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+ <hr align="left" width="100%">
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-
<div class="SECT1">
<h1 class="SECT1"><a name="CODING" id="CODING">4. Coding
Guidelines</a></h1>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S1" id="S1">4.1. Introduction</a></h2>
-
<p>This set of standards is designed to make our lives easier. It is
developed with the simple goal of helping us keep the "new and improved
<span class="APPLICATION">Privoxy</span>" consistent and reliable. Thus
making maintenance easier and increasing chances of success of the
project.</p>
-
<p>And that of course comes back to us as individuals. If we can
increase our development and product efficiencies then we can solve
more of the request for changes/improvements and in general feel good
about ourselves. ;-></p>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S2" id="S2">4.2. Using Comments</a></h2>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S3" id="S3">4.2.1. Comment, Comment,
Comment</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Comment as much as possible without commenting the obvious. For
example do not comment "variable_a is equal to variable_b". Instead
explain why variable_a should be equal to the variable_b. Just
because a person can read code does not mean they will understand why
or what is being done. A reader may spend a lot more time figuring
out what is going on when a simple comment or explanation would have
- prevented the extra research. Please help your brother IJB'ers
- out!</p>
-
+ prevented the extra research. Please help your fellow Privoxy
+ developers out!</p>
<p>The comments will also help justify the intent of the code. If the
comment describes something different than what the code is doing
then maybe a programming error is occurring.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-/* if page size greater than 1k ... */
-if ( page_length() > 1024 )
+ /* if page size greater than 1k ... */
+if (page_length() > 1024)
{
... "block" the page up ...
}
/* if page size is small, send it in blocks */
-if ( page_length() > 1024 )
+if (page_length() > 1024)
{
... "block" the page up ...
}
This demonstrates 2 cases of "what not to do". The first is a
"syntax comment". The second is a comment that does not fit what
-is actually being done.
-</pre>
+is actually being done.</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S4" id="S4">4.2.2. Use blocks for
comments</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Comments can help or they can clutter. They help when they are
differentiated from the code they describe. One line comments do not
offer effective separation between the comment and the code. Block
identifiers do, by surrounding the code with a clear, definable
pattern.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-/*********************************************************************
+ /*********************************************************************
* This will stand out clearly in your code!
*********************************************************************/
-if ( this_variable == that_variable )
+if (this_variable == that_variable)
{
do_something_very_important();
}
/* unfortunately, this may not */
-if ( this_variable == that_variable )
+if (this_variable == that_variable)
{
do_something_very_important();
}
-if ( this_variable == that_variable ) /* this may not either */
+if (this_variable == that_variable) /* this may not either */
{
do_something_very_important();
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Exception:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Exception:</i></span></p>
<p>If you are trying to add a small logic comment and do not wish to
"disrupt" the flow of the code, feel free to use a 1 line comment
which is NOT on the same line as the code.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S5" id="S5">4.2.3. Keep Comments on their
own line</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>It goes back to the question of readability. If the comment is on
the same line as the code it will be harder to read than the comment
that is on its own line.</p>
-
<p>There are three exceptions to this rule, which should be violated
freely and often: during the definition of variables, at the end of
closing braces, when used to comment parameters.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-/*********************************************************************
+ /*********************************************************************
* This will stand out clearly in your code,
* But the second example won't.
*********************************************************************/
-if ( this_variable == this_variable )
+if (this_variable == this_variable)
{
do_something_very_important();
}
-if ( this_variable == this_variable ) /*can you see me?*/
+if (this_variable == this_variable) /*can you see me?*/
{
do_something_very_important(); /*not easily*/
}
int urls_read = 0; /* # of urls read + rejected */
int urls_rejected = 0; /* # of urls rejected */
-if ( 1 == X )
+if (1 == X)
{
do_something_very_important();
}
{
...code here...
-} /* -END- do_something_very_important */
-</pre>
+} /* -END- do_something_very_important */</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S6" id="S6">4.2.4. Comment each logical
step</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Logical steps should be commented to help others follow the intent
of the written code and comments will make the code more
readable.</p>
-
<p>If you have 25 lines of code without a comment, you should
probably go back into it to see where you forgot to put one.</p>
-
<p>Most "for", "while", "do", etc... loops _probably_ need a comment.
