Line data    Source code

       1             : // SPDX-License-Identifier: BSD-2-Clause
       2             : // Copyright (C) 2011 Andrea Mazzoleni
       3             : 
       4             : /** \file
       5             :  * Dynamic array based on segments of exponentially growing size.
       6             :  *
       7             :  * This array is able to grow dynamically upon request, without any reallocation.
       8             :  *
       9             :  * The grow operation involves an allocation of a new array segment, without reallocating
      10             :  * the already used memory, and thus **not increasing** the heap fragmentation.
      11             :  * This also implies that the address of the stored elements never change.
      12             :  *
      13             :  * Allocated segments grow in size exponentially.
      14             :  */
      15             : 
      16             : #ifndef __TOMMYARRAY_H
      17             : #define __TOMMYARRAY_H
      18             : 
      19             : #include "tommytypes.h"
      20             : 
      21             : #include <assert.h> /* for assert */
      22             : 
      23             : /******************************************************************************/
      24             : /* array */
      25             : 
      26             : /**
      27             :  * Initial and minimal size of the array expressed as a power of 2.
      28             :  * The initial size is 2^TOMMY_ARRAY_BIT.
      29             :  */
      30             : #define TOMMY_ARRAY_BIT 6
      31             : 
      32             : /**
      33             :  * Array container type.
      34             :  * \note Don't use internal fields directly, but access the container only using functions.
      35             :  */
      36             : typedef struct tommy_array_struct {
      37             :         void** bucket[TOMMY_SIZE_BIT]; /**< Dynamic array of buckets. */
      38             :         tommy_size_t bucket_max; /**< Number of buckets. */
      39             :         tommy_size_t count; /**< Number of initialized elements in the array. */
      40             :         tommy_uint_t bucket_bit; /**< Bits used in the bit mask. */
      41             : } tommy_array;
      42             : 
      43             : /**
      44             :  * Initializes the array.
      45             :  */
      46             : TOMMY_API void tommy_array_init(tommy_array* array);
      47             : 
      48             : /**
      49             :  * Deinitializes the array.
      50             :  */
      51             : TOMMY_API void tommy_array_done(tommy_array* array);
      52             : 
      53             : /**
      54             :  * Grows the size up to the specified value.
      55             :  * All the new elements in the array are initialized with the 0 value.
      56             :  */
      57             : TOMMY_API void tommy_array_grow(tommy_array* array, tommy_size_t size);
      58             : 
      59             : /**
      60             :  * Gets a reference of the element at the specified position.
      61             :  * You must be sure that space for this position is already
      62             :  * allocated calling tommy_array_grow().
      63             :  */
      64     8946200 : tommy_inline void** tommy_array_ref(tommy_array* array, tommy_size_t pos)
      65             : {
      66             :         tommy_uint_t bsr;
      67             : 
      68     8946200 :         assert(pos < array->count);
      69             : 
      70             :         /* get the highest bit set, in case of all 0, return 0 */
      71     8946200 :         bsr = tommy_ilog2(pos | 1);
      72             : 
      73     8946200 :         return &array->bucket[bsr][pos];
      74             : }
      75             : 
      76             : /**
      77             :  * Sets the element at the specified position.
      78             :  * You must be sure that space for this position is already
      79             :  * allocated calling tommy_array_grow().
      80             :  */
      81        2454 : tommy_inline void tommy_array_set(tommy_array* array, tommy_size_t pos, void* element)
      82             : {
      83        2454 :         *tommy_array_ref(array, pos) = element;
      84        2454 : }
      85             : 
      86             : /**
      87             :  * Gets the element at the specified position.
      88             :  * You must be sure that space for this position is already
      89             :  * allocated calling tommy_array_grow().
      90             :  */
      91     8943746 : tommy_inline void* tommy_array_get(tommy_array* array, tommy_size_t pos)
      92             : {
      93     8943746 :         return *tommy_array_ref(array, pos);
      94             : }
      95             : 
      96             : /**
      97             :  * Grows and inserts a new element at the end of the array.
      98             :  */
      99         256 : tommy_inline void tommy_array_insert(tommy_array* array, void* element)
     100             : {
     101         256 :         tommy_size_t pos = array->count;
     102             : 
     103         256 :         tommy_array_grow(array, pos + 1);
     104             : 
     105         256 :         tommy_array_set(array, pos, element);
     106         256 : }
     107             : 
     108             : /**
     109             :  * Gets the initialized size of the array.
     110             :  */
     111     1711703 : tommy_inline tommy_size_t tommy_array_size(tommy_array* array)
     112             : {
     113     1711703 :         return array->count;
     114             : }
     115             : 
     116             : /**
     117             :  * Gets the size of allocated memory.
     118             :  */
     119             : TOMMY_API tommy_size_t tommy_array_memory_usage(tommy_array* array);
     120             : 
     121             : #endif