Implement faster mju_isZeroByte.

PiperOrigin-RevId: 814148714 Change-Id: Iaf5ed9d3502eaaaee8d46a986f2db00811ae0707
2025-10-02 02:53:02 -07:00
parent 401bf431b8
commit 91257896c0
4 changed files with 42 additions and 21 deletions
@@ -360,6 +360,35 @@ TEST_F(UtilMiscTest, MjuIsZero) {
  EXPECT_EQ(mju_isZeroByte((const unsigned char*)vec, sizeof(mjtNum)), 0);
 }

+TEST_F(UtilMiscTest, MjuIsZeroByte) {
+  // Zero length array
+  EXPECT_TRUE(mju_isZeroByte(nullptr, 0));
+
+  // zero length array with non-null pointer
+  unsigned char vec0[1] = {0};
+  EXPECT_TRUE(mju_isZeroByte(vec0, sizeof(vec0)));
+
+  // one zero element array
+  unsigned char vec1[1] = {0};
+  EXPECT_TRUE(mju_isZeroByte(vec1, sizeof(vec1)));
+
+  // one non-zero element array
+  unsigned char vec2[2] = {1};
+  EXPECT_FALSE(mju_isZeroByte(vec2, sizeof(vec2)));
+
+  // Non-zero at start
+  unsigned char vec3[3] = {1, 0, 0};
+  EXPECT_FALSE(mju_isZeroByte(vec3, sizeof(vec3)));
+
+  // Non-zero at end
+  unsigned char vec4[3] = {0, 0, 1};
+  EXPECT_FALSE(mju_isZeroByte(vec4, sizeof(vec4)));
+
+  // Non-zero in middle
+  unsigned char vec5[3] = {0, 1, 0};
+  EXPECT_FALSE(mju_isZeroByte(vec5, sizeof(vec5)));
+}
+
 // --------------------------------- Interpolation -----------------------------

 using InterpolationTest = MujocoTest;