After all, these are usually major logic containers.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S7" id="S7">4.2.5. Comment All Functions
Thoroughly</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>A reader of the code should be able to look at the comments just
prior to the beginning of a function and discern the reason for its
existence and the consequences of using it. The reader should not
functions should contain the information presented in the addendum
section of this document.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S8" id="S8">4.2.6. Comment at the end of
braces if the content is more than one screen length</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Each closing brace should be followed on the same line by a
comment that describes the origination of the brace if the original
brace is off of the screen, or otherwise far away from the closing
brace. This will simplify the debugging, maintenance, and readability
of the code.</p>
-
<p>As a suggestion , use the following flags to make the comment and
its brace more readable:</p>
-
<p>use following a closing brace: } /* -END- if() or while () or
etc... */</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-if ( 1 == X )
+ <pre class="PROGRAMLISTING">if (1 == X)
{
do_something_very_important();
...some long list of commands...
or:
-if ( 1 == X )
+if (1 == X)
{
do_something_very_important();
...some long list of commands...
-} /* -END- if ( 1 == X ) */
-</pre>
+} /* -END- if (1 == X) */</pre>
</td>
</tr>
</table>
</div>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S9" id="S9">4.3. Naming Conventions</a></h2>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S10" id="S10">4.3.1. Variable
Names</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Use all lowercase, and separate words via an underscore ('_'). Do
not start an identifier with an underscore. (ANSI C reserves these
for use by the compiler and system headers.) Do not use identifiers
which are reserved in ANSI C++. (E.g. template, class, true, false,
...). This is in case we ever decide to port Privoxy to C++.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-int ms_iis5_hack = 0;
-</pre>
+ <pre class="PROGRAMLISTING">int ms_iis5_hack = 0;</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-int msiis5hack = 0; int msIis5Hack = 0;
-</pre>
+ int msiis5hack = 0; int msIis5Hack = 0;</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S11" id="S11">4.3.2. Function
Names</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Use all lowercase, and separate words via an underscore ('_'). Do
not start an identifier with an underscore. (ANSI C reserves these
for use by the compiler and system headers.) Do not use identifiers
which are reserved in ANSI C++. (E.g. template, class, true, false,
...). This is in case we ever decide to port Privoxy to C++.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-int load_some_file( struct client_state *csp )
-</pre>
+ int load_some_file(struct client_state *csp)</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-int loadsomefile( struct client_state *csp )
-int loadSomeFile( struct client_state *csp )
-</pre>
+ int loadsomefile(struct client_state *csp)
+int loadSomeFile(struct client_state *csp)</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S12" id="S12">4.3.3. Header file
prototypes</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Use a descriptive parameter name in the function prototype in
header files. Use the same parameter name in the header file that you
use in the c file.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-(.h) extern int load_aclfile( struct client_state *csp );
-(.c) int load_aclfile( struct client_state *csp )
-</pre>
+ (.h) extern int load_aclfile(struct client_state *csp);
+(.c) int load_aclfile(struct client_state *csp)</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-(.h) extern int load_aclfile( struct client_state * ); or
+ (.h) extern int load_aclfile(struct client_state *); or
(.h) extern int load_aclfile();
-(.c) int load_aclfile( struct client_state *csp )
-</pre>
+(.c) int load_aclfile(struct client_state *csp)</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S13" id="S13">4.3.4. Enumerations, and
#defines</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Use all capital letters, with underscores between words. Do not
start an identifier with an underscore. (ANSI C reserves these for
use by the compiler and system headers.)</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-(enumeration) : enum Boolean { FALSE, TRUE };
-(#define) : #define DEFAULT_SIZE 100;
-</pre>
+ (enumeration) : enum Boolean {FALSE, TRUE};
+(#define) : #define DEFAULT_SIZE 100;</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> We have a standard
- naming scheme for #defines that toggle a feature in the preprocessor:
- FEATURE_>, where > is a short (preferably 1 or 2 word)
- description.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> We
+ have a standard naming scheme for #defines that toggle a feature in
+ the preprocessor: FEATURE_>, where > is a short (preferably 1
+ or 2 word) description.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-#define FEATURE_FORCE 1
+ <pre class="PROGRAMLISTING">#define FEATURE_FORCE 1
#ifdef FEATURE_FORCE
#define FORCE_PREFIX blah
-#endif /* def FEATURE_FORCE */
-</pre>
+#endif /* def FEATURE_FORCE */</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S14" id="S14">4.3.5. Constants</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Spell common words out entirely (do not remove vowels).</p>
-
<p>Use only widely-known domain acronyms and abbreviations.
Capitalize all letters of an acronym.</p>
-
<p>Use underscore (_) to separate adjacent acronyms and
abbreviations. Never terminate a name with an underscore.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-#define USE_IMAGE_LIST 1
-</pre>
+ <pre class="PROGRAMLISTING">#define USE_IMAGE_LIST 1</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-#define USE_IMG_LST 1 or
+ <pre class="PROGRAMLISTING">#define USE_IMG_LST 1 or
#define _USE_IMAGE_LIST 1 or
#define USE_IMAGE_LIST_ 1 or
#define use_image_list 1 or
-#define UseImageList 1
-</pre>
+#define UseImageList 1</pre>
</td>
</tr>
</table>
</div>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S15" id="S15">4.4. Using Space</a></h2>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S16" id="S16">4.4.1. Put braces on a line
by themselves.</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>The brace needs to be on a line all by itself, not at the end of
the statement. Curly braces should line up with the construct that
they're associated with. This practice makes it easier to identify
the opening and closing braces for a block.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-if ( this == that )
+ <pre class="PROGRAMLISTING">if (this == that)
{
...
