-<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
-<html>
- <head>
- <title>JunkBuster Coding Standards</title>
- </head>
-
- <body>
- <h1><a name="top"></a>JunkBuster Coding Standards</h1>
-
- <h1><a name="contents"></a>Contents</h1>
-
- <h3><a href="#s1">Introduction</a></h3>
-
- <h3><a href="#s2">Using Comments</a></h3>
-
- <ul>
- <li><a href="#s3">Comment, Comment, Comment</a></li>
-
- <li><a href="#s4">Use blocks for comments</a></li>
-
- <li><a href="#s5">Keep Comments on their own line</a></li>
-
- <li><a href="#s6">Comment each logical step</a></li>
-
- <li><a href="#s7">Comment All Functions Thoroughly</a></li>
-
- <li><a href="#s8">Comment at the end of braces if the content
- is more than one screen length</a></li>
- </ul>
-
- <h3><a href="#s9">Naming Conventions</a></h3>
-
- <ul>
- <li><a href="#s10">Variable Names</a></li>
-
- <li><a href="#s11">Function Names</a></li>
-
- <li><a href="#s12">Header file prototypes</a></li>
-
- <li><a href="#s13">Enumerations, and #defines</a></li>
-
- <li><a href="#s14">Constants</a></li>
- </ul>
-
- <h3><a href="#s15">Using Space</a></h3>
-
- <ul>
- <li><a href="#s16">Put braces on a line by
- themselves.</a></li>
-
- <li><a href="#s17">ALL control statements should have a
- block</a></li>
-
- <li><a href="#s18">Do not belabor/blow-up boolean
- expressions</a></li>
-
- <li><a href="#s19">Use white space freely because it is
- free</a></li>
-
- <li><a href="#s20">Don't use white space around structure
- operators</a></li>
-
- <li><a href="#s21">Make the last brace of a function stand
- out</a></li>
-
- <li><a href="#s22">Use 3 character indentions</a></li>
- </ul>
-
- <h3><a href="#s23">Initializing</a></h3>
-
- <ul>
- <li><a href="#s24">Initialize all variables</a></li>
- </ul>
-
- <h3><a href="#s25">Functions</a></h3>
-
- <ul>
- <li><a href="#s26">Name functions that return a boolean as a
- question.</a></li>
-
- <li><a href="#s27">Always specify a return type for a
- function.</a></li>
-
- <li><a href="#s28">Minimize function calls when iterating by
- using variables</a></li>
-
- <li><a href="#s29">Pass and Return by Const
- Reference</a></li>
-
- <li><a href="#s30">Pass and Return by Value</a></li>
-
- <li><a href="#s31">Use #include <fileName> and #include
- "fileName" for locals</a></li>
-
- <li><a href="#s32">Provide multiple inclusion
- protection</a></li>
-
- <li><a href="#s33">Use `extern "C"` when appropriate</a></li>
-
- <li><a href="#s34">Where Possible, Use Forward Struct
- Declaration Instead of Includes</a></li>
- </ul>
-
- <h3><a href="#s35">General Coding Practices</a></h3>
-
- <ul>
- <li><a href="#s36">Turn on warnings</a></li>
-
- <li><a href="#s37">Provide a default case for all switch
- statements</a></li>
-
- <li><a href="#s38">Try to avoid falling through cases in a
- switch statement.</a></li>
-
- <li><a href="#s39">Use 'long' or 'short' Instead of
- 'int'</a></li>
-
- <li><a href="#s40">Don't mix size_t and other types</a></li>
-
- <li><a href="#s41">Declare each variable and struct on its
- own line.</a></li>
-
- <li><a href="#s42">Use malloc/zalloc sparingly</a></li>
-
- <li><a href="#s43">The Programmer Who Uses 'malloc' is
- Responsible for Ensuring 'free'</a></li>
-
- <li><a href="#s44">Add loaders to the `file_list' structure
- and in order</a></li>
-
- <li><a href="#s45">"Uncertain" new code and/or changes to
- exitinst code, use FIXME</a></li>
- </ul>
-
- <h3><a href="#s46">Addendum: Template for files and function
- comment blocks:</a></h3>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s1"></a>Introduction</h1>
-
- <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 Junkbusters" 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>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s2"></a>Using Comments</h1>
-
- <p> </p>
-
- <h2><a name="s3"></a>Comment, Comment, Comment</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Comment as much as possible without commenting the obvious.
