1/*
2 * Copyright (C) 2013 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 are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "config.h"
32#include "core/html/HTMLDimension.h"
33
34#include "wtf/MathExtras.h"
35#include "wtf/text/WTFString.h"
36
37namespace blink {
38
39template <typename CharacterType>
40static HTMLDimension parseDimension(const CharacterType* characters, size_t lastParsedIndex, size_t endOfCurrentToken)
41{
42    HTMLDimension::HTMLDimensionType type = HTMLDimension::Absolute;
43    double value = 0.;
44
45    // HTML5's split removes leading and trailing spaces so we need to skip the leading spaces here.
46    while (lastParsedIndex < endOfCurrentToken && isASCIISpace((characters[lastParsedIndex])))
47        ++lastParsedIndex;
48
49    // This is Step 5.5. in the algorithm. Going to the last step would make the code less readable.
50    if (lastParsedIndex >= endOfCurrentToken)
51        return HTMLDimension(value, HTMLDimension::Relative);
52
53    size_t position = lastParsedIndex;
54    while (position < endOfCurrentToken && isASCIIDigit(characters[position]))
55        ++position;
56
57    if (position > lastParsedIndex) {
58        bool ok = false;
59        unsigned integerValue = charactersToUIntStrict(characters + lastParsedIndex, position - lastParsedIndex, &ok);
60        ASSERT(ok);
61        value += integerValue;
62
63        if (position < endOfCurrentToken && characters[position] == '.') {
64            ++position;
65            Vector<CharacterType> fractionNumbers;
66            while (position < endOfCurrentToken && (isASCIIDigit(characters[position]) || isASCIISpace(characters[position]))) {
67                if (isASCIIDigit(characters[position]))
68                    fractionNumbers.append(characters[position]);
69                ++position;
70            }
71
72            if (fractionNumbers.size()) {
73                double fractionValue = charactersToUIntStrict(fractionNumbers.data(), fractionNumbers.size(), &ok);
74                ASSERT(ok);
75
76                value += fractionValue / pow(10., static_cast<double>(fractionNumbers.size()));
77            }
78        }
79    }
80
81    while (position < endOfCurrentToken && isASCIISpace(characters[position]))
82        ++position;
83
84    if (position < endOfCurrentToken) {
85        if (characters[position] == '*')
86            type = HTMLDimension::Relative;
87        else if (characters[position] == '%')
88            type = HTMLDimension::Percentage;
89    }
90
91    return HTMLDimension(value, type);
92}
93
94static HTMLDimension parseDimension(const String& rawToken, size_t lastParsedIndex, size_t endOfCurrentToken)
95{
96    if (rawToken.is8Bit())
97        return parseDimension<LChar>(rawToken.characters8(), lastParsedIndex, endOfCurrentToken);
98    return parseDimension<UChar>(rawToken.characters16(), lastParsedIndex, endOfCurrentToken);
99}
100
101// This implements the "rules for parsing a list of dimensions" per HTML5.
102// http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#rules-for-parsing-a-list-of-dimensions
103Vector<HTMLDimension> parseListOfDimensions(const String& input)
104{
105    static const char comma = ',';
106
107    // Step 2. Remove the last character if it's a comma.
108    String trimmedString = input;
109    if (trimmedString.endsWith(comma))
110        trimmedString.truncate(trimmedString.length() - 1);
111
112    // HTML5's split doesn't return a token for an empty string so
113    // we need to match them here.
114    if (trimmedString.isEmpty())
115        return Vector<HTMLDimension>();
116
117    // Step 3. To avoid String copies, we just look for commas instead of splitting.
118    Vector<HTMLDimension> parsedDimensions;
119    size_t lastParsedIndex = 0;
120    while (true) {
121        size_t nextComma = trimmedString.find(comma, lastParsedIndex);
122        if (nextComma == kNotFound)
123            break;
124
125        parsedDimensions.append(parseDimension(trimmedString, lastParsedIndex, nextComma));
126        lastParsedIndex = nextComma + 1;
127    }
128
129    parsedDimensions.append(parseDimension(trimmedString, lastParsedIndex, trimmedString.length()));
130    return parsedDimensions;
131}
132
133} // namespace blink
134