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <p>if ( this == that ) { ... }</p>
-
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <p>if (this == that) { ... }</p>
<p>or</p>
-
- <p>if ( this == that ) { ... }</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> In the special
- case that the if-statement is inside a loop, and it is trivial, i.e.
- it tests for a condition that is obvious from the purpose of the
- block, one-liners as above may optically preserve the loop structure
- and make it easier to read.</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span>
+ <p>if (this == that) { ... }</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> In the
+ special case that the if-statement is inside a loop, and it is
+ trivial, i.e. it tests for a condition that is obvious from the
+ purpose of the block, one-liners as above may optically preserve the
+ loop structure and make it easier to read.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
developer-discretion.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example exception:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example
+ exception:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-while ( more lines are read )
+ <pre class="PROGRAMLISTING">while (more lines are read)
{
/* Please document what is/is not a comment line here */
- if ( it's a comment ) continue;
+ if (it's a comment) continue;
- do_something( line );
-}
-</pre>
+ do_something(line);
+}</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S17" id="S17">4.4.2. ALL control
statements should have a block</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Using braces to make a block will make your code more readable and
less prone to error. All control statements should have a block
defined.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-if ( this == that )
+ <pre class="PROGRAMLISTING">if (this == that)
{
do_something();
do_something_else();
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <p>if ( this == that ) do_something(); do_something_else();</p>
-
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <p>if (this == that) do_something(); do_something_else();</p>
<p>or</p>
-
- <p>if ( this == that ) do_something();</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> The first example
- in "Instead of" will execute in a manner other than that which the
- developer desired (per indentation). Using code braces would have
- prevented this "feature". The "explanation" and "exception" from the
- point above also applies.</p>
+ <p>if (this == that) do_something();</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The
+ first example in "Instead of" will execute in a manner other than
+ that which the developer desired (per indentation). Using code braces
+ would have prevented this "feature". The "explanation" and
+ "exception" from the point above also applies.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S18" id="S18">4.4.3. Do not
belabor/blow-up boolean expressions</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-structure->flag = ( condition );
-</pre>
+ structure->flag = (condition);</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <p>if ( condition ) { structure->flag = 1; } else {
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <p>if (condition) { structure->flag = 1; } else {
structure->flag = 0; }</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> The former is
- readable and concise. The later is wordy and inefficient. Please
- assume that any developer new to the project has at least a "good"
- knowledge of C/C++. (Hope I do not offend by that last comment ...
- 8-)</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The
+ former is readable and concise. The later is wordy and inefficient.
+ Please assume that any developer new to the project has at least a
+ "good" knowledge of C/C++. (Hope I do not offend by that last comment
+ ... 8-)</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S19" id="S19">4.4.4. Use white space
freely because it is free</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Make it readable. The notable exception to using white space
freely is listed in the next guideline.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-int first_value = 0;
+ <pre class="PROGRAMLISTING">int first_value = 0;
int some_value = 0;
int another_value = 0;
-int this_variable = 0;
-
-if ( this_variable == this_variable )
-
-first_value = old_value + ( ( some_value - another_value ) - whatever )
-</pre>
+int this_variable = 0;</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S20" id="S20">4.4.5. Don't use white space
around structure operators</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>- structure pointer operator ( "->" ) - member operator ( "." )
- functions and parentheses</p>
-
<p>It is a general coding practice to put pointers, references, and
function parentheses next to names. With spaces, the connection
between the object and variable/function name is not as clear.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-a_struct->a_member;
+ <pre class="PROGRAMLISTING">a_struct->a_member;
a_struct.a_member;
-function_name();
-</pre>
+function_name();</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span> a_struct
- -> a_member; a_struct . a_member; function_name ();</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Instead of:</i></span>
+ a_struct -> a_member; a_struct . a_member; function_name ();</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S21" id="S21">4.4.6. Make the last brace
of a function stand out</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-int function1( ... )
+ <pre class="PROGRAMLISTING">int function1( ... )
{
...code...
