Line data    Source code

       1             : /*
       2             :  * Copyright (c) 2011, Andrea Mazzoleni. All rights reserved.
       3             :  *
       4             :  * Redistribution and use in source and binary forms, with or without
       5             :  * modification, are permitted provided that the following conditions
       6             :  * are met:
       7             :  *
       8             :  * 1. Redistributions of source code must retain the above copyright
       9             :  *    notice, this list of conditions and the following disclaimer.
      10             :  *
      11             :  * 2. Redistributions in binary form must reproduce the above copyright
      12             :  *    notice, this list of conditions and the following disclaimer in the
      13             :  *    documentation and/or other materials provided with the distribution.
      14             :  *
      15             :  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
      16             :  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      17             :  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      18             :  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
      19             :  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
      20             :  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
      21             :  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
      22             :  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
      23             :  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
      24             :  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
      25             :  * POSSIBILITY OF SUCH DAMAGE.
      26             :  */
      27             : 
      28             : /** \file
      29             :  * Dynamic array based on segments of exponential growing size.
      30             :  *
      31             :  * This array is able to grow dynamically upon request, without any reallocation.
      32             :  *
      33             :  * The grow operation involves an allocation of a new array segment, without reallocating
      34             :  * the already used memory, and then not increasing the heap fragmentation.
      35             :  * This also implies that the address of the stored elements never change.
      36             :  *
      37             :  * Allocated segments grow in size exponentially.
      38             :  */
      39             : 
      40             : #ifndef __TOMMYARRAY_H
      41             : #define __TOMMYARRAY_H
      42             : 
      43             : #include "tommytypes.h"
      44             : 
      45             : #include <assert.h> /* for assert */
      46             : 
      47             : /******************************************************************************/
      48             : /* array */
      49             : 
      50             : /**
      51             :  * Initial and minimal size of the array expressed as a power of 2.
      52             :  * The initial size is 2^TOMMY_ARRAY_BIT.
      53             :  */
      54             : #define TOMMY_ARRAY_BIT 6
      55             : 
      56             : /**
      57             :  * Array container type.
      58             :  * \note Don't use internal fields directly, but access the container only using functions.
      59             :  */
      60             : typedef struct tommy_array_struct {
      61             :         void** bucket[TOMMY_SIZE_BIT]; /**< Dynamic array of buckets. */
      62             :         tommy_size_t bucket_max; /**< Number of buckets. */
      63             :         tommy_size_t count; /**< Number of initialized elements in the array. */
      64             :         tommy_uint_t bucket_bit; /**< Bits used in the bit mask. */
      65             : } tommy_array;
      66             : 
      67             : /**
      68             :  * Initializes the array.
      69             :  */
      70             : void tommy_array_init(tommy_array* array);
      71             : 
      72             : /**
      73             :  * Deinitializes the array.
      74             :  */
      75             : void tommy_array_done(tommy_array* array);
      76             : 
      77             : /**
      78             :  * Grows the size up to the specified value.
      79             :  * All the new elements in the array are initialized with the 0 value.
      80             :  */
      81             : void tommy_array_grow(tommy_array* array, tommy_size_t size);
      82             : 
      83             : /**
      84             :  * Gets a reference of the element at the specified position.
      85             :  * You must be sure that space for this position is already
      86             :  * allocated calling tommy_array_grow().
      87             :  */
      88     8302193 : tommy_inline void** tommy_array_ref(tommy_array* array, tommy_size_t pos)
      89             : {
      90             :         tommy_uint_t bsr;
      91             : 
      92     8302193 :         assert(pos < array->count);
      93             : 
      94             :         /* get the highest bit set, in case of all 0, return 0 */
      95     8302193 :         bsr = tommy_ilog2(pos | 1);
      96             : 
      97     8302193 :         return &array->bucket[bsr][pos];
      98             : }
      99             : 
     100             : /**
     101             :  * Sets the element at the specified position.
     102             :  * You must be sure that space for this position is already
     103             :  * allocated calling tommy_array_grow().
     104             :  */
     105        2221 : tommy_inline void tommy_array_set(tommy_array* array, tommy_size_t pos, void* element)
     106             : {
     107        2221 :         *tommy_array_ref(array, pos) = element;
     108        2221 : }
     109             : 
     110             : /**
     111             :  * Gets the element at the specified position.
     112             :  * You must be sure that space for this position is already
     113             :  * allocated calling tommy_array_grow().
     114             :  */
     115     8299972 : tommy_inline void* tommy_array_get(tommy_array* array, tommy_size_t pos)
     116             : {
     117     8299972 :         return *tommy_array_ref(array, pos);
     118             : }
     119             : 
     120             : /**
     121             :  * Grows and inserts a new element at the end of the array.
     122             :  */
     123         256 : tommy_inline void tommy_array_insert(tommy_array* array, void* element)
     124             : {
     125         256 :         tommy_size_t pos = array->count;
     126             : 
     127         256 :         tommy_array_grow(array, pos + 1);
     128             : 
     129         256 :         tommy_array_set(array, pos, element);
     130         256 : }
     131             : 
     132             : /**
     133             :  * Gets the initialized size of the array.
     134             :  */
     135     1578231 : tommy_inline tommy_size_t tommy_array_size(tommy_array* array)
     136             : {
     137     1578231 :         return array->count;
     138             : }
     139             : 
     140             : /**
     141             :  * Gets the size of allocated memory.
     142             :  */
     143             : tommy_size_t tommy_array_memory_usage(tommy_array* array);
     144             : 
     145             : #endif
     146             :