Simplify utility (util) functions

lib/asf/AsfObject.ts

@@ -254,8 +254,8 @@ export class FilePropertiesObject extends State<IFilePropertiesObject> {
       sendDuration: Token.UINT64_LE.get(buf, off + 48),
       preroll: Token.UINT64_LE.get(buf, off + 56),
       flags: {
-        broadcast: util.strtokBITSET.get(buf, off + 64, 24),
-        seekable: util.strtokBITSET.get(buf, off + 64, 25)
+        broadcast: util.getBit(buf, off + 64, 24),
+        seekable: util.getBit(buf, off + 64, 25)
       },
       // flagsNumeric: Token.UINT32_LE.get(buf, off + 64),
       minimumDataPacketSize: Token.UINT32_LE.get(buf, off + 68),
@@ -528,9 +528,9 @@ export class ExtendedStreamPropertiesObjectState extends State<IExtendedStreamPr
       alternateInitialBufferFullness: buf.readInt32LE(off + 32),
       maximumObjectSize: buf.readInt32LE(off + 36),
       flags: { // ToDo, check flag positions
-        reliableFlag: util.strtokBITSET.get(buf, off + 40, 0),
-        seekableFlag: util.strtokBITSET.get(buf, off + 40, 1),
-        resendLiveCleanpointsFlag: util.strtokBITSET.get(buf, off + 40, 2)
+        reliableFlag: util.getBit(buf, off + 40, 0),
+        seekableFlag: util.getBit(buf, off + 40, 1),
+        resendLiveCleanpointsFlag: util.getBit(buf, off + 40, 2)
       },
       // flagsNumeric: Token.UINT32_LE.get(buf, off + 64),
       streamNumber: buf.readInt16LE(off + 42),

lib/common/Util.ts

@@ -1,33 +1,30 @@
 import { Windows1292Decoder } from './Windows1292Decoder';
-import { IRatio } from "../type";
+import { IRatio } from '../type';
 
 export type StringEncoding = 'iso-8859-1' | 'utf16' | 'utf8' | 'utf16le';
 
-export const strtokBITSET = {
-  get: (buf: Buffer, off: number, bit: number): boolean => {
-    return (buf[off] & (1 << bit)) !== 0;
-  },
-  len: 1
-};
+export function getBit(buf: Uint8Array, off: number, bit: number): boolean {
+  return (buf[off] & (1 << bit)) !== 0;
+}
 
 /**
  *
- * @param buffer
+ * @param uint8Array
  * @param start
  * @param end
  * @param encoding // ToDo: ts.enum
  * @return {number}
  */
-export function findZero(buffer: Buffer, start: number, end: number, encoding?: string): number {
+export function findZero(uint8Array: Uint8Array, start: number, end: number, encoding?: string): number {
   let i = start;
   if (encoding === 'utf16') {
-    while (buffer[i] !== 0 || buffer[i + 1] !== 0) {
+    while (uint8Array[i] !== 0 || uint8Array[i + 1] !== 0) {
       if (i >= end) return end;
       i += 2;
     }
     return i;
   } else {
-    while (buffer[i] !== 0) {
+    while (uint8Array[i] !== 0) {
       if (i >= end) return end;
       i++;
     }
@@ -40,15 +37,15 @@ export function trimRightNull(x: string): string {
   return pos0 === -1 ? x : x.substr(0, pos0);
 }
 
-export function swapBytes(buffer: Buffer): Buffer {
-  const l = buffer.length;
+export function swapBytes<T extends Uint8Array>(uint8Array: T): T {
+  const l = uint8Array.length;
   if ((l & 1) !== 0) throw new Error('Buffer length must be even');
   for (let i = 0; i < l; i += 2) {
-    const a = buffer[i];
-    buffer[i] = buffer[i + 1];
-    buffer[i + 1] = a;
+    const a = uint8Array[i];
+    uint8Array[i] = uint8Array[i + 1];
+    uint8Array[i + 1] = a;
   }
-  return buffer;
+  return uint8Array;
 }
 