- return( ret_code );
+ return(ret_code);
-} /* -END- function1 */
+} /* -END- function1 */
int function2( ... )
{
-} /* -END- function2 */
-</pre>
+} /* -END- function2 */</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
- <p>int function1( ... ) { ...code... return( ret_code ); } int
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
+ <p>int function1( ... ) { ...code... return(ret_code); } int
function2( ... ) { }</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> Use 1 blank line
- before the closing brace and 2 lines afterward. This makes the end of
- function standout to the most casual viewer. Although function
- comments help separate functions, this is still a good coding
- practice. In fact, I follow these rules when using blocks in "for",
- "while", "do" loops, and long if {} statements too. After all
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> Use 1
+ blank line before the closing brace and 2 lines afterward. This makes
+ the end of function standout to the most casual viewer. Although
+ function comments help separate functions, this is still a good
+ coding practice. In fact, I follow these rules when using blocks in
+ "for", "while", "do" loops, and long if {} statements too. After all
whitespace is free!</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
developer-discretion on the number of blank lines. Enforced is the
end of function comments.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S22" id="S22">4.4.7. Use 3 character
indentions</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>If some use 8 character TABs and some use 3 character TABs, the
code can look *very* ragged. So use 3 character indentions only. If
you like to use TABs, pass your code through a filter such as "expand
-t3" before checking in your code.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-static const char * const url_code_map[256] =
+ static const char * const url_code_map[256] =
{
NULL, ...
};
int function1( ... )
{
- if ( 1 )
+ if (1)
{
- return( ALWAYS_TRUE );
+ return ALWAYS_TRUE;
}
else
{
- return( HOW_DID_YOU_GET_HERE );
+ return HOW_DID_YOU_GET_HERE;
}
- return( NEVER_GETS_HERE );
+ return NEVER_GETS_HERE;
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
</div>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S23" id="S23">4.5. Initializing</a></h2>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S24" id="S24">4.5.1. Initialize all
variables</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Do not assume that the variables declared will not be used until
after they have been assigned a value somewhere else in the code.
Remove the chance of accidentally using an unassigned variable.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-short a_short = 0;
+ <pre class="PROGRAMLISTING">short a_short = 0;
float a_float = 0;
-struct *ptr = NULL;
-</pre>
+struct *ptr = NULL;</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> It is much easier
- to debug a SIGSEGV if the message says you are trying to access
- memory address 00000000 and not 129FA012; or array_ptr[20] causes a
- SIGSEV vs. array_ptr[0].</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> It is
+ much easier to debug a SIGSEGV if the message says you are trying to
+ access memory address 00000000 and not 129FA012; or array_ptr[20]
+ causes a SIGSEV vs. array_ptr[0].</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
developer-discretion if and only if the variable is assigned a value
"shortly after" declaration.</p>
</div>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S25" id="S25">4.6. Functions</a></h2>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S26" id="S26">4.6.1. Name functions that
return a boolean as a question.</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Value should be phrased as a question that would logically be
answered as a true or false statement</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-should_we_block_this();
+ <pre class="PROGRAMLISTING">should_we_block_this();
contains_an_image();
-is_web_page_blank();
-</pre>
+is_web_page_blank();</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S27" id="S27">4.6.2. Always specify a
return type for a function.</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>The default return for a function is an int. To avoid ambiguity,
create a return for a function when the return has a purpose, and
create a void return type if the function does not need to return
anything.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S28" id="S28">4.6.3. Minimize function
calls when iterating by using variables</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>It is easy to write the following code, and a clear argument can
be made that the code is easy to understand:</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-for ( size_t cnt = 0; cnt < block_list_length(); cnt++ )
+ for (size_t cnt = 0; cnt < block_list_length(); cnt++)
{
....
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> Unfortunately,
- this makes a function call for each and every iteration. This
- increases the overhead in the program, because the compiler has to
- look up the function each time, call it, and return a value.
- Depending on what occurs in the block_list_length() call, it might
- even be creating and destroying structures with each iteration, even
- though in each case it is comparing "cnt" to the same value, over and
- over. Remember too - even a call to block_list_length() is a function
- call, with the same overhead.</p>
-
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span>
+ Unfortunately, this makes a function call for each and every
+ iteration. This increases the overhead in the program, because the
+ compiler has to look up the function each time, call it, and return a
+ value. Depending on what occurs in the block_list_length() call, it
+ might even be creating and destroying structures with each iteration,
+ even though in each case it is comparing "cnt" to the same value,
+ over and over. Remember too - even a call to block_list_length() is a
+ function call, with the same overhead.</p>
<p>Instead of using a function call during the iterations, assign the
value to a variable, and evaluate using the variable.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-size_t len = block_list_length();
+ <pre class="PROGRAMLISTING">size_t len = block_list_length();
-for ( size_t cnt = 0; cnt < len; cnt++ )
+for (size_t cnt = 0; cnt < len; cnt++)
{
....
