Re: [PATCH] dir.c: avoid c99 array initialization

From: Alex Riesen <raa.lkml@gmail.com>
Date: Aug 28, 2008, 20:01 UTC
Message-ID: <81b0412b0808281301m29830c20l3e16432ea8aef45d@mail.gmail.com>
In-Reply-To: <G-ipWASixyGW7nvO1KquifehvBB7FNKwjPtIB0ukyEJ1Si1CJWM34w@cipher.nrlssc.navy.mil>

2008/8/19 Brandon Casey <casey@nrlssc.navy.mil>:

Show 14 quoted lines

>  static int simple_length(const char *match)
>  {
> -       const char special[256] = {
> -               [0] = 1, ['?'] = 1,
> -               ['\\'] = 1, ['*'] = 1,
> -               ['['] = 1
> -       };
> +       char special[256] = { 1, };
>        int len = -1;
>
> +       special['?'] = 1;
> +       special['\\'] = 1;
> +       special['*'] = 1;
> +       special['['] = 1;

For just these 5 values it is likely more effective to just use a conditional statement (less stack requested, less likely some stupid compiler tries to optimize it wrongly). And just as readable.

diff --git a/dir.c b/dir.c
index 92452eb..1cf5985 100644
--- a/dir.c
+++ b/dir.c
@@ -680,17 +680,12 @@ static int cmp_name(const void *p1, const void *p2)
  */
 static int simple_length(const char *match)
 {
-	const char special[256] = {
-		[0] = 1, ['?'] = 1,
-		['\\'] = 1, ['*'] = 1,
-		['['] = 1
-	};
 	int len = -1;

 	for (;;) {
 		unsigned char c = *match++;
 		len++;
-		if (special[c])
+		if (!c || '?' == c || '\\' == c || '*' == c || '[' == c)
 			return len;
 	}
 }