Add ShapeResult::RunInfo glyph iterators

third_party/WebKit/Source/platform/fonts/shaping/ShapeResultInlineHeaders.h

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 BlackBerry Limited. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 80 matching lines @@
 
   size_t glyphToCharacterIndex(size_t i) const {
     return m_startIndex + m_glyphData[i].characterIndex;
   }
 
   // For memory reporting.
   size_t byteSize() const {
     return sizeof(this) + m_glyphData.size() * sizeof(HarfBuzzRunGlyphData);
   }
 
+  // Iterates over, and applies the functor to all the glyphs in this run.
+  // Also tracks (and returns) a seeded total advance.
+  //
+  // Functor signature:
+  //
+  //   bool func(const HarfBuzzRunGlyphData& glyphData, float totalAdvance)
+  //
+  // where the returned bool signals whether iteration should continue (true)
+  // or stop (false).
+  template <typename Func>
+  float forEachGlyph(float initialAdvance, Func func) const {
+    float totalAdvance = initialAdvance;
+
+    for (const auto& glyphData : m_glyphData) {
+      if (!func(glyphData, totalAdvance))
+        break;
+      totalAdvance += glyphData.advance;
+    }
+
+    return totalAdvance;
+  }
+
+  // Same as the above, except it only applies the functor to glyphs in the
+  // specified range, and stops after the range.
+  template <typename Func>
+  float forEachGlyphInRange(float initialAdvance,
+                            unsigned from,
+                            unsigned to,
+                            unsigned indexOffset,
+                            Func func) const {
+    return forEachGlyph(
+        initialAdvance,
+        [&](const HarfBuzzRunGlyphData& glyphData, float totalAdvance) -> bool {
+          const uint16_t characterIndex =
+              m_startIndex + glyphData.characterIndex + indexOffset;
+
+          if (characterIndex < from) {
+            // Glyph out-of-range; before the range (and must continue
+            // accumulating advance) in LTR.
+            return !rtl();
+          }
+
+          if (characterIndex >= to) {
+            // Glyph out-of-range; before the range (and must continue
+            // accumulating advance) in RTL.
+            return rtl();
+          }
+
+          // Glyph in range; apply functor.
+          return func(glyphData, totalAdvance, characterIndex);
+        });
+  }
+
   RefPtr<SimpleFontData> m_fontData;
   hb_direction_t m_direction;
   hb_script_t m_script;
   Vector<HarfBuzzRunGlyphData> m_glyphData;
   unsigned m_startIndex;
   unsigned m_numCharacters;
   float m_width;
 };
 
 }  // namespace blink
 
 #endif  // ShapeResultInlineHeaders_h