Test that Unmarshal doesn't do any allocations

The various Unmarshal functions are low-level functions that
should not do any extensive parsing.  Anything that requires
allocations should be done in a user-callable function so that
applications can call Unmarshal without concern for efficiency.

codecs/common_test.go

@@ -23,3 +23,237 @@ func TestCommon_Min(t *testing.T) {
 		t.Fatal("Error: 3 == 3")
 	}
 }
+
+var av1Payload = []byte{
+		0x68, 0x0c, 0x08, 0x00, 0x00, 0x00, 0x2c,
+		0xd6, 0xd3, 0x0c, 0xd5, 0x02, 0x00, 0x80,
+		0x30, 0x10, 0xc3, 0xc0, 0x07, 0xff, 0xff,
+		0xf8, 0xb7, 0x30, 0xc0, 0x00, 0x00, 0x88,
+		0x17, 0xf9, 0x0c, 0xcf, 0xc6, 0x7b, 0x9c,
+		0x0d, 0xda, 0x55, 0x82, 0x82, 0x67, 0x2f,
+		0xf0, 0x07, 0x26, 0x5d, 0xf6, 0xc6, 0xe3,
+		0x12, 0xdd, 0xf9, 0x71, 0x77, 0x43, 0xe6,
+		0xba, 0xf2, 0xce, 0x36, 0x08, 0x63, 0x92,
+		0xac, 0xbb, 0xbd, 0x26, 0x4c, 0x05, 0x52,
+		0x91, 0x09, 0xf5, 0x37, 0xb5, 0x18, 0xbe,
+		0x5c, 0x95, 0xb1, 0x2c, 0x13, 0x27, 0x81,
+		0xc2, 0x52, 0x8c, 0xaf, 0x27, 0xca, 0xf2,
+		0x93, 0xd6, 0x2e, 0x46, 0x32, 0xed, 0x71,
+		0x87, 0x90, 0x1d, 0x0b, 0x84, 0x46, 0x7f,
+		0xd1, 0x57, 0xc1, 0x0d, 0xc7, 0x5b, 0x41,
+		0xbb, 0x8a, 0x7d, 0xe9, 0x2c, 0xae, 0x36,
+		0x98, 0x13, 0x39, 0xb9, 0x0c, 0x66, 0x47,
+		0x05, 0xa2, 0xdf, 0x55, 0xc4, 0x09, 0xab,
+		0xe4, 0xfb, 0x11, 0x52, 0x36, 0x27, 0x88,
+		0x86, 0xf3, 0x4a, 0xbb, 0xef, 0x40, 0xa7,
+		0x85, 0x2a, 0xfe, 0x92, 0x28, 0xe4, 0xce,
+		0xce, 0xdc, 0x4b, 0xd0, 0xaa, 0x3c, 0xd5,
+		0x16, 0x76, 0x74, 0xe2, 0xfa, 0x34, 0x91,
+		0x4f, 0xdc, 0x2b, 0xea, 0xae, 0x71, 0x36,
+		0x74, 0xe1, 0x2a, 0xf3, 0xd3, 0x53, 0xe8,
+		0xec, 0xd6, 0x63, 0xf6, 0x6a, 0x75, 0x95,
+		0x68, 0xcc, 0x99, 0xbe, 0x17, 0xd8, 0x3b,
+		0x87, 0x5b, 0x94, 0xdc, 0xec, 0x32, 0x09,
+		0x18, 0x4b, 0x37, 0x58, 0xb5, 0x67, 0xfb,
+		0xdf, 0x66, 0x6c, 0x16, 0x9e, 0xba, 0x72,
