Merge pull request #2 from brianhelba/36

Add Python 3.6 support

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9"]
+        python-version: ["3.6", "3.7", "3.8", "3.9"]
     steps:
       - uses: actions/checkout@v2
         with:

.github/workflows/release.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Build manylinux wheels
         uses: RalfG/python-wheels-manylinux-build@v0.3.3-manylinux2014_x86_64
         with:
-          python-versions: 'cp37-cp37m cp38-cp38 cp39-cp39'
+          python-versions: 'cp36-cp36m cp37-cp37m cp38-cp38 cp39-cp39'
           # Necessary for setuptools_scm to read the version from Git
           system-packages: 'git-lfs'
       - name: Install tox

README.md

@@ -8,7 +8,7 @@ Extract DEFLATE64 ZIP archives with Python's `zipfile` API.
 pip install zipfile-deflate64
 ```
 
-Python 3.7, 3.8, and 3.9 supported, with [manylinux2014 wheels](https://github.com/pypa/manylinux) published to PyPI.
+Python 3.6, 3.7, 3.8, and 3.9 supported, with [manylinux2014 wheels](https://github.com/pypa/manylinux) published to PyPI.
 
 ## Usage
 Anywhere in a Python codebase:

setup.py

@@ -26,14 +26,15 @@
         'License :: OSI Approved :: Apache Software License',
         'Operating System :: POSIX :: Linux',
         'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python',
         'Topic :: System :: Archiving',
         'Topic :: System :: Archiving :: Compression',
     ],
-    python_requires='>=3.7',
+    python_requires='>=3.6',
     packages=find_packages(),
     ext_modules=[
         Extension(

zipfile_deflate64/deflate64/deflate64module.c

@@ -113,6 +113,20 @@ static int zlib_out(void* out_desc, unsigned char* buf, unsigned len) {
     // Concatenate buf onto self->output_buffer
     Py_ssize_t old_output_size = PyBytes_GET_SIZE(self->output_buffer);
 
+#if PY_VERSION_HEX < 0x3070700 // v3.7.3
+    // Workaround for bpo-33817, which was first (via backport) fixed in Python 3.7.3
+    // Before this, size-zero bytes objects could not be resized
+    if (old_output_size == 0) {
+        Py_DECREF(self->output_buffer);
+        // Just create a new buffer with the target size; the following resize will short-circuit
+        self->output_buffer = PyBytes_FromStringAndSize(NULL, old_output_size + len);
+        if (self->output_buffer == NULL) {
+            PyErr_NoMemory();
+            return -1;
+        }
+    }
+#endif
+
     int err = _PyBytes_Resize(&self->output_buffer, old_output_size + len);
     if (err < 0) {
         // MemoryError is set, and output_buffer is deallocated and set to NULL