Clarify EBML strings are ASCII

src/input-format.ts

@@ -154,7 +154,7 @@ export class MatroskaInputFormat extends InputFormat {
 					}
 				}; break;
 				case EBMLId.DocType: {
-					const docType = ebmlReader.readString(size);
+					const docType = ebmlReader.readAsciiString(size);
 					if (docType !== desiredDocType) {
 						return false;
 					}

src/matroska/ebml.ts

@@ -312,8 +312,7 @@ export class EBMLWriter {
 		this.writer.write(this.helper.subarray(0, pos));
 	}
 
-	// Assumes the string is ASCII
-	writeString(str: string) {
+	writeAsciiString(str: string) {
 		this.writer.write(new Uint8Array(str.split('').map(x => x.charCodeAt(0))));
 	}
 
@@ -359,7 +358,7 @@ export class EBMLWriter {
 				this.writeUnsignedInt(data.data, size);
 			} else if (typeof data.data === 'string') {
 				this.writeVarInt(data.data.length);
-				this.writeString(data.data);
+				this.writeAsciiString(data.data);
 			} else if (data.data instanceof Uint8Array) {
 				this.writeVarInt(data.data.byteLength, data.size);
 				this.writer.write(data.data);
@@ -495,7 +494,7 @@ export class EBMLReader {
 		return value;
 	}
 
-	readString(length: number) {
+	readAsciiString(length: number) {
 		const { view, offset } = this.reader.getViewAndOffset(this.pos, this.pos + length);
 		this.pos += length;
 

src/matroska/matroska-demuxer.ts

@@ -731,7 +731,7 @@ export class MatroskaDemuxer extends Demuxer {
 
 		switch (id) {
 			case EBMLId.DocType: {
-				this.isWebM = reader.readString(size) === 'webm';
+				this.isWebM = reader.readAsciiString(size) === 'webm';
 			}; break;
 
 			case EBMLId.Seek: {
@@ -940,7 +940,7 @@ export class MatroskaDemuxer extends Demuxer {
 			case EBMLId.CodecID: {
 				if (!this.currentTrack) break;
 
-				this.currentTrack.codecId = reader.readString(size);
+				this.currentTrack.codecId = reader.readAsciiString(size);
 			}; break;
 
 			case EBMLId.CodecPrivate: {
@@ -959,7 +959,7 @@ export class MatroskaDemuxer extends Demuxer {
 			case EBMLId.Language: {
 				if (!this.currentTrack) break;
 
-				this.currentTrack.languageCode = reader.readString(size);
+				this.currentTrack.languageCode = reader.readAsciiString(size);
 
 				if (!isIso639Dash2LanguageCode(this.currentTrack.languageCode)) {
 					this.currentTrack.languageCode = UNDETERMINED_LANGUAGE;