Added codec: kbshift

Author: dhondta

codext/others/__init__.py

@@ -1,5 +1,6 @@
 # -*- coding: UTF-8 -*-
 from .dna import *
+from .kbshift import *
 from .letters import *
 from .markdown import *
 from .uuencode import *

codext/others/kbshift.py

@@ -0,0 +1,66 @@
+# -*- coding: UTF-8 -*-
+"""Keyboard-Shift Codec - keyboard line shifting content encoding.
+
+This codec:
+- en/decodes strings from str to str
+- en/decodes strings from bytes to bytes
+- decodes file content to str (read)
+- encodes file content from str to bytes (write)
+"""
+from ..__common__ import *
+
+
+LAYOUTS = {
+    'ansi':      "~!@#$%^&*()_+\n`1234567890-=\nqwertyuiop{}|\n[]\\\nasdfghjkl:\"\n;'\nzxcvbnm<>\n,./",
+    'azerty':    "azertyuiop\nqsdfghjklm\nwxcvbn",
+    'azerty-be': "³1234567890°_\n²&é\"'(§è!çà)-\n|@#^{}\nazertyuiop$\n€[]\n¨*\nqsdfghjklm%£\nùµ\n´`\n>wxcvbn?./+\n<,;:=\n\\~",
+    'azerty-fr': "1234567890°+\n²&é\"'(-è_çà)=\n~#{[|`\\^@]}\nazertyuiop¨£\nqsdfghjklm%µ\nù*\n>wxcvbn?./§\n<,;:!",
+    'dvorak':    "~!@#$%^&*(){}\n`1234567890[]\n\"<>pyfgcrl?+|\n',./=\\\naoeuidhtns_\n-\n:qjkxbmwvz\n;",
+    'qwerty':    "qwertyuiop\nasdfghjkl\nzxcvbnm",
+    'qwerty-us': "~!@#$%^&*()_+\n`1234567890-=\nqwertyuiop{}|\n[]\\\nasdfghjkl:\"\n;,\nzxcvbnm<>?\n./",
+}
+__per_len = {}
+for k, s in LAYOUTS.items():
+    i = max(map(len, s.split("\n")))
+    __per_len.setdefault(i, [])
+    __per_len[i].append(k)
+
+
+__examples__ = {"enc-dec(kbshift_%s_%d)" % (kb, n): ["@irandom{256,512}"] for n in range(10) for kb in LAYOUTS.keys()}
+__guess__ = []
+for mlen, kbs in __per_len.items():
+    for k in kbs:
+        __guess__.extend(["kbshift-%s-%d" % (k, i+1) for i in range(mlen)])
+
+
+def _kbshift(text, keyboard="azerty", n=1, decode=False):
+    r = ""
+    for c in text:
+        nc = None
+        for l in LAYOUTS[keyboard].splitlines():
+            if c.lower() in l:
+                nc = l[(l.index(c.lower()) + [-1, 1][decode] * n) % len(l)]
+                break
+        r += c if nc is None else nc
+    return r
+
+
+def kbshift_encode(scheme):
+    kb, shift = re.match(r"^(.*?)[-_]?(\d+)$", scheme or "azerty-1").groups()
+    def encode(text, errors="strict"):
+        r = _kbshift(ensure_str(text), kb, int(shift))
+        return r, len(r)
+    return encode
+
+
+def kbshift_decode(scheme):
+    kb, shift = re.match(r"^(.*?)[-_]?(\d+)$", scheme or "azerty-1").groups()
+    def decode(text, errors="strict"):
+        r = _kbshift(ensure_str(text), kb, int(shift), True)
+        return r, len(r)
+    return decode
+
+
+add("kbshift", kbshift_encode, kbshift_decode, entropy=lambda e: e,printables_rate=lambda pr: pr, transitive=True,
+    pattern=r"^kbshift(?:|[-_]((?:az|qw)erty[-_]?[1-9]|(?:ansi|azerty-(?:be|fr)|dvorak|qwerty-us)[-_]?(?:[1-9]|1[0-2])))$")
+