third_party/WebKit/Source/platform/WebIconSizesParser.cpp

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "public/platform/WebIconSizesParser.h"

#include "public/platform/WebSize.h"
#include "public/platform/WebString.h"
#include "wtf/text/StringToNumber.h"
#include "wtf/text/WTFString.h"
#include <algorithm>

namespace blink {

namespace {

static inline bool isIntegerStart(UChar c) {
  return c > '0' && c <= '9';
}

static bool isWhitespace(UChar c) {
  // Sizes space characters are U+0020 SPACE, U+0009 CHARACTER TABULATION (tab),
  // U+000A LINE FEED (LF), U+000C FORM FEED (FF),
  // and U+000D CARRIAGE RETURN (CR).
  return c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r';
}

static bool isNotWhitespace(UChar c) {
  return !isWhitespace(c);
}

static bool isNonDigit(UChar c) {
  return !isASCIIDigit(c);
}

static inline size_t findEndOfWord(const String& string, size_t start) {
  return std::min(string.find(isWhitespace, start),
                  static_cast<size_t>(string.length()));
}

static inline int partialStringToInt(const String& string,
                                     size_t start,
                                     size_t end) {
  if (string.is8Bit())
    return charactersToInt(string.characters8() + start, end - start);
  return charactersToInt(string.characters16() + start, end - start);
}

}  // namespace

WebVector<WebSize> WebIconSizesParser::parseIconSizes(
    const WebString& webSizesString) {
  String sizesString = webSizesString;
  Vector<WebSize> iconSizes;
  if (sizesString.isEmpty())
    return iconSizes;

  unsigned length = sizesString.length();
  for (unsigned i = 0; i < length; ++i) {
    // Skip whitespaces.
    i = std::min(sizesString.find(isNotWhitespace, i),
                 static_cast<size_t>(length));
    if (i >= length)
      break;

    // See if the current size is "any".
    if (sizesString.findIgnoringCase("any", i) == i &&
        (i + 3 == length || isWhitespace(sizesString[i + 3]))) {
      iconSizes.append(WebSize(0, 0));
      i = i + 3;
      continue;
    }

    // Parse the width.
    if (!isIntegerStart(sizesString[i])) {
      i = findEndOfWord(sizesString, i);
      continue;
    }
    unsigned widthStart = i;
    i = std::min(sizesString.find(isNonDigit, i), static_cast<size_t>(length));
    if (i >= length || (sizesString[i] != 'x' && sizesString[i] != 'X')) {
      i = findEndOfWord(sizesString, i);
      continue;
    }
    unsigned widthEnd = i++;

    // Parse the height.
    if (i >= length || !isIntegerStart(sizesString[i])) {
      i = findEndOfWord(sizesString, i);
      continue;
    }
    unsigned heightStart = i;
    i = std::min(sizesString.find(isNonDigit, i), static_cast<size_t>(length));
    if (i < length && !isWhitespace(sizesString[i])) {
      i = findEndOfWord(sizesString, i);
      continue;
    }
    unsigned heightEnd = i;

    // Append the parsed size to iconSizes.
    iconSizes.append(
        WebSize(partialStringToInt(sizesString, widthStart, widthEnd),
                partialStringToInt(sizesString, heightStart, heightEnd)));
  }
  return iconSizes;
}

}  // namespace blink