Displaystring work.

Currently very incomplete, but tests are running.

src/displaystring.ts

@@ -0,0 +1,16 @@
+export class DisplayString {
+
+  private value: string;
+  constructor(value: string) {
+
+    this.value = value;
+
+  }
+
+  toString(): string {
+
+    return this.value;
+
+  }
+
+}

src/index.ts

@@ -3,3 +3,4 @@ export * from './parser';
 export * from './types';
 export * from './util';
 export { Token } from './token';
+export { DisplayString } from './displaystring';

src/parser.ts

@@ -11,6 +11,7 @@ import {
 import { Token } from './token';
 
 import { isAscii } from './util';
+import { DisplayString } from './displaystring';
 
 export function parseDictionary(input: string): Dictionary {
 
@@ -185,6 +186,9 @@ export default class Parser {
     if (char === '@') {
       return this.parseDate();
     }
+    if (char === '%') {
+      return this.parseDisplayString();
+    }
     throw new ParseError(this.pos, 'Unexpected input');
 
   }
@@ -299,6 +303,32 @@ export default class Parser {
 
   }
 
+  private parseDisplayString(): DisplayString {
+
+    this.expectChar('%');
+    this.pos++;
+    this.expectChar('"');
+    this.pos++;
+
+    let result = new Uint8Array();
+
+    while (!this.eof()) {
+
+      const char = this.getChar();
+      if (char.charCodeAt(0) <= 0x1F || (char.charCodeAt(0) >= 0x7F && char.charCodeAt(0) <= 0xFF)) {
+        throw new ParseError('Invalid byte found at offset: ' + this.pos);
+      }
+
+      if (char==='%') {
+        const hexChars = this.input.substr(this.pos,2);
+        if (/^[0-9a-f]{2}$/.test(hexChars)) {
+
+    }
+
+    return new DisplayString(result);
+
+  }
+
   private parseToken(): Token {
 
     // The specification wants this check, but it's an unreachable code block.

src/serializer.ts

@@ -11,6 +11,7 @@ import {
 import { Token } from './token';
 
 import { isAscii, isInnerList, isValidKeyStr } from './util';
+import { DisplayString } from './displaystring';
 
 export class SerializeError extends Error {}
 
@@ -80,6 +81,9 @@ export function serializeBareItem(input: BareItem): string {
   if (input instanceof ByteSequence) {
     return serializeByteSequence(input);
   }
+  if (input instanceof DisplayString) {
+    return serializeDisplayString(input);
+  }
   if (input instanceof Date) {
     return serializeDate(input);
   }
@@ -114,6 +118,10 @@ export function serializeString(input: string): string {
   return `"${input.replace(/("|\\)/g, (v) => '\\' + v)}"`;
 }
 
+export function serializeDisplayString(input: DisplayString): string {
+  return '%' + serializeString(input.toString());
+}
+
 export function serializeBoolean(input: boolean): string {
   return input ? '?1' : '?0';
 }

src/types.ts

@@ -1,4 +1,5 @@
 import { Token } from './token';
+import { DisplayString } from './displaystring';
 
 /**
  * Lists are arrays of zero or more members, each of which can be an Item
@@ -47,6 +48,6 @@ export class ByteSequence {
 
 }
 
-export type BareItem = number | string | Token | ByteSequence | Date | boolean;
+export type BareItem = number | string | Token | ByteSequence | Date | boolean | DisplayString;
 
 export type Item = [BareItem, Parameters];

test/httpwg-tests.js

@@ -10,7 +10,7 @@ const {
 
   ParseError,
 } = require('../dist');
-const { Token, ByteSequence } = require('../dist');
+const { Token, ByteSequence, DisplayString } = require('../dist');
 const base32Encode = require('base32-encode');
 const base32Decode = require('base32-decode');
 const fs = require('fs');
@@ -24,6 +24,7 @@ describe('HTTP-WG tests', () => {
     'string',
     'token',
     'date',
+    'display-string',
 
     'item',
 
@@ -284,6 +285,12 @@ function packTestValue(input) {
       value: input.toString()
     }
   }
+  if(input instanceof DisplayString) {
+    return {
+      __type: 'displaystring',
+      value: input.toString()
+    }
+  }
   if (input instanceof ByteSequence) {
     return {
       __type: 'binary',
@@ -340,6 +347,8 @@ function unpackTestValue(input) {
         return new ByteSequence(Buffer.from(base32Decode(input.value, 'RFC4648')).toString('base64'));
       case 'date' :
         return new Date(input.value * 1000);
+      case 'displaystring' :
+        return new DisplayString(input.value);
       default:
         throw new Error('Unknown input __type: ' + input.__type);
     }