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Fix off-by-one error in peek #368

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annevk merged 1 commit into from
Oct 19, 2026
Merged

Fix off-by-one error in peek #368

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36 changes: 17 additions & 19 deletions encoding.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,7 @@ present in <a for=/>I/O queues</a> of any type and it signifies that there are n

<div algorithm>
<p>To <dfn id=concept-stream-read for="I/O queue" export>read</dfn> an <a for=list>item</a> from an
<a for=/>I/O queue</a> <var>ioQueue</var>, run these steps:
<a for=/>I/O queue</a> <var>ioQueue</var>:

<ol>
<li><p>If <var>ioQueue</var> <a for=list>is empty</a>, then wait until its <a for=list>size</a> is
Expand All @@ -143,7 +143,7 @@ present in <a for=/>I/O queues</a> of any type and it signifies that there are n

<div algorithm="I/O queue/read items">
<p>To <a for="I/O queue">read</a> a number <var>number</var> of <a for=list>items</a> from
<var>ioQueue</var>, run these steps:
<var>ioQueue</var>:

<ol>
<li><p>Let <var>readItems</var> be « ».
Expand All @@ -165,7 +165,7 @@ present in <a for=/>I/O queues</a> of any type and it signifies that there are n

<div algorithm>
<p>To <dfn for="I/O queue" export>peek</dfn> a number <var>number</var> of <a for=list>items</a>
from an <a for=/>I/O queue</a> <var>ioQueue</var>, run these steps:
from an <a for=/>I/O queue</a> <var>ioQueue</var>:

<ol>
<li><p>Wait until either <var>ioQueue</var>'s <a for=list>size</a> is equal to or greater than
Expand All @@ -175,7 +175,8 @@ from an <a for=/>I/O queue</a> <var>ioQueue</var>, run these steps:
<li><p>Let <var>prefix</var> be « ».

<li>
<p><a for=list>For each</a> <var>n</var> in <a>the range</a> 1 to <var>number</var>, inclusive:
<p><a for=list>For each</a> <var>n</var> in <a lt="the exclusive range">the range</a> 0 to
<var>number</var>, exclusive:

<ol>
<li><p>If <var>ioQueue</var>[<var>n</var>] is <a>end-of-queue</a>, <a for=iteration>break</a>.
Expand All @@ -190,7 +191,7 @@ from an <a for=/>I/O queue</a> <var>ioQueue</var>, run these steps:

<div algorithm>
<p>To <dfn id=concept-stream-push for="I/O queue" export>push</dfn> an <a for=list>item</a>
<var>item</var> to an <a for=/>I/O queue</a> <var>ioQueue</var>, run these steps:
<var>item</var> to an <a for=/>I/O queue</a> <var>ioQueue</var>:

<ol>
<li>
Expand Down Expand Up @@ -234,7 +235,7 @@ items, in the given order, before the first item in the queue.

<div algorithm>
<p>To <dfn for="to I/O queue">convert</dfn> a <a for=/>list</a>, <a>string</a>, or
<a>byte sequence</a> <var>input</var> into an <a for=/>I/O queue</a>, run these steps:
<a>byte sequence</a> <var>input</var> into an <a for=/>I/O queue</a>:

<ol>
<li><p><a for=/>Assert</a>: <var>input</var> is not a <a for=/>list</a> or it does not
Expand Down Expand Up @@ -426,7 +427,7 @@ as "<code>utf-8</code>".
<div algorithm>
<p>To
<dfn export lt="get an encoding|getting an encoding" id=concept-encoding-get>get an encoding</dfn>
from a string <var>label</var>, run these steps:
from a string <var>label</var>:

<ol>
<li><p>Remove any leading and trailing <a>ASCII whitespace</a> from
Expand Down Expand Up @@ -816,7 +817,7 @@ plans to remove these.</p>
<h3 id=output-encodings>Output encodings</h3>

<p>To <dfn export>get an output encoding</dfn> from an <a for=/>encoding</a>
<var>encoding</var>, run these steps:
<var>encoding</var>:

<ol>
<li><p>If <var>encoding</var> is <a>replacement</a> or <a>UTF-16BE/LE</a>, then return
Expand Down Expand Up @@ -1081,7 +1082,7 @@ different format here, to be able to represent ranges.)

