/* 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__) */