hixie: Specify window.atob() and .btoa(). (ack Aryeh for the reverse-engineering to do this) (whatwg r5814)

hixie: Specify window.atob() and .btoa(). (ack Aryeh for the reverse-
engineering to do this) (whatwg r5814)

http://dev.w3.org/cvsweb/html5/spec/Overview.html?r1=1.4672&r2=1.4673&f=h
http://html5.org/tools/web-apps-tracker?from=5813&to=5814

===================================================================
RCS file: /sources/public/html5/spec/Overview.html,v
retrieving revision 1.4672
retrieving revision 1.4673
diff -u -d -r1.4672 -r1.4673
--- Overview.html 1 Feb 2011 01:30:12 -0000 1.4672
+++ Overview.html 1 Feb 2011 08:18:35 -0000 1.4673
@@ -240,6 +240,24 @@
 
    .details-example img { vertical-align: top; }
 
+   #base64-table {
+     white-space: nowrap;
+     font-size: 0.6em;
+     column-width: 6em;
+     column-count: 5;
+     column-gap: 1em;
+     -moz-column-width: 6em;
+     -moz-column-count: 5;
+     -moz-column-gap: 1em;
+     -webkit-column-width: 6em;
+     -webkit-column-count: 5;
+     -webkit-column-gap: 1em;
+   }
+   #base64-table thead { display: none; }
+   #base64-table * { border: none; }
+   #base64-table tbody td:first-child:after { content: ':'; }
+   #base64-table tbody td:last-child { text-align: right; }
+
    #named-character-references-table {
      white-space: nowrap;
      font-size: 0.6em;
@@ -1052,20 +1070,21 @@
        <li><a href="#event-firing"><span class="secno">6.1.6.3 </span>Event firing</a></li>
        <li><a href="#events-and-the-window-object"><span class="secno">6.1.6.4 </span>Events and the <code>Window</code> object</a></li>
        <li><a href="#runtime-script-errors"><span class="secno">6.1.6.5 </span>Runtime script errors</a></ol></ol></li>
-   <li><a href="#timers"><span class="secno">6.2 </span>Timers</a></li>
-   <li><a href="#user-prompts"><span class="secno">6.3 </span>User prompts</a>
+   <li><a href="#atob"><span class="secno">6.2 </span>Base64 utility methods</a></li>
+   <li><a href="#timers"><span class="secno">6.3 </span>Timers</a></li>
+   <li><a href="#user-prompts"><span class="secno">6.4 </span>User prompts</a>
     <ol>
-     <li><a href="#simple-dialogs"><span class="secno">6.3.1 </span>Simple dialogs</a></li>
-     <li><a href="#printing"><span class="secno">6.3.2 </span>Printing</a></li>
-     <li><a href="#dialogs-implemented-using-separate-documents"><span class="secno">6.3.3 </span>Dialogs implemented using separate documents</a></ol></li>
-   <li><a href="#system-state-and-capabilities:-the-navigator-object"><span class="secno">6.4 </span>System state and capabilities: the <code>Navigator</code> object</a>
+     <li><a href="#simple-dialogs"><span class="secno">6.4.1 </span>Simple dialogs</a></li>
+     <li><a href="#printing"><span class="secno">6.4.2 </span>Printing</a></li>
+     <li><a href="#dialogs-implemented-using-separate-documents"><span class="secno">6.4.3 </span>Dialogs implemented using separate documents</a></ol></li>
+   <li><a href="#system-state-and-capabilities:-the-navigator-object"><span class="secno">6.5 </span>System state and capabilities: the <code>Navigator</code> object</a>
     <ol>
-     <li><a href="#client-identification"><span class="secno">6.4.1 </span>Client identification</a></li>
-     <li><a href="#custom-handlers"><span class="secno">6.4.2 </span>Custom scheme and content handlers</a>
+     <li><a href="#client-identification"><span class="secno">6.5.1 </span>Client identification</a></li>
+     <li><a href="#custom-handlers"><span class="secno">6.5.2 </span>Custom scheme and content handlers</a>
       <ol>
-       <li><a href="#security-and-privacy"><span class="secno">6.4.2.1 </span>Security and privacy</a></li>
-       <li><a href="#sample-handler-impl"><span class="secno">6.4.2.2 </span>Sample user interface</a></ol></li>
-     <li><a href="#manually-releasing-the-storage-mutex"><span class="secno">6.4.3 </span>Manually releasing the storage mutex</a></ol></ol></li>
+       <li><a href="#security-and-privacy"><span class="secno">6.5.2.1 </span>Security and privacy</a></li>
+       <li><a href="#sample-handler-impl"><span class="secno">6.5.2.2 </span>Sample user interface</a></ol></li>
+     <li><a href="#manually-releasing-the-storage-mutex"><span class="secno">6.5.3 </span>Manually releasing the storage mutex</a></ol></ol></li>
  <li><a href="#editing"><span class="secno">7 </span>User interaction</a>
   <ol>
    <li><a href="#the-hidden-attribute"><span class="secno">7.1 </span>The <code>hidden</code> attribute</a></li>
@@ -2878,6 +2897,11 @@
     is passed an Infinity or Not-a-Number (NaN) value, a
     <code><a href="#not_supported_err">NOT_SUPPORTED_ERR</a></code> exception must be raised.</p>
 
