add getData to HbBlob

src/text-font.ts

@@ -173,13 +173,14 @@ export class FaceMatch {
   }
 
   getExclusiveLanguage() {
-    const os2 = this.face.reference_table('OS/2');
+    const os2 = this.face.referenceTable('OS/2');
     if (os2) {
-      const words = new Uint16Array(os2);
+      const buffer = os2.getData();
+      const words = new Uint16Array(buffer);
       const [version] = words;
 
       if (version === 1 || version === 2 || version === 3 || version == 4 || version === 5) {
-        const codePageRange1 = os2[78 /* bytes */ / 2];
+        const codePageRange1 = buffer[78 /* bytes */ / 2];
         const bits17to20 = codePageRange1 & 0x1E0000;
         if ((codePageRange1 & (1 << 17)) === bits17to20) return 'ja';
         if ((codePageRange1 & (1 << 18)) === bits17to20) return 'zh-cn';

src/text-harfbuzz.ts

@@ -148,6 +148,12 @@ export class HbBlob {
   countFaces(): number {
     return exports.hb_face_count(this.ptr);
   }
+
+  getData() {
+    const length = exports.hb_blob_get_length(this.ptr);
+    const ptr = exports.hb_blob_get_data(this.ptr, null);
+    return heapu8.subarray(ptr, ptr + length);
+  }
 }
 
 export function createBlob(blob: Uint8Array) {
@@ -189,14 +195,6 @@ export class HbFace {
     this.upem = exports.hb_face_get_upem(ptr);
   }
 
-  reference_table(table: string) {
-    const blob = exports.hb_face_reference_table(this.ptr, hb_tag(table));
-    const length = exports.hb_blob_get_length(blob);
-    if (!length) return;
-    const blobptr = exports.hb_blob_get_data(blob, null);
-    return heapu8.subarray(blobptr, blobptr + length);
-  }
-
   getAxisInfos() {
     const axis = exports.malloc(64 * 32);
     const c = exports.malloc(4);
@@ -245,6 +243,10 @@ export class HbFace {
     return exports.hb_ot_layout_has_positioning(this.ptr);
   }
 
+  referenceTable(tag: string) {
+    return new HbBlob(exports.hb_face_reference_table(this.ptr, hb_tag(tag)));
+  }
+
   getScripts() {
     const lengthPtr = bytes4;
     const maxLength = 8;