Add peekByte method to Stream, DecodeStream and ChunkedStream

src/core/chunked_stream.js

@@ -195,6 +195,12 @@ var ChunkedStream = (function ChunkedStreamClosure() {
       return bytes.subarray(pos, end);
     },
 
+    peekByte: function ChunkedStream_peekByte() {
+      var peekedByte = this.getByte();
+      this.pos--;
+      return peekedByte;
+    },
+
     peekBytes: function ChunkedStream_peekBytes(length) {
       var bytes = this.getBytes(length);
       this.pos -= bytes.length;

src/core/parser.js

@@ -478,7 +478,7 @@ var Lexer = (function LexerClosure() {
       return (this.currentChar = this.stream.getByte());
     },
     peekChar: function Lexer_peekChar() {
-      return this.stream.peekBytes(1)[0];
+      return this.stream.peekByte();
     },
     getNumber: function Lexer_getNumber() {
       var ch = this.currentChar;

src/core/stream.js

@@ -73,6 +73,11 @@ var Stream = (function StreamClosure() {
       this.pos = end;
       return bytes.subarray(pos, end);
     },
+    peekByte: function Stream_peekByte() {
+      var peekedByte = this.getByte();
+      this.pos--;
+      return peekedByte;
+    },
     peekBytes: function Stream_peekBytes(length) {
       var bytes = this.getBytes(length);
       this.pos -= bytes.length;
@@ -202,6 +207,11 @@ var DecodeStream = (function DecodeStreamClosure() {
       this.pos = end;
       return this.buffer.subarray(pos, end);
     },
+    peekByte: function DecodeStream_peekByte() {
+      var peekedByte = this.getByte();
+      this.pos--;
+      return peekedByte;
+    },
     peekBytes: function DecodeStream_peekBytes(length) {
       var bytes = this.getBytes(length);
       this.pos -= bytes.length;
@@ -527,7 +537,7 @@ var FlateStream = (function FlateStreamClosure() {
       var end = bufferLength + blockLen;
       this.bufferLength = end;
       if (blockLen === 0) {
-        if (str.peekBytes(1).length === 0) {
+        if (str.peekByte() === -1) {
           this.eof = true;
         }
       } else {