1/*
2 * Copyright (C) 2005, 2007, 2010 Apple Inc. All rights reserved.
3 * Copyright (C) 2011 Google Inc. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
15 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
16 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
18 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
20 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
21 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
22 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
23 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
24 * THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "config.h"
28#include "core/rendering/break_lines.h"
29
30#include "platform/text/TextBreakIterator.h"
31#include "wtf/ASCIICType.h"
32#include "wtf/StdLibExtras.h"
33#include "wtf/unicode/CharacterNames.h"
34
35namespace blink {
36
37template<bool treatNoBreakSpaceAsBreak>
38static inline bool isBreakableSpace(UChar ch)
39{
40    switch (ch) {
41    case ' ':
42    case '\n':
43    case '\t':
44        return true;
45    case noBreakSpace:
46        return treatNoBreakSpaceAsBreak;
47    default:
48        return false;
49    }
50}
51
52static const UChar asciiLineBreakTableFirstChar = '!';
53static const UChar asciiLineBreakTableLastChar = 127;
54
55// Pack 8 bits into one byte
56#define B(a, b, c, d, e, f, g, h) \
57    ((a) | ((b) << 1) | ((c) << 2) | ((d) << 3) | ((e) << 4) | ((f) << 5) | ((g) << 6) | ((h) << 7))
58
59// Line breaking table row for each digit (0-9)
60#define DI { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
61
62// Line breaking table row for ascii letters (a-z A-Z)
63#define AL { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
64
65#define F 0xFF
66
67// Line breaking table for printable ASCII characters. Line breaking opportunities in this table are as below:
68// - before opening punctuations such as '(', '<', '[', '{' after certain characters (compatible with Firefox 3.6);
69// - after '-' and '?' (backward-compatible, and compatible with Internet Explorer).
70// Please refer to <https://bugs.webkit.org/show_bug.cgi?id=37698> for line breaking matrixes of different browsers
71// and the ICU standard.
72static const unsigned char asciiLineBreakTable[][(asciiLineBreakTableLastChar - asciiLineBreakTableFirstChar) / 8 + 1] = {
73    //  !  "  #  $  %  &  '  (     )  *  +  ,  -  .  /  0  1-8   9  :  ;  <  =  >  ?  @     A-X      Y  Z  [  \  ]  ^  _  `     a-x      y  z  {  |  }  ~  DEL
74    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // !
75    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // "
76    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // #
77    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // $
78    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // %
79    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // &
80    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // '
81    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // (
82    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // )
83    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // *
84    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // +
85    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // ,
86    { B(1, 1, 1, 1, 1, 1, 1, 1), B(1, 1, 1, 1, 1, 0, 1, 0), 0, B(0, 1, 1, 1, 1, 1, 1, 1), F, F, F, B(1, 1, 1, 1, 1, 1, 1, 1), F, F, F, B(1, 1, 1, 1, 1, 1, 1, 1) }, // - Note: breaking before '0'-'9' is handled hard-coded in shouldBreakAfter().
87    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // .
88    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // /
89    DI,  DI,  DI,  DI,  DI,  DI,  DI,  DI,  DI,  DI, // 0-9
90    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // :
91    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // ;
92    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // <
93    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // =
94    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // >
95    { B(0, 0, 1, 1, 1, 1, 0, 1), B(0, 1, 1, 0, 1, 0, 0, 1), F, B(1, 0, 0, 1, 1, 1, 0, 1), F, F, F, B(1, 1, 1, 1, 0, 1, 1, 1), F, F, F, B(1, 1, 1, 1, 0, 1, 1, 0) }, // ?
96    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // @
97    AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL, // A-Z
98    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // [
99    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // '\'
100    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // ]
101    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // ^
102    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // _
103    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // `
104    AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL,  AL, // a-z
105    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // {
106    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // |
107    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // }
108    { B(0, 0, 0, 0, 0, 0, 0, 1), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 1, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 1, 0, 0, 0, 0, 0) }, // ~
109    { B(0, 0, 0, 0, 0, 0, 0, 0), B(0, 0, 0, 0, 0, 0, 0, 0), 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0), 0, 0, 0, B(0, 0, 0, 0, 0, 0, 0, 0) }, // DEL
110};
111
112#undef B
113#undef F
114#undef DI
115#undef AL
116
117COMPILE_ASSERT(WTF_ARRAY_LENGTH(asciiLineBreakTable) == asciiLineBreakTableLastChar - asciiLineBreakTableFirstChar + 1, TestLineBreakTableConsistency);
118
119static inline bool shouldBreakAfter(UChar lastCh, UChar ch, UChar nextCh)
120{
121    // Don't allow line breaking between '-' and a digit if the '-' may mean a minus sign in the context,
122    // while allow breaking in 'ABCD-1234' and '1234-5678' which may be in long URLs.
