ryan/mozjpeg
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Get rid of the HAVE_PROTOTYPES configuration option, as well as the related JMETHOD and JPP macros. libjpeg-turbo has never supported compilers that don't handle prototypes. Doing so requires ansi2knr, which isn't even supported in the IJG code anymore.

Browse Source 
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1308 632fc199-4ca6-4c93-a231-07263d6284db
This commit is contained in:
DRC
2014-05-16 10:43:44 +00:00
parent 52ded87680
commit bc56b754e1
42 changed files with 1077 additions and 1332 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
coderules.txt
View File

@@ -1,7 +1,11 @@
IJG JPEG LIBRARY: CODING RULES
Copyright (C) 1991-1996, Thomas G. Lane.
This file is part of the Independent JPEG Group's software.
This file was part of the Independent JPEG Group's software.
It was modified by The libjpeg-turbo Project to include only information
relevant to libjpeg-turbo.
For conditions of distribution and use, see the accompanying README file.
@@ -32,22 +36,7 @@ handled automatically by GNU Emacs and many other text editors.)
Multi-word names should be written in lower case with underscores, e.g.,
multi_word_name (not multiWordName). Preprocessor symbols and enum constants
are similar but upper case (MULTI_WORD_NAME). Names should be unique within
the first fifteen characters. (On some older systems, global names must be
unique within six characters. We accommodate this without cluttering the
source code by using macros to substitute shorter names.)
We use function prototypes everywhere; we rely on automatic source code
transformation to feed prototype-less C compilers. Transformation is done
by the simple and portable tool 'ansi2knr.c' (courtesy of Ghostscript).
ansi2knr is not very bright, so it imposes a format requirement on function
declarations: the function name MUST BEGIN IN COLUMN 1. Thus all functions
should be written in the following style:
LOCAL(int *)
function_name (int a, char *b)
{
code...
}
the first fifteen characters.
Note that each function definition must begin with GLOBAL(type), LOCAL(type),
or METHODDEF(type). These macros expand to "static type" or just "type" as
@@ -55,27 +44,8 @@ appropriate. They provide a readable indication of the routine's usage and
can readily be changed for special needs. (For instance, special linkage
keywords can be inserted for use in Windows DLLs.)
ansi2knr does not transform method declarations (function pointers in
structs). We handle these with a macro JMETHOD, defined as
#ifdef HAVE_PROTOTYPES
#define JMETHOD(type,methodname,arglist) type (*methodname) arglist
#else
#define JMETHOD(type,methodname,arglist) type (*methodname) ()
#endif
which is used like this:
struct function_pointers {
JMETHOD(void, init_entropy_encoder, (int somearg, jparms *jp));
JMETHOD(void, term_entropy_encoder, (void));
};
Note the set of parentheses surrounding the parameter list.
A similar solution is used for forward and external function declarations
(see the EXTERN and JPP macros).
If the code is to work on non-ANSI compilers, we cannot rely on a prototype
declaration to coerce actual parameters into the right types. Therefore, use
explicit casts on actual parameters whenever the actual parameter type is not
identical to the formal parameter. Beware of implicit conversions to "int".
A similar solution is used for external function declarations (see the EXTERN
macro.)
It seems there are some non-ANSI compilers in which the sizeof() operator
is defined to return int, yet size_t is defined as long. Needless to say,
@@ -105,10 +75,9 @@ the system architecture document, structure.txt).
5. Source file names should begin with "j" for files that are part of the
library proper; source files that are not part of the library, such as cjpeg.c
and djpeg.c, do not begin with "j". Keep source file names to eight
characters (plus ".c" or ".h", etc) to make life easy for MS-DOSers. Keep
compression and decompression code in separate source files --- some
applications may want only one half of the library.
and djpeg.c, do not begin with "j". Keep compression and decompression code in
separate source files --- some applications may want only one half of the
library.
Note: these rules (particularly #4) are not followed religiously in the
modules that are used in cjpeg/djpeg but are not part of the JPEG library