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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* bit vectors for sets of CSS properties */
#ifndef nsCSSPropertyIDSet_h__
#define nsCSSPropertyIDSet_h__
#include "mozilla/ArrayUtils.h"
#include "mozilla/PodOperations.h"
#include "nsCSSPropertyID.h"
#include <limits.h> // for CHAR_BIT
/**
* nsCSSPropertyIDSet 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 nsCSSPropertyIDSet {
public:
nsCSSPropertyIDSet() { Empty(); }
// auto-generated copy-constructor OK
void AssertInSetRange(nsCSSPropertyID 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(nsCSSPropertyID aProperty) {
AssertInSetRange(aProperty);
size_t p = aProperty;
mProperties[p / kBitsInChunk] |=
property_set_type(1) << (p % kBitsInChunk);
}
void RemoveProperty(nsCSSPropertyID aProperty) {
AssertInSetRange(aProperty);
size_t p = aProperty;
mProperties[p / kBitsInChunk] &=
~(property_set_type(1) << (p % kBitsInChunk));
}
bool HasProperty(nsCSSPropertyID 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);
}
}
bool Equals(const nsCSSPropertyIDSet& aOther) const {
return mozilla::PodEqual(mProperties, aOther.mProperties);
}
// Return a new nsCSSPropertyIDSet which is the inverse of this set.
nsCSSPropertyIDSet Invert() const {
nsCSSPropertyIDSet result;
for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
result.mProperties[i] = ~mProperties[i];
}
return result;
}
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 nsCSSPropertyID CSSPropertyAt(size_t aChunk, size_t aBit) {
return nsCSSPropertyID(aChunk * kBitsInChunk + aBit);
}
private:
property_set_type mProperties[kChunkCount];
};
#endif /* !defined(nsCSSPropertyIDSet_h__) */
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