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/gecko_api/include/prbit.h

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C Header | 136 lines | 57 code | 11 blank | 68 comment | 14 complexity | 15598efa055554cff77be7820d9876aa MD5 | raw file
  1. /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
  2. /* ***** BEGIN LICENSE BLOCK *****
  3. * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  4. *
  5. * The contents of this file are subject to the Mozilla Public License Version
  6. * 1.1 (the "License"); you may not use this file except in compliance with
  7. * the License. You may obtain a copy of the License at
  8. * http://www.mozilla.org/MPL/
  9. *
  10. * Software distributed under the License is distributed on an "AS IS" basis,
  11. * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12. * for the specific language governing rights and limitations under the
  13. * License.
  14. *
  15. * The Original Code is the Netscape Portable Runtime (NSPR).
  16. *
  17. * The Initial Developer of the Original Code is
  18. * Netscape Communications Corporation.
  19. * Portions created by the Initial Developer are Copyright (C) 1998-2000
  20. * the Initial Developer. All Rights Reserved.
  21. *
  22. * Contributor(s):
  23. *
  24. * Alternatively, the contents of this file may be used under the terms of
  25. * either the GNU General Public License Version 2 or later (the "GPL"), or
  26. * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27. * in which case the provisions of the GPL or the LGPL are applicable instead
  28. * of those above. If you wish to allow use of your version of this file only
  29. * under the terms of either the GPL or the LGPL, and not to allow others to
  30. * use your version of this file under the terms of the MPL, indicate your
  31. * decision by deleting the provisions above and replace them with the notice
  32. * and other provisions required by the GPL or the LGPL. If you do not delete
  33. * the provisions above, a recipient may use your version of this file under
  34. * the terms of any one of the MPL, the GPL or the LGPL.
  35. *
  36. * ***** END LICENSE BLOCK ***** */
  37. #ifndef prbit_h___
  38. #define prbit_h___
  39. #include "prtypes.h"
  40. PR_BEGIN_EXTERN_C
  41. /*
  42. ** A prbitmap_t is a long integer that can be used for bitmaps
  43. */
  44. typedef unsigned long prbitmap_t;
  45. #define PR_TEST_BIT(_map,_bit) \
  46. ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] & (1L << ((_bit) & (PR_BITS_PER_LONG-1))))
  47. #define PR_SET_BIT(_map,_bit) \
  48. ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] |= (1L << ((_bit) & (PR_BITS_PER_LONG-1))))
  49. #define PR_CLEAR_BIT(_map,_bit) \
  50. ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] &= ~(1L << ((_bit) & (PR_BITS_PER_LONG-1))))
  51. /*
  52. ** Compute the log of the least power of 2 greater than or equal to n
  53. */
  54. NSPR_API(PRIntn) PR_CeilingLog2(PRUint32 i);
  55. /*
  56. ** Compute the log of the greatest power of 2 less than or equal to n
  57. */
  58. NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i);
  59. /*
  60. ** Macro version of PR_CeilingLog2: Compute the log of the least power of
  61. ** 2 greater than or equal to _n. The result is returned in _log2.
  62. */
  63. #define PR_CEILING_LOG2(_log2,_n) \
  64. PR_BEGIN_MACRO \
  65. PRUint32 j_ = (PRUint32)(_n); \
  66. (_log2) = 0; \
  67. if ((j_) & ((j_)-1)) \
  68. (_log2) += 1; \
  69. if ((j_) >> 16) \
  70. (_log2) += 16, (j_) >>= 16; \
  71. if ((j_) >> 8) \
  72. (_log2) += 8, (j_) >>= 8; \
  73. if ((j_) >> 4) \
  74. (_log2) += 4, (j_) >>= 4; \
  75. if ((j_) >> 2) \
  76. (_log2) += 2, (j_) >>= 2; \
  77. if ((j_) >> 1) \
  78. (_log2) += 1; \
  79. PR_END_MACRO
  80. /*
  81. ** Macro version of PR_FloorLog2: Compute the log of the greatest power of
  82. ** 2 less than or equal to _n. The result is returned in _log2.
  83. **
  84. ** This is equivalent to finding the highest set bit in the word.
  85. */
  86. #define PR_FLOOR_LOG2(_log2,_n) \
  87. PR_BEGIN_MACRO \
  88. PRUint32 j_ = (PRUint32)(_n); \
  89. (_log2) = 0; \
  90. if ((j_) >> 16) \
  91. (_log2) += 16, (j_) >>= 16; \
  92. if ((j_) >> 8) \
  93. (_log2) += 8, (j_) >>= 8; \
  94. if ((j_) >> 4) \
  95. (_log2) += 4, (j_) >>= 4; \
  96. if ((j_) >> 2) \
  97. (_log2) += 2, (j_) >>= 2; \
  98. if ((j_) >> 1) \
  99. (_log2) += 1; \
  100. PR_END_MACRO
  101. /*
  102. ** Macros for rotate left and right. The argument 'a' must be an unsigned
  103. ** 32-bit integer type such as PRUint32.
  104. **
  105. ** There is no rotate operation in the C Language, so the construct
  106. ** (a << 4) | (a >> 28) is frequently used instead. Most compilers convert
  107. ** this to a rotate instruction, but MSVC doesn't without a little help.
  108. ** To get MSVC to generate a rotate instruction, we have to use the _rotl
  109. ** or _rotr intrinsic and use a pragma to make it inline.
  110. **
  111. ** Note: MSVC in VS2005 will do an inline rotate instruction on the above
  112. ** construct.
  113. */
  114. #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \
  115. defined(_M_X64))
  116. #include <stdlib.h>
  117. #pragma intrinsic(_rotl, _rotr)
  118. #define PR_ROTATE_LEFT32(a, bits) _rotl(a, bits)
  119. #define PR_ROTATE_RIGHT32(a, bits) _rotr(a, bits)
  120. #else
  121. #define PR_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits))))
  122. #define PR_ROTATE_RIGHT32(a, bits) (((a) >> (bits)) | ((a) << (32 - (bits))))
  123. #endif
  124. PR_END_EXTERN_C
  125. #endif /* prbit_h___ */