Add ASCII reader (#22)

* add ASCII reader

* improve performance of ASCII STL reader; update README

.gitignore

@@ -13,4 +13,5 @@ CMakeCache.txt
 CMakeFiles/
 Makefile
 cmake_install.cmake
-compile_commands.json
+compile_commands.json
+.cache/

CONTRIBUTING.md

@@ -9,7 +9,7 @@ extensions.
 If using emacs and helm, generate the project configuration files using `-DCMAKE_EXPORT_COMPILE_COMMANDS=ON`. Here's a sample configuration for C++11 on Linux:
 
 ```
-pip install nanobind
+pip install nanobind -U
 export NANOBIND_INCLUDE=$(python -c "import nanobind, os; print(os.path.join(os.path.dirname(nanobind.__file__), 'cmake'))")
 cmake -Dnanobind_DIR=$NANOBIND_INCLUDE -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DCMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES="/usr/include/c++/11;/usr/include/x86_64-linux-gnu/c++/11/;/usr/lib/gcc/x86_64-linux-gnu/11/include/"
 ```

README.rst

@@ -10,8 +10,8 @@
 .. |MIT| image:: https://img.shields.io/badge/License-MIT-yellow.svg
    :target: https://opensource.org/licenses/MIT
 
-``stl-reader`` is a Python library for raipidly reading binary STL
-files. It wraps a `nanobind
+``stl-reader`` is a Python library for rapidly reading binary and ASCII
+STL files. It wraps a `nanobind
 <https://nanobind.readthedocs.io/en/latest/>`_ interface to the fast STL
 library provided by `libstl <https://github.com/aki5/libstl>`_. Thanks
 @aki5!
@@ -169,6 +169,40 @@ Here's an additional benchmark comparing VTK with ``stl-reader``:
 
 .. image:: https://github.com/pyvista/stl-reader/raw/main/bench1.png
 
+Read in ASCII Meshes
+====================
+
+The `stl-reader` also supports ASCII files and is around 2.4 times
+faster than VTK at reading ASCII files.
+
+.. code:: python
+
+   import time
+   import stl_reader
+   import pyvista as pv
+   import numpy as np
+
+   # create and save a ASCII file
+   n = 1000
+   mesh = pv.Plane(i_resolution=n, j_resolution=n).triangulate()
+   mesh.save("/tmp/tmp-ascii.stl", binary=False)
+
+   # stl reader
+   tstart = time.time()
+   mesh = stl_reader.read_as_mesh("/tmp/tmp-ascii.stl")
+   print("stl-reader    ", time.time() - tstart)
+
+   tstart = time.time()
+   pv_mesh = pv.read("/tmp/tmp-ascii.stl")
+   print("pyvista reader", time.time() - tstart)
+
+   # verify meshes are identical
+   assert np.allclose(mesh.points, pv_mesh.points)
+
+   # approximate time to read in the 1M point file:
+   # stl-reader     0.80303955078125
+   # pyvista reader 1.916085958480835
+
 *****************************
  License and Acknowledgments
 *****************************

src/stl_reader/reader.py

@@ -11,12 +11,6 @@
     from pyvista.core.pointset import PolyData
 
 
-def _check_stl_ascii(filename: str) -> bool:
-    """Check if a STL is ASCII."""
-    with open(filename, "rb") as fid:
-        return fid.read(5) == b"solid"
-
-
 def _polydata_from_faces(points: npt.NDArray[float], faces: npt.NDArray[int]) -> "PolyData":
     """Generate a polydata from a faces array containing no padding and all triangles.
 
@@ -99,9 +93,6 @@ def read(filename: str) -> Tuple[npt.NDArray[np.float32], npt.NDArray[np.uint32]
            [9005998, 9005999, 9005995]], dtype=uint32)
 
     """
-    if _check_stl_ascii(filename):
-        raise RuntimeError("stl-reader only supports binary STL files")
-
     return _stlfile_wrapper.get_stl_data(filename)