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comparison: layout/style/nsCSSPropertySet.h
layout/style/nsCSSPropertySet.h
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| -1:000000000000 | 0:6b333ff2681c |
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 /* bit vectors for sets of CSS properties */ | |
| 6 | |
| 7 #ifndef nsCSSPropertySet_h__ | |
| 8 #define nsCSSPropertySet_h__ | |
| 9 | |
| 10 #include "mozilla/ArrayUtils.h" | |
| 11 | |
| 12 #include "nsCSSProperty.h" | |
| 13 #include <limits.h> // for CHAR_BIT | |
| 14 | |
| 15 /** | |
| 16 * nsCSSPropertySet maintains a set of non-shorthand CSS properties. In | |
| 17 * other words, for each longhand CSS property we support, it has a bit | |
| 18 * for whether that property is in the set. | |
| 19 */ | |
| 20 class nsCSSPropertySet { | |
| 21 public: | |
| 22 nsCSSPropertySet() { Empty(); } | |
| 23 // auto-generated copy-constructor OK | |
| 24 | |
| 25 void AssertInSetRange(nsCSSProperty aProperty) const { | |
| 26 NS_ASSERTION(0 <= aProperty && | |
| 27 aProperty < eCSSProperty_COUNT_no_shorthands, | |
| 28 "out of bounds"); | |
| 29 } | |
| 30 | |
| 31 // Conversion of aProperty to |size_t| after AssertInSetRange | |
| 32 // lets the compiler generate significantly tighter code. | |
| 33 | |
| 34 void AddProperty(nsCSSProperty aProperty) { | |
| 35 AssertInSetRange(aProperty); | |
| 36 size_t p = aProperty; | |
| 37 mProperties[p / kBitsInChunk] |= | |
| 38 property_set_type(1) << (p % kBitsInChunk); | |
| 39 } | |
| 40 | |
| 41 void RemoveProperty(nsCSSProperty aProperty) { | |
| 42 AssertInSetRange(aProperty); | |
| 43 size_t p = aProperty; | |
| 44 mProperties[p / kBitsInChunk] &= | |
| 45 ~(property_set_type(1) << (p % kBitsInChunk)); | |
| 46 } | |
| 47 | |
| 48 bool HasProperty(nsCSSProperty aProperty) const { | |
| 49 AssertInSetRange(aProperty); | |
| 50 size_t p = aProperty; | |
| 51 return (mProperties[p / kBitsInChunk] & | |
| 52 (property_set_type(1) << (p % kBitsInChunk))) != 0; | |
| 53 } | |
| 54 | |
| 55 void Empty() { | |
| 56 memset(mProperties, 0, sizeof(mProperties)); | |
| 57 } | |
| 58 | |
| 59 void AssertIsEmpty(const char* aText) const { | |
| 60 for (size_t i = 0; i < mozilla::ArrayLength(mProperties); ++i) { | |
| 61 NS_ASSERTION(mProperties[i] == 0, aText); | |
| 62 } | |
| 63 } | |
| 64 | |
| 65 private: | |
| 66 typedef unsigned long property_set_type; | |
| 67 public: | |
| 68 // number of bits in |property_set_type|. | |
| 69 static const size_t kBitsInChunk = sizeof(property_set_type)*CHAR_BIT; | |
| 70 // number of |property_set_type|s in the set | |
| 71 static const size_t kChunkCount = | |
| 72 (eCSSProperty_COUNT_no_shorthands + kBitsInChunk - 1) / kBitsInChunk; | |
| 73 | |
| 74 /* | |
| 75 * For fast enumeration of all the bits that are set, callers can | |
| 76 * check each chunk against zero (since in normal cases few bits are | |
| 77 * likely to be set). | |
| 78 */ | |
| 79 bool HasPropertyInChunk(size_t aChunk) const { | |
| 80 return mProperties[aChunk] != 0; | |
| 81 } | |
| 82 bool HasPropertyAt(size_t aChunk, size_t aBit) const { | |
| 83 return (mProperties[aChunk] & (property_set_type(1) << aBit)) != 0; | |
| 84 } | |
| 85 static nsCSSProperty CSSPropertyAt(size_t aChunk, size_t aBit) { | |
| 86 return nsCSSProperty(aChunk * kBitsInChunk + aBit); | |
| 87 } | |
| 88 | |
| 89 private: | |
| 90 property_set_type mProperties[kChunkCount]; | |
| 91 }; | |
| 92 | |
| 93 #endif /* !defined(nsCSSPropertySet_h__) */ |
