Added support for Codabar(NW-7) (#115)

Author: tetsutalow

.gitignore

@@ -17,3 +17,5 @@ MANIFEST
 barcode/version.py
 tests/index.html
 tests/test_outputs/
+tests/test.py
+test.py

barcode/__init__.py

@@ -8,6 +8,7 @@
 from typing import Dict
 from typing import Union
 
+from barcode.codabar import CODABAR
 from barcode.codex import PZN
 from barcode.codex import Code39
 from barcode.codex import Code128
@@ -47,6 +48,8 @@
     "code128": Code128,
     "itf": ITF,
     "gs1_128": Gs1_128,
+    "codabar": CODABAR,
+    "nw-7": CODABAR,
 }
 
 PROVIDED_BARCODES = list(__BARCODE_MAP)

barcode/charsets/codabar.py

@@ -0,0 +1,25 @@
+# W = Wide bar
+# w = wide space
+# N = Narrow bar
+# n = narrow space
+
+CODES = {
+    "0": "NnNnNwW",
+    "1": "NnNnWwN",
+    "2": "NnNwNnW",
+    "3": "WwNnNnN",
+    "4": "NnWnNwN",
+    "5": "WnNnNwN",
+    "6": "NwNnNnW",
+    "7": "NwNnWnN",
+    "8": "NwWnNnN",
+    "9": "WnNwNnN",
+    "-": "NnNwWnN",
+    "$": "NnWwNnN",
+    ":": "WnNnWnW",
+    "/": "WnWnNnW",
+    ".": "WnWnWnN",
+    "+": "NnWnWnW",
+}
+
+STARTSTOP = {"A": "NnWwNwN", "B": "NwNwNnW", "C": "NnNwNwW", "D": "NnNwWwN"}

barcode/codabar.py

@@ -0,0 +1,73 @@
+"""Module: barcode.codabar
+
+:Provided barcodes: Codabar (NW-7)
+"""
+__docformat__ = "restructuredtext en"
+
+from barcode.base import Barcode
+from barcode.charsets import codabar
+from barcode.errors import BarcodeError
+from barcode.errors import IllegalCharacterError
+
+
+class CODABAR(Barcode):
+    """Initializes a new CODABAR instance.
+
+    :parameters:
+        code : String
+            Codabar (NW-7) string that matches [ABCD][0-9$:/.+-]+[ABCD]
+        writer : barcode.writer Instance
+            The writer to render the barcode (default: SVGWriter).
+        narrow: Integer
+            Width of the narrow elements (default: 2)
+        wide: Integer
+            Width of the wide elements (default: 5)
+            wide/narrow must be in the range 2..3
+    """
+
+    name = "Codabar (NW-7)"
+
+    def __init__(self, code, writer=None, narrow=2, wide=5):
+        self.code = code
+        self.writer = writer or self.default_writer()
+        self.narrow = narrow
+        self.wide = wide
+
+    def __str__(self):
+        return self.code
+
+    def get_fullcode(self):
+        return self.code
+
+    def build(self):
+        try:
+            data = (
+                codabar.STARTSTOP[self.code[0]] + "n"
+            )  # Start with [A-D], followed by a narrow space
+
+        except KeyError:
+            raise BarcodeError("Codabar should start with either A,B,C or D")
+
+        try:
+            data += "n".join(
+                [codabar.CODES[c] for c in self.code[1:-1]]
+            )  # separated by a narrow space
+        except KeyError:
+            raise IllegalCharacterError("Codabar can only contain numerics or $:/.+-")
+
+        try:
+            data += "n" + codabar.STARTSTOP[self.code[-1]]  # End with [A-D]
+        except KeyError:
+            raise BarcodeError("Codabar should end with either A,B,C or D")
+
+        raw = ""
+        for e in data:
+            if e == "W":
+                raw += "1" * self.wide
+            if e == "w":
+                raw += "0" * self.wide
+            if e == "N":
+                raw += "1" * self.narrow
+            if e == "n":
+                raw += "0" * self.narrow
+        return [raw]