text: /*
   * Copyright 2011 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  // Unit tests for src/core/SkPoint.cpp and its header
  
  #include "include/core/SkRect.h"
  #include "src/core/SkPointPriv.h"
  #include "tests/Test.h"
  
  static void test_casts(skiatest::Reporter* reporter) {
    SkPoint p = {0, 0};
    SkRect r = {0, 0, 0, 0};
  
    const SkScalar* pPtr = reinterpret_cast<const SkScalar*>(&p);
    const SkScalar* rPtr = reinterpret_cast<const SkScalar*>(&r);
  
    REPORTER_ASSERT(reporter, SkPointPriv::AsScalars(p) == pPtr);
    REPORTER_ASSERT(reporter, r.asScalars() == rPtr);
  }
  
  // Tests SkPoint::Normalize() for this (x,y)
  static void test_Normalize(skiatest::Reporter* reporter, SkScalar x, SkScalar y) {
    SkPoint point;
    point.set(x, y);
    SkScalar oldLength = point.length();
    SkScalar returned = SkPoint::Normalize(&point);
    SkScalar newLength = point.length();
    REPORTER_ASSERT(reporter, SkScalarNearlyEqual(returned, oldLength));
    REPORTER_ASSERT(reporter, SkScalarNearlyEqual(newLength, SK_Scalar1));
  }
  
  static void test_normalize_cannormalize_consistent(skiatest::Reporter* reporter) {
    const SkScalar values[] = {1, 1e18f, 1e20f, 1e38f, SK_ScalarInfinity, SK_ScalarNaN};
  
    for (SkScalar val : values) {
      const SkScalar variants[] = {val, -val, SkScalarInvert(val), -SkScalarInvert(val)};
  
      for (SkScalar v : variants) {
        const SkPoint pts[] = {{0, v}, {v, 0}, {1, v}, {v, 1}, {v, v}};
  
        for (SkPoint p : pts) {
          bool can = SkPointPriv::CanNormalize(p.fX, p.fY);
          bool nor = p.normalize();
          REPORTER_ASSERT(reporter, can == nor);
        }
      }
    }
  }
  
  // Tests that SkPoint::length() and SkPoint::Length() both return
  // approximately expectedLength for this (x,y).
  static void test_length(
      skiatest::Reporter* reporter, SkScalar x, SkScalar y, SkScalar expectedLength) {
    SkPoint point;
    point.set(x, y);
    SkScalar s1 = point.length();
    SkScalar s2 = SkPoint::Length(x, y);
    // The following should be exactly the same, but need not be.
    // See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323
    REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, s2));
    REPORTER_ASSERT(reporter, SkScalarNearlyEqual(s1, expectedLength));
  
    test_Normalize(reporter, x, y);
  }
  
  // Ugh. Windows compiler can dive into other .cpp files, and sometimes
  // notices that I will generate an overflow... which is exactly the point
  // of this test!
  //
  // To avoid this warning, I need to convince the compiler that I might not
  // use that big value, hence this hacky helper function: reporter is
  // ALWAYS non-null. (shhhhhh, don't tell the compiler that).
  template <typename T>
  T get_value(skiatest::Reporter* reporter, T value) {
    return reporter ? value : 0;
  }
  
  // On linux gcc, 32bit, we are seeing the compiler propagate up the value
  // of SkPoint::length() as a double (which we use sometimes to avoid overflow
  // during the computation), even though the signature says float (SkScalar).
  //
  // force_as_float is meant to capture our latest technique (horrible as
  // it is) to force the value to be a float, so we can test whether it was
  // finite or not.
  static float force_as_float(skiatest::Reporter* reporter, float value) {
    uint32_t storage;
    memcpy(&storage, &value, 4);
    // even the pair of memcpy calls are not sufficient, since those seem to
    // be no-op'd, so we add a runtime tests (just like get_value) to force
    // the compiler to give us an actual float.
    if (nullptr == reporter) {
      storage = ~storage;
    }
    memcpy(&value, &storage, 4);
    return value;
  }
  
  // test that we handle very large values correctly. i.e. that we can
  // successfully normalize something whose mag overflows a float.
  static void test_overflow(skiatest::Reporter* reporter) {
    SkScalar bigFloat = get_value(reporter, 3.4e38f);
    SkPoint pt = {bigFloat, bigFloat};
  
    SkScalar length = pt.length();
    length = force_as_float(reporter, length);
  
    // expect this to be non-finite, but dump the results if not.
    if (SkScalarIsFinite(length)) {
      SkDebugf("length(%g, %g) == %g\n", pt.fX, pt.fY, length);
      REPORTER_ASSERT(reporter, !SkScalarIsFinite(length));
    }
  
    // this should succeed, even though we can't represent length
    REPORTER_ASSERT(reporter, pt.setLength(SK_Scalar1));
  
    // now that pt is normalized, we check its length
    length = pt.length();
    REPORTER_ASSERT(reporter, SkScalarNearlyEqual(length, SK_Scalar1));
  }
  
  DEF_TEST(Point, reporter) {
    test_casts(reporter);
  
    static const struct {
      SkScalar fX;
      SkScalar fY;
      SkScalar fLength;
    } gRec[] = {
        {SkIntToScalar(3), SkIntToScalar(4), SkIntToScalar(5)},
        {0.6f, 0.8f, SK_Scalar1},
    };
  
    for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
      test_length(reporter, gRec[i].fX, gRec[i].fY, gRec[i].fLength);
    }
  
    test_overflow(reporter);
    test_normalize_cannormalize_consistent(reporter);
  }
  
  DEF_TEST(Point_setLengthFast, reporter) {
    // Scale a (1,1) point to a bunch of different lengths,
    // making sure the slow and fast paths are within 0.1%.
    const float tests[] = {1.0f, 0.0f, 1.0e-37f, 3.4e38f, 42.0f, 0.00012f};
  
    const SkPoint kOne = {1.0f, 1.0f};
    for (unsigned i = 0; i < SK_ARRAY_COUNT(tests); i++) {
      SkPoint slow = kOne, fast = kOne;
  
      slow.setLength(tests[i]);
      SkPointPriv::SetLengthFast(&fast, tests[i]);
  
      if (slow.length() < FLT_MIN && fast.length() < FLT_MIN) continue;
  
      SkScalar ratio = slow.length() / fast.length();
      REPORTER_ASSERT(reporter, ratio > 0.999f);
      REPORTER_ASSERT(reporter, ratio < 1.001f);
    }
  }
  