+    <p>Except where otherwise specified, if a method has an argument
+    of type <code>DOMString</code>, the user agent must <span title="dfn-obtain-unicode">convert the <code>DOMString</code> to a
+    sequence of Unicode characters</span> when the method is invoked,
+    to obtain the string on which the method is to operate. <a href="#refsWEBIDL">[WEBIDL]</a></p>
+
    </dd>
 
    <dt>JavaScript</dt>
@@ -48624,7 +48648,228 @@
 
    </dd>
 
-  </dl></div><h3 id="timers"><span class="secno">6.2 </span>Timers</h3><p>The <code title="dom-windowtimers-setTimeout"><a href="#dom-windowtimers-settimeout">setTimeout()</a></code>
+  </dl></div><h3 id="atob"><span class="secno">6.2 </span>Base64 utility methods</h3><p>The <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob()</a></code> and <code title="dom-windowbase64-btoa"><a href="#dom-windowbase64-btoa">btoa()</a></code> methods allow authors to
+  transform content to and from the base64 encoding.</p><!-- v2: actual binary support --><pre class="idl">[Supplemental, NoInterfaceObject]
+interface <dfn id="windowbase64">WindowBase64</dfn> {
+  DOMString <a href="#dom-windowbase64-btoa" title="dom-windowbase64-btoa">btoa</a>(in DOMString btoa);
+  DOMString <a href="#dom-windowbase64-atob" title="dom-windowbase64-atob">atob</a>(in DOMString atob);
+};
+<a href="#window">Window</a> implements <a href="#windowbase64">WindowBase64</a>;</pre><p class="note">In these APIs, for mnemonic purposes, the "b" can be
+  considered to stand for "binary", and the "a" for "ASCII". In
+  practice, though, for primarily historical reasons, both the input
+  and output of these functions are Unicode strings.<dl class="domintro"><dt><var title="">result</var> = <var title="">window</var> . <code title="dom-windowbase64-btoa"><a href="#dom-windowbase64-btoa">btoa</a></code>( <var title="">data</var> )</dt>
+
+   <dd>
+
+    <p>Takes the input data, in the form of a Unicode string
+    containing only characters in the range U+0000 to U+00FF, each
+    representing a binary byte with values 0x00 to 0xFF respectively,
+    and converts it to its base64 representation, which it returns.</p>
+
+    <p>Throws an <code><a href="#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception if the
+    input string contains any out-of-range characters.</p>
+
+   </dd>
+
+   <dt><var title="">result</var> = <var title="">window</var> . <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob</a></code>( <var title="">data</var> )</dt>
+
+   <dd>
+
+    <p>Takes the input data, in the form of a Unicode string
+    containing base64-encoded binary data, decodes it, and returns a
+    string consisting of characters in the range U+0000 to U+00FF,
+    each representing a binary byte with values 0x00 to 0xFF
+    respectively, corresponding to that binary data.</p>
+
+    <p>Throws an <code><a href="#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception if the
+    input string is not valid base64 data.</p>
+
+   </dd>
+
+  </dl><div class="impl">
+
+  <p class="note">The <code><a href="#windowbase64">WindowBase64</a></code> interface adds to the
+  <code><a href="#window">Window</a></code> interface and the <code>WorkerUtils</code>
+  interface (part of Web Workers).</p>
+
+  <p>The <dfn id="dom-windowbase64-btoa" title="dom-windowbase64-btoa"><code>btoa()</code></dfn>
+  method must throw an <code><a href="#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exeption if
+  the method's first argument contains any character whose code point
+  is greater than U+00FF. Otherwise, the user agent must convert that
