Re: multi stack question/grumble
Dave Whipp wrote:
Matt Fowles
Were this C++ I would say that we could write a single general
purpose stack and use template meta-programming to avoid the
overhead. Is there a similar solution available in C?
My instincts tell me that this solution will be dirty to the tune of
massive macroing, but perhaps someone better with pure C than I am
could provide a better answer.
C does do templates, sort-of:
#define STACK_TYPE int
#define STACK_MAX_SIZE 1024
#include stack_template_decl.h
#include stack_template_impl.h
#undef STACK_TYPE
#undef STACK_MAX_SIZE
(often one instances the stack_decl in a header file, and the _impl in
a .c file.) I've also seen the calling convention where the template
files do the #undefs.
There can be some issues debugging this stuff though: gcc will give
currect line numbers, but will not tell you which instance of the
stack template you're in. So if a bug is only in, say, stacks of
double: then this won't be immediately apparent.
Any chance that this could be fixed with a #line pragma, with a filename
which is generated from the parameters? E.g., something like:
#define STRINGIFY(X) ??? /* make a string literal from a token */
#define STACK_TYPE_STR STRINGIFY(STACK_TYPE)
#define STACK_SIZE_STR STRINGIFY(STACK_MAX_SIZE)
#define GENFILENAME \
__LINE__ [ STACK_TYPE_STR x STACK_SIZE_STR ]
#line 0 GENFILENAME
On the plus side, the lack of type information means that you don't
get c++'s 8000-character error messages.
--
$a=24;split//,240513;s/\B/ = /for@@=qw(ac ab bc ba cb ca
);{push(@b,$a),($a-=6)^=1 for 2..$a/6x--$|;print [EMAIL PROTECTED]
]\n;((6=($a-=6))?$a+=$_[$a%6]-$a%6:($a=pop @b))redo;}
Re: multi stack question/grumble
Matt Fowles [EMAIL PROTECTED] Were this C++ I would say that we could write a single general purpose stack and use template meta-programming to avoid the overhead. Is there a similar solution available in C? My instincts tell me that this solution will be dirty to the tune of massive macroing, but perhaps someone better with pure C than I am could provide a better answer. C does do templates, sort-of: #define STACK_TYPE int #define STACK_MAX_SIZE 1024 #include stack_template_decl.h #include stack_template_impl.h #undef STACK_TYPE #undef STACK_MAX_SIZE (often one instances the stack_decl in a header file, and the _impl in a .c file.) I've also seen the calling convention where the template files do the #undefs. There can be some issues debugging this stuff though: gcc will give currect line numbers, but will not tell you which instance of the stack template you're in. So if a bug is only in, say, stacks of double: then this won't be immediately apparent. On the plus side, the lack of type information means that you don't get c++'s 8000-character error messages. Dave.
Re: multi stack question/grumble
Dave Whipp [EMAIL PROTECTED] wrote: C does do templates, sort-of: #define STACK_TYPE int #define STACK_MAX_SIZE 1024 #include stack_template_decl.h #include stack_template_impl.h #undef STACK_TYPE #undef STACK_MAX_SIZE There can be some issues debugging this stuff though: And this is the big problem with it. I think, we should have a general stack engine which just knows about item size and chunk size. The base functions return a (void *) to an entry. The fast paths (now chunk add/del needed) could even be inlined. A separate handling of the entries like in stacks.c could be on top of this. Dave. leo
multi stack question/grumble
Leopold Toetsch wrote: ( /me again mumbling why we have 6 different stack implementations with a lot of duplicate code. One general stack with different sized data items would do it too - with some overhead ;-) Were this C++ I would say that we could write a single general purpose stack and use template meta-programming to avoid the overhead. Is there a similar solution available in C? My instincts tell me that this solution will be dirty to the tune of massive macroing, but perhaps someone better with pure C than I am could provide a better answer. Matt
