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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 ADT
  30.  * @ingroup kernel
  31.  * @{
  32.  */
  33. /**
  34.  * @file
  35.  * @brief   Implementation of bitmap ADT.
  36.  *
  37.  * This file implements bitmap ADT and provides functions for
  38.  * setting and clearing ranges of bits.
  39.  */
  40.  
  41. #include <adt/bitmap.h>
  42. #include <typedefs.h>
  43. #include <arch/types.h>
  44. #include <align.h>
  45. #include <debug.h>
  46. #include <macros.h>
  47.  
  48. #define ALL_ONES    0xff
  49. #define ALL_ZEROES  0x00
  50.  
  51. /** Initialize bitmap.
  52.  *
  53.  * No portion of the bitmap is set or cleared by this function.
  54.  *
  55.  * @param bitmap Bitmap structure.
  56.  * @param map Address of the memory used to hold the map.
  57.  * @param bits Number of bits stored in bitmap.
  58.  */
  59. void bitmap_initialize(bitmap_t *bitmap, __u8 *map, count_t bits)
  60. {
  61.     bitmap->map = map;
  62.     bitmap->bits = bits;
  63. }
  64.  
  65. /** Set range of bits.
  66.  *
  67.  * @param bitmap Bitmap structure.
  68.  * @param start Starting bit.
  69.  * @param bits Number of bits to set.
  70.  */
  71. void bitmap_set_range(bitmap_t *bitmap, index_t start, count_t bits)
  72. {
  73.     index_t i=0;
  74.     index_t aligned_start;
  75.     count_t lub;        /* leading unaligned bits */
  76.     count_t amb;        /* aligned middle bits */
  77.     count_t tab;        /* trailing aligned bits */
  78.    
  79.     ASSERT(start + bits <= bitmap->bits);
  80.    
  81.     aligned_start = ALIGN_UP(start, 8);
  82.     lub = min(aligned_start - start, bits);
  83.     amb = bits > lub ? bits - lub : 0;
  84.     tab = amb % 8;
  85.    
  86.     if ( start + bits < aligned_start ) {
  87.         /*
  88.         * Set bits in the middle of byte
  89.         */
  90.         bitmap->map[start / 8] |= ((1 << lub)-1) << (start&7);
  91.         return;
  92.     }
  93.    
  94.     if (lub) {
  95.         /*
  96.          * Make sure to set any leading unaligned bits.
  97.          */
  98.         bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1);
  99.     }
  100.     for (i = 0; i < amb / 8; i++) {
  101.         /*
  102.          * The middle bits can be set byte by byte.
  103.          */
  104.         bitmap->map[aligned_start / 8 + i] = ALL_ONES;
  105.     }
  106.     if (tab) {
  107.         /*
  108.          * Make sure to set any trailing aligned bits.
  109.          */
  110.         bitmap->map[aligned_start / 8 + i] |= (1 << tab) - 1;
  111.     }
  112.    
  113. }
  114.  
  115. /** Clear range of bits.
  116.  *
  117.  * @param bitmap Bitmap structure.
  118.  * @param start Starting bit.
  119.  * @param bits Number of bits to clear.
  120.  */
  121. void bitmap_clear_range(bitmap_t *bitmap, index_t start, count_t bits)
  122. {
  123.     index_t i=0;
  124.     index_t aligned_start;
  125.     count_t lub;        /* leading unaligned bits */
  126.     count_t amb;        /* aligned middle bits */
  127.     count_t tab;        /* trailing aligned bits */
  128.    
  129.     ASSERT(start + bits <= bitmap->bits);
  130.    
  131.     aligned_start = ALIGN_UP(start, 8);
  132.     lub = min(aligned_start - start, bits);
  133.     amb = bits > lub ? bits - lub : 0;
  134.     tab = amb % 8;
  135.  
  136.     if ( start + bits < aligned_start )
  137.     {
  138.         /*
  139.         * Set bits in the middle of byte
  140.         */
  141.         bitmap->map[start / 8] &= ~(((1 << lub)-1) << (start&7));
  142.         return;
  143.     }
  144.  
  145.  
  146.     if (lub) {
  147.         /*
  148.          * Make sure to clear any leading unaligned bits.
  149.          */
  150.         bitmap->map[start / 8] &= (1 << (8 - lub)) - 1;
  151.     }
  152.     for (i = 0; i < amb / 8; i++) {
  153.         /*
  154.          * The middle bits can be cleared byte by byte.
  155.          */
  156.         bitmap->map[aligned_start / 8 + i] = ALL_ZEROES;
  157.     }
  158.     if (tab) {
  159.         /*
  160.          * Make sure to clear any trailing aligned bits.
  161.          */
  162.         bitmap->map[aligned_start / 8 + i] &= ~((1 << tab) - 1);
  163.     }
  164.  
  165. }
  166.  
  167. /** Copy portion of one bitmap into another bitmap.
  168.  *
  169.  * @param dst Destination bitmap.
  170.  * @param src Source bitmap.
  171.  * @param bits Number of bits to copy.
  172.  */
  173. void bitmap_copy(bitmap_t *dst, bitmap_t *src, count_t bits)
  174. {
  175.     index_t i;
  176.    
  177.     ASSERT(bits <= dst->bits);
  178.     ASSERT(bits <= src->bits);
  179.    
  180.     for (i = 0; i < bits / 8; i++)
  181.         dst->map[i] = src->map[i];
  182.    
  183.     if (bits % 8) {
  184.         bitmap_clear_range(dst, i * 8, bits % 8);
  185.         dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1);
  186.     }
  187. }
  188.  
  189.  /** @}
  190.  */
  191.  
  192.