<div algorithm>
<p>To <dfn export>UTF-8 decode</dfn> an I/O queue of bytes <var>ioQueue</var> given an optional I/O
queue of scalar values <var>output</var> (default « »), run these steps:
queue of scalar values <var>output</var> (default « »):

<ol>
<li><p>Let <var>buffer</var> be the result of <a for="I/O queue">peeking</a> three bytes from
Expand All @@ -1099,7 +1100,7 @@ queue of scalar values <var>output</var> (default « »), run these steps:

<div algorithm>
<p>To <dfn export>UTF-8 decode without BOM</dfn> an I/O queue of bytes <var>ioQueue</var> given an
optional I/O queue of scalar values <var>output</var> (default « »), run these steps:
optional I/O queue of scalar values <var>output</var> (default « »):

<ol>
<li><p><a>Process a queue</a> with an instance of <a>UTF-8</a>'s <a for=/>decoder</a>,
Expand All @@ -1111,7 +1112,7 @@ optional I/O queue of scalar values <var>output</var> (default « »), run these

<div algorithm>
<p>To <dfn export>UTF-8 decode without BOM or fail</dfn> an I/O queue of bytes <var>ioQueue</var>
given an optional I/O queue of scalar values <var>output</var> (default « »), run these steps:
given an optional I/O queue of scalar values <var>output</var> (default « »):
<!-- Needed by https://tools.ietf.org/html/rfc6455#section-8.1 and
https://webassembly.github.io/spec/js-api/#dom-module-customsections-moduleobject-sectionname
-->
Expand Down Expand Up @@ -1152,8 +1153,7 @@ optional I/O queue of bytes <var>output</var> (default « »), return the result

<div algorithm>
<p>To <dfn export>decode</dfn> an I/O queue of bytes <var>ioQueue</var> given a fallback encoding
<var>encoding</var> and an optional I/O queue of scalar values <var>output</var> (default « »), run
these steps:
<var>encoding</var> and an optional I/O queue of scalar values <var>output</var> (default « »):

<ol>
<li><p>Let <var>BOMEncoding</var> be the result of <a>BOM sniffing</a> <var>ioQueue</var>.
Expand All @@ -1180,7 +1180,7 @@ these steps:
</div>

<div algorithm>
<p>To <dfn export>BOM sniff</dfn> an I/O queue of bytes <var>ioQueue</var>, run these steps:
<p>To <dfn export>BOM sniff</dfn> an I/O queue of bytes <var>ioQueue</var>:

<ol>
<li><p>Let <var>BOM</var> be the result of <a for="I/O queue">peeking</a> 3 bytes from
Expand Down Expand Up @@ -1210,8 +1210,7 @@ corresponding to the byte order mark found, or null otherwise.

<div algorithm>
<p>To <dfn export>encode</dfn> an I/O queue of scalar values <var>ioQueue</var> given an encoding
<var>encoding</var> and an optional I/O queue of bytes <var>output</var> (default « »), run these
steps:
<var>encoding</var> and an optional I/O queue of bytes <var>output</var> (default « »):

<ol>
<li><p>Let <var>encoder</var> be the result of <a>getting an encoder</a> from <var>encoding</var>.
Expand Down Expand Up @@ -1241,8 +1240,7 @@ is safe as it never triggers <a>errors</a>. [[HTML]]

<div algorithm>
<p>To <dfn export>encode or fail</dfn> an I/O queue of scalar values <var>ioQueue</var> given an
<a for=/>encoder</a> instance <var>encoder</var> and an I/O queue of bytes <var>output</var>, run
these steps:
<a for=/>encoder</a> instance <var>encoder</var> and an I/O queue of bytes <var>output</var>:

<ol>
<li><p>Let <var>potentialError</var> be the result of <a>processing a queue</a> with
Expand Down Expand Up @@ -1863,7 +1861,7 @@ constructor steps are:
<p>To <dfn export>set up a text decoder stream</dfn> given a {{TextDecoderStream}} object
<var>stream</var>, an optional [=/encoding=] <var>encoding</var> (default <a>UTF-8</a>), an optional
<a for=/>error mode</a> <var>errorMode</var> (default "<code>replacement</code>"), and an optional
boolean <var>ignoreBOM</var> (default false), run these steps:
boolean <var>ignoreBOM</var> (default false):

<ol>
<li><p><a>Assert</a>: <var>encoding</var> is not <a>replacement</a>.
Expand Down