Tab or Spaces1?
From the http://www.jwz.org/doc/tabs-vs-spaces.html . We prefer to use spaces.
Vim configuration
{.example}
"To interpret tab as an 'indent' command instead of an insert-a-tab command, do this:
set softtabstop=4
"To set the mod-N indentation used when you hit the tab key in vim
set shiftwidth=4
"To cause the TAB file-character to be displayed as mod-N in vim
set tabstop=4
"To cause TAB characters to not be used in the file for compression, and for only spaces to be used
set expandtab
Emacs configuration
{.example}
;;To set the mod-N indentation used when you hit the tab key in vim
(setq c-basic-offset 4)
;;To cause the TAB file-character to be displayed as mod-N in vim
(setq tab-width 4)
;;To cause TAB characters to not be used in the file for compression, and for only spaces to be used
(setq indent-tabs-mode nil)
Astyle Configuaration2
{.example}
#Indent using # spaces per indent
--indent=spaces=4 / -s4
}
Bracket
Astyle Configuration
{.example}
--brackets=linux / -l
Break brackets from namespace, class, and function definitions, but attach brackets to statements within a function ( e.g. K&R / Linux style ). For example:
{.c}
void Foo(bool isFoo)
{
if (isFoo) {
bar();
} else {
anotherBar;
}
}
Indentation Options
Astyle Configuration
{.example}
--indent-switches / -S
Indent ‘switch’ blocks so that the ‘case X:’ statements are indented in the switch block. The entire case block is indented. For example:
``` {.c} switch (foo) { case 1: a += 1; break;
case 2:
{
a += 2;
break;
} } ```
{.example}
--indent-cases / -K
Indent ‘case X:’ blocks from the ‘case X:’ headers. Case statements not enclosed in blocks are NOT indented. For example:
``` {.c} switch (foo) { case 1: a += 1; break;
case 2:
{
a += 2;
break;
} } ```
{.example}
--indent-preprocessor / -w
Indent multi-line preprocessor definitions ending with a backslash. Should be used with –convert-tabs for proper results. For example:
{.c}
#define Is_Bar(arg,a,b) \
(Is_Foo((arg), (a)) \
| | Is_Foo((arg), (b))) |
{.example}
--indent-col1-comments / -Y
This option will allow the comments to be indented with the code. For example:
{.c}
void Foo()
{
// comment
if (isFoo)
bar();
}
{.example}
--min-conditional-indent=0 OR -m0
Set the minimal indent that is added when a header is built of multiple-lines. For example:
{.c}
// setting makes this non-bracketed code less clear
if (a < b
| | c > d) { |
foo++;
}
Padding Options
Astyle configuration
{.example}
--pad-oper / -p
Insert space padding around operators. For example:
{.c}
if (foo == 2)
a = bar((b - c) * a, * d--);
{.example}
--pad-header / -H
Insert space padding after paren headers only (e.g. ‘if’, ‘for’, ‘while’…). Any end of line comments will remain in the original column, if possible. For example:
{.c}
if (isFoo(a, b))
bar(a, b);
{.example}
--unpad-paren / -U
Remove extra space padding around parenthesis on the inside and outside. For example:
{.c}
if ( isFoo( a, b ) )
bar ( a, b );
becomes (with no padding option requested):
{.c}
if (isFoo(a, b))
bar(a, b);
Formatting Options
{.example}
--add-brackets / -j
Add brackets to unbracketed one line conditional statements. For example:
{.c}
if (isFoo)
isFoo = false;
becomes:
{.c}
if (isFoo) {
isFoo = false;
}
{.example}
--align-pointer=name / -k3
Attach a pointer or reference operator (* or &) to variable name (right). For example:
{.c}
char &foo3;
int *bar;
{.example}
--mode=c
--mode=cs
--mode=java
Indent a C/C++, C#, or Java file. The option is usually set from the file extension for each file. You can override the setting with this entry. It will be used for all files regardless of the file extension. It allows the formatter to identify language specific syntax such as C++ classes, templates, and keywords.
{.example}
--lineend=windows / -z1
--lineend=linux / -z2
--lineend=macold / -z3
Force use of the specified line end style. Valid options are windows (CRLF), linux (LF), and macold (CR). MacOld style is the format for OS 9 and earlier. Mac OS X uses the Linux style. If one of these options is not used the line ends will be determined automatically from the input file.
Naming
We follow the linux naming style3, variable and method identifiers in lowercase words seperated by underscores.
Local variable
Local variable should be short, and to the point. If you have some random integer loop counter, it should probably be called “i”.
Global variable
Do not use it. Please use descriptive name if you really need it.
Function/Method name
Functions/Methods should be short and sweet, and do just one thing. The function/method name should be descriptive as well. For example:
Enums
Enum members and constants in ALL~CAPS~, words seperated by underscores.
Class/Struct
Type identifiers in CamelCase.
Source files name.
Source files all lowercase, with no separators between words, in the
format namespacefilename.c.
Copyright header
Header at top of file contains:
``` {.c}
/* Copyright (C) 2003-2010, Alpha Networks Co., LTD.