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Exceptions:</span> if the value
- of block_list_length() *may* change or could *potentially* change,
- then you must code the function call in the for/while loop.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span>
+ if the value of block_list_length() *may* change or could
+ *potentially* change, then you must code the function call in the
+ for/while loop.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S29" id="S29">4.6.4. Pass and Return by
Const Reference</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>This allows a developer to define a const pointer and call your
function. If your function does not have the const keyword, we may
not be able to use your function. Consider strcmp, if it were defined
- as: extern int strcmp( char *s1, char *s2 );</p>
-
- <p>I could then not use it to compare argv's in main: int main( int
- argc, const char *argv[] ) { strcmp( argv[0], "privoxy" ); }</p>
-
+ as: extern int strcmp(char *s1, char *s2);</p>
+ <p>I could then not use it to compare argv's in main: int main(int
+ argc, const char *argv[]) { strcmp(argv[0], "privoxy"); }</p>
<p>Both these pointers are *const*! If the c runtime library
maintainers do it, we should too.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S30" id="S30">4.6.5. Pass and Return by
Value</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Most structures cannot fit onto a normal stack entry (i.e. they
are not 4 bytes or less). Aka, a function declaration like: int
- load_aclfile( struct client_state csp )</p>
-
+ load_aclfile(struct client_state csp)</p>
<p>would not work. So, to be consistent, we should declare all
- prototypes with "pass by value": int load_aclfile( struct
- client_state *csp )</p>
+ prototypes with "pass by value": int load_aclfile(struct client_state
+ *csp)</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S31" id="S31">4.6.6. Names of include
files</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Your include statements should contain the file name without a
path. The path should be listed in the Makefile, using -I as
processor directive to search the indicated paths. An exception to
this would be for some proprietary software that utilizes a partial
path to distinguish their header files from system or other header
files.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-#include <iostream.h> /* This is not a local include */
-#include "config.h" /* This IS a local include */
-</pre>
+ #include <iostream.h> /* This is not a local include */
+#include "config.h" /* This IS a local include */</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Exception:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Exception:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-/* This is not a local include, but requires a path element. */
-#include <sys/fileName.h>
-</pre>
+ /* This is not a local include, but requires a path element. */
+#include <sys/fileName.h></pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> Please! do not add
- "-I." to the Makefile without a _very_ good reason. This duplicates
- the #include "file.h" behavior.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span>
+ Please! do not add "-I." to the Makefile without a _very_ good
+ reason. This duplicates the #include "file.h" behavior.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S32" id="S32">4.6.7. Provide multiple
inclusion protection</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Prevents compiler and linker errors resulting from redefinition of
items.</p>
-
<p>Wrap each header file with the following syntax to prevent
multiple inclusions of the file. Of course, replace PROJECT_H with
your file name, with "." Changed to "_", and make it uppercase.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-#ifndef PROJECT_H_INCLUDED
+ <pre class="PROGRAMLISTING">#ifndef PROJECT_H_INCLUDED
#define PROJECT_H_INCLUDED
...
-#endif /* ndef PROJECT_H_INCLUDED */
-</pre>
+#endif /* ndef PROJECT_H_INCLUDED */</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S33" id="S33">4.6.8. Use `extern "C"` when
appropriate</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>If our headers are included from C++, they must declare our
functions as `extern "C"`. This has no cost in C, but increases the
potential re-usability of our code.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-#ifdef __cplusplus
+ <pre class="PROGRAMLISTING">#ifdef __cplusplus
extern "C"
{
#endif /* def __cplusplus */
#ifdef __cplusplus
}
-#endif /* def __cplusplus */
-</pre>
+#endif /* def __cplusplus */</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S34" id="S34">4.6.9. Where Possible, Use
Forward Struct Declaration Instead of Includes</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Useful in headers that include pointers to other struct's.
Modifications to excess header files may cause needless compiles.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-/*********************************************************************
+ /*********************************************************************
* We're avoiding an include statement here!
*********************************************************************/
struct file_list;
-extern file_list *xyz;
-</pre>
+extern file_list *xyz;</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> If you declare
- "file_list xyz;" (without the pointer), then including the proper
- header file is necessary. If you only want to prototype a pointer,
- however, the header file is unnecessary.</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span> Use with
- discretion.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you
+ declare "file_list xyz;" (without the pointer), then including the
+ proper header file is necessary. If you only want to prototype a
+ pointer, however, the header file is unnecessary.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span> Use
+ with discretion.</p>
</div>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S35" id="S35">4.7. General Coding
Practices</a></h2>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S36" id="S36">4.7.1. Turn on
warnings</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation</i></span></p>
<p>Compiler warnings are meant to help you find bugs. You should turn
on as many as possible. With GCC, the switch is "-Wall". Try and fix
as many warnings as possible.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S37" id="S37">4.7.2. Provide a default
case for all switch statements</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>What you think is guaranteed is never really guaranteed. The value
that you don't think you need to check is the one that someday will
be passed. So, to protect yourself from the unknown, always have a
default step in a switch statement.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-switch( hash_string( cmd ) )
+ <pre class="PROGRAMLISTING">switch (hash_string(cmd))
{
- case hash_actions_file :
+ case hash_actions_file:
... code ...
