Re: [Linux-NTFS-Dev] [PATCH] reduce large stack usage

[Andrew Clausen <clausen@gnu.org>]

Hi Randy,

On Fri, Feb 28, 2003 at 11:06:23PM -0800, Randy.Dunlap wrote:
> This patch to 2.5.63 reduces stack usage in generate_default_upcase()
> from 0x3d4 bytes to just noise (on x86).
> 
> The arrays are static so they are still private (hidden), but
> now they aren't allocated on the stack and copied there for
> temp use.

BTW, you can declare "local" variables inside a function as static,
which makes them "global", but locally scoped.  The code should be
basically equivalent, but perhaps more elegant...

i.e.:

 uchar_t *generate_default_upcase(void)
 {
-	const int uc_run_table[][3] = { /* Start, End, Add */
+static const int uc_run_table[][3] = { /* Start, End, Add */
 	{0x0061, 0x007B,  -32}, {0x0451, 0x045D, -80}, {0x1F70, 0x1F72,  74},
 	{0x00E0, 0x00F7,  -32}, {0x045E, 0x0460, -80}, {0x1F72, 0x1F76,  86},
 	{0x00F8, 0x00FF,  -32}, {0x0561, 0x0587, -48}, {0x1F76, 0x1F78, 100},

Cheers,
Andrew