Add support to import zip file

utils/readonly_zip.ts

@@ -0,0 +1,92 @@
+import * as lz from "@lifegpc/libzip/raw";
+
+function get_err(err: number) {
+    const e = lz.ZipErrorT.new();
+    lz.zip_error_init_with_code(e, err);
+    const s = lz.zip_error_strerror(e);
+    lz.zip_error_fini(e);
+    return s;
+}
+
+class ZipFile {
+    #file: lz.ZipFileT;
+    #closed = false;
+    constructor(f: lz.ZipFileT) {
+        this.#file = f;
+    }
+
+    #check_close() {
+        if (this.#closed) throw Error("Already closed.");
+    }
+
+    close() {
+        if (this.#closed) return;
+        this.#closed = true;
+        const er = lz.zip_fclose(this.#file);
+        if (er) {
+            throw Error(`Failed to close file: ${get_err(er)}`);
+        }
+    }
+
+    read(buf: Uint8Array) {
+        this.#check_close();
+        const num = lz.zip_fread(this.#file, buf);
+        if (num == -1) {
+            throw Error(
+                `Failed to read file: ${lz.zip_file_strerror(this.#file)}`,
+            );
+        }
+        return num;
+    }
+}
+
+export class ReadonlyZip {
+    #zip: lz.ZipT;
+    #discarded = false;
+    #opened_file_list: ZipFile[] = [];
+    constructor(path: string) {
+        const ep = lz.IntPointer.new();
+        const z = lz.zip_open(path, lz.ZipOpenFlag.RDONLY, ep);
+        if (!z) {
+            throw Error(`Failed to open archive: ${get_err(ep.int)}.`);
+        }
+        this.#zip = z;
+    }
+    close() {
+        if (this.#discarded) return;
+        for (const f of this.#opened_file_list) {
+            f.close();
+        }
+        this.#discarded = true;
+        lz.zip_discard(this.#zip);
+    }
+    get count() {
+        return lz.zip_get_num_entries(this.#zip, 0);
+    }
+    get_index(name: string) {
+        return lz.zip_name_locate(this.#zip, name, lz.ZipFlags.ENC_UTF_8);
+    }
+    get_name(index: number | bigint) {
+        return lz.zip_get_name(this.#zip, index, 0);
+    }
+    open(name: string) {
+        const z = lz.zip_fopen(this.#zip, name, lz.ZipFlags.ENC_UTF_8);
+        if (!z) {
+            const errmsg = lz.zip_strerror(this.#zip);
+            return errmsg;
+        }
+        const f = new ZipFile(z);
+        this.#opened_file_list.push(f);
+        return f;
+    }
+    open_index(index: number | bigint) {
+        const z = lz.zip_fopen_index(this.#zip, index, 0);
+        if (!z) {
+            const errmsg = lz.zip_strerror(this.#zip);
+            return errmsg;
+        }
+        const f = new ZipFile(z);
+        this.#opened_file_list.push(f);
+        return f;
+    }
+}