- For example do not comment "aVariable is equal to bVariable".
- Instead explain why aVariable should be equal to the bVariable.
- 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>
-
- <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><b>Example:</b></p>
-<pre>
-/* if page size greater than 1k ... */
-if ( PageLength() > 1024 )
-{
- ... "block" the page up ...
-}
-
-/* if page size is small, send it in blocks */
-if ( PageLength() > 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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s4"></a>Use blocks for comments</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-/*********************************************************************
- * This will stand out clearly in your code!
- *********************************************************************/
-if ( thisVariable == thatVariable )
-{
- DoSomethingVeryImportant();
-}
-
-
-/* unfortunately, this may not */
-if ( thisVariable == thatVariable )
-{
- DoSomethingVeryImportant();
-}
-
-
-if ( thisVariable == thatVariable ) /* this may not either */
-{
- DoSomethingVeryImportant();
-}
-
-</pre>
-
- <p><b>Exception:</b></p>
-
- <p>If you are trying to add a small logic comment and do not
- wish to "disrubt" the flow of the code, feel free to use a 1
- line comment which is NOT on the same line as the code.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s5"></a>Keep Comments on their own line</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-/*********************************************************************
- * This will stand out clearly in your code,
- * But the second example won't.
- *********************************************************************/
-if ( thisVariable == thatVariable )
-{
- DoSomethingVeryImportant();
-}
-
-if ( thisVariable == thatVariable ) /*can you see me?*/
-{
- DoSomethingVeryImportant(); /*not easily*/
-}
-
-
-/*********************************************************************
- * But, the encouraged exceptions:
- *********************************************************************/
-int urls_read = 0; /* # of urls read + rejected */
-int urls_rejected = 0; /* # of urls rejected */
-
-if ( 1 == X )
-{
- DoSomethingVeryImportant();
-}
-
-
-short DoSomethingVeryImportant(
- short firstParam, /* represents something */
- short nextParam /* represents something else */ )
-{
- ...code here...
-
-} /* -END- DoSomethingVeryImportant */
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s6"></a>Comment each logical step</h2>
-
- <p><b>Explanation:</b></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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s7"></a>Comment All Functions Thoroughly</h2>
-
- <p><b>Explanation:</b></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 have to read through the code to determine if
- a given function is safe for a desired use. The proper
- information thoroughly presented at the introduction of a
- function not only saves time for subsequent maintenance or
- debugging, it more importantly aids in code reuse by allowing a
- user to determine the safety and applicability of any function
- for the problem at hand. As a result of such benefits, all
- functions should contain the information presented in the
- addendum section of this document.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s8"></a>Comment at the end of braces if the
- content is more than one screen length</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-if ( 1 == X )
-{
- DoSomethingVeryImportant();
- ...some long list of commands...
-} /* -END- if x is 1 */
-
-or:
-
-if ( 1 == X )
-{
- DoSomethingVeryImportant();
- ...some long list of commands...
