X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fstandards.texi;h=7d30a4b4cfbe1c218a6390f752c4fb16ff484364;hb=919347c164606c3f1544b2e8bd62f505aeda80a1;hp=7af266e9c10b9cecb5be44f8ae190acf9a8048ef;hpb=c574297b7acbcbf04d128113cf91dbbcc1730f9c;p=pintos-anon diff --git a/doc/standards.texi b/doc/standards.texi index 7af266e..7d30a4b 100644 --- a/doc/standards.texi +++ b/doc/standards.texi @@ -1,26 +1,19 @@ -@node Coding Standards, Project Documentation, Multilevel Feedback Scheduling, Top +@node Coding Standards @appendix Coding Standards -All of you should have taken a class like CS 107, so we expect you to -be familiar with some set of coding standards such as -@uref{http://www.stanford.edu/class/cs140/projects/misc/CodingStandards.pdf, -, CS 107 Coding Standards}. Even if you've taken 107, we recommend -reviewing that document. We expect code at the "Peer-Review Quality" -level as described there. - -Our standards for coding are mostly important in grading. More -information on our grading methodology can be found on the Course Info -page and the Grading page. We also want to stress that aside from the -fact that we are explicitly basing part of your grade on these things, -good coding practices will improve the quality of your code. This -makes it easier for your partners to interact with it, and ultimately, -will improve your chances of having a good working program. That said -once, the rest of this document will discuss only the ways in which -our coding standards will affect our grading. +@localcodingstandards{} + +Our standards for coding are most important for grading. We want to +stress that aside from the fact that we are explicitly basing part of +your grade on these things, good coding practices will improve the +quality of your code. This makes it easier for your partners to +interact with it, and ultimately, will improve your chances of having a +good working program. That said once, the rest of this document will +discuss only the ways in which our coding standards will affect our +grading. @menu * Coding Style:: -* Conditional Compilation:: * C99:: * Unsafe String Functions:: @end menu @@ -39,66 +32,44 @@ follows the @uref{http://www.gnu.org/prep/standards_toc.html, , GNU Coding Standards}. We encourage you to follow the applicable parts of them too, especially chapter 5, ``Making the Best Use of C.'' Using a different style won't cause actual problems, but it's ugly to see -gratuitous differences in style from one function to another. - -Pintos comments sometimes refer to outside standards or -specifications by writing a name inside square brackets, like this: -@code{[IA32-v3]}. These names refer to the reference names used in -this documentation (@pxref{References}). - -@node Conditional Compilation -@section Conditional Compilation +gratuitous differences in style from one function to another. If your +code is too ugly, it will cost you points. -Given the scope and complexity of your assignments this quarter, you -may find it convenient while coding and debugging (and we will find it -convenient while grading) to be able to independently turn different -parts of the assignments on and off. To do this, choose a macro name -and use it in conditional -compilation directives, e.g.: +Please limit C source file lines to at most 79 characters long. -@example -#ifdef @var{NAME} -@dots{}your code@dots{} -#endif -@end example - -In general, the code that you turn in must not depend on conditional -compilation directives. Project code should be written so that all of -the subproblems for the project function together, and it should -compile properly without the need for any new macros to be defined. -There are a few exceptions: - -@itemize @bullet -@item -Problem 1-2, @func{thread_join}. Some other code expects -@code{THREAD_JOIN_IMPLEMENTED} to be defined once you've implemented -this function. - -@item -Problem 1-4, the advanced scheduler. We must be able to turn this on -and off with a compile-time directive. You must use the macro name we -specify for that part. @xref{Problem 1-4 Advanced Scheduler}, for -details. - -@item -Code written for extra credit may be included conditionally. If the -extra credit code changes the normally expected functionality of the -code, then it @emph{must} be included conditionally, and it must not -be enabled by default. -@end itemize - -You can use @file{constants.h} in @file{pintos/src} to define macros -for conditional compilation. We will replace the @file{constants.h} -that you supply with one of our own when we test your code, so do not -define anything important in it. +Pintos comments sometimes refer to external standards or +specifications by writing a name inside square brackets, like this: +@code{[IA32-v3a]}. These names refer to the reference names used in +this documentation (@pxref{Bibliography}). + +If you remove existing Pintos code, please delete it from your source +file entirely. Don't just put it into a comment or a conditional +compilation directive, because that makes the