/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* * The contents of this file are subject to the Mozilla Public * License Version 1.1 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is the Netscape Portable Runtime (NSPR). * * The Initial Developer of the Original Code is Netscape * Communications Corporation. Portions created by Netscape are * Copyright (C) 1998-2000 Netscape Communications Corporation. All * Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the * terms of the GNU General Public License Version 2 or later (the * "GPL"), in which case the provisions of the GPL are applicable * instead of those above. If you wish to allow use of your * version of this file only under the terms of the GPL and not to * allow others to use your version of this file under the MPL, * indicate your decision by deleting the provisions above and * replace them with the notice and other provisions required by * the GPL. If you do not delete the provisions above, a recipient * may use your version of this file under either the MPL or the * GPL. */ #ifndef prbit_h___ #define prbit_h___ #include "prtypes.h" PR_BEGIN_EXTERN_C /* ** A prbitmap_t is a long integer that can be used for bitmaps */ typedef unsigned long prbitmap_t; #define PR_TEST_BIT(_map,_bit) \ ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] & (1L << ((_bit) & (PR_BITS_PER_LONG-1)))) #define PR_SET_BIT(_map,_bit) \ ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] |= (1L << ((_bit) & (PR_BITS_PER_LONG-1)))) #define PR_CLEAR_BIT(_map,_bit) \ ((_map)[(_bit)>>PR_BITS_PER_LONG_LOG2] &= ~(1L << ((_bit) & (PR_BITS_PER_LONG-1)))) /* ** Compute the log of the least power of 2 greater than or equal to n */ NSPR_API(PRIntn) PR_CeilingLog2(PRUint32 i); /* ** Compute the log of the greatest power of 2 less than or equal to n */ NSPR_API(PRIntn) PR_FloorLog2(PRUint32 i); /* ** Macro version of PR_CeilingLog2: Compute the log of the least power of ** 2 greater than or equal to _n. The result is returned in _log2. */ #define PR_CEILING_LOG2(_log2,_n) \ PR_BEGIN_MACRO \ PRUint32 j_ = (PRUint32)(_n); \ (_log2) = 0; \ if ((j_) & ((j_)-1)) \ (_log2) += 1; \ if ((j_) >> 16) \ (_log2) += 16, (j_) >>= 16; \ if ((j_) >> 8) \ (_log2) += 8, (j_) >>= 8; \ if ((j_) >> 4) \ (_log2) += 4, (j_) >>= 4; \ if ((j_) >> 2) \ (_log2) += 2, (j_) >>= 2; \ if ((j_) >> 1) \ (_log2) += 1; \ PR_END_MACRO /* ** Macro version of PR_FloorLog2: Compute the log of the greatest power of ** 2 less than or equal to _n. The result is returned in _log2. ** ** This is equivalent to finding the highest set bit in the word. */ #define PR_FLOOR_LOG2(_log2,_n) \ PR_BEGIN_MACRO \ PRUint32 j_ = (PRUint32)(_n); \ (_log2) = 0; \ if ((j_) >> 16) \ (_log2) += 16, (j_) >>= 16; \ if ((j_) >> 8) \ (_log2) += 8, (j_) >>= 8; \ if ((j_) >> 4) \ (_log2) += 4, (j_) >>= 4; \ if ((j_) >> 2) \ (_log2) += 2, (j_) >>= 2; \ if ((j_) >> 1) \ (_log2) += 1; \ PR_END_MACRO PR_END_EXTERN_C #endif /* prbit_h___ */