/gecko_api/include/prbit.h
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 38#ifndef prbit_h___ 39#define prbit_h___ 40 41#include "prtypes.h" 42PR_BEGIN_EXTERN_C 43 44/* 45** A prbitmap_t is a long integer that can be used for bitmaps 46*/ 47typedef unsigned long prbitmap_t; 48 49#define PR_TEST_BIT(_map,_bit) \ 50 ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] & (1L << ((_bit) & (PR_BITS_PER_LONG-1)))) 51#define PR_SET_BIT(_map,_bit) \ 52 ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] |= (1L << ((_bit) & (PR_BITS_PER_LONG-1)))) 53#define PR_CLEAR_BIT(_map,_bit) \ 54 ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] &= ~(1L << ((_bit) & (PR_BITS_PER_LONG-1)))) 55 56/* 57** Compute the log of the least power of 2 greater than or equal to n 58*/ 59NSPR_API(PRIntn) PR_CeilingLog2(PRUint32 i); 60 61/* 62** Compute the log of the greatest power of 2 less than or equal to n 63*/ 64NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i); 65 66/* 67** Macro version of PR_CeilingLog2: Compute the log of the least power of 68** 2 greater than or equal to _n. The result is returned in _log2. 69*/ 70#define PR_CEILING_LOG2(_log2,_n) \ 71 PR_BEGIN_MACRO \ 72 PRUint32 j_ = (PRUint32)(_n); \ 73 (_log2) = 0; \ 74 if ((j_) & ((j_)-1)) \ 75 (_log2) += 1; \ 76 if ((j_) >> 16) \ 77 (_log2) += 16, (j_) >>= 16; \ 78 if ((j_) >> 8) \ 79 (_log2) += 8, (j_) >>= 8; \ 80 if ((j_) >> 4) \ 81 (_log2) += 4, (j_) >>= 4; \ 82 if ((j_) >> 2) \ 83 (_log2) += 2, (j_) >>= 2; \ 84 if ((j_) >> 1) \ 85 (_log2) += 1; \ 86 PR_END_MACRO 87 88/* 89** Macro version of PR_FloorLog2: Compute the log of the greatest power of 90** 2 less than or equal to _n. The result is returned in _log2. 91** 92** This is equivalent to finding the highest set bit in the word. 93*/ 94#define PR_FLOOR_LOG2(_log2,_n) \ 95 PR_BEGIN_MACRO \ 96 PRUint32 j_ = (PRUint32)(_n); \ 97 (_log2) = 0; \ 98 if ((j_) >> 16) \ 99 (_log2) += 16, (j_) >>= 16; \ 100 if ((j_) >> 8) \ 101 (_log2) += 8, (j_) >>= 8; \ 102 if ((j_) >> 4) \ 103 (_log2) += 4, (j_) >>= 4; \ 104 if ((j_) >> 2) \ 105 (_log2) += 2, (j_) >>= 2; \ 106 if ((j_) >> 1) \ 107 (_log2) += 1; \ 108 PR_END_MACRO 109 110/* 111** Macros for rotate left and right. The argument 'a' must be an unsigned 112** 32-bit integer type such as PRUint32. 113** 114** There is no rotate operation in the C Language, so the construct 115** (a << 4) | (a >> 28) is frequently used instead. Most compilers convert 116** this to a rotate instruction, but MSVC doesn't without a little help. 117** To get MSVC to generate a rotate instruction, we have to use the _rotl 118** or _rotr intrinsic and use a pragma to make it inline. 119** 120** Note: MSVC in VS2005 will do an inline rotate instruction on the above 121** construct. 122*/ 123 124#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \ 125 defined(_M_X64)) 126#include <stdlib.h> 127#pragma intrinsic(_rotl, _rotr) 128#define PR_ROTATE_LEFT32(a, bits) _rotl(a, bits) 129#define PR_ROTATE_RIGHT32(a, bits) _rotr(a, bits) 130#else 131#define PR_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits)))) 132#define PR_ROTATE_RIGHT32(a, bits) (((a) >> (bits)) | ((a) << (32 - (bits)))) 133#endif 134 135PR_END_EXTERN_C 136#endif /* prbit_h___ */