add PIRegularExpression

3rd/pcre2/maint/UpdateCommon.py

@@ -0,0 +1,28 @@
+# Common helpers for UpdateRelease.py and UpdateDates.py.
+
+import re
+
+def get_current_release():
+    with open('configure.ac', 'r') as file:
+        content = file.read()
+
+    matches = [match[1] for match in re.findall(r"m4_define\(pcre2_(major|minor|prerelease), \[(.*?)\]\)", content)]
+    current_release = '%s.%s%s' % tuple(matches)
+
+    return current_release
+
+CURRENT_RELEASE = get_current_release()
+
+# Update a file, using a pattern. Verify that it matches the file, and perform
+# the replacement.
+def update_file(filename, pattern, replacement):
+    with open(filename, 'r') as file:
+        content = file.read()
+
+    if not re.search(pattern, content):
+        raise Exception('Pattern not found in %s' % filename)
+
+    content = re.sub(pattern, replacement, content)
+
+    with open(filename, 'w') as file:
+        file.write(content)