Initial commit

resources/js/hashes.js

@@ -0,0 +1,56 @@
+function createCrcTable() {
+    const table = [];
+    for (let n = 0; n < 256; n++) {
+        let c = n;
+        for (let k = 0; k < 8; k++) {
+            c = (c & 1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1);
+        }
+        table[n] = c;
+    }
+    return table;
+}
+
+async function crc32(buffer) {
+    let crc = 0 ^ (-1);
+    const bytes = new Uint8Array(buffer);
+    for (let i = 0; i < bytes.byteLength; i++) {
+        crc = (crc >>> 8) ^ crcTable[(crc ^ bytes[i]) & 0xFF];
+    }
+    return ((crc ^ (-1)) >>> 0).toString(16).padStart(8, '0');
+}
+
+async function sha1(buffer) {
+    const hashBuffer = await crypto.subtle.digest('SHA-1', buffer);
+    return Array.from(new Uint8Array(hashBuffer))
+        .map(b => b.toString(16).padStart(2, '0'))
+        .join('');
+}
+
+const crcTable = createCrcTable();
+
+export async function calculate( file ){
+    return new Promise( ( resolve, reject ) => {
+        const freader = new FileReader();
+
+        freader.onload = async e => {
+            try {
+                const buffer = e.target.result;
+                const crc32V = await crc32(buffer);
+                const sha1V = await sha1(buffer);
+
+                resolve({
+                    filename: file.name,
+                    crc32: crc32V,
+                    sha1: sha1V
+                });
+            } catch (error) {
+                reject(error);
+            }
+        }
+
+        freader.onerror = () => {
+            reject( new Error(`Could not parse file: ${file.name}`) );
+        }
+        freader.readAsArrayBuffer(file);
+    })
+}