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 "HTMLEntitySearch.h"
28
29#include "HTMLEntityTable.h"
30
31namespace WebCore {
32
33static const HTMLEntityTableEntry* halfway(const HTMLEntityTableEntry* left, const HTMLEntityTableEntry* right)
34{
35 return &left[(right - left) / 2];
36}
37
38HTMLEntitySearch::HTMLEntitySearch()
39 : m_currentLength(0)
40 , m_mostRecentMatch(0)
41 , m_first(HTMLEntityTable::firstEntry())
42 , m_last(HTMLEntityTable::lastEntry())
43{
44}
45
46HTMLEntitySearch::CompareResult HTMLEntitySearch::compare(const HTMLEntityTableEntry* entry, UChar nextCharacter) const
47{
48 if (entry->length < m_currentLength + 1)
49 return Before;
50 UChar entryNextCharacter = entry->entity[m_currentLength];
51 if (entryNextCharacter == nextCharacter)
52 return Prefix;
53 return entryNextCharacter < nextCharacter ? Before : After;
54}
55
56const HTMLEntityTableEntry* HTMLEntitySearch::findFirst(UChar nextCharacter) const
57{
58 const HTMLEntityTableEntry* left = m_first;
59 const HTMLEntityTableEntry* right = m_last;
60 if (left == right)
61 return left;
62 CompareResult result = compare(left, nextCharacter);
63 if (result == Prefix)
64 return left;
65 if (result == After)
66 return right;
67 while (left + 1 < right) {
68 const HTMLEntityTableEntry* probe = halfway(left, right);
69 result = compare(probe, nextCharacter);
70 if (result == Before)
71 left = probe;
72 else {
73 ASSERT(result == After || result == Prefix);
74 right = probe;
75 }
76 }
77 ASSERT(left + 1 == right);
78 return right;
79}
80
81const HTMLEntityTableEntry* HTMLEntitySearch::findLast(UChar nextCharacter) const
82{
83 const HTMLEntityTableEntry* left = m_first;
84 const HTMLEntityTableEntry* right = m_last;
85 if (left == right)
86 return right;
87 CompareResult result = compare(right, nextCharacter);
88 if (result == Prefix)
89 return right;
90 if (result == Before)
91 return left;
92 while (left + 1 < right) {
93 const HTMLEntityTableEntry* probe = halfway(left, right);
94 result = compare(probe, nextCharacter);
95 if (result == After)
96 right = probe;
97 else {
98 ASSERT(result == Before || result == Prefix);
99 left = probe;
100 }
101 }
102 ASSERT(left + 1 == right);
103 return left;
104}
105
106void HTMLEntitySearch::advance(UChar nextCharacter)
107{
108 ASSERT(isEntityPrefix());
109 if (!m_currentLength) {
110 m_first = HTMLEntityTable::firstEntryStartingWith(nextCharacter);
111 m_last = HTMLEntityTable::lastEntryStartingWith(nextCharacter);
112 if (!m_first || !m_last)
113 return fail();
114 } else {
115 m_first = findFirst(nextCharacter);
116 m_last = findLast(nextCharacter);
117 if (m_first == m_last && compare(m_first, nextCharacter) != Prefix)
118 return fail();
119 }
120 ++m_currentLength;
121 if (m_first->length != m_currentLength) {
122 return;
123 }
124 m_mostRecentMatch = m_first;
125}
126
127}
128