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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /layout/style/nsCSSPropertyIDSet.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'layout/style/nsCSSPropertyIDSet.h')
-rw-r--r-- | layout/style/nsCSSPropertyIDSet.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/layout/style/nsCSSPropertyIDSet.h b/layout/style/nsCSSPropertyIDSet.h new file mode 100644 index 000000000..4de0471d1 --- /dev/null +++ b/layout/style/nsCSSPropertyIDSet.h @@ -0,0 +1,107 @@ +/* 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__) */ |