+		0xc6, 0x21, 0xac, 0x02, 0x6d, 0x6b, 0x17,
+		0xf9, 0x68, 0x22, 0x2e, 0x10, 0xd7, 0xdf,
+		0xfb, 0x24, 0x69, 0x7c, 0xaf, 0x11, 0x64,
+		0x80, 0x7a, 0x9d, 0x09, 0xc4, 0x1f, 0xf1,
+		0xd7, 0x3c, 0x5a, 0xc2, 0x2c, 0x8e, 0xf5,
+		0xff, 0xee, 0xc2, 0x7c, 0xa1, 0xe4, 0xcb,
+		0x1c, 0x6d, 0xd8, 0x15, 0x0e, 0x40, 0x36,
+		0x85, 0xe7, 0x04, 0xbb, 0x64, 0xca, 0x6a,
+		0xd9, 0x21, 0x8e, 0x95, 0xa0, 0x83, 0x95,
+		0x10, 0x48, 0xfa, 0x00, 0x54, 0x90, 0xe9,
+		0x81, 0x86, 0xa0, 0x4a, 0x6e, 0xbe, 0x9b,
+		0xf0, 0x73, 0x0a, 0x17, 0xbb, 0x57, 0x81,
+		0x17, 0xaf, 0xd6, 0x70, 0x1f, 0xe8, 0x6d,
+		0x32, 0x59, 0x14, 0x39, 0xd8, 0x1d, 0xec,
+		0x59, 0xe4, 0x98, 0x4d, 0x44, 0xf3, 0x4f,
+		0x7b, 0x47, 0xd9, 0x92, 0x3b, 0xd9, 0x5c,
+		0x98, 0xd5, 0xf1, 0xc9, 0x8b, 0x9d, 0xb1,
+		0x65, 0xb3, 0xe1, 0x87, 0xa4, 0x6a, 0xcc,
+		0x42, 0x96, 0x66, 0xdb, 0x5f, 0xf9, 0xe1,
+		0xa1, 0x72, 0xb6, 0x05, 0x02, 0x1f, 0xa3,
+		0x14, 0x3e, 0xfe, 0x99, 0x7f, 0xeb, 0x42,
+		0xcf, 0x76, 0x09, 0x19, 0xd2, 0xd2, 0x99,
+		0x75, 0x1c, 0x67, 0xda, 0x4d, 0xf4, 0x87,
+		0xe5, 0x55, 0x8b, 0xed, 0x01, 0x82, 0xf6,
+		0xd6, 0x1c, 0x5c, 0x05, 0x96, 0x96, 0x79,
+		0xc1, 0x61, 0x87, 0x74, 0xcd, 0x29, 0x83,
+		0x27, 0xae, 0x47, 0x87, 0x36, 0x34, 0xab,
+		0xc4, 0x73, 0x76, 0x58, 0x1b, 0x4a, 0xec,
+		0x0e, 0x4c, 0x2f, 0xb1, 0x76, 0x08, 0x7f,
+		0xaf, 0xfa, 0x6d, 0x8c, 0xde, 0xe4, 0xae,
+		0x58, 0x87, 0xe7, 0xa0, 0x27, 0x05, 0x0d,
+		0xf5, 0xa7, 0xfb, 0x2a, 0x75, 0x33, 0xd9,
+		0x3b, 0x65, 0x60, 0xa4, 0x13, 0x27, 0xa5,
+		0xe5, 0x1b, 0x83, 0x78, 0x7a, 0xd7, 0xec,
+		0x0c, 0xed, 0x8b, 0xe6, 0x4e, 0x8f, 0xfe,
+		0x6b, 0x5d, 0xbb, 0xa8, 0xee, 0x38, 0x81,
+		0x6f, 0x09, 0x23, 0x08, 0x8f, 0x07, 0x21,
+		0x09, 0x39, 0xf0, 0xf8, 0x03, 0x17, 0x24,
+		0x2a, 0x22, 0x44, 0x84, 0xe1, 0x5c, 0xf3,
+		0x4f, 0x20, 0xdc, 0xc1, 0xe7, 0xeb, 0xbc,
+		0x0b, 0xfb, 0x7b, 0x20, 0x66, 0xa4, 0x27,
+		0xe2, 0x01, 0xb3, 0x5f, 0xb7, 0x47, 0xa1,
