1 files changed, 39 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/gpu/GrSamplePatternDictionary.h b/gfx/skia/skia/src/gpu/GrSamplePatternDictionary.h
new file mode 100644
index 0000000000..b0044782a6
--- /dev/null
+++ b/gfx/skia/skia/src/gpu/GrSamplePatternDictionary.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrSamplePatternDictionary_DEFINED
+#define GrSamplePatternDictionary_DEFINED
+
+#include "include/core/SkPoint.h"
+#include "include/private/SkTArray.h"
+#include <map>
+
+/**
+ * A bidirectional dictionary mapping between sample patterns (i.e., a list of sample locations) and
+ * unique keys. Since we expect that most render targets will draw from the same small pool of
+ * sample patterns, we favor sample pattern keys over actual arrays of points.
+ */
+class GrSamplePatternDictionary {
+public:
+    static constexpr int kInvalidSamplePatternKey = -1;
+
+    int findOrAssignSamplePatternKey(const SkTArray<SkPoint>& sampleLocations);
+
+    const SkTArray<SkPoint>& retrieveSampleLocations(int samplePatternKey) const {
+        return *fSampleLocationsArray[samplePatternKey];
+    }
+
+private:
+    struct LessThan {
+        bool operator()(const SkTArray<SkPoint>&, const SkTArray<SkPoint>&) const;
+    };
+
+    std::map<SkTArray<SkPoint>, int, LessThan> fSamplePatternKeyMap;
+    SkTArray<const SkTArray<SkPoint>*> fSampleLocationsArray;
+};
+
+#endif