Basic support for MSI / Plessey

barcode/__init__.py

@@ -1,5 +1,5 @@
-"""This package provides a simple way to create standard barcodes.
-It needs no external packages to be installed, the barcodes are
+"""This package provides a simple way to create standard barcodes.  It needs no
+external packages to be installed (exception: 'luhn' for MSI), the barcodes are
 created as SVG objects. If Pillow is installed, the barcodes can also be
 rendered as images (all formats supported by Pillow).
 """
@@ -9,6 +9,7 @@
 from typing import Union
 
 from barcode.codabar import CODABAR
+from barcode.codex import MSI
 from barcode.codex import PZN
 from barcode.codex import Code39
 from barcode.codex import Code128
@@ -50,6 +51,7 @@
     "gs1_128": Gs1_128,
     "codabar": CODABAR,
     "nw-7": CODABAR,
+    "msi": MSI,
 }
 
 PROVIDED_BARCODES = list(__BARCODE_MAP)

barcode/codex.py

@@ -1,6 +1,6 @@
 """Module: barcode.codex
 
-:Provided barcodes: Code 39, Code 128, PZN
+:Provided barcodes: Code 39, Code 128, PZN, MSI
 """
 from barcode.base import Barcode
 from barcode.charsets import code39
@@ -129,7 +129,7 @@ class Code128(Barcode):
             The writer to render the barcode (default: SVGWriter).
     """
 
-    name = "Code 128"
+    ame = "Code 128"
 
     def __init__(self, code, writer=None):
         self.code = code
@@ -271,5 +271,72 @@ def get_fullcode(self):
         return super().get_fullcode()[1:]
 
 
+class MSI(Barcode):
+    """Initializes a new MSI (Modified Plessey) instance. The checksum is added automatically
+    when building the bars.
+
+    :parameters:
+        code : int or bytes or string
+            Code MSI int without checksum (added automatically).
+            Code MSI bytes without checksum. requires byteorder for int conversion
+            Code MSI string without checksum. requires encoding and byteorder for int conversion
+        writer : barcode.writer Instance
+            The writer to render the barcode (default: SVGWriter).
+        byteorder : string
+            'big' or 'little' ; to convert bytes to int
+        encoding : string
+            if set, convert bytes to string and use this as a label. defaults to utf-8
+
+    limitations:
+        - only one check digit (Luhn Mod10)
+        - only standard prefix/suffix
+    """
+
+    name = "MSI/Modified Plessey"
+
+    def __init__(self, code, writer=None, byteorder=None, encoding=None):
+        self.writer = writer or self.default_writer()
+        self._buffer = ""
+
+        if type(code) is int:
+            self.code = str(code)
+        elif type(code) is bytes:
+            self.code = str(int.from_bytes(code, byteorder))
+            if encoding is not None:
+                self.label = code.decode(encoding)
+            else:
+                self.label = self.code
+        elif type(code) is str:
+            self.code = str(int.from_bytes(bytes(code, encoding), byteorder))
+            self.label = code
+
+    def __str__(self):
+        return self.label
+
+    @property
+    def encoded(self):
+        return self._build()
+
+    def get_fullcode(self):
+        return self.label
+
+    def _build(self):
+        """
+        check digit is computed with https://pypi.org/project/luhn/
+        """
+        from luhn import append as luhn_check_append
+
+        bcd = "".join([f"{bin(int(n))[2:]:0>4}" for n in luhn_check_append(self.code)])
+
+        conv = {
+            "0": "100",
+            "1": "110",
+        }
+        return ["110" + "".join([conv[i] for i in bcd]) + "1001"]
+
+    def build(self):
+        return self.encoded
+
+
 # For pre 0.8 compatibility
 PZN = PZN7