1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/style/nsCSSPropertySet.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,93 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +/* bit vectors for sets of CSS properties */
1.9 +
1.10 +#ifndef nsCSSPropertySet_h__
1.11 +#define nsCSSPropertySet_h__
1.12 +
1.13 +#include "mozilla/ArrayUtils.h"
1.14 +
1.15 +#include "nsCSSProperty.h"
1.16 +#include <limits.h> // for CHAR_BIT
1.17 +
1.18 +/**
1.19 + * nsCSSPropertySet maintains a set of non-shorthand CSS properties. In
1.20 + * other words, for each longhand CSS property we support, it has a bit
1.21 + * for whether that property is in the set.
1.22 + */
1.23 +class nsCSSPropertySet {
1.24 +public:
1.25 + nsCSSPropertySet() { Empty(); }
1.26 + // auto-generated copy-constructor OK
1.27 +
1.28 + void AssertInSetRange(nsCSSProperty aProperty) const {
1.29 + NS_ASSERTION(0 <= aProperty &&
1.30 + aProperty < eCSSProperty_COUNT_no_shorthands,
1.31 + "out of bounds");
1.32 + }
1.33 +
1.34 + // Conversion of aProperty to |size_t| after AssertInSetRange
1.35 + // lets the compiler generate significantly tighter code.
1.36 +
1.37 + void AddProperty(nsCSSProperty aProperty) {
1.38 + AssertInSetRange(aProperty);
1.39 + size_t p = aProperty;
1.40 + mProperties[p / kBitsInChunk] |=
1.41 + property_set_type(1) << (p % kBitsInChunk);
1.42 + }
1.43 +
1.44 + void RemoveProperty(nsCSSProperty aProperty) {
1.45 + AssertInSetRange(aProperty);
1.46 + size_t p = aProperty;
1.47 + mProperties[p / kBitsInChunk] &=
1.48 + ~(property_set_type(1) << (p % kBitsInChunk));
1.49 + }
1.50 +
1.51 + bool HasProperty(nsCSSProperty aProperty) const {
1.52 + AssertInSetRange(aProperty);
1.53 + size_t p = aProperty;
1.54 + return (mProperties[p / kBitsInChunk] &
1.55 + (property_set_type(1) << (p % kBitsInChunk))) != 0;
1.56 + }
1.57 +
1.58 + void Empty() {
1.59 + memset(mProperties, 0, sizeof(mProperties));
1.60 + }
1.61 +
1.62 + void AssertIsEmpty(const char* aText) const {
1.63 + for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) {
1.64 + NS_ASSERTION(mProperties[i] == 0, aText);
1.65 + }
1.66 + }
1.67 +
1.68 +private:
1.69 + typedef unsigned long property_set_type;
1.70 +public:
1.71 + // number of bits in |property_set_type|.
1.72 + static const size_t kBitsInChunk = sizeof(property_set_type)*CHAR_BIT;
1.73 + // number of |property_set_type|s in the set
1.74 + static const size_t kChunkCount =
1.75 + (eCSSProperty_COUNT_no_shorthands + kBitsInChunk - 1) / kBitsInChunk;
1.76 +
1.77 + /*
1.78 + * For fast enumeration of all the bits that are set, callers can
1.79 + * check each chunk against zero (since in normal cases few bits are
1.80 + * likely to be set).
1.81 + */
1.82 + bool HasPropertyInChunk(size_t aChunk) const {
1.83 + return mProperties[aChunk] != 0;
1.84 + }
1.85 + bool HasPropertyAt(size_t aChunk, size_t aBit) const {
1.86 + return (mProperties[aChunk] & (property_set_type(1) << aBit)) != 0;
1.87 + }
1.88 + static nsCSSProperty CSSPropertyAt(size_t aChunk, size_t aBit) {
1.89 + return nsCSSProperty(aChunk * kBitsInChunk + aBit);
1.90 + }
1.91 +
1.92 +private:
1.93 + property_set_type mProperties[kChunkCount];
1.94 +};
1.95 +
1.96 +#endif /* !defined(nsCSSPropertySet_h__) */
