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[CPP-434] Use a bullet list instead of a table in order to placate Jenkins.

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Ziemowit Laski
2019-11-04 12:30:52 -08:00
parent 2bad9394b7
commit ce8ba86f2d
1 changed files with 27 additions and 75 deletions
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102
cpp/ql/src/Likely Bugs/Arithmetic/SignedOverflowCheck.qhelp
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@@ -22,85 +22,36 @@ categories: (1) rewrite the signed expression so that overflow cannot occur
but the signedness remains, or (2) rewrite (or cast) the signed expression
into unsigned form.
The table below lists various expressions where signed overflow may
The bullet list below lists various expressions where signed overflow may
occur, along with proposed rewritings. It should not be
considered exhaustive.
</p>
<table>
<thead><tr>
<th>Original Construct</th>
<th>Alternate Construct(s)</th>
<th>Notes</th>
</tr></thead>
<tbody><tr>
<td><tt><table>
<tbody><tr>
<td>unsigned short i, delta;</td>
</tr><tr>
<td>i + delta &lt; i</td>
</tr></tbody>
</table></tt></td>
<td><tt><table>
<tbody><tr>
<td>unsigned short i, delta;</td>
</tr><tr>
<td>(unsigned short)(i + delta)&nbsp;&lt;&nbsp;i</td>
</tr></tbody>
</table></tt></td>
<td><tt>i + delta</tt>does not actually overflow due to <tt>int</tt> promotion</td>
</tr>
<tr>
<td>&nbsp;</td>
<td><tt><table>
<tbody><tr>
<td>unsigned short i, delta;</td>
</tr><tr>
<td>i > USHORT_MAX - delta</td>
</tr></tbody>
</table></tt></td>
<td>Must include <tt>limits.h</tt> or <tt>climits</tt>; <tt>delta &gt; 0</tt></td>
</tr>
<tr>
<td><tt><table>
<tbody><tr>
<td>int i, delta;</td>
</tr><tr>
<td>i + delta &lt; i</td>
</tr></tbody>
</table></tt></td>
<td><tt><table>
<tbody><tr>
<td>int i, delta;</td>
</tr><tr>
<td>i &gt; INT_MAX - delta</td>
</tr></tbody>
</table></tt></td>
<td>Must include <tt>limits.h</tt> or <tt>climits</tt>; <tt>delta &gt; 0</tt></td>
</tr>
<tr>
<td>&nbsp;</td>
<td><tt><table>
<tbody><tr>
<td>int i, delta;</td>
</tr><tr>
<td>(unsigned)i + delta &lt; i</td>
</tr></tbody>
</table></tt></td>
<td>Change in program semantics</td>
</tr>
<tr>
<td>&nbsp;</td>
<td><tt><table>
<tbody><tr>
<td>unsigned int i, delta;</td>
</tr><tr>
<td>i + delta &lt; i</td>
</tr></tbody>
</table></tt></td>
<td>Change in program semantics</td>
</tr></tbody>
</table>
<li>Given <code>unsigned short i, delta</code> and <code>i + delta &lt; i</code>,
it is possible to rewrite it as <code>(unsigned short)(i + delta)&nbsp;&lt;&nbsp;i</code>.
Note that <code>i + delta</code>does not actually overflow, due to <code>int</code> promotion</li>
<li>Given <code>unsigned short i, delta</code> and <code>i + delta &lt; i</code>,
it is also possible to rewrite it as <code>USHORT_MAX - delta</code>. It must be true
that <code>delta &gt; 0</code> and the <code>limits.h</code> or <code>climits</code>
header has been included.</li>
<li>Given <code>int i, delta</code> and <code>i + delta &lt; i</code>,
it is possible to rewrite it as <code>INT_MAX - delta</code>. It must be true
that <code>delta &gt; 0</code> and the <code>limits.h</code> or <code>climits</code>
header has been included.</li>
<li>Given <code>int i, delta</code> and <code>i + delta &lt; i</code>,
it is also possible to rewrite it as <code>(unsigned)i + delta &lt; i</code>.
Note that program semantics are affected by this change.</li>
<li>Given <code>int i, delta</code> and <code>i + delta &lt; i</code>,
it is also possible to rewrite it as <code>unsigned int i, delta</code> and
<code>i + delta &lt; i</code>. Note that program semantics are
affected by this change.</li>
</recommendation>
<example>
<p>
In the following example, even though <code>delta</code> has been declared
@@ -142,6 +93,7 @@ so that <code>unsigned short</code> "wrap around" may now be observed.
Furthermore, since the left-hand side is now of type <code>unsigned short</code>,
the right-hand side does not need to be promoted to a <code>signed int</code>.
</p>
<sample src="SignedOverflowCheck-good2.cpp" />
</example>
<references>