-} /* -END- if ( 1 == X ) */
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s9"></a>Naming Conventions</h1>
-
- <p> </p>
-
- <h2><a name="s10"></a>Variable Names</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Use all lowercase, and seperate 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 JunkBuster to C++.</p>
-
- <p><b>Example:</b></p>
-<pre>
-int ms_iis5_hack = 0;
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>int msiis5hack = 0; int msIis5Hack = 0;</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s11"></a>Function Names</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Use all lowercase, and seperate 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 JunkBuster to C++.</p>
-
- <p><b>Example:</b></p>
-<pre>
-int load_some_file( struct client_state *csp )
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>int loadsomefile( struct client_state *csp ) int
- loadSomeFile( struct client_state *csp )</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s12"></a>Header file prototypes</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-(.h) extern int load_aclfile( struct client_state *csp );
-(.c) int load_aclfile( struct client_state *csp )
-
-</pre>
-
- <p><b>Instead of:</b> (.h) extern int load_aclfile( struct
- client_state * ); or (.h) extern int load_aclfile(); (.c) int
- load_aclfile( struct client_state *csp )</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s13"></a>Enumerations, and #defines</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-(enumeration) : enum Boolean { FALSE, TRUE };
-(#define) : #define DEFAULT_SIZE 100;
-
-</pre>
-
- <p><b>Note:</b> We have a standard naming scheme for #defines
- that toggle a feature in the preprocessor: FEATURE_xxx, where
- xxx is a short (preferably 1 or 2 word) description.</p>
-
- <p><b>Example:</b></p>
-<pre>
-#define FEATURE_FORCE 1
-
-#ifdef FEATURE_FORCE
-#define FORCE_PREFIX blah
-#endif /* def FEATURE_FORCE */
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s14"></a>Constants</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-#define USE_IMAGE_LIST 1
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>#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</p>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s15"></a>Using Space</h1>
-
- <p> </p>
-
- <h2><a name="s16"></a>Put braces on a line by themselves.</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-if ( this == that )
-{
- ...
-}
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>if ( this == that ) { ... }</p>
-
- <p>or</p>
-
- <p>if ( this == that ) { ... }</p>
-
- <p><b>Note:</b> In the special case that the if-statement is
- inside a loop, and it is trivial, i.e. it tests for a
- condidtion 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><b>Status:</b> developer-discrection.</p>
-
- <p><b>Example exception:</b></p>
-<pre>
-while ( more lines are read )
-{
- /* Please document what is/is not a comment line here */
- if ( it's a comment ) continue;
-
- do_something( line );
-}
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s17"></a>ALL control statements should have a
- block</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-if ( this == that )
-{
- DoSomething();
- DoSomethingElse();
-}
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>if ( this == that ) DoSomething(); DoSomethingElse();</p>
-
- <p>or</p>
-
- <p>if ( this == that ) DoSomething();</p>
-
- <p><b>Note:</b> 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> </p>
-
- <p> </p>
-
- <h2><a name="s18"></a>Do not belabor/blow-up boolean
- expressions</h2>
-
- <p><b>Example:</b></p>
-<pre>
-structure->flag = ( condition );
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>if ( condition ) { structure->flag = 1; } else {
- structure->flag = 0; }</p>
-
- <p><b>Note:</b> The former is readable and consice. 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> </p>
-
- <p> </p>
-
- <h2><a name="s19"></a>Use white space freely because it is
- free</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Make it readable. The notable exception to using white space
- freely is listed in the next guideline.</p>
-
- <p><b>Example:</b></p>
-<pre>
-int firstValue = 0;
-int someValue = 0;
-int anotherValue = 0;
-int thisVariable = 0;
-
-if ( thisVariable == thatVariable )
-
-firstValue = oldValue + ( ( someValue - anotherValue ) - whatever )
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s20"></a>Don't use white space around structure
- operators</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-aStruct->aMember;
-aStruct.aMember;
-FunctionName();
-
-</pre>
-
- <p><b>Instead of:</b> aStruct -> aMember; aStruct . aMember;
- FunctionName ();</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s21"></a>Make the last brace of a function stand
- out</h2>
-
- <p><b>Example:</b></p>
-<pre>
-int function1( ... )
-{
- ...code...
- return( retCode );
-
-} /* -END- function1 */
-
-
-int function2( ... )
-{
-} /* -END- function2 */
-
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>int function1( ... ) { ...code... return( retCode ); } int
- function2( ... ) { }</p>
-
- <p><b>Note:</b> Use 1 blank line before the closing brace and 2
- lines afterwards. This makes the end of function standout to
- the most casual viewer. Although function comments help
- seperate 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><b>Status:</b> developer-discrection on the number of blank
- lines. Enforced is the end of function comments.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s22"></a>Use 3 character indentions</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-static const char * const url_code_map[256] =
-{
- NULL, ...
