# -*- coding: utf-8 -*-
from __future__ import absolute_import, print_function
import numpy
import os
import struct
from .base import BaseMesh
class Stl(BaseMesh):
MODE_AUTO = 0
MODE_ASCII = 1
MODE_BINARY = 2
HEADER_SIZE = 80
COUNT_SIZE = 4
MAX_COUNT = 1e6
BUFFER_SIZE = 4096
stl_dtype = numpy.dtype([
('normals', numpy.float32, (3, )),
('vectors', numpy.float32, (3, 3)),
('attr', numpy.uint16, (1, )),
])
def __init__(self, path=None, mode_policy=MODE_AUTO):
"""Craete a instance of Stl.
:param str path: The file path to open
:param int mode_policy: The mode to open, default is :py:data:`AUTOMATIC`.
"""
super(Stl, self).__init__()
if path is None:
# Create EMPTY data
self.name = "empty"
self.data = numpy.zeros(0, dtype=Stl.stl_dtype)
self.mode = Stl.MODE_BINARY
else:
# Create data from file
with open(path, "rb") as fh:
name, data, mode = Stl.__load(fh, mode=mode_policy)
self.name = name
self.data = data
self.mode = mode
super(Stl, self).set_initial_values()
return
@staticmethod
def __load(fh, mode=MODE_AUTO):
"""Load Mesh from STL file
:param FileIO fh: The file handle to open
:param int mode: The mode to open, default is :py:data:`AUTOMATIC`.
:return:
"""
header = fh.read(Stl.HEADER_SIZE).lower()
name = ""
data = None
if not header.strip():
return
if mode in (Stl.MODE_AUTO, Stl.MODE_ASCII) and header.startswith('solid'):
try:
name = header.split('\n', 1)[0][:5].strip()
data = Stl.__load_ascii(fh, header)
mode = Stl.MODE_ASCII
except:
pass
else:
data = Stl.__load_binary(fh)
mode = Stl.MODE_BINARY
return name, data, mode
@staticmethod
def __load_binary(fh):
# Read the triangle count
count, = struct.unpack("i", fh.read(Stl.COUNT_SIZE))
assert count < Stl.MAX_COUNT, \
'File too large, got {} triangles which exceeds the maximum of {}' .format(
count, Stl.MAX_COUNT
)
return numpy.fromfile(fh, Stl.stl_dtype, count=count)
@staticmethod
def __load_ascii(fh, header):
return numpy.fromiter(Stl.__ascii_reader(fh, header), dtype=Stl.stl_dtype)
@staticmethod
def __ascii_reader(fh, header):
"""
:param fh:
:param header:
:return:
"""
lines = header.split('\n')
recoverable = [True]
def get(prefix=''):
if lines:
line = lines.pop(0)
else:
raise RuntimeError(recoverable[0], 'Unable to find more lines')
if not lines:
recoverable[0] = False
# Read more lines and make sure we prepend any old data
lines[:] = fh.read(Stl.BUFFER_SIZE).split('\n')
line += lines.pop(0)
line = line.lower().strip()
if prefix:
if line.startswith(prefix):
values = line.replace(prefix, '', 1).strip().split()
elif line.startswith('endsolid'):
raise StopIteration()
else:
raise RuntimeError(recoverable[0],
'%r should start with %r' % (line,
prefix))
if len(values) == 3:
vertex = [float(v) for v in values]
return vertex
else: # pragma: no cover
raise RuntimeError(recoverable[0],
'Incorrect value %r' % line)
else:
return line
line = get()
if not line.startswith('solid ') and line.startswith('solid'):
print("Error")
if not lines:
raise RuntimeError(recoverable[0],
'No lines found, impossible to read')
while True:
# Read from the header lines first, until that point we can recover
# and go to the binary option. After that we cannot due to
# unseekable files such as sys.stdin
#
# Numpy doesn't support any non-file types so wrapping with a
# buffer and/or StringIO does not work.
try:
normals = get('facet normal')
assert get() == 'outer loop'
v0 = get('vertex')
v1 = get('vertex')
v2 = get('vertex')
assert get() == 'endloop'
assert get() == 'endfacet'
attrs = 0
yield (normals, (v0, v1, v2), attrs)
except AssertionError as e:
raise RuntimeError(recoverable[0], e)
except StopIteration:
if any(lines):
# Seek back to where the next solid should begin
fh.seek(-len('\n'.join(lines)), os.SEEK_CUR)
raise
