#195 Fix minor errors in DSF chunk parsing

Borewit · Apr 9, 2019 · 4263624 · 4263624
1 parent 20ec202
commit 4263624
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Showing 2 changed files with 26 additions and 22 deletions.
diff --git a/src/dsf/DsfChunk.ts b/src/dsf/DsfChunk.ts
@@ -120,7 +120,7 @@ export interface IFormatChunk {
  * Common chunk DSD header: the 'chunk name (Four-CC)' & chunk size
  */
 export const FormatChunk: Token.IGetToken<IFormatChunk> = {
-  len: 44,
+  len: 40,
 
   get: (buf: Buffer, off: number): IFormatChunk => {
     return {

diff --git a/src/dsf/DsfParser.ts b/src/dsf/DsfParser.ts
@@ -4,8 +4,8 @@ import { AbstractID3Parser } from '../id3v2/AbstractID3Parser';
 import * as assert from 'assert';
 
 import * as _debug from 'debug';
-import {ChunkHeader, DsdChunk, FormatChunk, IChunkHeader, IDsdChunk} from "./DsfChunk";
-import {ID3v2Parser} from "../id3v2/ID3v2Parser";
+import { ChunkHeader, DsdChunk, FormatChunk, IChunkHeader, IDsdChunk } from "./DsfChunk";
+import { ID3v2Parser } from "../id3v2/ID3v2Parser";
 
 const debug = _debug('music-metadata:parser:DSF');
 
@@ -17,6 +17,7 @@ export class DsfParser extends AbstractID3Parser {
 
   public async _parse(): Promise<void> {
 
+    const p0 = this.tokenizer.position; // mark start position, normally 0
     const chunkHeader = await this.tokenizer.readToken<IChunkHeader>(ChunkHeader);
     assert.strictEqual(chunkHeader.id, 'DSD ');
     this.metadata.setFormat('dataformat', 'DSF');
@@ -26,30 +27,33 @@ export class DsfParser extends AbstractID3Parser {
       debug(`No ID3v2 tag present`);
     } else {
       debug(`expect ID3v2 at offset=${dsdChunk.metadataPointer}`);
-      await this.parseChunks();
+      await this.parseChunks(dsdChunk.fileSize - chunkHeader.size);
       // Jump to ID3 header
-      this.tokenizer.ignore(dsdChunk.metadataPointer - this.tokenizer.position);
+      this.tokenizer.ignore(dsdChunk.metadataPointer - this.tokenizer.position - p0);
       return new ID3v2Parser().parse(this.metadata, this.tokenizer, this.options);
     }
   }
 
-  private async parseChunks() {
-    const chunkHeader = await this.tokenizer.readToken<IChunkHeader>(ChunkHeader);
-    debug(`Parsing chunk name=${chunkHeader.id} size=${chunkHeader.size}`);
-    switch (chunkHeader.id) {
-      case 'fmt ':
-        const formatChunk = await this.tokenizer.readToken(FormatChunk);
-        this.metadata.setFormat('numberOfChannels', formatChunk.channelNum);
-        this.metadata.setFormat('sampleRate', formatChunk.samplingFrequency);
-        this.metadata.setFormat('bitsPerSample', formatChunk.bitsPerSample);
-        this.metadata.setFormat('numberOfSamples', formatChunk.sampleCount);
-        this.metadata.setFormat('duration', formatChunk.sampleCount / formatChunk.samplingFrequency);
-        const bitrate = formatChunk.bitsPerSample * formatChunk.samplingFrequency * formatChunk.channelNum;
-        this.metadata.setFormat('bitrate', bitrate);
-        return;
-      default:
-        this.tokenizer.ignore(chunkHeader.size - ChunkHeader.len);
-        break;
+  private async parseChunks(bytesRemaining: number) {
+    while (bytesRemaining >= ChunkHeader.len) {
+      const chunkHeader = await this.tokenizer.readToken<IChunkHeader>(ChunkHeader);
+      debug(`Parsing chunk name=${chunkHeader.id} size=${chunkHeader.size}`);
+      switch (chunkHeader.id) {
+        case 'fmt ':
+          const formatChunk = await this.tokenizer.readToken(FormatChunk);
+          this.metadata.setFormat('numberOfChannels', formatChunk.channelNum);
+          this.metadata.setFormat('sampleRate', formatChunk.samplingFrequency);
+          this.metadata.setFormat('bitsPerSample', formatChunk.bitsPerSample);
+          this.metadata.setFormat('numberOfSamples', formatChunk.sampleCount);
+          this.metadata.setFormat('duration', formatChunk.sampleCount / formatChunk.samplingFrequency);
+          const bitrate = formatChunk.bitsPerSample * formatChunk.samplingFrequency * formatChunk.channelNum;
+          this.metadata.setFormat('bitrate', bitrate);
+          return; // We got what we want, stop further processing of chunks
+        default:
+          this.tokenizer.ignore(chunkHeader.size - ChunkHeader.len);
+          break;
+      }
+      bytesRemaining -= chunkHeader.size;
     }
   }
 }