Add setter for sample_count property

src/nitypes/waveform/_analog.py

@@ -482,7 +482,6 @@ def __init__(
                 of this array. If not specified, an ndarray is created based on the specified dtype,
                 start index, sample count, and capacity.
             start_index: The sample index at which the analog waveform data begins.
-            sample_count: The number of samples in the analog waveform.
             capacity: The number of samples to allocate. Pre-allocating a larger buffer optimizes
                 appending samples to the waveform.
             extended_properties: The extended properties of the analog waveform.

src/nitypes/waveform/_complex.py

@@ -386,7 +386,6 @@ def __init__(
                 of this array. If not specified, an ndarray is created based on the specified dtype,
                 start index, sample count, and capacity.
             start_index: The sample index at which the waveform data begins.
-            sample_count: The number of samples in the waveform.
             capacity: The number of samples to allocate. Pre-allocating a larger buffer optimizes
                 appending samples to the waveform.
             extended_properties: The extended properties of the waveform.

src/nitypes/waveform/_digital/_waveform.py

@@ -905,6 +905,16 @@ def sample_count(self) -> int:
         """The number of samples in the waveform."""
         return self._sample_count
 
+    @sample_count.setter
+    def sample_count(self, value: int) -> None:
+        """Set the number of samples in the waveform."""
+        value = arg_to_uint("sample count", value)
+        if self._start_index + value > self.capacity:
+            raise create_start_index_or_sample_count_too_large_error(
+                self._start_index, value, "capacity", self.capacity
+            )
+        self._sample_count = value
+
     @property
     def signal_count(self) -> int:
         """The number of signals in the waveform."""

src/nitypes/waveform/_numeric.py

@@ -456,6 +456,16 @@ def sample_count(self) -> int:
         """The number of samples in the waveform."""
         return self._sample_count
 
+    @sample_count.setter
+    def sample_count(self, value: int) -> None:
+        """Set the number of samples in the waveform."""
+        value = arg_to_uint("sample count", value)
+        if self._start_index + value > self.capacity:
+            raise create_start_index_or_sample_count_too_large_error(
+                self._start_index, value, "capacity", self.capacity
+            )
+        self._sample_count = value
+
     @property
     def capacity(self) -> int:
         """The total capacity available for waveform data.

tests/unit/waveform/test_analog_waveform.py

@@ -851,6 +851,32 @@ def test___array_subset___get_scaled_data___returns_array_subset() -> None:
     assert list(scaled_data) == [2.5, 4.5]
 
 
+###############################################################################
+# sample count
+###############################################################################
+def test___waveform___set_sample_count___updates_sample_count() -> None:
+    waveform = AnalogWaveform(10, np.float64)
+
+    waveform.sample_count = 5
+
+    assert waveform.sample_count == 5
+    assert waveform.capacity == 10  # Capacity should remain unchanged
+    assert len(waveform.raw_data) == 5  # Raw data length should reflect new sample count
+
+
+def test___waveform___set_sample_count_exceeds_capacity___raises_value_error() -> None:
+    waveform = AnalogWaveform(5, np.float64, capacity=10)
+
+    with pytest.raises(ValueError) as exc:
+        waveform.sample_count = 15
+
+    assert exc.value.args[0].startswith(
+        "The sum of the start index and sample count must be less than or equal to the capacity."
+    )
+
+    assert waveform.sample_count == 5  # Original sample count preserved
+
+
 ###############################################################################
 # capacity
 ###############################################################################

tests/unit/waveform/test_digital_waveform.py

@@ -548,6 +548,42 @@ def test___invalid_array_subset___get_data___returns_array_subset(
     assert exc.value.args[0].startswith(expected_message)
 
 
+###############################################################################
+# sample_count
+###############################################################################
+def test___waveform___set_sample_count___updates_sample_count() -> None:
+    waveform = DigitalWaveform(10, 2, np.uint8)
+
+    waveform.sample_count = 5
+
+    assert waveform.sample_count == 5
+    assert waveform.capacity == 10  # Capacity should remain unchanged
+    assert waveform.signal_count == 2  # Signal count should remain unchanged
+    assert waveform.data.shape == (5, 2)  # Data shape should reflect new sample count
+
+
+def test___waveform___set_sample_count_to_zero___creates_empty_waveform() -> None:
+    waveform = DigitalWaveform.from_lines([[1, 2], [3, 4]], np.uint8)
+
+    waveform.sample_count = 0
+
+    assert waveform.sample_count == 0
+    assert waveform.data.tolist() == []
+    assert waveform.capacity == 2  # Capacity preserved
+
+
+def test___waveform___set_sample_count_exceeds_capacity___raises_value_error() -> None:
+    waveform = DigitalWaveform(5, 2, np.uint8, capacity=10)
+
+    with pytest.raises(ValueError) as exc:
+        waveform.sample_count = 15
+
+    assert exc.value.args[0].startswith(
+        "The sum of the start index and sample count must be less than or equal to the capacity."
+    )
+    assert waveform.sample_count == 5  # Original sample count preserved
+
+
 ###############################################################################
 # capacity
 ###############################################################################