gecko-dev/layout/style/nsCSSPropertySet.h

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/* ***** 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 nsCSSDataBlock.h.
*
* The Initial Developer of the Original Code is L. David Baron.
* Portions created by the Initial Developer are Copyright (C) 2003
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* L. David Baron <dbaron@dbaron.org> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either 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
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* 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 ***** */
/* bit vectors for sets of CSS properties */
#ifndef nsCSSPropertySet_h__
#define nsCSSPropertySet_h__
#include "mozilla/Util.h"
#include "nsCSSProperty.h"
#include <limits.h> // for CHAR_BIT
/**
* nsCSSPropertySet maintains a set of non-shorthand CSS properties. In
* other words, for each longhand CSS property we support, it has a bit
* for whether that property is in the set.
*/
class nsCSSPropertySet {
public:
nsCSSPropertySet() { Empty(); }
// auto-generated copy-constructor OK
void AssertInSetRange(nsCSSProperty aProperty) const {
NS_ASSERTION(0 <= aProperty &&
aProperty < eCSSProperty_COUNT_no_shorthands,
"out of bounds");
}
// Conversion of aProperty to |size_t| after AssertInSetRange
// lets the compiler generate significantly tighter code.
void AddProperty(nsCSSProperty aProperty) {
AssertInSetRange(aProperty);
size_t p = aProperty;
mProperties[p / kBitsInChunk] |=
property_set_type(1) << (p % kBitsInChunk);
}
void RemoveProperty(nsCSSProperty aProperty) {
AssertInSetRange(aProperty);
size_t p = aProperty;
mProperties[p / kBitsInChunk] &=
~(property_set_type(1) << (p % kBitsInChunk));
}
bool HasProperty(nsCSSProperty aProperty) const {
AssertInSetRange(aProperty);
size_t p = aProperty;
return (mProperties[p / kBitsInChunk] &
(property_set_type(1) << (p % kBitsInChunk))) != 0;
}
void Empty() {
memset(mProperties, 0, sizeof(mProperties));
}
void AssertIsEmpty(const char* aText) const {
for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
NS_ASSERTION(mProperties[i] == 0, aText);
}
}
private:
typedef unsigned long property_set_type;
public:
// number of bits in |property_set_type|.
static const size_t kBitsInChunk = sizeof(property_set_type)*CHAR_BIT;
// number of |property_set_type|s in the set
static const size_t kChunkCount =
(eCSSProperty_COUNT_no_shorthands + kBitsInChunk - 1) / kBitsInChunk;
/*
* For fast enumeration of all the bits that are set, callers can
* check each chunk against zero (since in normal cases few bits are
* likely to be set).
*/
bool HasPropertyInChunk(size_t aChunk) const {
return mProperties[aChunk] != 0;
}
bool HasPropertyAt(size_t aChunk, size_t aBit) const {
return (mProperties[aChunk] & (property_set_type(1) << aBit)) != 0;
}
static nsCSSProperty CSSPropertyAt(size_t aChunk, size_t aBit) {
return nsCSSProperty(aChunk * kBitsInChunk + aBit);
}
private:
property_set_type mProperties[kChunkCount];
};
#endif /* !defined(nsCSSPropertySet_h__) */