BREAKING CHANGE(storage,engine,server): add session & transaction management, index/query planner, WAL and checksum support; integrate index-accelerated queries and update storage API (findByIds) to enable index optimizations

ts/tsmdb/utils/checksum.ts

@@ -0,0 +1,88 @@
+/**
+ * CRC32 checksum utilities for data integrity
+ */
+
+// CRC32 lookup table
+const CRC32_TABLE: number[] = [];
+
+// Initialize the CRC32 table
+function initCRC32Table(): void {
+  if (CRC32_TABLE.length > 0) return;
+
+  for (let i = 0; i < 256; i++) {
+    let crc = i;
+    for (let j = 0; j < 8; j++) {
+      crc = (crc & 1) ? (0xEDB88320 ^ (crc >>> 1)) : (crc >>> 1);
+    }
+    CRC32_TABLE[i] = crc >>> 0;
+  }
+}
+
+/**
+ * Calculate CRC32 checksum for a string
+ */
+export function calculateCRC32(data: string): number {
+  initCRC32Table();
+
+  let crc = 0xFFFFFFFF;
+  for (let i = 0; i < data.length; i++) {
+    const byte = data.charCodeAt(i) & 0xFF;
+    crc = CRC32_TABLE[(crc ^ byte) & 0xFF] ^ (crc >>> 8);
+  }
+  return (~crc) >>> 0;
+}
+
+/**
+ * Calculate CRC32 checksum for a Buffer
+ */
+export function calculateCRC32Buffer(data: Buffer): number {
+  initCRC32Table();
+
+  let crc = 0xFFFFFFFF;
+  for (let i = 0; i < data.length; i++) {
+    crc = CRC32_TABLE[(crc ^ data[i]) & 0xFF] ^ (crc >>> 8);
+  }
+  return (~crc) >>> 0;
+}
+
+/**
+ * Calculate checksum for a document (serialized as JSON)
+ */
+export function calculateDocumentChecksum(doc: Record<string, any>): number {
+  // Exclude _checksum field from calculation
+  const { _checksum, ...docWithoutChecksum } = doc;
+  const json = JSON.stringify(docWithoutChecksum);
+  return calculateCRC32(json);
+}
+
+/**
+ * Add checksum to a document
+ */
+export function addChecksum<T extends Record<string, any>>(doc: T): T & { _checksum: number } {
+  const checksum = calculateDocumentChecksum(doc);
+  return { ...doc, _checksum: checksum };
+}
+
+/**
+ * Verify checksum of a document
+ * Returns true if checksum is valid or if document has no checksum
+ */
+export function verifyChecksum(doc: Record<string, any>): boolean {
+  if (!('_checksum' in doc)) {
+    // No checksum to verify
+    return true;
+  }
+
+  const storedChecksum = doc._checksum;
+  const calculatedChecksum = calculateDocumentChecksum(doc);
+
+  return storedChecksum === calculatedChecksum;
+}
+
+/**
+ * Remove checksum from a document
+ */
+export function removeChecksum<T extends Record<string, any>>(doc: T): Omit<T, '_checksum'> {
+  const { _checksum, ...docWithoutChecksum } = doc;
+  return docWithoutChecksum as Omit<T, '_checksum'>;
+}