Handle unknown chunk types gracefully

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "cdb-converter",
-	"version": "0.2.0",
+	"version": "0.3.0",
 	"description": "Convert Pro Cycling Manager CDB files to/from SQLite and other formats. TypeScript library with zero configuration.",
 	"license": "MIT",
 	"author": "mpicciolli",

src/reader.ts

@@ -248,9 +248,24 @@ export class CDBReader {
 				break;
 
 			default:
-				throw new Error(
-					`Unknown chunk type: 0x${(header.chunkType as number).toString(16)}`,
-				);
+				{
+					if (typeof console !== "undefined") {
+						console.warn(
+							`Skipping unknown chunk type: 0x${(header.chunkType as number).toString(16)} at position ${chunkStartPos}`,
+						);
+					}
+					const skippedBytes = chunkEndPos - this.pos - 4;
+					if (skippedBytes < 0) {
+						throw new Error(
+							`Invalid chunk size for unknown chunk type 0x${(header.chunkType as number).toString(16)} at position ${chunkStartPos}`,
+						);
+					}
+					result = {
+						type: header.chunkType,
+						value: this.readBytes(skippedBytes),
+					};
+				}
+				break;
 		}
 
 		this.readPadding();

test/reader.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import { CDBReader } from "../src/reader";
 import { CHUNK_TYPE, DATA_TYPE, MAGIC } from "../src/tableMetadata";
 import { CDBWriter } from "../src/writer";
@@ -59,6 +59,22 @@ function createWrapperWithMissingColumnDescription(): Uint8Array {
 	return writer.getData();
 }
 
+function createUnknownChunkBuffer(payloadLength: number): Uint8Array {
+	const chunkSize = 28 + payloadLength;
+	const buffer = new ArrayBuffer(chunkSize);
+	const view = new DataView(buffer);
+
+	view.setUint32(0, MAGIC.CHUNK_BEGIN, true);
+	view.setUint32(4, chunkSize, true);
+	view.setUint32(8, 0x99, true); // unknown chunk type
+	view.setUint32(12, 0, true);
+	view.setUint32(16, 0, true);
+	view.setUint32(20, MAGIC.CHUNK_SEPARATOR, true);
+	view.setUint32(24 + payloadLength, MAGIC.CHUNK_END, true);
+
+	return new Uint8Array(buffer);
+}
+
 function createFloatListTable(rows: string[]): Uint8Array {
 	const writer = new CDBWriter();
 
@@ -134,6 +150,39 @@ describe("CDBReader", () => {
 		);
 	});
 
+	it("skips an unknown chunk type instead of throwing", () => {
+		const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+		try {
+			const reader = new CDBReader(createUnknownChunkBuffer(8));
+
+			const chunk = reader.readChunk();
+
+			expect(chunk.type).toBe(0x99);
+			expect(chunk.value).toBeInstanceOf(Uint8Array);
+			expect((chunk.value as Uint8Array).length).toBe(8);
+			expect(warnSpy).toHaveBeenCalledWith(
+				expect.stringContaining("Skipping unknown chunk type: 0x99"),
+			);
+		} finally {
+			warnSpy.mockRestore();
+		}
+	});
+
+	it("throws when an unknown chunk declares an impossibly small size", () => {
+		const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+		try {
+			const buffer = createUnknownChunkBuffer(0);
+			new DataView(buffer.buffer).setUint32(4, 4, true);
+			const reader = new CDBReader(buffer);
+
+			expect(() => reader.readChunk()).toThrowError(
+				"Invalid chunk size for unknown chunk type 0x99 at position 0",
+			);
+		} finally {
+			warnSpy.mockRestore();
+		}
+	});
+
 	describe("FLOAT_LIST formatting", () => {
 		it("round-trips small magnitude values without losing precision", () => {
 			const original = Math.fround(1e-8);