+		0x88, 0x4b, 0x8c, 0x47, 0xda, 0x36, 0x98,
+		0x60, 0xd7, 0x46, 0x92, 0x0b, 0x7e, 0x5b,
+		0x4e, 0x34, 0x50, 0x12, 0x67, 0x50, 0x8d,
+		0xe7, 0xc9, 0xe4, 0x96, 0xef, 0xae, 0x2b,
+		0xc7, 0xfa, 0x36, 0x29, 0x05, 0xf5, 0x92,
+		0xbd, 0x62, 0xb7, 0xbb, 0x90, 0x66, 0xe0,
+		0xad, 0x14, 0x3e, 0xe7, 0xb4, 0x24, 0xf3,
+		0x04, 0xcf, 0x22, 0x14, 0x86, 0xa4, 0xb8,
+		0xfb, 0x83, 0x56, 0xce, 0xaa, 0xb4, 0x87,
+		0x5a, 0x9e, 0xf2, 0x0b, 0xaf, 0xad, 0x40,
+		0xe1, 0xb5, 0x5c, 0x6b, 0xa7, 0xee, 0x9f,
+		0xbb, 0x1a, 0x68, 0x4d, 0xc3, 0xbf, 0x22,
+		0x4d, 0xbe, 0x58, 0x52, 0xc9, 0xcc, 0x0d,
+		0x88, 0x04, 0xf1, 0xf8, 0xd4, 0xfb, 0xd6,
+		0xad, 0xcf, 0x13, 0x84, 0xd6, 0x2f, 0x90,
+		0x0c, 0x5f, 0xb4, 0xe2, 0xd8, 0x29, 0x26,
+		0x8d, 0x7c, 0x6b, 0xab, 0x91, 0x91, 0x3c,
+		0x25, 0x39, 0x9c, 0x86, 0x08, 0x39, 0x54,
+		0x59, 0x0d, 0xa4, 0xa8, 0x31, 0x9f, 0xa3,
+		0xbc, 0xc2, 0xcb, 0xf9, 0x30, 0x49, 0xc3,
+		0x68, 0x0e, 0xfc, 0x2b, 0x9f, 0xce, 0x59,
+		0x02, 0xfa, 0xd4, 0x4e, 0x11, 0x49, 0x0d,
+		0x93, 0x0c, 0xae, 0x57, 0xd7, 0x74, 0xdd,
+		0x13, 0x1a, 0x15, 0x79, 0x10, 0xcc, 0x99,
+		0x32, 0x9b, 0x57, 0x6d, 0x53, 0x75, 0x1f,
+		0x6d, 0xbb, 0xe4, 0xbc, 0xa9, 0xd4, 0xdb,
+		0x06, 0xe7, 0x09, 0xb0, 0x6f, 0xca, 0xb3,
+		0xb1, 0xed, 0xc5, 0x0b, 0x8d, 0x8e, 0x70,
+		0xb0, 0xbf, 0x8b, 0xad, 0x2f, 0x29, 0x92,
+		0xdd, 0x5a, 0x19, 0x3d, 0xca, 0xca, 0xed,
+		0x05, 0x26, 0x25, 0xee, 0xee, 0xa9, 0xdd,
+		0xa0, 0xe3, 0x78, 0xe0, 0x56, 0x99, 0x2f,
+		0xa1, 0x3f, 0x07, 0x5e, 0x91, 0xfb, 0xc4,
+		0xb3, 0xac, 0xee, 0x07, 0xa4, 0x6a, 0xcb,
+		0x42, 0xae, 0xdf, 0x09, 0xe7, 0xd0, 0xbb,
+		0xc6, 0xd4, 0x38, 0x58, 0x7d, 0xb4, 0x45,
+		0x98, 0x38, 0x21, 0xc8, 0xc1, 0x3c, 0x81,
+		0x12, 0x7e, 0x37, 0x03, 0xa8, 0xcc, 0xf3,
+		0xf9, 0xd9, 0x9d, 0x8f, 0xc1, 0xa1, 0xcc,
+		0xc1, 0x1b, 0xe3, 0xa8, 0x93, 0x91, 0x2c,
+		0x0a, 0xe8, 0x1f, 0x28, 0x13, 0x44, 0x07,
