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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. #include <adt/bitmap.h>
  30. #include <typedefs.h>
  31. #include <arch/types.h>
  32. #include <align.h>
  33. #include <debug.h>
  34.  
  35. #define ALL_ONES    0xff
  36. #define ALL_ZEROES  0x00
  37.  
  38. /** Initialize bitmap.
  39.  *
  40.  * No portion of the bitmap is set or cleared by this function.
  41.  *
  42.  * @param bitmap Bitmap structure.
  43.  * @param map Address of the memory used to hold the map.
  44.  * @param bits Number of bits stored in bitmap.
  45.  */
  46. void bitmap_initialize(bitmap_t *bitmap, __u8 *map, count_t bits)
  47. {
  48.     bitmap->map = map;
  49.     bitmap->bits = bits;
  50. }
  51.  
  52. /** Set range of bits.
  53.  *
  54.  * @param bitmap Bitmap structure.
  55.  * @param start Starting bit.
  56.  * @param bits Number of bits to set.
  57.  */
  58. void bitmap_set_range(bitmap_t *bitmap, index_t start, count_t bits)
  59. {
  60.     index_t i;
  61.     index_t aligned_start;
  62.     count_t lub;        /* leading unaligned bits */
  63.     count_t tub;        /* trailing unaligned bits */
  64.    
  65.     ASSERT(start + bits <= bitmap->bits);
  66.    
  67.     aligned_start = ALIGN_UP(start, 8);
  68.     lub = aligned_start - start;
  69.     tub = (bits - lub) % 8;
  70.    
  71.     if (lub) {
  72.         /*
  73.          * Make sure to set any leading unaligned bits.
  74.          */
  75.         bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1);
  76.     }
  77.     for (i = 0; i < (bits - lub) / 8; i++) {
  78.         /*
  79.          * The middle bits can be set byte by byte.
  80.          */
  81.         bitmap->map[aligned_start / 8 + i] = ALL_ONES;
  82.     }
  83.     if (tub) {
  84.         /*
  85.          * Make sure to set any trailing unaligned bits.
  86.          */
  87.         bitmap->map[aligned_start / 8 + i] |= (1 << tub) - 1;
  88.     }
  89.    
  90. }
  91.  
  92. /** Clear range of bits.
  93.  *
  94.  * @param bitmap Bitmap structure.
  95.  * @param start Starting bit.
  96.  * @param bits Number of bits to clear.
  97.  */
  98. void bitmap_clear_range(bitmap_t *bitmap, index_t start, count_t bits)
  99. {
  100.     index_t i;
  101.     index_t aligned_start;
  102.     count_t lub;        /* leading unaligned bits */
  103.     count_t tub;        /* trailing unaligned bits */
  104.    
  105.     ASSERT(start + bits <= bitmap->bits);
  106.    
  107.     aligned_start = ALIGN_UP(start, 8);
  108.     lub = aligned_start - start;
  109.     tub = (bits - lub) % 8;
  110.    
  111.     if (lub) {
  112.         /*
  113.          * Make sure to clear any leading unaligned bits.
  114.          */
  115.         bitmap->map[start / 8] &= (1 << (8 - lub)) - 1;
  116.     }
  117.     for (i = 0; i < (bits - lub) / 8; i++) {
  118.         /*
  119.          * The middle bits can be cleared byte by byte.
  120.          */
  121.         bitmap->map[aligned_start / 8 + i] = ALL_ZEROES;
  122.     }
  123.     if (tub) {
  124.         /*
  125.          * Make sure to clear any trailing unaligned bits.
  126.          */
  127.         bitmap->map[aligned_start / 8 + i] &= ~((1 << tub) - 1);
  128.     }
  129.    
  130. }
  131.  
  132. /** Copy portion of one bitmap into another bitmap.
  133.  *
  134.  * @param dst Destination bitmap.
  135.  * @param src Source bitmap.
  136.  * @param bits Number of bits to copy.
  137.  */
  138. void bitmap_copy(bitmap_t *dst, bitmap_t *src, count_t bits)
  139. {
  140.     index_t i;
  141.    
  142.     ASSERT(bits <= dst->bits);
  143.     ASSERT(bits <= src->bits);
  144.    
  145.     for (i = 0; i < bits / 8; i++)
  146.         dst->map[i] = src->map[i];
  147.    
  148.     if (bits % 8) {
  149.         bitmap_clear_range(dst, i * 8, bits % 8);
  150.         dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1);
  151.     }
  152. }
  153.