*
* Author: Author Name <Author_Name@alphanetworks.com>
* $Header$
* vim:ts=4:sw=4:
* -- mode: C; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil --
*/
/*
* The file description here.
* ..
*/
```
Appendix
Command line using astyle
Install astyle
- Gentoo
{.example}
sudo emerge dev-util/astyle
- Debian/Ubuntu
{.example}
sudo apt-get install astyle
Using astlye to format the code
{.example}
astyle -s4lSKwYm0pHUjk3z2 test1.c test2.c
Astyle configuration for vim
Add following line into the .vimrc
{.example}
""""""""""""""""""""""""""""""""""""""""""""""""""
" tab setting
""""""""""""""""""""""""""""""""""""""""""""""""""
set tabstop=4
set softtabstop=4
set shiftwidth=4
set expandtab
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
" Format the code with astyle
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
map <S-F> <Esc>:%! astyle -s4lSKwYm0pHUjk3z2<CR>
autocmd BufNewFile,BufRead *.c set formatprg=astyle\ -s4lSKwYm0pHUjk3z2
Format the current buffer with astyle
- Format the whole buffer
press Shift-F Or press gggqG
- Format the current line to the end of the buffer
press gqG = Format the next line press gq+1 = Format current line
and next line press gqj
Astyle configuration for emacs
Adding following line into the emacs configuration file
``` {.example} ;set c coding style (eval-when-compile (require ‘cc-defs))
;; Wrapper function needed for Emacs 21 and XEmacs (Emacs 22 offers the more ;; elegant solution of composing a list of lineup functions or quantities with ;; operators such as “add”) (defun alpha-c-lineup-expression-plus-4 (langelem) “Indents to the beginning of the current C expression plus 4 spaces.” (save-excursion (back-to-indentation) ;; Go to beginning of previous line: (c-backward-syntactic-ws) (back-to-indentation) ;; We are making a reasonable assumption that if there is a control ;; structure to indent past, it has to be at the beginning of the line. (if (looking-at “\(\(if\|for\|while\)\s *(\)”) (goto-char (match-end 1))) (vector (+ 4 (current-column)))))
(defconst alpha-c-style `((c-recognize-knr-p . nil) (c-enable-xemacs-performance-kludge-p . t) ; speed up indentation in XEmacs (c-basic-offset . 4) (indent-tabs-mode . nil) (c-comment-only-line-offset . 0) (c-hanging-braces-alist . ((defun-open after) (defun-close before after) (class-open after) (class-close before after) (namespace-open after) (inline-open after) (inline-close before after) (block-open after) (block-close . c-snug-do-while) (extern-lang-open after) (extern-lang-close after) (statement-case-open after) (substatement-open after))) (c-hanging-colons-alist . ((case-label) (label after) (access-label after) (member-init-intro before) (inher-intro))) (c-hanging-semi&comma-criteria . (c-semi&comma-no-newlines-for-oneline-inliners c-semi&comma-inside-parenlist c-semi&comma-no-newlines-before-nonblanks)) (c-indent-comments-syntactically-p . nil) (comment-column . 40) (c-cleanup-list . (brace-else-brace brace-elseif-brace brace-catch-brace empty-defun-braces defun-close-semi list-close-comma scope-operator)) (c-offsets-alist . ((arglist-intro alpha-c-lineup-expression-plus-4) (func-decl-cont . ++) (member-init-intro . ++) (inher-intro . ++) (comment-intro . 0) (arglist-close . c-lineup-arglist) (topmost-intro . 0) (block-open . 0) (inline-open . 0) (substatement-open . 0) (statement-cont . (,(when (fboundp ‘c-no-indent-after-java-annotations) ‘c-no-indent-after-java-annotations) ,(when (fboundp ‘c-lineup-assignments) ‘c-lineup-assignments) ++)) (label . /) (case-label . +) (statement-case-open . +) (statement-case-intro . +) ; case w/o { (access-label . /) (innamespace . 0)))) “Alpha C/C++ Programming Style”)
(defun alpha-set-c-style () “Set the current buffer’s c-style to Alpha C/C++ Programming Style. Meant to be added to `c-mode-common-hook’.” (interactive) (make-local-variable ‘c-tab-always-indent) (setq c-tab-always-indent t) (c-add-style “Alpha” alpha-c-style t))
(defun alpha-make-newline-indent () “Sets up preferred newline behavior. Not set by default. Meant to be added to `c-mode-common-hook’.” (interactive) (define-key c-mode-base-map “\C-m” ‘newline-and-indent) (define-key c-mode-base-map [ret] ‘newline-and-indent))
(defun astyle-this-buffer (pmin pmax) (interactive “r”) (shell-command-on-region pmin pmax “astyle -s4lSKwYm0pHUjk3z2” ;; add options here… (current-buffer) t (get-buffer-create “Astyle Errors”) t))
(add-hook ‘c-mode-common-hook ‘alpha-set-c-style) (add-hook ‘c-mode-common-hook ‘alpha-make-newline-indent) ```