Merged esm branch into feature-magic. Ported FileType ops.

src/core/operations/FromBCD.mjs

@@ -0,0 +1,122 @@
+/**
+ * @author n1474335 [n1474335@gmail.com]
+ * @copyright Crown Copyright 2017
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import Utils from "../Utils";
+import OperationError from "../errors/OperationError";
+import {ENCODING_SCHEME, ENCODING_LOOKUP, FORMAT} from "../lib/BCD";
+import BigNumber from "bignumber.js";
+
+/**
+ * From BCD operation
+ */
+class FromBCD extends Operation {
+
+    /**
+     * FromBCD constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "From BCD";
+        this.module = "Default";
+        this.description = "Binary-Coded Decimal (BCD) is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of bits, usually four or eight. Special bit patterns are sometimes used for a sign.";
+        this.inputType = "string";
+        this.outputType = "BigNumber";
+        this.args = [
+            {
+                "name": "Scheme",
+                "type": "option",
+                "value": ENCODING_SCHEME
+            },
+            {
+                "name": "Packed",
+                "type": "boolean",
+                "value": true
+            },
+            {
+                "name": "Signed",
+                "type": "boolean",
+                "value": false
+            },
+            {
+                "name": "Input format",
+                "type": "option",
+                "value": FORMAT
+            }
+        ];
+        this.patterns = [
+            {
+                match: "^(?:\\d{4} ){3,}\\d{4}$",
+                flags: "",
+                args: ["8 4 2 1", true, false, "Nibbles"]
+            },
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {BigNumber}
+     */
+    run(input, args) {
+        const encoding = ENCODING_LOOKUP[args[0]],
+            packed = args[1],
+            signed = args[2],
+            inputFormat = args[3],
+            nibbles = [];
+
+        let output = "",
+            byteArray;
+
+        // Normalise the input
+        switch (inputFormat) {
+            case "Nibbles":
+            case "Bytes":
+                input = input.replace(/\s/g, "");
+                for (let i = 0; i < input.length; i += 4) {
+                    nibbles.push(parseInt(input.substr(i, 4), 2));
+                }
+                break;
+            case "Raw":
+            default:
+                byteArray = Utils.strToByteArray(input);
+                byteArray.forEach(b => {
+                    nibbles.push(b >>> 4);
+                    nibbles.push(b & 15);
+                });
+                break;
+        }
+
+        if (!packed) {
+            // Discard each high nibble
+            for (let i = 0; i < nibbles.length; i++) {
+                nibbles.splice(i, 1);
+            }
+        }
+
+        if (signed) {
+            const sign = nibbles.pop();
+            if (sign === 13 ||
+                sign === 11) {
+                // Negative
+                output += "-";
+            }
+        }
+
+        nibbles.forEach(n => {
+            if (isNaN(n)) throw new OperationError("Invalid input");
+            const val = encoding.indexOf(n);
+            if (val < 0) throw new OperationError(`Value ${Utils.bin(n, 4)} is not in the encoding scheme`);
+            output += val.toString();
+        });
+
+        return new BigNumber(output);
+    }
+
+}
+
+export default FromBCD;