Add Python 3 support (#33)

Adding backwards-compatible Python 3 support, tested up to 3.8.2.
Verified to still work with Python 2.7.
Also adds a makefile and scripts to build binary manylinux wheels for several python versions.

.gitignore

@@ -19,6 +19,7 @@ lib64/
 parts/
 sdist/
 var/
+wheelhouse/
 wheels/
 *.egg-info/
 .installed.cfg

Makefile

@@ -0,0 +1,14 @@
+.PHONEY: help
+help:
+	@echo "Targets:"
+	@echo "  clean: Removes distribution folders and artifacts from building"
+	@echo "  manylinux-wheels: Builds binary and manylinux wheels for several python versions"
+
+.PHONY: clean
+clean:
+	rm -rf dist wheelhouse build __pycache__ *.so *.egg-info
+
+.PHONY: manylinux-wheels
+manylinux-wheels:
+	docker run -v $(shell pwd):/io quay.io/pypa/manylinux1_x86_64:latest \
+		/io/bin/build-manylinux-wheel.sh 27 35 36 37 38

bin/build-manylinux-wheel.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+
+PYTHON_VERSIONS=$@
+
+if [[ -z "${PYTHON_VERSIONS}" ]] ; then
+    echo "Usage: $(basename $0) <version>..." >&2
+    echo "  A version is the two numbers in the major.minor python that you want to build" >&2
+    echo "  Example: for python 2.7 and 3.8 both" >&2
+    echo "" >&2
+    echo "    $ $(basename $0) 27 38" >&2
+    exit 1
+fi
+
+function get-variants() {
+    local version="$1"
+
+    if [[ "${version}" = '38' ]] ; then
+        echo /
+    elif [[ "${version}" = '27' ]] ; then
+        echo m mu
+    else
+        echo m
+    fi
+}
+
+cd /io
+
+for version in ${PYTHON_VERSIONS} ; do
+    for variant in $(get-variants "${version}") ; do
+        /opt/python/cp${version}-cp${version}${variant}/bin/python setup.py bdist_wheel
+    done
+done
+
+for f in dist/*.whl ; do
+    /opt/python/cp37-cp37m/bin/auditwheel repair "${f}"
+done

predict.c

@@ -3678,11 +3678,29 @@ static PyMethodDef pypredict_funcs[] = {
     {NULL, NULL, 0, NULL}
 };
 
-void initcpredict(void)
+#if PY_MAJOR_VERSION >= 3
+	static struct PyModuleDef moduledef = {
+		PyModuleDef_HEAD_INIT,
+		"cpredict",     /* m_name */
+		"Python port of the predict open source satellite tracking library",  /* m_doc */
+		-1,                  /* m_size */
+		pypredict_funcs,    /* m_methods */
+		NULL,                /* m_reload */
+		NULL,                /* m_traverse */
+		NULL,                /* m_clear */
+		NULL,                /* m_free */
+	};
+#endif
+
+static PyObject * cpredictinit(void)
 {
 	PyObject *m;
+#if PY_MAJOR_VERSION >= 3
+	m = PyModule_Create(&moduledef);
+#else
 	m = Py_InitModule3("cpredict", pypredict_funcs,
 					"Python port of the predict open source satellite tracking library");
+#endif
 	if (m == NULL) {
 		fprintf(stderr, "ERROR: Unable to initialize python module 'cpredict'\n");
 	}
@@ -3696,4 +3714,18 @@ void initcpredict(void)
 	NoTransitException = PyErr_NewException("cpredict.NoTransitException", PredictException, NULL);
 	Py_INCREF(NoTransitException);
 	PyModule_AddObject(m, "NoTransitException", NoTransitException);
+
+	return m;
+}
+
+#if PY_MAJOR_VERSION >= 3
+PyMODINIT_FUNC PyInit_cpredict(void)
+{
+	return cpredictinit();
+}
+#else
+PyMODINIT_FUNC initcpredict(void)
+{
+	cpredictinit();
 }
+#endif

predict.py

@@ -1,3 +1,4 @@
+import sys
 import os
 import time
 
@@ -19,6 +20,8 @@ def quick_predict(tle, ts, qth):
     return _quick_predict(tle, ts, qth)
 
 
+STR_TYPE = str if sys.version_info.major > 2 else basestring  # Quick python3 compatibility
+
 def host_qth(path="~/.predict/predict.qth"):
     path = os.path.abspath(os.path.expanduser(path))
     try:
@@ -33,7 +36,7 @@ def host_qth(path="~/.predict/predict.qth"):
 def massage_tle(tle):
     try:
         # TLE may or may not have been split into lines already
-        if isinstance(tle, basestring):
+        if isinstance(tle, STR_TYPE):
             tle = tle.rstrip().split('\n')
         assert len(tle) == 3, "TLE must be 3 lines, not %d: %s" % (len(tle), tle)
         return tle

setup.py

@@ -1,15 +1,20 @@
 #!/usr/bin/env python
 
-from distutils.core import setup, Extension
+from setuptools import setup, Extension
 setup(
     name='pypredict',
-    version='1.5.0',
+    version='1.6.0',
     author="Jesse Trutna",
     author_email="jesse@spire.com",
     url="https://github.com/nsat/pypredict",
+    py_modules=['predict'],
+    ext_modules=[Extension('cpredict', ['predict.c'])],
     classifiers=[
         'License :: OSI Approved :: GNU General Public License v2 or later (GPLv2+)',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
     ],
-    py_modules=['predict'],
-    ext_modules=[Extension('cpredict', ['predict.c'])]
     )