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 /* * Copyright 2023 Google LLC * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "fuzz/Fuzz.h" #include "include/private/base/SkAssert.h" #include "include/private/base/SkFloatingPoint.h" #include "src/base/SkCubics.h" #include "src/base/SkQuads.h" #include "src/base/SkUtils.h" #include static void fuzz_quad_real_roots(double A, double B, double C) { double roots[2]; const int numSolutions = SkQuads::RootsReal(A, B, C, roots); SkASSERT_RELEASE(numSolutions >= 0 && numSolutions <= 2); for (int i = 0; i < numSolutions; i++) { SkASSERT_RELEASE(std::isfinite(roots[i])); // You may be tempted to add assertions that plug the provided solutions into // the quadratic equation and verify that the result is zero. Be advised // that the fuzzer is very good at finding float values that result in // seemingly arbitrarily large errors, due to the imprecision of floating // point math. Unless the input range is sufficiently small, such an // effort seems fruitless. } if (numSolutions == 2) { // Roots should not be duplicated SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[1])); } } static void fuzz_cubic_real_roots(double A, double B, double C, double D) { double roots[3]; const int numSolutions = SkCubics::RootsReal(A, B, C, D, roots); SkASSERT_RELEASE(numSolutions >= 0 && numSolutions <= 3); for (int i = 0; i < numSolutions; i++) { SkASSERT_RELEASE(std::isfinite(roots[i])); } // Roots should not be duplicated if (numSolutions >= 2) { SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[1])); } if (numSolutions == 3) { SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[1], roots[2])); SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[2])); } } static void fuzz_cubic_roots_valid_t(double A, double B, double C, double D) { double roots[3]; const int numSolutions = SkCubics::RootsValidT(A, B, C, D, roots); SkASSERT_RELEASE(numSolutions >= 0 && numSolutions <= 3); for (int i = 0; i < numSolutions; i++) { SkASSERT_RELEASE(std::isfinite(roots[i])); SkASSERT_RELEASE(roots[i] >= 0.0); SkASSERT_RELEASE(roots[i] <= 1.0); } // Roots should not be duplicated if (numSolutions >= 2) { SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[1])); } if (numSolutions == 3) { SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[1], roots[2])); SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[2])); } } static void fuzz_cubic_roots_binary_search(double A, double B, double C, double D) { double roots[3]; const int numSolutions = SkCubics::BinarySearchRootsValidT(A, B, C, D, roots); SkASSERT_RELEASE(numSolutions >= 0 && numSolutions <= 3); for (int i = 0; i < numSolutions; i++) { SkASSERT_RELEASE(std::isfinite(roots[i])); SkASSERT_RELEASE(roots[i] >= 0.0); SkASSERT_RELEASE(roots[i] <= 1.0); double actual = SkCubics::EvalAt(A, B, C, D, roots[i]); // The binary search algorithm *should* be accurate regardless of the inputs. SkASSERT_RELEASE(std::abs(actual) < 0.001); } // Roots should not be duplicated if (numSolutions >= 2) { SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[1])); } if (numSolutions == 3) { SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[1], roots[2])); SkASSERT_RELEASE(!sk_doubles_nearly_equal_ulps(roots[0], roots[2])); } } DEF_FUZZ(CubicQuadRoots, fuzz) { double A, B, C, D; fuzz->next(&A); fuzz->next(&B); fuzz->next(&C); fuzz->next(&D); // Uncomment for easy test case creation // SkDebugf("A %16e (0x%lx) B %16e (0x%lx) C %16e (0x%lx) D %16e (0x%lx)\n", // A, sk_bit_cast(A), B, sk_bit_cast(B), // C, sk_bit_cast(C), D, sk_bit_cast(D)); fuzz_quad_real_roots(A, B, C); fuzz_cubic_real_roots(A, B, C, D); fuzz_cubic_roots_valid_t(A, B, C, D); fuzz_cubic_roots_binary_search(A, B, C, D); }