 export function readUTF16String(buffer: Buffer): string {

lib/flac/FlacParser.ts

@@ -193,7 +193,7 @@ class Metadata {
 
     get: (buf: Buffer, off: number): IBlockHeader => {
       return {
-        lastBlock: util.strtokBITSET.get(buf, off, 7),
+        lastBlock: util.getBit(buf, off, 7),
         type: util.getBitAllignedNumber(buf, off, 1, 7),
         length: Token.UINT24_BE.get(buf, off + 1)
       };

lib/id3v2/ID3v2Parser.ts

@@ -62,16 +62,16 @@ export class ID3v2Parser {
   private static readFrameFlags(b: Buffer): IFrameFlags {
     return {
       status: {
-        tag_alter_preservation: util.strtokBITSET.get(b, 0, 6),
-        file_alter_preservation: util.strtokBITSET.get(b, 0, 5),
-        read_only: util.strtokBITSET.get(b, 0, 4)
+        tag_alter_preservation: util.getBit(b, 0, 6),
+        file_alter_preservation: util.getBit(b, 0, 5),
+        read_only: util.getBit(b, 0, 4)
       },
       format: {
-        grouping_identity: util.strtokBITSET.get(b, 1, 7),
-        compression: util.strtokBITSET.get(b, 1, 3),
-        encryption: util.strtokBITSET.get(b, 1, 2),
-        unsynchronisation: util.strtokBITSET.get(b, 1, 1),
-        data_length_indicator: util.strtokBITSET.get(b, 1, 0)
+        grouping_identity: util.getBit(b, 1, 7),
+        compression: util.getBit(b, 1, 3),
+        encryption: util.getBit(b, 1, 2),
+        unsynchronisation: util.getBit(b, 1, 1),
+        data_length_indicator: util.getBit(b, 1, 0)
       }
     };
   }

lib/id3v2/ID3v2Token.ts

@@ -98,12 +98,12 @@ export const ID3v2Header: IGetToken<IID3v2header> = {
       // ID3v2 flags
       flags: {
         // Unsynchronisation
-        unsynchronisation: util.strtokBITSET.get(buf, off + 5, 7),
+        unsynchronisation: util.getBit(buf, off + 5, 7),
         // Extended header
-        isExtendedHeader: util.strtokBITSET.get(buf, off + 5, 6),
+        isExtendedHeader: util.getBit(buf, off + 5, 6),
         // Experimental indicator
-        expIndicator: util.strtokBITSET.get(buf, off + 5, 5),
-        footer: util.strtokBITSET.get(buf, off + 5, 4)
+        expIndicator: util.getBit(buf, off + 5, 5),
+        footer: util.getBit(buf, off + 5, 4)
       },
       size: UINT32SYNCSAFE.get(buf, off + 6)
     };
@@ -122,7 +122,7 @@ export const ExtendedHeader: IGetToken<IExtendedHeader> = {
       // Size of padding
       sizeOfPadding: Token.UINT32_BE.get(buf, off + 6),
       // CRC data present
-      crcDataPresent: util.strtokBITSET.get(buf, off + 4, 31)
+      crcDataPresent: util.getBit(buf, off + 4, 31)
     };
   }
 };

lib/ogg/OggParser.ts

@@ -51,9 +51,9 @@ export class OggParser extends BasicParser {
         version: buf.readUInt8(off + 4),
 
         headerType: {
-          continued: util.strtokBITSET.get(buf, off + 5, 0),
-          firstPage: util.strtokBITSET.get(buf, off + 5, 1),
-          lastPage: util.strtokBITSET.get(buf, off + 5, 2)
+          continued: util.getBit(buf, off + 5, 0),
+          firstPage: util.getBit(buf, off + 5, 1),
+          lastPage: util.getBit(buf, off + 5, 2)
         },
         // packet_flag: buf.readUInt8(off + 5),
         absoluteGranulePosition: buf.readIntLE(off + 6, 6), // cannot read 2 of 8 most significant bytes