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