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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 <arch/types.h>
  42. #include <align.h>
  43. #include <debug.h>
  44. #include <macros.h>
  45.  
  46. #define ALL_ONES    0xff
  47. #define ALL_ZEROES  0x00
  48.  
  49. /** Initialize bitmap.
  50.  *
  51.  * No portion of the bitmap is set or cleared by this function.
  52.  *
  53.  * @param bitmap Bitmap structure.
  54.  * @param map Address of the memory used to hold the map.
  55.  * @param bits Number of bits stored in bitmap.
  56.  */
  57. void bitmap_initialize(bitmap_t *bitmap, uint8_t *map, size_t bits)
  58. {
  59.     bitmap->map = map;
  60.     bitmap->bits = bits;
  61. }
  62.  
  63. /** Set range of bits.
  64.  *
  65.  * @param bitmap Bitmap structure.
  66.  * @param start Starting bit.
  67.  * @param bits Number of bits to set.
  68.  */
  69. void bitmap_set_range(bitmap_t *bitmap, size_t start, size_t bits)
  70. {
  71.     size_t i = 0;
  72.     size_t aligned_start;
  73.     size_t lub;     /* leading unaligned bits */
  74.     size_t amb;     /* aligned middle bits */
  75.     size_t tab;     /* trailing aligned bits */
  76.    
  77.     ASSERT(start + bits <= bitmap->bits);
  78.    
  79.     aligned_start = ALIGN_UP(start, 8);
  80.     lub = min(aligned_start - start, bits);
  81.     amb = bits > lub ? bits - lub : 0;
  82.     tab = amb % 8;
  83.    
  84.     if ( start + bits < aligned_start ) {
  85.         /*
  86.         * Set bits in the middle of byte
  87.         */
  88.         bitmap->map[start / 8] |= ((1 << lub)-1) << (start&7);
  89.         return;
  90.     }
  91.    
  92.     if (lub) {
  93.         /*
  94.          * Make sure to set any leading unaligned bits.
  95.          */
  96.         bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1);
  97.     }
  98.     for (i = 0; i < amb / 8; i++) {
  99.         /*
  100.          * The middle bits can be set byte by byte.
  101.          */
  102.         bitmap->map[aligned_start / 8 + i] = ALL_ONES;
  103.     }
  104.     if (tab) {
  105.         /*
  106.          * Make sure to set any trailing aligned bits.
  107.          */
  108.         bitmap->map[aligned_start / 8 + i] |= (1 << tab) - 1;
  109.     }
  110.    
  111. }
  112.  
  113. /** Clear range of bits.
  114.  *
  115.  * @param bitmap Bitmap structure.
  116.  * @param start Starting bit.
  117.  * @param bits Number of bits to clear.
  118.  */
  119. void bitmap_clear_range(bitmap_t *bitmap, size_t start, size_t bits)
  120. {
  121.     size_t i = 0;
  122.     size_t aligned_start;
  123.     size_t lub;     /* leading unaligned bits */
  124.     size_t amb;     /* aligned middle bits */
  125.     size_t tab;     /* trailing aligned bits */
  126.    
  127.     ASSERT(start + bits <= bitmap->bits);
  128.    
  129.     aligned_start = ALIGN_UP(start, 8);
  130.     lub = min(aligned_start - start, bits);
  131.     amb = bits > lub ? bits - lub : 0;
  132.     tab = amb % 8;
  133.  
  134.     if ( start + bits < aligned_start )
  135.     {
  136.         /*
  137.         * Set bits in the middle of byte
  138.         */
  139.         bitmap->map[start / 8] &= ~(((1 << lub)-1) << (start&7));
  140.         return;
  141.     }
  142.  
  143.  
  144.     if (lub) {
  145.         /*
  146.          * Make sure to clear any leading unaligned bits.
  147.          */
  148.         bitmap->map[start / 8] &= (1 << (8 - lub)) - 1;
  149.     }
  150.     for (i = 0; i < amb / 8; i++) {
  151.         /*
  152.          * The middle bits can be cleared byte by byte.
  153.          */
  154.         bitmap->map[aligned_start / 8 + i] = ALL_ZEROES;
  155.     }
  156.     if (tab) {
  157.         /*
  158.          * Make sure to clear any trailing aligned bits.
  159.          */
  160.         bitmap->map[aligned_start / 8 + i] &= ~((1 << tab) - 1);
  161.     }
  162.  
  163. }
  164.  
  165. /** Copy portion of one bitmap into another bitmap.
  166.  *
  167.  * @param dst Destination bitmap.
  168.  * @param src Source bitmap.
  169.  * @param bits Number of bits to copy.
  170.  */
  171. void bitmap_copy(bitmap_t *dst, bitmap_t *src, size_t bits)
  172. {
  173.     size_t i;
  174.    
  175.     ASSERT(bits <= dst->bits);
  176.     ASSERT(bits <= src->bits);
  177.    
  178.     for (i = 0; i < bits / 8; i++)
  179.         dst->map[i] = src->map[i];
  180.    
  181.     if (bits % 8) {
  182.         bitmap_clear_range(dst, i * 8, bits % 8);
  183.         dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1);
  184.     }
  185. }
  186.  
  187. /** @}
  188.  */
  189.