Try to correctly read points on files shorter than expected

Try to correctly read points if the file does not have enough bytes for the expected number of points by recalculating the actual number of points if point_size is a multiple of the bytes_len read

pylas/point/record.py

@@ -9,6 +9,10 @@
 
 from . import dims, packing
 from ..compression import decompress_buffer
+from .. import errors
+import logging
+
+logger = logging.getLogger(__name__)
 
 
 class PointRecord(ABC):
@@ -211,7 +215,36 @@ def from_stream(cls, stream, point_format_id, count, extra_dims=None):
             point_format_id, extra_dims=extra_dims
         )
         point_data_buffer = bytearray(stream.read(count * points_dtype.itemsize))
-        data = np.frombuffer(point_data_buffer, dtype=points_dtype, count=count)
+        expected_bytes_len = count * points_dtype.itemsize
+
+        try:
+            data = np.frombuffer(point_data_buffer, dtype=points_dtype, count=count)
+        except ValueError:
+            if len(point_data_buffer) % points_dtype.itemsize != 0:
+                missing_bytes_len = expected_bytes_len - len(point_data_buffer)
+                raise errors.PylasError(
+                    "The file does not contain enough bytes to store the expected number of points\n"
+                    "expected {} bytes, read {} bytes ({} bytes missing == {} points) and it cannot be corrected\n"
+                    "{} (bytes) / {} (point_size) = {} (points)".format(
+                        expected_bytes_len,
+                        len(point_data_buffer),
+                        missing_bytes_len,
+                        missing_bytes_len / points_dtype.itemsize,
+                        len(point_data_buffer),
+                        points_dtype.itemsize,
+                        len(point_data_buffer) / points_dtype.itemsize,
+                    )
+                )
+            else:
+                actual_count = len(point_data_buffer) // points_dtype.itemsize
+                logger.warning(
+                    "Expected {} points, there are {} ({} missing)".format(
+                        count, actual_count, count - actual_count
+                    )
+                )
+                data = np.frombuffer(
+                    point_data_buffer, dtype=points_dtype, count=actual_count
+                )
 
         return cls(data, point_format_id)