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  1. /*
  2.  * Copyright (C) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - 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.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericadt
  30.  * @{
  31.  */
  32. /**
  33.  * @file
  34.  * @brief   Implementation of bitmap ADT.
  35.  *
  36.  * This file implements bitmap ADT and provides functions for
  37.  * setting and clearing ranges of bits.
  38.  */
  39.  
  40. #include <adt/bitmap.h>
  41. #include <typedefs.h>
  42. #include <arch/types.h>
  43. #include <align.h>
  44. #include <debug.h>
  45. #include <macros.h>
  46.  
  47. #define ALL_ONES    0xff
  48. #define ALL_ZEROES  0x00
  49.  
  50. /** Initialize bitmap.
  51.  *
  52.  * No portion of the bitmap is set or cleared by this function.
  53.  *
  54.  * @param bitmap Bitmap structure.
  55.  * @param map Address of the memory used to hold the map.
  56.  * @param bits Number of bits stored in bitmap.
  57.  */
  58. void bitmap_initialize(bitmap_t *bitmap, __u8 *map, count_t bits)
  59. {
  60.     bitmap->map = map;
  61.     bitmap->bits = bits;
  62. }
  63.  
  64. /** Set range of bits.
  65.  *
  66.  * @param bitmap Bitmap structure.
  67.  * @param start Starting bit.
  68.  * @param bits Number of bits to set.
  69.  */
  70. void bitmap_set_range(bitmap_t *bitmap, index_t start, count_t bits)
  71. {
  72.     index_t i=0;
  73.     index_t aligned_start;
  74.     count_t lub;        /* leading unaligned bits */
  75.     count_t amb;        /* aligned middle bits */
  76.     count_t tab;        /* trailing aligned bits */
  77.    
  78.     ASSERT(start + bits <= bitmap->bits);
  79.    
  80.     aligned_start = ALIGN_UP(start, 8);
  81.     lub = min(aligned_start - start, bits);
  82.     amb = bits > lub ? bits - lub : 0;
  83.     tab = amb % 8;
  84.    
  85.     if ( start + bits < aligned_start ) {
  86.         /*
  87.         * Set bits in the middle of byte
  88.         */
  89.         bitmap->map[start / 8] |= ((1 << lub)-1) << (start&7);
  90.         return;
  91.     }
  92.    
  93.     if (lub) {
  94.         /*
  95.          * Make sure to set any leading unaligned bits.
  96.          */
  97.         bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1);
  98.     }
  99.     for (i = 0; i < amb / 8; i++) {
  100.         /*
  101.          * The middle bits can be set byte by byte.
  102.          */
  103.         bitmap->map[aligned_start / 8 + i] = ALL_ONES;
  104.     }
  105.     if (tab) {
  106.         /*
  107.          * Make sure to set any trailing aligned bits.
  108.          */
  109.         bitmap->map[aligned_start / 8 + i] |= (1 << tab) - 1;
  110.     }
  111.    
  112. }
  113.  
  114. /** Clear range of bits.
  115.  *
  116.  * @param bitmap Bitmap structure.
  117.  * @param start Starting bit.
  118.  * @param bits Number of bits to clear.
  119.  */
  120. void bitmap_clear_range(bitmap_t *bitmap, index_t start, count_t bits)
  121. {
  122.     index_t i=0;
  123.     index_t aligned_start;
  124.     count_t lub;        /* leading unaligned bits */
  125.     count_t amb;        /* aligned middle bits */
  126.     count_t tab;        /* trailing aligned bits */
  127.    
  128.     ASSERT(start + bits <= bitmap->bits);
  129.    
  130.     aligned_start = ALIGN_UP(start, 8);
  131.     lub = min(aligned_start - start, bits);
  132.     amb = bits > lub ? bits - lub : 0;
  133.     tab = amb % 8;
  134.  
  135.     if ( start + bits < aligned_start )
  136.     {
  137.         /*
  138.         * Set bits in the middle of byte
  139.         */
  140.         bitmap->map[start / 8] &= ~(((1 << lub)-1) << (start&7));
  141.         return;
  142.     }
  143.  
  144.  
  145.     if (lub) {
  146.         /*
  147.          * Make sure to clear any leading unaligned bits.
  148.          */
  149.         bitmap->map[start / 8] &= (1 << (8 - lub)) - 1;
  150.     }
  151.     for (i = 0; i < amb / 8; i++) {
  152.         /*
  153.          * The middle bits can be cleared byte by byte.
  154.          */
  155.         bitmap->map[aligned_start / 8 + i] = ALL_ZEROES;
  156.     }
  157.     if (tab) {
  158.         /*
  159.          * Make sure to clear any trailing aligned bits.
  160.          */
  161.         bitmap->map[aligned_start / 8 + i] &= ~((1 << tab) - 1);
  162.     }
  163.  
  164. }
  165.  
  166. /** Copy portion of one bitmap into another bitmap.
  167.  *
  168.  * @param dst Destination bitmap.
  169.  * @param src Source bitmap.
  170.  * @param bits Number of bits to copy.
  171.  */
  172. void bitmap_copy(bitmap_t *dst, bitmap_t *src, count_t bits)
  173. {
  174.     index_t i;
  175.    
  176.     ASSERT(bits <= dst->bits);
  177.     ASSERT(bits <= src->bits);
  178.    
  179.     for (i = 0; i < bits / 8; i++)
  180.         dst->map[i] = src->map[i];
  181.    
  182.     if (bits % 8) {
  183.         bitmap_clear_range(dst, i * 8, bits % 8);
  184.         dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1);
  185.     }
  186. }
  187.  
  188. /** @}
  189.  */
  190.