/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* 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 Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
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* decision by deleting the provisions above and replace them with the notice
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* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef jsbit_h___
#define jsbit_h___
#include "jstypes.h"
JS_BEGIN_EXTERN_C
/*
** A jsbitmap_t is a long integer that can be used for bitmaps
*/
typedef JSUword jsbitmap_t; /* NSPR name, a la Unix system types */
typedef jsbitmap_t jsbitmap; /* JS-style scalar typedef name */
#define JS_TEST_BIT(_map,_bit) \
((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] & (1L << ((_bit) & (JS_BITS_PER_WORD-1))))
#define JS_SET_BIT(_map,_bit) \
((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] |= (1L << ((_bit) & (JS_BITS_PER_WORD-1))))
#define JS_CLEAR_BIT(_map,_bit) \
((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &= ~(1L << ((_bit) & (JS_BITS_PER_WORD-1))))
/*
** Compute the log of the least power of 2 greater than or equal to n
*/
extern JS_PUBLIC_API(JSIntn) JS_CeilingLog2(JSUint32 i);
/*
** Compute the log of the greatest power of 2 less than or equal to n
*/
extern JS_PUBLIC_API(JSIntn) JS_FloorLog2(JSUint32 i);
/*
** Macro version of JS_CeilingLog2: Compute the log of the least power of
** 2 greater than or equal to _n. The result is returned in _log2.
*/
#define JS_CEILING_LOG2(_log2,_n) \
JS_BEGIN_MACRO \
JSUint32 j_ = (JSUint32)(_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; \
JS_END_MACRO
/*
** Macro version of JS_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 JS_FLOOR_LOG2(_log2,_n) \
JS_BEGIN_MACRO \
JSUint32 j_ = (JSUint32)(_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; \
JS_END_MACRO
JS_END_EXTERN_C
#endif /* jsbit_h___ */