fis-gtm/sr_port/stpg_sort.c

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/****************************************************************
* *
* Copyright 2001, 2007 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "stpg_sort.h"
#define S_CUTOFF 15
/* stpg_sort sorts an array of pointers to mstr's using the value
of each mstr's addr field as the key. The algorithm is a modified
QuickSort algorithm.
*/
void stpg_sort (mstr **base, mstr **top)
{
mstr **stack[50], ***sp;
mstr *v, *t;
mstr **l, **r;
mstr **ix, **jx, **kx;
char *tval;
sp = stack;
l = base;
r = top;
for (;;)
{
if (r - l < S_CUTOFF)
{
for (ix = l + 1; ix <= r; ix++)
{
for (jx = ix, t= *ix, tval = t->addr; jx > l && (*(jx - 1))->addr > tval; jx--)
{
*jx = *(jx - 1);
}
*jx = t;
}
if (sp <= stack)
{
break;
}
else
{
l = *--sp;
r = *--sp;
}
}
else
{
ix = l;
jx = r;
kx = l + ((int)(r - l) / 2);
kx = ((*ix)->addr > (*jx)->addr) ?
(((*jx)->addr > (*kx)->addr) ?
jx :
(((*ix)->addr > (*kx)->addr) ? kx : ix)) :
(((*jx)->addr < (*kx)->addr) ?
jx :
(((*ix)->addr > (*kx)->addr) ? ix : kx));
v = *kx;
*kx = *jx;
*jx = v;
tval = v->addr;
ix--;
do
{
do
{
ix++;
} while ((*ix)->addr < tval);
do
{
jx--;
} while ((*jx)->addr > tval);
t = *ix;
*ix = *jx;
*jx = t;
} while (jx > ix);
*jx = *ix;
*ix = *r;
*r = t;
if (ix - l > r - ix)
{
*sp++ = ix - 1;
*sp++ = l;
l = ix + 1;
}
else
{
*sp++ = r;
*sp++ = ix + 1;
r = ix - 1;
}
}
}
return;
}