ESM: Ported Bzip2, Diff and Tar operations

src/core/operations/Untar.mjs

@@ -0,0 +1,138 @@
+/**
+ * @author tlwr [toby@toby.codes]
+ * @copyright Crown Copyright 2016
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import Utils from "../Utils";
+
+/**
+ * Untar operation
+ */
+class Untar extends Operation {
+
+    /**
+     * Untar constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Untar";
+        this.module = "Compression";
+        this.description = "Unpacks a tarball and displays it per file.";
+        this.inputType = "byteArray";
+        this.outputType = "List<File>";
+        this.presentType = "html";
+        this.args = [];
+        this.patterns = [
+            {
+                "match": "^.{257}\\x75\\x73\\x74\\x61\\x72",
+                "flags": "",
+                "args": []
+            }
+        ];
+    }
+
+    /**
+     * @param {byteArray} input
+     * @param {Object[]} args
+     * @returns {List<File>}
+     */
+    run(input, args) {
+        const Stream = function(input) {
+            this.bytes = input;
+            this.position = 0;
+        };
+
+        Stream.prototype.getBytes = function(bytesToGet) {
+            const newPosition = this.position + bytesToGet;
+            const bytes = this.bytes.slice(this.position, newPosition);
+            this.position = newPosition;
+            return bytes;
+        };
+
+        Stream.prototype.readString = function(numBytes) {
+            let result = "";
+            for (let i = this.position; i < this.position + numBytes; i++) {
+                const currentByte = this.bytes[i];
+                if (currentByte === 0) break;
+                result += String.fromCharCode(currentByte);
+            }
+            this.position += numBytes;
+            return result;
+        };
+
+        Stream.prototype.readInt = function(numBytes, base) {
+            const string = this.readString(numBytes);
+            return parseInt(string, base);
+        };
+
+        Stream.prototype.hasMore = function() {
+            return this.position < this.bytes.length;
+        };
+
+        const stream = new Stream(input),
+            files = [];
+
+        while (stream.hasMore()) {
+            const dataPosition = stream.position + 512;
+
+            const file = {
+                fileName: stream.readString(100),
+                fileMode: stream.readString(8),
+                ownerUID: stream.readString(8),
+                ownerGID: stream.readString(8),
+                size: parseInt(stream.readString(12), 8), // Octal
+                lastModTime: new Date(1000 * stream.readInt(12, 8)), // Octal
+                checksum: stream.readString(8),
+                type: stream.readString(1),
+                linkedFileName: stream.readString(100),
+                USTARFormat: stream.readString(6).indexOf("ustar") >= 0,
+            };
+
+            if (file.USTARFormat) {
+                file.version = stream.readString(2);
+                file.ownerUserName = stream.readString(32);
+                file.ownerGroupName = stream.readString(32);
+                file.deviceMajor = stream.readString(8);
+                file.deviceMinor = stream.readString(8);
+                file.filenamePrefix = stream.readString(155);
+            }
+
+            stream.position = dataPosition;
+
+            if (file.type === "0") {
+                // File
+                let endPosition = stream.position + file.size;
+                if (file.size % 512 !== 0) {
+                    endPosition += 512 - (file.size % 512);
+                }
+
+                file.bytes = stream.getBytes(file.size);
+                files.push(new File([new Uint8Array(file.bytes)], file.fileName));
+                stream.position = endPosition;
+            } else if (file.type === "5") {
+                // Directory
+                files.push(new File([new Uint8Array(file.bytes)], file.fileName));
+            } else {
+                // Symlink or empty bytes
+            }
+        }
+
+        return files;
+    }
+
+    /**
+     * Displays the files in HTML for web apps.
+     *
+     * @param {File[]} files
+     * @returns {html}
+     */
+    async present(files) {
+        return await Utils.displayFilesAsHTML(files);
+    }
+
+}
+
+export default Untar;