Introduce SkArenaAlloc - should be fast for POD types and RAII for types with dtors.

- Implementation.
- Use in SkLinearPipeline.
 
TBR=mtklein@google.com
Change-Id: Ia8efd09b2f3139a57182889ba84d1610eae92749
Reviewed-on: https://skia-review.googlesource.com/6352
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Herb Derby <herb@google.com>

1 files changed, 89 insertions, 1 deletions

diff --git a/tests/FixedAllocTest.cpp b/tests/FixedAllocTest.cpp
index 0a00f00935..5c36b537fa 100644
--- a/tests/FixedAllocTest.cpp
+++ b/tests/FixedAllocTest.cpp
@@ -13,7 +13,8 @@ namespace {
     static int created, destroyed;
 
     struct Foo {
-         Foo(int X, float Y) : x(X), y(Y) { created++; }
+        Foo() : x(-2), y(-3.0f) { created++; }
+        Foo(int X, float Y) : x(X), y(Y) { created++; }
         ~Foo() { destroyed++; }
 
         int x;
@@ -111,3 +112,90 @@ DEF_TEST(FallbackAlloc, r) {
     REPORTER_ASSERT(r, !in_buf(big));
     REPORTER_ASSERT(r, !in_buf(smallB));
 }
+
+struct WithDtor {
+    ~WithDtor() { }
+};
+
+DEF_TEST(ArenaAlloc, r) {
+    {
+        created = 0;
+        destroyed = 0;
+
+        SkArenaAlloc arena{nullptr, 0};
+        REPORTER_ASSERT(r, *arena.make<int>(3) == 3);
+        Foo* foo = arena.make<Foo>(3, 4.0f);
+        REPORTER_ASSERT(r, foo->x == 3);
+        REPORTER_ASSERT(r, foo->y == 4.0f);
+        REPORTER_ASSERT(r, created == 1);
+        REPORTER_ASSERT(r, destroyed == 0);
+        arena.makeArrayDefault<int>(10);
+        int* zeroed = arena.makeArray<int>(10);
+        for (int i = 0; i < 10; i++) {
+            REPORTER_ASSERT(r, zeroed[i] == 0);
+        }
+        Foo* fooArray = arena.makeArrayDefault<Foo>(10);
+        REPORTER_ASSERT(r, fooArray[3].x == -2);
+        REPORTER_ASSERT(r, fooArray[4].y == -3.0f);
+        REPORTER_ASSERT(r, created == 11);
+        REPORTER_ASSERT(r, destroyed == 0);
+        arena.make<typename std::aligned_storage<10,8>::type>();
+    }
+    REPORTER_ASSERT(r, created == 11);
+    REPORTER_ASSERT(r, destroyed == 11);
+
+    {
+        created = 0;
+        destroyed = 0;
+        char block[1024];
+        SkArenaAlloc arena{block};
+
+        REPORTER_ASSERT(r, *arena.make<int>(3) == 3);
+        Foo* foo = arena.make<Foo>(3, 4.0f);
+        REPORTER_ASSERT(r, foo->x == 3);
+        REPORTER_ASSERT(r, foo->y == 4.0f);
+        REPORTER_ASSERT(r, created == 1);
+        REPORTER_ASSERT(r, destroyed == 0);
+        arena.makeArrayDefault<int>(10);
+        int* zeroed = arena.makeArray<int>(10);
+        for (int i = 0; i < 10; i++) {
+            REPORTER_ASSERT(r, zeroed[i] == 0);
+        }
+        Foo* fooArray = arena.makeArrayDefault<Foo>(10);
+        REPORTER_ASSERT(r, fooArray[3].x == -2);
+        REPORTER_ASSERT(r, fooArray[4].y == -3.0f);
+        REPORTER_ASSERT(r, created == 11);
+        REPORTER_ASSERT(r, destroyed == 0);
+        arena.make<typename std::aligned_storage<10,8>::type>();
+    }
+    REPORTER_ASSERT(r, created == 11);
+    REPORTER_ASSERT(r, destroyed == 11);
+
+    {
+        created = 0;
+        destroyed = 0;
+        std::unique_ptr<char[]> block{new char[1024]};
+        SkArenaAlloc arena{block.get(), 1024};
+
+        REPORTER_ASSERT(r, *arena.make<int>(3) == 3);
+        Foo* foo = arena.make<Foo>(3, 4.0f);
+        REPORTER_ASSERT(r, foo->x == 3);
+        REPORTER_ASSERT(r, foo->y == 4.0f);
+        REPORTER_ASSERT(r, created == 1);
+        REPORTER_ASSERT(r, destroyed == 0);
+        arena.makeArrayDefault<int>(10);
+        int* zeroed = arena.makeArray<int>(10);
+        for (int i = 0; i < 10; i++) {
+            REPORTER_ASSERT(r, zeroed[i] == 0);
+        }
+        Foo* fooArray = arena.makeArrayDefault<Foo>(10);
+        REPORTER_ASSERT(r, fooArray[3].x == -2);
+        REPORTER_ASSERT(r, fooArray[4].y == -3.0f);
+        REPORTER_ASSERT(r, created == 11);
+        REPORTER_ASSERT(r, destroyed == 0);
+        arena.make<typename std::aligned_storage<10,8>::type>();
+    }
+    REPORTER_ASSERT(r, created == 11);
+    REPORTER_ASSERT(r, destroyed == 11);
+
+}