+  argument to a sequence of octets whose <var title="">n</var>th octet
+  is the eight-bit representation of the code point of the <var title="">n</var>th character of the argument, and then must apply
+  the base64 algorithm to that sequence of octets, and return the
+  result. <a href="#refsRFC4648">[RFC4648]</a><!--base64--></p>
+  <!-- Aryeh says: This seems to be what all browsers do as of January
+  2011 (except IE, which doesn't support these functions at all). -->
+
+
+  <p>The <dfn id="dom-windowbase64-atob" title="dom-windowbase64-atob"><code>atob()</code></dfn>
+  method must run the following steps to parse the string passed in
+  the method's first argument:</p>
+
+  <ol><!-- Aryeh says: Copies Firefox behavior as of January 2011
+   (4.0b8). WebKit is somewhat laxer, and Opera throws no exceptions
+   at all. gsnedders reports Opera's behavior causes site-compat
+   problems, and I figure most sites depend on Firefox if on anything,
+   so go with that. --><li><p>Let <var title="">input</var> be the string being
+   parsed.</li>
+
+   <li><p>Let <var title="">position</var> be a pointer into <var title="">input</var>, initially pointing at the start of the
+   string.</li>
+
+   <li><p>If the length of <var title="">input</var> divides by 4
+   leaving no remainder, then: if <var title="">input</var> ends with
+   one or two U+003D EQUALS SIGN (=) characters, remove them from <var title="">input</var>.</li>
+
+   <li><p>If the length of <var title="">input</var> divides by 4
+   leaving a remainder of 1, throw an
+   <code><a href="#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception and abort these
+   steps.</p>
+
+   <li>
+
+    <p>If <var title="">input</var> contains a character that is not
+    in the following list of characters and character ranges, throw an
+    <code><a href="#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception and abort these
+    steps:</p>
+
+    <ul class="brief"><li>U+002B PLUS SIGN (+)
+     <li>U+002F SOLIDUS (/)
+     <li>U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9)
+     <li>U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z
+     <li>U+0061 LATIN SMALL LETTER A to U+007A LATIN SMALL LETTER Z
+    </ul></li>
+
+   <li><p>Let <var title="">output</var> be a string, initially
+   empty.</li>
+
+   <li><p>Let <var title="">buffer</var> be a buffer that can have
+   bits appended to it, initially empty.</li>
+
+   <li>
+
+    <p>While <var title="">position</var> does not point past the end
+    of <var title="">input</var>, run these substeps:</p>
+
+    <ol><li>
+
+      <p>Find the character pointed to by <var title="">position</var>
+      in the first column of the following table. Let <var title="">n</var> be the number given in the second cell of the
+      same row.</p>
+
+      <div id="base64-table">
+       <table><thead><tr><th>Character
+          <th>Number
+        <tbody><tr><td>A<td>0
+         <tr><td>B<td>1
+         <tr><td>C<td>2
+         <tr><td>D<td>3
+         <tr><td>E<td>4
+         <tr><td>F<td>5
+         <tr><td>G<td>6
+         <tr><td>H<td>7
+         <tr><td>I<td>8
+         <tr><td>J<td>9
+         <tr><td>K<td>10
+         <tr><td>L<td>11
+         <tr><td>M<td>12
+         <tr><td>N<td>13
+         <tr><td>O<td>14
+         <tr><td>P<td>15
+         <tr><td>Q<td>16
+         <tr><td>R<td>17
+         <tr><td>S<td>18
+         <tr><td>T<td>19
+         <tr><td>U<td>20
+         <tr><td>V<td>21
+         <tr><td>W<td>22
+         <tr><td>X<td>23
+         <tr><td>Y<td>24
+         <tr><td>Z<td>25
+         <tr><td>a<td>26
+         <tr><td>b<td>27
+         <tr><td>c<td>28
