Split out common parsing code for Position/Size VTT cue settings

Source/core/html/track/vtt/VTTCue.cpp

 /*
  * Copyright (c) 2013, Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 840 matching lines @@
     if (name == sizeKeyword)
         return Size;
     if (name == alignKeyword)
         return Align;
     if (RuntimeEnabledFeatures::webVTTRegionsEnabled() && name == regionIdKeyword)
         return RegionId;
 
     return None;
 }
 
+// Used for 'position' and 'size'.
+static bool scanPercentage(const String& input, unsigned* position, int& number)
+{
+    ASSERT(position);
+    // 1. If value contains any characters other than U+0025 PERCENT SIGN
+    //    characters (%) and characters in the range U+0030 DIGIT ZERO (0) to
+    //    U+0039 DIGIT NINE (9), then jump to the step labeled next setting.
+    // 2. If value does not contain at least one character in the range U+0030
+    //    DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then jump to the step
+    //    labeled next setting.
+    if (!VTTParser::collectDigitsToInt(input, position, number))
+        return false;
+    if (*position >= input.length())
+        return false;
+
+    // 3. If any character in value other than the last character is a U+0025
+    //    PERCENT SIGN character (%), then jump to the step labeled next
+    //    setting.
+    // 4. If the last character in value is not a U+0025 PERCENT SIGN character
+    //    (%), then jump to the step labeled next setting.
+    if (input[(*position)++] != '%')
+        return false;
+    if (*position < input.length() && !VTTParser::isValidSettingDelimiter(input[*position]))
+        return false;
+
+    // 5. Ignoring the trailing percent sign, interpret value as an integer,
+    //    and let number be that number.
+    // 6. If number is not in the range 0 ≤ number ≤ 100, then jump to the step
+    //    labeled next setting.
+    return number >= 0 && number <= 100;
+}
+
 void VTTCue::parseSettings(const String& input)
 {
     unsigned position = 0;
 
     while (position < input.length()) {
 
         // The WebVTT cue settings part of a WebVTT cue consists of zero or more of the following components, in any order,
         // separated from each other by one or more U+0020 SPACE characters or U+0009 CHARACTER TABULATION (tab) characters.
         while (position < input.length() && VTTParser::isValidSettingDelimiter(input[position]))
             position++;
@@ skipping 16 matching lines @@
         // 2. Let name be the leading substring of setting up to and excluding the first U+003A COLON character (:) in that string.
         name = settingName(setting.substring(0, colonOffset));
 
         // 3. Let value be the trailing substring of setting starting from the character immediately after the first U+003A COLON character (:) in that string.
         position += colonOffset + 1;
         if (position >= input.length())
             break;
 
         // 4. Run the appropriate substeps that apply for the value of name, as follows:
         switch (name) {
-        case Vertical:
-            {
+        case Vertical: {
             // If name is a case-sensitive match for "vertical"
             // 1. If value is a case-sensitive match for the string "rl", then let cue's text track cue writing direction
             //    be vertical growing left.
             String writingDirection = VTTParser::collectWord(input, &position);
             if (writingDirection == verticalGrowingLeftKeyword())
                 m_writingDirection = VerticalGrowingLeft;
 
             // 2. Otherwise, if value is a case-sensitive match for the string "lr", then let cue's text track cue writing
             //    direction be vertical growing right.
             else if (writingDirection == verticalGrowingRightKeyword())
                 m_writingDirection = VerticalGrowingRight;
-            }
             break;
-        case Line:
-            {
+        }
+        case Line: {
             // 1-2 - Collect chars that are either '-', '%', or a digit.
             // 1. If value contains any characters other than U+002D HYPHEN-MINUS characters (-), U+0025 PERCENT SIGN
             //    characters (%), and characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then jump
             //    to the step labeled next setting.
             StringBuilder linePositionBuilder;
             while (position < input.length() && (input[position] == '-' || input[position] == '%' || isASCIIDigit(input[position])))
                 linePositionBuilder.append(input[position++]);
             if (position < input.length() && !VTTParser::isValidSettingDelimiter(input[position]))
                 break;
 
@@ skipping 27 matching lines @@
             //    snap-to-lines flag be false. Otherwise, let it be true.
             if (linePosition[linePosition.length() - 1] == '%') {
                 if (number < 0 || number > 100)
                     break;
 