-};
-
-
-int function1( ... )
-{
- if ( 1 )
- {
- return( ALWAYS_TRUE );
- }
- else
- {
- return( HOW_DID_YOU_GET_HERE );
- }
-
- return( NEVER_GETS_HERE );
-
-}
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s23"></a>Initializing</h1>
-
- <p> </p>
-
- <h2><a name="s24"></a>Initialize all variables</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-short anShort = 0;
-float aFloat = 0;
-struct *ptr = NULL;
-
-</pre>
-
- <p><b>Note:</b> It is much easier to debug a SIGSEGV if the
- message says you are trying to access memory address 00000000
- and not 129FA012; or arrayPtr[20] causes a SIGSEV vs.
- arrayPtr[0].</p>
-
- <p><b>Status:</b> developer-discrection if and only if the
- variable is assigned a value "shortly after" declaration.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s25"></a>Functions</h1>
-
- <p> </p>
-
- <h2><a name="s26"></a>Name functions that return a boolean as a
- question.</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Value should be phrased as a question that would logically
- be answered as a true or false statement</p>
-
- <p><b>Example:</b></p>
-<pre>
-ShouldWeBlockThis();
-ContainsAnImage();
-IsWebPageBlank();
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s27"></a>Always specify a return type for a
- function.</h2>
-
- <p><b>Explanation:</b></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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s28"></a>Minimize function calls when iterating by
- using variables</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-for ( size_t cnt = 0; cnt < blockListLength(); cnt ++ )
-{
- ....
-}
-
-</pre>
-
- <p><b>Note:</b> 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 blockListLength() 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 blockListLength() 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><b>Example:</b></p>
-<pre>
-size_t len = blockListLength();
-
-for ( size_t cnt = 0; cnt < len; cnt ++ )
-{
- ....
-}
-
-</pre>
-
- <p><b>Exceptions:</b> if the value of blockListLength() *may*
- change or could *potentially* change, then you must code the
- function call in the for/while loop.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s29"></a>Pass and Return by Const Reference</h2>
-
- <p><b>Explanation:</b></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], "junkbusters"
- ); }</p>
-
- <p>Both these pointers are *const*! If the c runtime library
- maintainers do it, we should too.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s30"></a>Pass and Return by Value</h2>
-
- <p><b>Explanation:</b></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>
-
- <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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s31"></a>Use #include <fileName> and
- #include "fileName" for locals</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-#include <iostream.h> /* This is not a local include */
-#include "config.h" /* This IS a local include */
-
-</pre>
-
- <p><b>Exception:</b></p>
-
- <p>/* This is not a local include, but requires a path element.
- */ #include <sys/fileName.h></p>
-
- <p><b>Note:</b> Please! do not add "-I." to the Makefile
- without a _very_ good reason. This duplicates the #include
- "file.h" behaviour.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s32"></a>Provide multiple inclusion
- protection</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-#ifndef PROJECT_H_INCLUDED
-#define PROJECT_H_INCLUDED
- ...
-#endif /* ndef PROJECT_H_INCLUDED */
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s33"></a>Use `extern "C"` when appropriate</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-#ifdef __cplusplus
-extern "C"
-{
-#endif /* def __cplusplus */
-
-... function definitions here ...
-
-#ifdef __cplusplus
-}
-#endif /* def __cplusplus */
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s34"></a>Where Possible, Use Forward Struct
- Declaration Instead of Includes</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Useful in headers that include pointers to other struct's.
- Modifications to excess header files may cause needless
- compiles.</p>
-
- <p><b>Example:</b></p>
-<pre>
-/*********************************************************************
- * We're avoiding an include statement here!
- *********************************************************************/
-struct file_list;
-extern file_list *xyz;
-
-</pre>
-
- <p><b>Note:</b> 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 unneccessary.</p>
-
- <p><b>Status:</b> Use with discrection.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s35"></a>General Coding Practices</h1>
-
- <p> </p>
-
- <h2><a name="s36"></a>Turn on warnings</h2>
-
- <p><b>Explanation</b></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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s37"></a>Provide a default case for all switch
- statements</h2>
-
- <p><b>Explanation:</b></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><b>Example:</b></p>
-<pre>
-switch( hash_string( cmd ) )
-{
- case hash_actions_file :
- ... code ...
- break;
-
- case hash_confdir :
- ... code ...