+		0x68, 0x5a, 0x8f, 0x27, 0x41, 0x18, 0xc9,
+		0x31, 0xc4, 0xc1, 0x71, 0xe2, 0xf0, 0xc4,
+		0xf4, 0x1e, 0xac, 0x29, 0x49, 0x2f, 0xd0,
+		0xc0, 0x98, 0x13, 0xa6, 0xbc, 0x5e, 0x34,
+		0x28, 0xa7, 0x30, 0x13, 0x8d, 0xb4, 0xca,
+		0x91, 0x26, 0x6c, 0xda, 0x35, 0xb5, 0xf1,
+		0xbf, 0x3f, 0x35, 0x3b, 0x87, 0x37, 0x63,
+		0x40, 0x59, 0x73, 0x49, 0x06, 0x59, 0x04,
+		0xe0, 0x84, 0x16, 0x3a, 0xe8, 0xc4, 0x28,
+		0xd1, 0xf5, 0x11, 0x9c, 0x34, 0xf4, 0x5a,
+		0xc0, 0xf8, 0x67, 0x47, 0x1c, 0x90, 0x63,
+		0xbc, 0x06, 0x39, 0x2e, 0x8a, 0xa5, 0xa0,
+		0xf1, 0x6b, 0x41, 0xb1, 0x16, 0xbd, 0xb9,
+		0x50, 0x78, 0x72, 0x91, 0x8e, 0x8c, 0x99,
+		0x0f, 0x7d, 0x99, 0x7e, 0x77, 0x36, 0x85,
+		0x87, 0x1f, 0x2e, 0x47, 0x13, 0x55, 0xf8,
+		0x07, 0xba, 0x7b, 0x1c, 0xaa, 0xbf, 0x20,
+		0xd0, 0xfa, 0xc4, 0xe1, 0xd0, 0xb3, 0xe4,
+		0xf4, 0xf9, 0x57, 0x8d, 0x56, 0x19, 0x4a,
+		0xdc, 0x4c, 0x83, 0xc8, 0xf1, 0x30, 0xc0,
+		0xb5, 0xdf, 0x67, 0x25, 0x58, 0xd8, 0x09,
+		0x41, 0x37, 0x2e, 0x0b, 0x47, 0x2b, 0x86,
+		0x4b, 0x73, 0x38, 0xf0, 0xa0, 0x6b, 0x83,
+		0x30, 0x80, 0x3e, 0x46, 0xb5, 0x09, 0xc8,
+		0x6d, 0x3e, 0x97, 0xaa, 0x70, 0x4e, 0x8c,
+		0x75, 0x29, 0xec, 0x8a, 0x37, 0x4a, 0x81,
+		0xfd, 0x92, 0xf1, 0x29, 0xf0, 0xe8, 0x9d,
+		0x8c, 0xb4, 0x39, 0x2d, 0x67, 0x06, 0xcd,
+		0x5f, 0x25, 0x02, 0x30, 0xbb, 0x6b, 0x41,
+		0x93, 0x55, 0x1e, 0x0c, 0xc9, 0x6e, 0xb5,
+		0xd5, 0x9f, 0x80, 0xf4, 0x7d, 0x9d, 0x8a,
+		0x0d, 0x8d, 0x3b, 0x15, 0x14, 0xc9, 0xdf,
+		0x03, 0x9c, 0x78, 0x39, 0x4e, 0xa0, 0xdc,
+		0x3a, 0x1b, 0x8c, 0xdf, 0xaa, 0xed, 0x25,
+		0xda, 0x60, 0xdd, 0x30, 0x64, 0x09, 0xcc,
+		0x94, 0x53, 0xa1, 0xad, 0xfd, 0x9e, 0xe7,
+		0x65, 0x15, 0xb8, 0xb1, 0xda, 0x9a, 0x28,
+		0x80, 0x51, 0x88, 0x93, 0x92, 0xe3, 0x03,
+		0xdf, 0x70, 0xba, 0x1b, 0x59, 0x3b, 0xb4,
+		0x8a, 0xb6, 0x0b, 0x0a, 0xa8, 0x48, 0xdf,
+		0xcc, 0x74, 0x4c, 0x71, 0x80, 0x08, 0xec,
