to memory allocated.
    133  */
    134 void *regional_alloc_zero(struct regional *r, size_t size);
    135 
    136 /**
    137  * Duplicate string and allocate the result in regional.
    138  * @param r: the region.
    139  * @param string: null terminated string.
    140  * @return: pointer to memory allocated.
    141  */
    142 char *regional_strdup(struct regional *r, const char *string);
    143 
    144 /** Debug print regional statistics to log */
    145 void regional_log_stats(struct regional *r);
    146 
    147 /** get total memory size in use by region */
    148 size_t regional_get_mem(struct regional* r);
    149 
    150 #endif /* UTIL_REGIONAL_H_ */
    151