| /* -*- 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___ */ |