зеркало из https://github.com/mozilla/gecko-dev.git
109 строки
3.7 KiB
C
109 строки
3.7 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/*
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* The contents of this file are subject to the Netscape Public
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* License Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.mozilla.org/NPL/
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express oqr
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* implied. See the License for the specific language governing
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* rights and limitations under the License.
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*
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* The Original Code is Mozilla Communicator client code, released
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* March 31, 1998.
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*
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* The Initial Developer of the Original Code is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All
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* Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the
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* terms of the GNU Public License (the "GPL"), in which case the
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* provisions of the GPL are applicable instead of those above.
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* If you wish to allow use of your version of this file only
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* under the terms of the GPL and not to allow others to use your
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* version of this file under the NPL, indicate your decision by
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* deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL. If you do not delete
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* the provisions above, a recipient may use your version of this
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* file under either the NPL or the GPL.
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*/
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#ifndef jsbit_h___
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#define jsbit_h___
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#include "jstypes.h"
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JS_BEGIN_EXTERN_C
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/*
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** A jsbitmap_t is a long integer that can be used for bitmaps
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*/
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typedef unsigned long jsbitmap_t;
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#define JS_TEST_BIT(_map,_bit) \
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((_map)[(_bit)>>JS_BITS_PER_LONG_LOG2] & (1L << ((_bit) & (JS_BITS_PER_LONG-1))))
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#define JS_SET_BIT(_map,_bit) \
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((_map)[(_bit)>>JS_BITS_PER_LONG_LOG2] |= (1L << ((_bit) & (JS_BITS_PER_LONG-1))))
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#define JS_CLEAR_BIT(_map,_bit) \
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((_map)[(_bit)>>JS_BITS_PER_LONG_LOG2] &= ~(1L << ((_bit) & (JS_BITS_PER_LONG-1))))
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/*
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** Compute the log of the least power of 2 greater than or equal to n
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*/
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extern JS_PUBLIC_API(JSIntn) JS_CeilingLog2(JSUint32 i);
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/*
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** Compute the log of the greatest power of 2 less than or equal to n
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*/
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extern JS_PUBLIC_API(JSIntn) JS_FloorLog2(JSUint32 i);
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/*
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** Macro version of JS_CeilingLog2: Compute the log of the least power of
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** 2 greater than or equal to _n. The result is returned in _log2.
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*/
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#define JS_CEILING_LOG2(_log2,_n) \
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JS_BEGIN_MACRO \
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JSUint32 j_ = (JSUint32)(_n); \
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(_log2) = 0; \
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if ((j_) & ((j_)-1)) \
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(_log2) += 1; \
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if ((j_) >> 16) \
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(_log2) += 16, (j_) >>= 16; \
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if ((j_) >> 8) \
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(_log2) += 8, (j_) >>= 8; \
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if ((j_) >> 4) \
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(_log2) += 4, (j_) >>= 4; \
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if ((j_) >> 2) \
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(_log2) += 2, (j_) >>= 2; \
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if ((j_) >> 1) \
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(_log2) += 1; \
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JS_END_MACRO
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/*
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** Macro version of JS_FloorLog2: Compute the log of the greatest power of
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** 2 less than or equal to _n. The result is returned in _log2.
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**
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** This is equivalent to finding the highest set bit in the word.
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*/
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#define JS_FLOOR_LOG2(_log2,_n) \
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JS_BEGIN_MACRO \
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JSUint32 j_ = (JSUint32)(_n); \
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(_log2) = 0; \
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if ((j_) >> 16) \
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(_log2) += 16, (j_) >>= 16; \
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if ((j_) >> 8) \
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(_log2) += 8, (j_) >>= 8; \
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if ((j_) >> 4) \
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(_log2) += 4, (j_) >>= 4; \
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if ((j_) >> 2) \
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(_log2) += 2, (j_) >>= 2; \
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if ((j_) >> 1) \
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(_log2) += 1; \
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JS_END_MACRO
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JS_END_EXTERN_C
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#endif /* jsbit_h___ */
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