Source code for wscodec.encoder.pyencoder.unitc

#  cuplcodec encodes environmental sensor data into a URL and the reverse.
#  Original Author: Malcolm Mackay
#  Email:
#  Website:
#  Copyright (C) 2021. Plotsensor Ltd.
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  GNU General Public License for more details.
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <>.

import cffi
import subprocess
import re
import pycparser
from pycparser import c_generator
import os
import importlib
import weakref
import pkg_resources

resource_package = __package__
c_encoder_path = '/'.join(('', 'c_encoder', ''))
pycparser_path = '/'.join(('', 'pycparser', ''))
sharedobj_path = '/'.join(('', 'sharedobj', ''))

ENCODER_CSOURCE_PATH = pkg_resources.resource_filename(resource_package, c_encoder_path)
PYCPARSER_PATH = pkg_resources.resource_filename(resource_package, pycparser_path)
SHAREDOBJ_PATH = pkg_resources.resource_filename(resource_package, sharedobj_path)

global_weakkeydict = weakref.WeakKeyDictionary()

[docs]class CFFIGenerator(pycparser.c_generator.CGenerator): def __init__(self, blacklist): super().__init__() self.blacklist = blacklist def visit_Decl(self, n, *args, **kwargs): result = super().visit_Decl(n, *args, **kwargs) if isinstance(n.type, pycparser.c_ast.FuncDecl): if not in self.blacklist: return 'extern "Python+C" ' + result return result
def convert_function_declarations(source, blacklist): return CFFIGenerator(blacklist).visit(pycparser.CParser().parse(source))
[docs]class FunctionList(pycparser.c_ast.NodeVisitor): def __init__(self, source): self.funcs = set() self.visit(pycparser.CParser().parse(source)) def update(self, otherlist): self.funcs.update(otherlist) def visit_FuncDef(self, node): self.funcs.add(
def preprocess(source): return['gcc', '-E', '-P', '-', '-I'+ENCODER_CSOURCE_PATH, '-I'+PYCPARSER_PATH+'/utils/fake_libc_include'], input=source, stdout=subprocess.PIPE, universal_newlines=True, check=True).stdout
[docs]def load(filename, depfilenames=list()): """ Load a file """ name = __package__ + '.sharedobj.' + filename + 'py' # load source code source = open(ENCODER_CSOURCE_PATH + filename + '.c').read() for depfilename in depfilenames: depsource = open(ENCODER_CSOURCE_PATH + depfilename + '.c').read() source = source + depsource # preprocess all header files for CFFI includes = preprocess(''.join(re.findall('\s*#include\s+.*', source))) # Obtain a list of local functions local_functions = FunctionList(preprocess(source)).funcs # prefix external functions (not in the list) with extern "Python+C" includes = convert_function_declarations(includes, local_functions) # Obtain the absolute directory path of this file. abspath = os.path.dirname(__file__) # Pass source code and libraries to FFI Builder ffibuilder = cffi.FFI() # Add all includes to the cdef attribute ffibuilder.cdef(includes + "nv_t nv;", packed=False) print("SOURCE " + source) # Add the source, library sources and include directories ffibuilder.set_source(name, source, include_dirs=[ENCODER_CSOURCE_PATH]) return ffibuilder