- break;
-
- default :
- log_error( ... );
- ... anomly code goes here ...
- continue; / break; / exit( 1 ); / etc ...
-
-} /* end switch( hash_string( cmd ) ) */
-
-</pre>
-
- <p><b>Note:</b> 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><b>Another Note:</b> This is not so much a readability issue
- as a robust programming issue. The "anomly code goes here" may
- be no more than a print to the STDERR stream (as in
- load_config). Or it may really be an ABEND condition.</p>
-
- <p><b>Status:</b> Programmer discretion is advised.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s38"></a>Try to avoid falling through cases in a
- switch statement.</h2>
-
- <p><b>Explanation:</b></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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s39"></a>Use 'long' or 'short' Instead of
- 'int'</h2>
-
- <p><b>Explanation:</b></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><b>Status:</b> 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>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s40"></a>Don't mix size_t and other types</h2>
-
- <p><b>Explanation:</b></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. Try to avoid using size_t if
- you can.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s41"></a>Declare each variable and struct on its
- own line.</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>It can be tempting to declare a series of variables all on
- one line. Don't.</p>
-
- <p><b>Example:</b></p>
-<pre>
-long a = 0;
-long b = 0;
-long c = 0;
-
-</pre>
-
- <p><b>Instead of:</b></p>
-
- <p>long a, b, c;</p>
-
- <p><b>Explanation:</b> - 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><b>Exceptions:</b> when you want to declare a bunch of loop
- variables or other trivial variables; feel free to declare them
- on 1 line. You should, although, provide a good comment on
- their functions.</p>
-
- <p><b>Status:</b> developer-discrection.</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s42"></a>Use malloc/zalloc sparingly</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>Create a local stuct (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><b>Example:</b></p>
-<pre>
-If a function creates a struct and stores a pointer to it in a
-list, then it should definately be allocated via `malloc'.
-
-
-</pre>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s43"></a>The Programmer Who Uses 'malloc' is
- Responsible for Ensuring 'free'</h2>
-
- <p><b>Explanation:</b></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 for ensuring that deletion is timely (i.e. not too
- soon, not too late). This is known as "low-coupling" and is a
- "good thing (tm)". You may need to offer a
- free/unload/destuctor type function to accomodate this.</p>
-
- <p><b>Example:</b></p>
-<pre>
-int load_re_filterfile( struct client_state *csp ) { ... }
-static void unload_re_filterfile( void *f ) { ... }
-
-</pre>
-
- <p><b>Exceptions:</b></p>
-
- <p>The developer cannot be expected to provide `free'ing
- functions for C run-time library functions ... such as
- `strdup'.</p>
-
- <p><b>Status:</b> developer-discrection. The "main" use of this
- standard is for allocating and freeing data structures (complex
- or nested).</p>
-
- <p> </p>
-
- <p> </p>
-
- <h2><a name="s44"></a>Add loaders to the `file_list' structure
- and in order</h2>
-
- <p><b>Explanation:</b></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><b>Note:</b> 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> </p>
-
- <p> </p>
-
- <h2><a name="s45"></a>"Uncertain" new code and/or changes to
- exitinst code, use FIXME</h2>
-
- <p><b>Explanation:</b></p>
-
- <p>If you have enough confidence in new code or confidence in
- your changes, but are not *quite* sure of the reprocussions,
- add this:</p>
-
- <p>/* FIXME: this code has a logic error on platform XYZ, *
- attempthing to fix */ #ifdef PLATFORM ...changed code here...
- #endif</p>
-
- <p>or:</p>
-
- <p>/* FIXME: 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><b>Note:</b> 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 conversly exclude from the
- project).</p>
-
- <p> </p>
-
- <p> </p>
-
- <h1><a name="s46"></a>Addendum: Template for files and function
- comment blocks:</h1>
-
- <p><b>Example for file comments:</b></p>
-<pre>
-const char FILENAME_rcs[] = "$Id: STANDARDS.txt,v 1.5 2001/09/10 18:37:48 jongfoster Exp $";
-/*********************************************************************
- *
- * File : $S<!-- Break CVS Substitution -->ource$
- *
- * Purpose : (Fill me in with a good description!)
