1 /*
2 * Copyright (C) 2010 Google, Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "config.h"
27 #include "core/html/parser/HTMLEntitySearch.h"
28
29 #include "core/html/parser/HTMLEntityTable.h"
30
31 namespace WebCore {
32
halfway(const HTMLEntityTableEntry * left,const HTMLEntityTableEntry * right)33 static const HTMLEntityTableEntry* halfway(const HTMLEntityTableEntry* left, const HTMLEntityTableEntry* right)
34 {
35 return &left[(right - left) / 2];
36 }
37
HTMLEntitySearch()38 HTMLEntitySearch::HTMLEntitySearch()
39 : m_currentLength(0)
40 , m_mostRecentMatch(0)
41 , m_first(HTMLEntityTable::firstEntry())
42 , m_last(HTMLEntityTable::lastEntry())
43 {
44 }
45
compare(const HTMLEntityTableEntry * entry,UChar nextCharacter) const46 HTMLEntitySearch::CompareResult HTMLEntitySearch::compare(const HTMLEntityTableEntry* entry, UChar nextCharacter) const
47 {
48 if (entry->length < m_currentLength + 1)
49 return Before;
50 const LChar* entityString = HTMLEntityTable::entityString(*entry);
51 UChar entryNextCharacter = entityString[m_currentLength];
52 if (entryNextCharacter == nextCharacter)
53 return Prefix;
54 return entryNextCharacter < nextCharacter ? Before : After;
55 }
56
findFirst(UChar nextCharacter) const57 const HTMLEntityTableEntry* HTMLEntitySearch::findFirst(UChar nextCharacter) const
58 {
59 const HTMLEntityTableEntry* left = m_first;
60 const HTMLEntityTableEntry* right = m_last;
61 if (left == right)
62 return left;
63 CompareResult result = compare(left, nextCharacter);
64 if (result == Prefix)
65 return left;
66 if (result == After)
67 return right;
68 while (left + 1 < right) {
69 const HTMLEntityTableEntry* probe = halfway(left, right);
70 result = compare(probe, nextCharacter);
71 if (result == Before)
72 left = probe;
73 else {
74 ASSERT(result == After || result == Prefix);
75 right = probe;
76 }
77 }
78 ASSERT(left + 1 == right);
79 return right;
80 }
81
findLast(UChar nextCharacter) const82 const HTMLEntityTableEntry* HTMLEntitySearch::findLast(UChar nextCharacter) const
83 {
84 const HTMLEntityTableEntry* left = m_first;
85 const HTMLEntityTableEntry* right = m_last;
86 if (left == right)
87 return right;
88 CompareResult result = compare(right, nextCharacter);
89 if (result == Prefix)
90 return right;
91 if (result == Before)
92 return left;
93 while (left + 1 < right) {
94 const HTMLEntityTableEntry* probe = halfway(left, right);
95 result = compare(probe, nextCharacter);
96 if (result == After)
97 right = probe;
98 else {
99 ASSERT(result == Before || result == Prefix);
100 left = probe;
101 }
102 }
103 ASSERT(left + 1 == right);
104 return left;
105 }
106
advance(UChar nextCharacter)107 void HTMLEntitySearch::advance(UChar nextCharacter)
108 {
109 ASSERT(isEntityPrefix());
110 if (!m_currentLength) {
111 m_first = HTMLEntityTable::firstEntryStartingWith(nextCharacter);
112 m_last = HTMLEntityTable::lastEntryStartingWith(nextCharacter);
113 if (!m_first || !m_last)
114 return fail();
115 } else {
116 m_first = findFirst(nextCharacter);
117 m_last = findLast(nextCharacter);
118 if (m_first == m_last && compare(m_first, nextCharacter) != Prefix)
119 return fail();
120 }
121 ++m_currentLength;
122 if (m_first->length != m_currentLength) {
123 return;
124 }
125 m_mostRecentMatch = m_first;
126 }
127
128 }
129