From 0ff238a1e57609d8e2eb3e5f4055112b39fe978d Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Thu, 31 Jan 2019 11:45:06 +0100
Subject: add data_parameters (numeric description of JSON-like data)

---
 lib/data_parameters.py | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 lib/data_parameters.py

diff --git a/lib/data_parameters.py b/lib/data_parameters.py
new file mode 100644
index 0000000..8f1fbb0
--- /dev/null
+++ b/lib/data_parameters.py
@@ -0,0 +1,48 @@
+"""
+Utilities for parameter extraction from data layout.
+
+Parameters include the amount of keys, length of strings (both keys and values),
+length of lists, ane more.
+"""
+
+def _string_value_length(json):
+    if type(json) == str:
+        return len(json)
+
+    if type(json) == dict:
+        return sum(map(_string_value_length, json.values()))
+
+    if type(json) == list:
+        return sum(map(_string_value_length, json))
+
+    return 0
+
+def _string_key_length(json):
+    if type(json) == dict:
+        return sum(map(len, json.keys())) + sum(map(_string_key_length, json.values()))
+
+    return 0
+
+def _num_keys(json):
+    if type(json) == dict:
+        return len(json.keys()) + sum(map(_num_keys, json.values()))
+
+    return 0
+
+def _num_objects(json):
+    if type(json) == dict:
+        return 1 + sum(map(_num_objects, json.values()))
+
+    return 0
+
+def json_to_param(json):
+    """Return numeric parameters describing the structure of JSON data."""
+
+    ret = dict()
+
+    ret['strlen_keys'] = _string_key_length(json)
+    ret['strlen_values'] = _string_value_length(json)
+    ret['num_keys'] = _num_keys(json)
+    ret['num_objects'] = _num_objects(json)
+
+    return ret
-- 
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