- *
- * Copyright : Written by and Copyright (C) 2001 the SourceForge
- * IJBSWA team. http://ijbswa.sourceforge.net
- *
- * Based on the Internet Junkbuster originally written
- * by and Copyright (C) 1997 Anonymous Coders and
- * Junkbusters Corporation. http://www.junkbusters.com
- *
- * This program is free software; you can redistribute it
- * and/or modify it under the terms of the GNU General
- * Public License as published by the Free Software
- * Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will
- * be useful, but WITHOUT ANY WARRANTY; without even the
- * implied warranty of MERCHANTABILITY or FITNESS FOR A
- * PARTICULAR PURPOSE. See the GNU General Public
- * License for more details.
- *
- * The GNU General Public License should be included with
- * this file. If not, you can view it at
- * http://www.gnu.org/copyleft/gpl.html
- * or write to the Free Software Foundation, Inc., 59
- * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Revisions :
- * $L<!-- Break CVS Substitution -->og$
- *
- *********************************************************************/
-
-
-#include "config.h"
-
- ...necessary include files for us to do our work...
-
-const char FILENAME_h_rcs[] = FILENAME_H_VERSION;
-
-
-</pre>
-
- <p><b>Note:</b> 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><b>Note:</b> The formfeed character that is present right
- after the comment flower box is handy for (X|GNU)Emacs users to
- skip the verbige and get to the heart of the code (via
- `forward-page' and `backward-page'). Please include it if you
- can.</p>
-
- <p><b>Example for file header comments:</b></p>
-<pre>
-#ifndef _FILENAME_H
-#define _FILENAME_H
-#define FILENAME_H_VERSION "$Id: STANDARDS.txt,v 1.5 2001/09/10 18:37:48 jongfoster Exp $"
-/*********************************************************************
- *
- * File : $S<!-- Break CVS Substitution -->ource$
- *
- * Purpose : (Fill me in with a good description!)
- *
- * Copyright : Written by and Copyright (C) 2001 the SourceForge
- * IJBSWA team. http://ijbswa.sourceforge.net
- *
- * Based on the Internet Junkbuster originally written
- * by and Copyright (C) 1997 Anonymous Coders and
- * Junkbusters Corporation. http://www.junkbusters.com
- *
- * This program is free software; you can redistribute it
- * and/or modify it under the terms of the GNU General
- * Public License as published by the Free Software
- * Foundation; either version 2 of the License, or (at
- * your option) any later version.
- *
- * This program is distributed in the hope that it will
- * be useful, but WITHOUT ANY WARRANTY; without even the
- * implied warranty of MERCHANTABILITY or FITNESS FOR A
- * PARTICULAR PURPOSE. See the GNU General Public
- * License for more details.
- *
- * The GNU General Public License should be included with
- * this file. If not, you can view it at
- * http://www.gnu.org/copyleft/gpl.html
- * or write to the Free Software Foundation, Inc., 59
- * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * Revisions :
- * $L<!-- Break CVS Substitution -->og$
- *
- *********************************************************************/
-
-
-#include "project.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
- ... function headers here ...
-
-
-/* Revision control strings from this header and associated .c file */
-extern const char FILENAME_rcs[];
-extern const char FILENAME_h_rcs[];
-
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-#endif /* ndef _FILENAME_H */
-
-/*
- Local Variables:
- tab-width: 3
- end:
-*/
-
-
-</pre>
-
- <p><b>Example for function comments:</b></p>
-<pre>
-/*********************************************************************
- *
- * Function : FUNCTION_NAME
- *
- * Description : (Fill me in with a good description!)
- *
- * Parameters :
- * 1 : param1 = pointer to an important thing
- * 2 : x = pointer to something else
- *
- * Returns : 0 => Ok, everything else is an error.
- *
- *********************************************************************/
-int FUNCTION_NAME( void *param1, const char *x )
-{
- ...
- return( 0 );
-
-}
-
-
-</pre>
-
- <p><b>Note:</b> If we all follow this practice, we should be
- able to parse our code to create a "self-documenting" web
- page.</p>
-
- <p> </p>
-
- <p> </p>
- </body>
-</html>
-