resulting code hard to +read. + +We're only going to do a compile in the directory for the project being +submitted. You don't need to make sure that the previous projects also +compile. + +Project code should be written so that all of the subproblems for the +project function together, that is, without the need to rebuild with +different macros defined, etc. If you do extra credit work that +changes normal Pintos behavior so as to interfere with grading, then +you must implement it so that it only acts that way when given a +special command-line option of the form @option{-@var{name}}, where +@var{name} is a name of your choice. You can add such an option by +modifying @func{parse_options} in @file{threads/init.c}. + +The introduction describes additional coding style requirements +(@pxref{Design}). @node C99 @section C99 The Pintos source code uses a few features of the ``C99'' standard -library that were not in the original 1989 standard for C. Because -they are so new, most classes do not cover these features, so this -section will describe them. The new features used in Pintos are +library that were not in the original 1989 standard for C. Many +programmers are unaware of these feature, so we will describe them. The +new features used in Pintos are mostly in new headers: @table @file @@ -110,7 +81,7 @@ expands to 0. @item On systems that support them, this header defines types @code{int@var{n}_t} and @code{uint@var{n}_t} for @var{n} = 8, 16, 32, -64, and possibly others. These are 2's complement signed and unsigned +64, and possibly other values. These are 2's complement signed and unsigned types, respectively, with the given number of bits. On systems where it is possible, this header also defines types @@ -121,17 +92,17 @@ On all systems, this header defines types @code{intmax_t} and @code{uintmax_t}, which are the system's signed and unsigned integer types with the widest ranges. -For every signed integer type @code{@var{type}_t} it defines, as well +For every signed integer type @code{@var{type}_t} defined here, as well as for @code{ptrdiff_t} defined in @file{}, this header also -defines macros @code{@var{type}_MAX} and @code{@var{type}_MIN} that +defines macros @code{@var{TYPE}_MAX} and @code{@var{TYPE}_MIN} that give the type's range. Similarly, for every unsigned integer type @code{@var{type}_t} defined here, as well as for @code{size_t} defined -in @file{}, this header defines a @code{@var{type}_MAX} +in @file{}, this header defines a @code{@var{TYPE}_MAX} macro giving its maximum value. @item -@file{} is useful on its own, but it provides no way to pass -the types it defines to @func{printf} and related functions. This +@file{} provides no straightforward way to format +the types it defines with @func{printf} and related functions. This header provides macros to help with that. For every @code{int@var{n}_t} defined by @file{}, it provides macros @code{PRId@var{n}} and @code{PRIi@var{n}} for formatting values of @@ -150,7 +121,7 @@ printf ("value=%08"PRId32"\n", value); @noindent The @samp{%} is not supplied by the @code{PRI} macros. As shown above, you supply it yourself and follow it by any flags, field -widths, etc. +width, etc. @item The @func{printf} function has some new type modifiers for printing @@ -169,7 +140,7 @@ For @code{ptrdiff_t} (e.g.@: @samp{%td}). @end table Pintos @func{printf} also implements a nonstandard @samp{'} flag that -group large numbers with commas to make them easier to read. +groups large numbers with commas to make them easier to read. @end table @node Unsafe String Functions @@ -180,7 +151,7 @@ A few of the string functions declared in the standard The worst offenders are intentionally not included in the Pintos C library: -@table @func +@table @code @item strcpy When used carelessly this function can overflow the buffer reserved for its output string. Use @func{strlcpy} instead. Refer to @@ -188,16 +159,16 @@ comments in its source code in @code{lib/string.c} for documentation. @item strncpy This function can leave its destination buffer without a null string -terminator and it has performance problems besides. Again, use +terminator. It also has performance problems. Again, use @func{strlcpy}. @item strcat -Same issue as @func{strcpy}, but substitute @func{strlcat}. +Same issue as @func{strcpy}. Use @func{strlcat} instead. Again, refer to comments in its source code in @code{lib/string.c} for documentation. @item strncat -The meaning of its buffer size argument often leads to problems. +The meaning of its buffer size argument is surprising. Again, use @func{strlcat}. @item strtok @@ -213,6 +184,6 @@ to comments in @code{lib/stdio.h} for documentation. Same issue as @func{strcpy}. Use @func{vsnprintf} instead. @end table -If you try to use any of these functions, you should get a hint from -the error message, which will refer to an identifier like +If you try to use any of these functions, the error message will give +you a hint by referring to an identifier like @code{dont_use_sprintf_use_snprintf}.