                 // 10 - If '%' then set snap-to-lines flag to false.
                 m_snapToLines = false;
             }
 
             m_linePosition = number;
-            }
             break;
-        case Position:
-            {
-            // 1. If value contains any characters other than U+0025 PERCENT SIGN characters (%) and characters in the range
-            //    U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then jump to the step labeled next setting.
-            // 2. If value does not contain at least one character in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9),
-            //    then jump to the step labeled next setting.
+        }
+        case Position: {
             int number;
-            if (!VTTParser::collectDigitsToInt(input, &position, number))
-                break;
-            if (position >= input.length())
-                break;
-
-            // 3. If any character in value other than the last character is a U+0025 PERCENT SIGN character (%), then jump
-            //    to the step labeled next setting.
-            // 4. If the last character in value is not a U+0025 PERCENT SIGN character (%), then jump to the step labeled
-            //    next setting.
-            if (input[position++] != '%')
-                break;
-            if (position < input.length() && !VTTParser::isValidSettingDelimiter(input[position]))
-                break;
-
-            // 5. Ignoring the trailing percent sign, interpret value as an integer, and let number be that number.
-            // 6. If number is not in the range 0 ≤ number ≤ 100, then jump to the step labeled next setting.
-            // NOTE: toInt ignores trailing non-digit characters, such as '%'.
-            if (number < 0 || number > 100)
+            // Steps 1 - 6.
+            if (!scanPercentage(input, &position, number))
                 break;
 
             // 7. Let cue's text track cue text position be number.
             m_textPosition = number;
-            }
             break;
-        case Size:
-            {
-            // 1. If value contains any characters other than U+0025 PERCENT SIGN characters (%) and characters in the
-            //    range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9), then jump to the step labeled next setting.
-            // 2. If value does not contain at least one character in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT
-            //    NINE (9), then jump to the step labeled next setting.
+        }
+        case Size: {
             int number;
-            if (!VTTParser::collectDigitsToInt(input, &position, number))
-                break;
-            if (position >= input.length())
-                break;
-
-            // 3. If any character in value other than the last character is a U+0025 PERCENT SIGN character (%),
-            //    then jump to the step labeled next setting.
-            // 4. If the last character in value is not a U+0025 PERCENT SIGN character (%), then jump to the step
-            //    labeled next setting.
-            if (input[position++] != '%')
-                break;
-            if (position < input.length() && !VTTParser::isValidSettingDelimiter(input[position]))
-                break;
-
-            // 5. Ignoring the trailing percent sign, interpret value as an integer, and let number be that number.
-            // 6. If number is not in the range 0 ≤ number ≤ 100, then jump to the step labeled next setting.
-            if (number < 0 || number > 100)
+            // Steps 1 - 6.
+            if (!scanPercentage(input, &position, number))
                 break;
 
             // 7. Let cue's text track cue size be number.
             m_cueSize = number;
-            }
             break;
-        case Align:
-            {
+        }
+        case Align: {
             String cueAlignment = VTTParser::collectWord(input, &position);
 
             // 1. If value is a case-sensitive match for the string "start", then let cue's text track cue alignment be start alignment.
             if (cueAlignment == startKeyword())
                 m_cueAlignment = Start;
 
             // 2. If value is a case-sensitive match for the string "middle", then let cue's text track cue alignment be middle alignment.
             else if (cueAlignment == middleKeyword())
                 m_cueAlignment = Middle;
 
             // 3. If value is a case-sensitive match for the string "end", then let cue's text track cue alignment be end alignment.
             else if (cueAlignment == endKeyword())
                 m_cueAlignment = End;
 
             // 4. If value is a case-sensitive match for the string "left", then let cue's text track cue alignment be left alignment.
             else if (cueAlignment == leftKeyword())
                 m_cueAlignment = Left;
 
             // 5. If value is a case-sensitive match for the string "right", then let cue's text track cue alignment be right alignment.
             else if (cueAlignment == rightKeyword())
                 m_cueAlignment = Right;
-            }
             break;
+        }
         case RegionId:
             m_regionId = VTTParser::collectWord(input, &position);
             break;
         case None:
             break;
         }
 
 NextSetting:
         position = endOfSetting;
     }
@@ skipping 42 matching lines @@
     return m_cueBackgroundBox->executionContext();
 }
 
 Document& VTTCue::document() const
 {
     ASSERT(m_cueBackgroundBox);
     return m_cueBackgroundBox->document();
 }
 
 } // namespace WebCore