break;
- case hash_confdir :
+ case hash_confdir:
... code ...
break;
- default :
+ default:
log_error( ... );
... anomaly code goes here ...
continue; / break; / exit( 1 ); / etc ...
-} /* end switch( hash_string( cmd ) ) */
-</pre>
+} /* end switch (hash_string(cmd)) */</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> If you already
- have a default condition, you are obviously exempt from this point.
- Of note, most of the WIN32 code calls `DefWindowProc' after the
- switch statement. This API call *should* be included in a default
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you
+ already have a default condition, you are obviously exempt from this
+ point. Of note, most of the WIN32 code calls `DefWindowProc' after
+ the switch statement. This API call *should* be included in a default
statement.</p>
-
- <p><span class="emphasis EMPHASIS c2">Another Note:</span> This is
- not so much a readability issue as a robust programming issue. The
- "anomaly code goes here" may be no more than a print to the STDERR
- stream (as in load_config). Or it may really be an abort
- condition.</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span> Programmer
- discretion is advised.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Another
+ Note:</i></span> This is not so much a readability issue as a robust
+ programming issue. The "anomaly code goes here" may be no more than a
+ print to the STDERR stream (as in load_config). Or it may really be
+ an abort condition.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
+ Programmer discretion is advised.</p>
</div>
-
<div class="SECT3">
<h3 class="SECT3"><a name="S38" id="S38">4.7.3. Try to avoid falling
through cases in a switch statement.</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>In general, you will want to have a 'break' statement within each
'case' of a switch statement. This allows for the code to be more
readable and understandable, and furthermore can prevent unwanted
surprises if someone else later gets creative and moves the code
around.</p>
-
<p>The language allows you to plan the fall through from one case
statement to another simply by omitting the break statement within
the case statement. This feature does have benefits, but should only
be used in rare cases. In general, use a break statement for each
case statement.</p>
-
<p>If you choose to allow fall through, you should comment both the
fact of the fall through and reason why you felt it was
necessary.</p>
</div>
-
- <div class="SECT3">
- <h3 class="SECT3"><a name="S39" id="S39">4.7.4. Use 'long' or 'short'
- Instead of 'int'</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
- <p>On 32-bit platforms, int usually has the range of long. On 16-bit
- platforms, int has the range of short.</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span> open-to-debate.
- In the case of most FSF projects (including X/GNU-Emacs), there are
- typedefs to int4, int8, int16, (or equivalence ... I forget the exact
- typedefs now). Should we add these to IJB now that we have a
- "configure" script?</p>
- </div>
-
<div class="SECT3">
- <h3 class="SECT3"><a name="S40" id="S40">4.7.5. Don't mix size_t and
+ <h3 class="SECT3"><a name="S40" id="S40">4.7.4. Don't mix size_t and
other types</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>The type of size_t varies across platforms. Do not make
assumptions about whether it is signed or unsigned, or about how long
it is. Do not compare a size_t against another variable of a
different type (or even against a constant) without casting one of
the values.</p>
</div>
-
<div class="SECT3">
- <h3 class="SECT3"><a name="S41" id="S41">4.7.6. Declare each variable
+ <h3 class="SECT3"><a name="S41" id="S41">4.7.5. Declare each variable
and struct on its own line.</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>It can be tempting to declare a series of variables all on one
line. Don't.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-long a = 0;
+ <pre class="PROGRAMLISTING">long a = 0;
long b = 0;
-long c = 0;
-</pre>
+long c = 0;</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Instead of:</span></p>
-
+ <p><span class="emphasis"><i class="EMPHASIS">Instead
+ of:</i></span></p>
<p>long a, b, c;</p>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span> - there is
- more room for comments on the individual variables - easier to add
- new variables without messing up the original ones - when searching
- on a variable to find its type, there is less clutter to "visually"
- eliminate</p>
-
- <p><span class="emphasis EMPHASIS c2">Exceptions:</span> when you
- want to declare a bunch of loop variables or other trivial variables;
- feel free to declare them on one line. You should, although, provide
- a good comment on their functions.</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span>
+ <p><span class="emphasis"><i class="EMPHASIS">Explanation:</i></span>
+ - there is more room for comments on the individual variables -
+ easier to add new variables without messing up the original ones -
+ when searching on a variable to find its type, there is less clutter
+ to "visually" eliminate</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Exceptions:</i></span>
+ when you want to declare a bunch of loop variables or other trivial
+ variables; feel free to declare them on one line. You should,
+ although, provide a good comment on their functions.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
developer-discretion.</p>
</div>
-
<div class="SECT3">
- <h3 class="SECT3"><a name="S42" id="S42">4.7.7. Use malloc/zalloc
+ <h3 class="SECT3"><a name="S42" id="S42">4.7.6. Use malloc/zalloc
sparingly</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>Create a local struct (on the stack) if the variable will live and
die within the context of one function call.</p>
-
<p>Only "malloc" a struct (on the heap) if the variable's life will
extend beyond the context of one function call.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-If a function creates a struct and stores a pointer to it in a
-list, then it should definitely be allocated via `malloc'.