+         <tr><td>d<td>29
+         <tr><td>e<td>30
+         <tr><td>f<td>31
+         <tr><td>g<td>32
+         <tr><td>h<td>33
+         <tr><td>i<td>34
+         <tr><td>j<td>35
+         <tr><td>k<td>36
+         <tr><td>l<td>37
+         <tr><td>m<td>38
+         <tr><td>n<td>39
+         <tr><td>o<td>40
+         <tr><td>p<td>41
+         <tr><td>q<td>42
+         <tr><td>r<td>43
+         <tr><td>s<td>44
+         <tr><td>t<td>45
+         <tr><td>u<td>46
+         <tr><td>v<td>47
+         <tr><td>w<td>48
+         <tr><td>x<td>49
+         <tr><td>y<td>50
+         <tr><td>z<td>51
+         <tr><td>0<td>52
+         <tr><td>1<td>53
+         <tr><td>2<td>54
+         <tr><td>3<td>55
+         <tr><td>4<td>56
+         <tr><td>5<td>57
+         <tr><td>6<td>58
+         <tr><td>7<td>59
+         <tr><td>8<td>60
+         <tr><td>9<td>61
+         <tr><td>+<td>62
+         <tr><td>/<td>63
+       </table></div>
+
+     </li>
+
+     <li><p>Append to <var title="">buffer</var> the six bits
+     corresponding to <var title="">number</var>, most significant bit
+     first.</li>
+
+     <li><p>If <var title="">buffer</var> has accumulated 24 bits,
+     interpret them as three 8-bit big-endian numbers. Append the
+     three characters with code points equal to those numbers to <var title="">output</var>, in the same order, and then empty <var title="">buffer</var>.</li>
+
+     <li><p>Advance <var title="">position</var> by one
+     character.</li>
+
+    </ol></li>
+
+   <li>
+
+    <p>If <var title="">buffer</var> is not empty, it contains either
+    12 or 18 bits. If it contains 12 bits, discard the last four and
+    interpret the remaining eight as an 8-bit big-endian number. If it
+    contains 18 bits, discard the last two and interpret the remaining
+    16 as two 8-bit big-endian numbers. Append the one or two
+    characters with code points equal to those one or two numbers to
+    <var title="">output</var>, in the same order.</p>
+
+    <p>The discarded bits mean that, for instance, <code title="">atob("YQ")</code> and <code title="">atob("YR")</code>
+    both return "<code title="">a</code>".</p>
+
+   </li>
+
+   <li><p>Return <var title="">output</var>.</li>
+
+  </ol><!-- Note: this function is defined explicitly here because RFC4648
+  does not specify how to handle erroneous input, and no preexisting
+  browser implementation simply throws an exception on all erroneous
+  input. --><p class="note">Some base64 encoders add newlines or other
+  whitespace to their output. The <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob()</a></code> method throws an
+  exception if its input contains characters other than those
+  described by the regular expression bracket expression <code title="">[+/=0-9A-Za-z]</code>, so other characters need to be
+  removed before <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob()</a></code> is
+  used for decoding.</p>
+
+  </div><h3 id="timers"><span class="secno">6.3 </span>Timers</h3><p>The <code title="dom-windowtimers-setTimeout"><a href="#dom-windowtimers-settimeout">setTimeout()</a></code>
   and <code title="dom-windowtimers-setInterval"><a href="#dom-windowtimers-setinterval">setInterval()</a></code>
   methods allow authors to schedule timer-based callbacks.<pre class="idl">[Supplemental, NoInterfaceObject]
 interface <dfn id="windowtimers">WindowTimers</dfn> {
@@ -48932,14 +49177,14 @@
   </ol><hr><p>The <a href="#task-source">task source</a> for these <a href="#concept-task" title="concept-task">tasks</a> is the <dfn id="timer-task-source">timer task
   source</dfn>.</p>
 