+		0xc8, 0x8a, 0x73, 0xf5, 0x0e, 0x3d, 0xec,
+		0x16, 0xf6, 0x32, 0xfd, 0xf3, 0x6b, 0xba,
+		0xa9, 0x65, 0xd1, 0x87, 0xe2, 0x56, 0xcd,
+		0xde, 0x2c, 0xa4, 0x1b, 0x25, 0x81, 0xb2,
+		0xed, 0xea, 0xe9, 0x11, 0x07, 0xf5, 0x17,
+		0xd0, 0xca, 0x5d, 0x07, 0xb9, 0xb2, 0xa9,
+		0xa9, 0xee, 0x42, 0x33, 0x93, 0x21, 0x30,
+		0x5e, 0xd2, 0x58, 0xfd, 0xdd, 0x73, 0x0d,
+		0xb2, 0x93, 0x58, 0x77, 0x78, 0x40, 0x69,
+		0xba, 0x3c, 0x95, 0x1c, 0x61, 0xc6, 0xc6,
+		0x97, 0x1c, 0xef, 0x4d, 0x91, 0x0a, 0x42,
+		0x91, 0x1d, 0x14, 0x93, 0xf5, 0x78, 0x41,
+		0x32, 0x8a, 0x0a, 0x43, 0xd4, 0x3e, 0x6b,
+		0xb0, 0xd8, 0x0e, 0x04,
+}
+
+func TestZeroAllocations(t *testing.T) {
+	type unmarshaller interface {
+		Unmarshal(data []byte) ([]byte, error)
+	}
+	type tst struct {
+		packet unmarshaller
+		data []byte
+	}
+	tests := []tst{
+		{
+			packet: &VP8Packet{},
+			data: []byte{
+				0x00, 0x11, 0x22, 0x33,
+				0x44, 0x55, 0x66, 0x90,
+			},
+		}, {
+			packet: &VP9Packet{},
+			data: []byte{0xA0, 0x02, 0x23, 0x01, 0xAA},
+		}, {
+			packet: &H264Packet{},
+			data: []byte{
+				0x78, 0x00, 0x0f, 0x67,
+				0x42, 0xc0, 0x1f, 0x1a,
+				0x32, 0x35, 0x01, 0x40,
+				0x7a, 0x40, 0x3c, 0x22,
+				0x11, 0xa8, 0x00, 0x05,
+				0x68, 0x1a, 0x34, 0xe3,
+				0xc8},
+		}, {
+			packet: &H265Packet{},
+			data: []byte{
+				0x62, 0x01, 0x93, 0xcc,
+				0xdd, 0xaf, 0x0d, 0x5a,
+			},
+		}, {
+			packet: &AV1Packet{},
+			data: av1Payload,
+
+		},
+	}
+
+	type dontParser interface {
+		DontParse(dont bool)
+	}
+
+	for _, test := range tests {
+		allocs := testing.AllocsPerRun(10, func() {
+			if d, ok := test.packet.(dontParser); ok {
+				d.DontParse(true)
+			}
+			_, err := test.packet.Unmarshal(test.data)
+			if err != nil {
+				t.Errorf("Unmarshal failed: %v", err)
+			}
+		})
+
+		if allocs != 0 {
+			t.Errorf("%T: %v allocs", test.packet, allocs)
+		}
+	}
+}