DOC, TST: refactor CFFI test, add file names to documentation

2 files changed, 49 insertions, 35 deletions

diff --git a/numpy/random/_examples/cffi/extending.py b/numpy/random/_examples/cffi/extending.py
index 732cbbb1d..8440d400e 100644
--- a/numpy/random/_examples/cffi/extending.py
+++ b/numpy/random/_examples/cffi/extending.py
@@ -1,9 +1,10 @@
 """
-Use cffi to access the underlying C functions from distributions.h
+Use cffi to access any of the underlying C functions from distributions.h
 """
 import os
 import numpy as np
 import cffi
+from .parse import parse_distributions_h
 ffi = cffi.FFI()
 
 inc_dir = os.path.join(np.get_include(), 'numpy')
@@ -15,40 +16,7 @@ ffi.cdef('''
 
 ''')
 
-with open(os.path.join(inc_dir, 'random', 'bitgen.h')) as fid:
-    s = []
-    for line in fid:
-        # massage the include file
-        if line.strip().startswith('#'):
-            continue
-        s.append(line)
-    ffi.cdef('\n'.join(s))
-        
-with open(os.path.join(inc_dir, 'random', 'distributions.h')) as fid:
-    s = []
-    in_skip = 0
-    for line in fid:
-        # massage the include file
-        if line.strip().startswith('#'):
-            continue
-
-        # skip any inlined function definition
-        # which starts with 'static NPY_INLINE xxx(...) {'
-        # and ends with a closing '}'
-        if line.strip().startswith('static NPY_INLINE'):
-            in_skip += line.count('{')
-            continue
-        elif in_skip > 0:
-            in_skip += line.count('{')
-            in_skip -= line.count('}')
-            continue
-
-        # replace defines with their value or remove them
-        line = line.replace('DECLDIR', '')
-        line = line.replace('NPY_INLINE', '')
-        line = line.replace('RAND_INT_TYPE', 'int64_t')
-        s.append(line)
-    ffi.cdef('\n'.join(s))
+parse_distributions_h(ffi, inc_dir)
 
 lib = ffi.dlopen(np.random._generator.__file__)
 
diff --git a/numpy/random/_examples/cffi/parse.py b/numpy/random/_examples/cffi/parse.py
new file mode 100644
index 000000000..73d8646c7
--- /dev/null
+++ b/numpy/random/_examples/cffi/parse.py
@@ -0,0 +1,46 @@
+import os
+
+
+def parse_distributions_h(ffi, inc_dir):
+    """
+    Parse distributions.h located in inc_dir for CFFI, filling in the ffi.cdef
+
+    Read the function declarations without the "#define ..." macros that will
+    be filled in when loading the library.
+    """
+
+    with open(os.path.join(inc_dir, 'random', 'bitgen.h')) as fid:
+        s = []
+        for line in fid:
+            # massage the include file
+            if line.strip().startswith('#'):
+                continue
+            s.append(line)
+        ffi.cdef('\n'.join(s))
+            
+    with open(os.path.join(inc_dir, 'random', 'distributions.h')) as fid:
+        s = []
+        in_skip = 0
+        for line in fid:
+            # massage the include file
+            if line.strip().startswith('#'):
+                continue
+    
+            # skip any inlined function definition
+            # which starts with 'static NPY_INLINE xxx(...) {'
+            # and ends with a closing '}'
+            if line.strip().startswith('static NPY_INLINE'):
+                in_skip += line.count('{')
+                continue
+            elif in_skip > 0:
+                in_skip += line.count('{')
+                in_skip -= line.count('}')
+                continue
+    
+            # replace defines with their value or remove them
+            line = line.replace('DECLDIR', '')
+            line = line.replace('NPY_INLINE', '')
+            line = line.replace('RAND_INT_TYPE', 'int64_t')
+            s.append(line)
+        ffi.cdef('\n'.join(s))
+