-  </div><h3 id="user-prompts"><span class="secno">6.3 </span>User prompts</h3><!--
+  </div><h3 id="user-prompts"><span class="secno">6.4 </span>User prompts</h3><!--
    v2 ideas:
     * in-window modal dialogs
        - escape/enter handling
        - dragging the window out of the tab
     * in-window non-modal palettes
        - with a solution for the mobile space
-  --><h4 id="simple-dialogs"><span class="secno">6.3.1 </span>Simple dialogs</h4><dl class="domintro"><dt><var title="">window</var> . <code title="dom-alert"><a href="#dom-alert">alert</a></code>(<var title="">message</var>)</dt>
+  --><h4 id="simple-dialogs"><span class="secno">6.4.1 </span>Simple dialogs</h4><dl class="domintro"><dt><var title="">window</var> . <code title="dom-alert"><a href="#dom-alert">alert</a></code>(<var title="">message</var>)</dt>
    <dd>
 
     <p>Displays a modal alert with the given message, and waits for the user to dismiss it.</p>
@@ -49001,7 +49246,7 @@
   user aborts, then the method must return null; otherwise, the method
   must return the string that the user responded with.</p>
 
-  </div><h4 id="printing"><span class="secno">6.3.2 </span>Printing</h4><dl class="domintro"><dt><var title="">window</var> . <code title="dom-print"><a href="#dom-print">print</a></code>()</dt>
+  </div><h4 id="printing"><span class="secno">6.4.2 </span>Printing</h4><dl class="domintro"><dt><var title="">window</var> . <code title="dom-print"><a href="#dom-print">print</a></code>()</dt>
 
    <dd>
 
@@ -49090,7 +49335,7 @@
 
    </li>
 
-  </ol></div><h4 id="dialogs-implemented-using-separate-documents"><span class="secno">6.3.3 </span>Dialogs implemented using separate documents</h4><dl class="domintro"><dt><var title="">result</var> = <var title="">window</var> . <code title="dom-showModalDialog"><a href="#dom-showmodaldialog">showModalDialog</a></code>(<var title="">url</var> [, <var title="">argument</var>] )</dt>
+  </ol></div><h4 id="dialogs-implemented-using-separate-documents"><span class="secno">6.4.3 </span>Dialogs implemented using separate documents</h4><dl class="domintro"><dt><var title="">result</var> = <var title="">window</var> . <code title="dom-showModalDialog"><a href="#dom-showmodaldialog">showModalDialog</a></code>(<var title="">url</var> [, <var title="">argument</var>] )</dt>
 
    <dd>
 
@@ -49296,7 +49541,7 @@
   value</a> to the given new value.</p>
 
   </div><p class="note">The <code title="dom-window-close"><a href="#dom-window-close">window.close()</a></code> method can be used to
-  close the browsing context.<h3 id="system-state-and-capabilities:-the-navigator-object"><span class="secno">6.4 </span>System state and capabilities: the <code><a href="#navigator">Navigator</a></code> object</h3><div class="impl">
+  close the browsing context.<h3 id="system-state-and-capabilities:-the-navigator-object"><span class="secno">6.5 </span>System state and capabilities: the <code><a href="#navigator">Navigator</a></code> object</h3><div class="impl">
 