-</pre>
+ If a function creates a struct and stores a pointer to it in a
+list, then it should definitely be allocated via `malloc'.</pre>
</td>
</tr>
</table>
</div>
-
<div class="SECT3">
- <h3 class="SECT3"><a name="S43" id="S43">4.7.8. The Programmer Who
+ <h3 class="SECT3"><a name="S43" id="S43">4.7.7. The Programmer Who
Uses 'malloc' is Responsible for Ensuring 'free'</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>If you have to "malloc" an instance, you are responsible for
insuring that the instance is `free'd, even if the deallocation event
falls within some other programmer's code. You are also responsible
late). This is known as "low-coupling" and is a "good thing (tm)".
You may need to offer a free/unload/destructor type function to
accommodate this.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-int load_re_filterfile( struct client_state *csp ) { ... }
-static void unload_re_filterfile( void *f ) { ... }
-</pre>
+ int load_re_filterfile(struct client_state *csp) { ... }
+static void unload_re_filterfile(void *f) { ... }</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Exceptions:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Exceptions:</i></span></p>
<p>The developer cannot be expected to provide `free'ing functions
for C run-time library functions ... such as `strdup'.</p>
-
- <p><span class="emphasis EMPHASIS c2">Status:</span>
+ <p><span class="emphasis"><i class="EMPHASIS">Status:</i></span>
developer-discretion. The "main" use of this standard is for
allocating and freeing data structures (complex or nested).</p>
</div>
-
<div class="SECT3">
- <h3 class="SECT3"><a name="S44" id="S44">4.7.9. Add loaders to the
+ <h3 class="SECT3"><a name="S44" id="S44">4.7.8. Add loaders to the
`file_list' structure and in order</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>I have ordered all of the "blocker" file code to be in alpha
order. It is easier to add/read new blockers when you expect a
certain order.</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> It may appear that
- the alpha order is broken in places by POPUP tests coming before PCRS
- tests. But since POPUPs can also be referred to as KILLPOPUPs, it is
- clear that it should come first.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> It may
+ appear that the alpha order is broken in places by POPUP tests coming
+ before PCRS tests. But since POPUPs can also be referred to as
+ KILLPOPUPs, it is clear that it should come first.</p>
</div>
-
<div class="SECT3">
- <h3 class="SECT3"><a name="S45" id="S45">4.7.10. "Uncertain" new code
- and/or changes to existing code, use FIXME or XXX</a></h3>
-
- <p><span class="emphasis EMPHASIS c2">Explanation:</span></p>
-
+ <h3 class="SECT3"><a name="S45" id="S45">4.7.9. "Uncertain" new code
+ and/or changes to existing code, use XXX</a></h3>
+ <p><span class="emphasis"><i class=
+ "EMPHASIS">Explanation:</i></span></p>
<p>If you have enough confidence in new code or confidence in your
changes, but are not *quite* sure of the repercussions, add this:</p>
-
- <p>/* FIXME: this code has a logic error on platform XYZ, *
- attempting to fix */ #ifdef PLATFORM ...changed code here...
- #endif</p>
-
+ <p>/* XXX: this code has a logic error on platform XYZ, * attempting
+ to fix */ #ifdef PLATFORM ...changed code here... #endif</p>
<p>or:</p>
-
- <p>/* FIXME: I think the original author really meant this... */
+ <p>/* XXX: I think the original author really meant this... */
...changed code here...</p>
-
<p>or:</p>
-
- <p>/* FIXME: new code that *may* break something else... */ ...new
- code here...</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> If you make it
- clear that this may or may not be a "good thing (tm)", it will be
- easier to identify and include in the project (or conversely exclude
- from the project).</p>
+ <p>/* XXX: new code that *may* break something else... */ ...new code
+ here...</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If you
+ make it clear that this may or may not be a "good thing (tm)", it
+ will be easier to identify and include in the project (or conversely
+ exclude from the project).</p>
</div>
</div>
-
<div class="SECT2">
<h2 class="SECT2"><a name="S46" id="S46">4.8. Addendum: Template for
files and function comment blocks:</a></h2>
-
- <p><span class="emphasis EMPHASIS c2">Example for file
- comments:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example for file
+ comments:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-const char FILENAME_rcs[] = "$Id$";
+ const char FILENAME_rcs[] = "$I<!-- Break CVS Substitution -->d$";
/*********************************************************************
*
- * File : $Source$
+ * File : $S<!-- Break CVS Substitution -->ource$
*
* Purpose : (Fill me in with a good description!)
