third_party/WebKit/Source/core/html/HTMLDimension.cpp

   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
  37 namespace blink {
  38
  39 template <typename CharacterType>
  40 static 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         if (!ok)
  61             return HTMLDimension(0., HTMLDimension::Relative);
  62         value += integerValue;
  63
  64         if (position < endOfCurrentToken && characters[position] == '.') {
  65             ++position;
  66             Vector<CharacterType> fractionNumbers;
  67             while (position < endOfCurrentToken && (isASCIIDigit(characters[position]) || isASCIISpace(characters[position]))) {
  68                 if (isASCIIDigit(characters[position]))
  69                     fractionNumbers.append(characters[position]);
  70                 ++position;
  71             }
  72
  73             if (fractionNumbers.size()) {
  74                 double fractionValue = charactersToUIntStrict(fractionNumbers.data(), fractionNumbers.size(), &ok);
  75                 if (!ok)
  76                     return HTMLDimension(0., HTMLDimension::Relative);
  77
  78                 value += fractionValue / pow(10., static_cast<double>(fractionNumbers.size()));
  79             }
  80         }
  81     }
  82
  83     while (position < endOfCurrentToken && isASCIISpace(characters[position]))
  84         ++position;
  85
  86     if (position < endOfCurrentToken) {
  87         if (characters[position] == '*')
  88             type = HTMLDimension::Relative;
  89         else if (characters[position] == '%')
  90             type = HTMLDimension::Percentage;
  91     }
  92
  93     return HTMLDimension(value, type);
  94 }
  95
  96 static HTMLDimension parseDimension(const String& rawToken, size_t lastParsedIndex, size_t endOfCurrentToken)
  97 {
  98     if (rawToken.is8Bit())
  99         return parseDimension<LChar>(rawToken.characters8(), lastParsedIndex, endOfCurrentToken);
 100     return parseDimension<UChar>(rawToken.characters16(), lastParsedIndex, endOfCurrentToken);
 101 }
 102
 103 // This implements the "rules for parsing a list of dimensions" per HTML5.
 104 // http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#rules-for-parsing-a-list-of-dimensions
 105 Vector<HTMLDimension> parseListOfDimensions(const String& input)
 106 {
 107     static const char comma = ',';
 108
 109     // Step 2. Remove the last character if it's a comma.
 110     String trimmedString = input;
 111     if (trimmedString.endsWith(comma))
 112         trimmedString.truncate(trimmedString.length() - 1);
 113
 114     // HTML5's split doesn't return a token for an empty string so
 115     // we need to match them here.
 116     if (trimmedString.isEmpty())
 117         return Vector<HTMLDimension>();
 118
 119     // Step 3. To avoid String copies, we just look for commas instead of splitting.
 120     Vector<HTMLDimension> parsedDimensions;
 121     size_t lastParsedIndex = 0;
 122     while (true) {
 123         size_t nextComma = trimmedString.find(comma, lastParsedIndex);
 124         if (nextComma == kNotFound)
 125             break;
 126
 127         parsedDimensions.append(parseDimension(trimmedString, lastParsedIndex, nextComma));
 128         lastParsedIndex = nextComma + 1;
 129     }
 130
 131     parsedDimensions.append(parseDimension(trimmedString, lastParsedIndex, trimmedString.length()));
 132     return parsedDimensions;
 133 }
 134
 135 } // namespace blink