   <p>The <dfn id="dom-navigator" title="dom-navigator"><code>navigator</code></dfn>
   attribute of the <code><a href="#window">Window</a></code> interface must return an
@@ -49352,7 +49597,7 @@
    <dd><p>Must return either null or a language tag representing the user's preferred language.</p></dd>
    -->
 
-  </div><h4 id="client-identification"><span class="secno">6.4.1 </span>Client identification</h4><p>In certain cases, despite the best efforts of the entire
+  </div><h4 id="client-identification"><span class="secno">6.5.1 </span>Client identification</h4><p>In certain cases, despite the best efforts of the entire
   industry, Web browsers have bugs and limitations that Web authors
   are forced to work around.<p>This section defines a collection of attributes that can be used
   to determine, from script, the kind of user agent in use, in order
@@ -49417,7 +49662,7 @@
   identified. For this reason, user agent implementors are strongly
   urged to include as little information in this API as possible.</p>
 
-  </div><h4 id="custom-handlers"><span class="secno">6.4.2 </span>Custom scheme and content handlers</h4><p>The <dfn id="dom-navigator-registerprotocolhandler" title="dom-navigator-registerProtocolHandler"><code>registerProtocolHandler()</code></dfn>
+  </div><h4 id="custom-handlers"><span class="secno">6.5.2 </span>Custom scheme and content handlers</h4><p>The <dfn id="dom-navigator-registerprotocolhandler" title="dom-navigator-registerProtocolHandler"><code>registerProtocolHandler()</code></dfn>
   method allows Web sites to register themselves as possible handlers
   for particular schemes. For example, an online telephone messaging
   service could register itself as a handler of the <code>sms:</code>
@@ -49605,7 +49850,7 @@
 
   </div><div class="impl">
 
-  <h5 id="security-and-privacy"><span class="secno">6.4.2.1 </span>Security and privacy</h5>
+  <h5 id="security-and-privacy"><span class="secno">6.5.2.1 </span>Security and privacy</h5>
 
   <p>These mechanisms can introduce a number of concerns, in
   particular privacy concerns.</p>
@@ -49686,7 +49931,7 @@
 
   </div><div class="impl">
 
-  <h5 id="sample-handler-impl"><span class="secno">6.4.2.2 </span>Sample user interface</h5>
+  <h5 id="sample-handler-impl"><span class="secno">6.5.2.2 </span>Sample user interface</h5>
 
   <p><i>This section is non-normative.</i></p>
 
@@ -49728,7 +49973,7 @@
   method would work equivalently, but for schemes instead of unknown
   content types.</p>
 
-  </div><h4 id="manually-releasing-the-storage-mutex"><span class="secno">6.4.3 </span>Manually releasing the storage mutex</h4><dl class="domintro"><dt><var title="">window</var> . <code title="dom-navigator"><a href="#dom-navigator">navigator</a></code> . <code title="dom-navigator-yieldForStorageUpdates"><a href="#dom-navigator-yieldforstorageupdates">yieldForStorageUpdates</a></code>()</dt>
+  </div><h4 id="manually-releasing-the-storage-mutex"><span class="secno">6.5.3 </span>Manually releasing the storage mutex</h4><dl class="domintro"><dt><var title="">window</var> . <code title="dom-navigator"><a href="#dom-navigator">navigator</a></code> . <code title="dom-navigator-yieldForStorageUpdates"><a href="#dom-navigator-yieldforstorageupdates">yieldForStorageUpdates</a></code>()</dt>
 
    <dd>

Received on Tuesday, 1 February 2011 08:19:59 UTC