*
* Copyright : Written by and Copyright (C) 2001-2009
- * the Privoxy team. http://www.privoxy.org/
+ * the Privoxy team. https://www.privoxy.org/
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General
...necessary include files for us to do our work...
-const char FILENAME_h_rcs[] = FILENAME_H_VERSION;
-</pre>
+const char FILENAME_h_rcs[] = FILENAME_H_VERSION;</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> This declares the
- rcs variables that should be added to the "show-proxy-args" page. If
- this is a brand new creation by you, you are free to change the
- "Copyright" section to represent the rights you wish to maintain.</p>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> The formfeed
- character that is present right after the comment flower box is handy
- for (X|GNU)Emacs users to skip the verbiage and get to the heart of the
- code (via `forward-page' and `backward-page'). Please include it if you
- can.</p>
-
- <p><span class="emphasis EMPHASIS c2">Example for file header
- comments:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> This
+ declares the rcs variables that should be added to the
+ "show-proxy-args" page. If this is a brand new creation by you, you are
+ free to change the "Copyright" section to represent the rights you wish
+ to maintain.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> The
+ formfeed character that is present right after the comment flower box
+ is handy for (X|GNU)Emacs users to skip the verbiage and get to the
+ heart of the code (via `forward-page' and `backward-page'). Please
+ include it if you can.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Example for file header
+ comments:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
- <pre class="PROGRAMLISTING">
-#ifndef _FILENAME_H
+ <pre class="PROGRAMLISTING">#ifndef _FILENAME_H
#define _FILENAME_H
-#define FILENAME_H_VERSION "$Id$"
+#define FILENAME_H_VERSION "$I<!-- Break CVS Substitution -->d$"
/*********************************************************************
*
- * File : $Source$
+ * File : $S<!-- Break CVS Substitution -->ource$
*
* Purpose : (Fill me in with a good description!)
*
* Copyright : Written by and Copyright (C) 2001-2009
- * the Privoxy team. http://www.privoxy.org/
+ * the Privoxy team. https://www.privoxy.org/
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General
Local Variables:
tab-width: 3
end:
-*/
-</pre>
+*/</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Example for function
- comments:</span></p>
-
- <table class="c3" border="0" width="100%">
+ <p><span class="emphasis"><i class="EMPHASIS">Example for function
+ comments:</i></span></p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
-/*********************************************************************
+ /*********************************************************************
*
* Function : FUNCTION_NAME
*
* Returns : 0 => Ok, everything else is an error.
*
*********************************************************************/
-int FUNCTION_NAME( void *param1, const char *x )
+int FUNCTION_NAME(void *param1, const char *x)
{
...
- return( 0 );
+ return 0;
-}
-</pre>
+}</pre>
</td>
</tr>
</table>
-
- <p><span class="emphasis EMPHASIS c2">Note:</span> If we all follow
- this practice, we should be able to parse our code to create a
- "self-documenting" web page.</p>
+ <p><span class="emphasis"><i class="EMPHASIS">Note:</i></span> If we
+ all follow this practice, we should be able to parse our code to create
+ a "self-documenting" web page.</p>
</div>
</div>
-
<div class="NAVFOOTER">
- <hr class="c1" width="100%">
-
+ <hr align="left" width="100%">
<table summary="Footer navigation table" width="100%" border="0"
cellpadding="0" cellspacing="0">
<tr>
<td width="33%" align="left" valign="top"><a href=
"documentation.html" accesskey="P">Prev</a></td>
-
<td width="34%" align="center" valign="top"><a href="index.html"
accesskey="H">Home</a></td>
-
<td width="33%" align="right" valign="top"><a href="testing.html"
accesskey="N">Next</a></td>
</tr>
-
<tr>
<td width="33%" align="left" valign="top">Documentation
Guidelines</td>
-
<td width="34%" align="center" valign="top"> </td>
-
<td width="33%" align="right" valign="top">Testing Guidelines</td>
</tr>
</table>
projects / privoxy.git / blobdiff