123    if (ch == '-' && isASCIIDigit(nextCh))
124        return isASCIIAlphanumeric(lastCh);
125
126    // If both ch and nextCh are ASCII characters, use a lookup table for enhanced speed and for compatibility
127    // with other browsers (see comments for asciiLineBreakTable for details).
128    if (ch >= asciiLineBreakTableFirstChar && ch <= asciiLineBreakTableLastChar
129            && nextCh >= asciiLineBreakTableFirstChar && nextCh <= asciiLineBreakTableLastChar) {
130        const unsigned char* tableRow = asciiLineBreakTable[ch - asciiLineBreakTableFirstChar];
131        int nextChIndex = nextCh - asciiLineBreakTableFirstChar;
132        return tableRow[nextChIndex / 8] & (1 << (nextChIndex % 8));
133    }
134    // Otherwise defer to the Unicode algorithm by returning false.
135    return false;
136}
137
138template<bool treatNoBreakSpaceAsBreak>
139inline bool needsLineBreakIterator(UChar ch)
140{
141    if (treatNoBreakSpaceAsBreak)
142        return ch > asciiLineBreakTableLastChar;
143    return ch > asciiLineBreakTableLastChar && ch != noBreakSpace;
144}
145
146template<typename CharacterType, bool treatNoBreakSpaceAsBreak>
147static inline int nextBreakablePosition(LazyLineBreakIterator& lazyBreakIterator, const CharacterType* str, unsigned length, int pos)
148{
149    int len = static_cast<int>(length);
150    int nextBreak = -1;
151
152    CharacterType lastLastCh = pos > 1 ? str[pos - 2] : static_cast<CharacterType>(lazyBreakIterator.secondToLastCharacter());
153    CharacterType lastCh = pos > 0 ? str[pos - 1] : static_cast<CharacterType>(lazyBreakIterator.lastCharacter());
154    unsigned priorContextLength = lazyBreakIterator.priorContextLength();
155    for (int i = pos; i < len; i++) {
156        CharacterType ch = str[i];
157
158        if (isBreakableSpace<treatNoBreakSpaceAsBreak>(ch) || shouldBreakAfter(lastLastCh, lastCh, ch))
159            return i;
160
161        if (needsLineBreakIterator<treatNoBreakSpaceAsBreak>(ch) || needsLineBreakIterator<treatNoBreakSpaceAsBreak>(lastCh)) {
162            if (nextBreak < i) {
163                // Don't break if positioned at start of primary context and there is no prior context.
164                if (i || priorContextLength) {
165                    TextBreakIterator* breakIterator = lazyBreakIterator.get(priorContextLength);
166                    if (breakIterator) {
167                        nextBreak = breakIterator->following(i - 1 + priorContextLength);
168                        if (nextBreak >= 0) {
169                            nextBreak -= priorContextLength;
170                        }
171                    }
172                }
173            }
174            if (i == nextBreak && !isBreakableSpace<treatNoBreakSpaceAsBreak>(lastCh))
175                return i;
176        }
177
178        lastLastCh = lastCh;
179        lastCh = ch;
180    }
181
182    return len;
183}
184
185int nextBreakablePositionIgnoringNBSP(LazyLineBreakIterator& lazyBreakIterator, int pos)
186{
187    String string = lazyBreakIterator.string();
188    if (string.is8Bit())
189        return nextBreakablePosition<LChar, false>(lazyBreakIterator, string.characters8(), string.length(), pos);
190    return nextBreakablePosition<UChar, false>(lazyBreakIterator, string.characters16(), string.length(), pos);
191}
192
193} // namespace blink
194