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 Mozilla Communicator client code, released
16 * March 31, 1998.
17 *
18 * The Initial Developer of the Original Code is
19 * Netscape Communications Corporation.
20 * Portions created by the Initial Developer are Copyright (C) 1998
21 * the Initial Developer. All Rights Reserved.
22 *
23 * Contributor(s):
24 *
25 * Alternatively, the contents of this file may be used under the terms of
26 * either of the GNU General Public License Version 2 or later (the "GPL"),
27 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 * in which case the provisions of the GPL or the LGPL are applicable instead
29 * of those above. If you wish to allow use of your version of this file only
30 * under the terms of either the GPL or the LGPL, and not to allow others to
31 * use your version of this file under the terms of the MPL, indicate your
32 * decision by deleting the provisions above and replace them with the notice
33 * and other provisions required by the GPL or the LGPL. If you do not delete
34 * the provisions above, a recipient may use your version of this file under
35 * the terms of any one of the MPL, the GPL or the LGPL.
36 *
37 * ***** END LICENSE BLOCK ***** */
39 #ifndef jsbit_h___
40 #define jsbit_h___
42 #include "jstypes.h"
43 JS_BEGIN_EXTERN_C
45 /*
46 ** A jsbitmap_t is a long integer that can be used for bitmaps
47 */
48 typedef JSUword jsbitmap_t; /* NSPR name, a la Unix system types */
49 typedef jsbitmap_t jsbitmap; /* JS-style scalar typedef name */
51 #define JS_TEST_BIT(_map,_bit) \
52 ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] & (1L << ((_bit) & (JS_BITS_PER_WORD-1))))
53 #define JS_SET_BIT(_map,_bit) \
54 ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] |= (1L << ((_bit) & (JS_BITS_PER_WORD-1))))
55 #define JS_CLEAR_BIT(_map,_bit) \
56 ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &= ~(1L << ((_bit) & (JS_BITS_PER_WORD-1))))
58 /*
59 ** Compute the log of the least power of 2 greater than or equal to n
60 */
61 extern JS_PUBLIC_API(JSIntn) JS_CeilingLog2(JSUint32 i);
63 /*
64 ** Compute the log of the greatest power of 2 less than or equal to n
65 */
66 extern JS_PUBLIC_API(JSIntn) JS_FloorLog2(JSUint32 i);
68 /*
69 ** Macro version of JS_CeilingLog2: Compute the log of the least power of
70 ** 2 greater than or equal to _n. The result is returned in _log2.
71 */
72 #define JS_CEILING_LOG2(_log2,_n) \
73 JS_BEGIN_MACRO \
74 JSUint32 j_ = (JSUint32)(_n); \
75 (_log2) = 0; \
76 if ((j_) & ((j_)-1)) \
77 (_log2) += 1; \
78 if ((j_) >> 16) \
79 (_log2) += 16, (j_) >>= 16; \
80 if ((j_) >> 8) \
81 (_log2) += 8, (j_) >>= 8; \
82 if ((j_) >> 4) \
83 (_log2) += 4, (j_) >>= 4; \
84 if ((j_) >> 2) \
85 (_log2) += 2, (j_) >>= 2; \
86 if ((j_) >> 1) \
87 (_log2) += 1; \
88 JS_END_MACRO
90 /*
91 ** Macro version of JS_FloorLog2: Compute the log of the greatest power of
92 ** 2 less than or equal to _n. The result is returned in _log2.
93 **
94 ** This is equivalent to finding the highest set bit in the word.
95 */
96 #define JS_FLOOR_LOG2(_log2,_n) \
97 JS_BEGIN_MACRO \
98 JSUint32 j_ = (JSUint32)(_n); \
99 (_log2) = 0; \
100 if ((j_) >> 16) \
101 (_log2) += 16, (j_) >>= 16; \
102 if ((j_) >> 8) \
103 (_log2) += 8, (j_) >>= 8; \
104 if ((j_) >> 4) \
105 (_log2) += 4, (j_) >>= 4; \
106 if ((j_) >> 2) \
107 (_log2) += 2, (j_) >>= 2; \
108 if ((j_) >> 1) \
109 (_log2) += 1; \
110 JS_END_MACRO
112 JS_END_EXTERN_C
113 #endif /* jsbit_h___ */