158 lines
2.8 KiB
C
158 lines
2.8 KiB
C
/*
|
|
get_ptr_compare(len) returns a pointer to a optimal byte-compare function
|
|
for a array of stringpointer where all strings have size len.
|
|
The bytes are compare as unsigned chars.
|
|
Because the size is saved in a static variable.
|
|
When using threads the program must have called my_init and the thread
|
|
my_init_thread()
|
|
*/
|
|
|
|
#include <global.h>
|
|
#include "m_string.h"
|
|
|
|
static int ptr_compare(uchar **a, uchar **b);
|
|
static int ptr_compare_0(uchar **a, uchar **b);
|
|
static int ptr_compare_1(uchar **a, uchar **b);
|
|
static int ptr_compare_2(uchar **a, uchar **b);
|
|
static int ptr_compare_3(uchar **a, uchar **b);
|
|
|
|
#ifdef THREAD
|
|
#include <my_pthread.h>
|
|
#define compare_length my_thread_var->cmp_length
|
|
#else
|
|
static uint compare_length;
|
|
#endif
|
|
|
|
/* Get a pointer to a optimal byte-compare function for a given size */
|
|
|
|
qsort_cmp get_ptr_compare (size)
|
|
uint size;
|
|
{
|
|
compare_length=size; /* Remember for loop */
|
|
|
|
if (size < 4)
|
|
return (qsort_cmp) ptr_compare;
|
|
switch (size & 3) {
|
|
case 0: return (qsort_cmp) ptr_compare_0;
|
|
case 1: return (qsort_cmp) ptr_compare_1;
|
|
case 2: return (qsort_cmp) ptr_compare_2;
|
|
case 3: return (qsort_cmp) ptr_compare_3;
|
|
}
|
|
return 0; /* Impossible */
|
|
}
|
|
|
|
|
|
/*
|
|
Compare to keys to see witch is smaller.
|
|
Loop unrolled to make it quick !!
|
|
*/
|
|
|
|
#define cmp(N) if (first[N] != last[N]) return (int) first[N] - (int) last[N]
|
|
|
|
static int ptr_compare(a,b)
|
|
uchar **a,**b;
|
|
{
|
|
reg3 int length= compare_length;
|
|
reg1 uchar *first,*last;
|
|
|
|
first= *a; last= *b;
|
|
while (--length)
|
|
{
|
|
if (*first++ != *last++)
|
|
return (int) first[-1] - (int) last[-1];
|
|
}
|
|
return (int) first[0] - (int) last[0];
|
|
}
|
|
|
|
|
|
static int ptr_compare_0(a,b)
|
|
uchar **a,**b;
|
|
{
|
|
reg3 int length= compare_length;
|
|
reg1 uchar *first,*last;
|
|
|
|
first= *a; last= *b;
|
|
loop:
|
|
cmp(0);
|
|
cmp(1);
|
|
cmp(2);
|
|
cmp(3);
|
|
if ((length-=4))
|
|
{
|
|
first+=4;
|
|
last+=4;
|
|
goto loop;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
|
|
static int ptr_compare_1(a,b)
|
|
uchar **a,**b;
|
|
{
|
|
reg3 int length= compare_length-1;
|
|
reg1 uchar *first,*last;
|
|
|
|
first= *a+1; last= *b+1;
|
|
cmp(-1);
|
|
loop:
|
|
cmp(0);
|
|
cmp(1);
|
|
cmp(2);
|
|
cmp(3);
|
|
if ((length-=4))
|
|
{
|
|
first+=4;
|
|
last+=4;
|
|
goto loop;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int ptr_compare_2(a,b)
|
|
uchar **a,**b;
|
|
{
|
|
reg3 int length= compare_length-2;
|
|
reg1 uchar *first,*last;
|
|
|
|
first= *a +2 ; last= *b +2;
|
|
cmp(-2);
|
|
cmp(-1);
|
|
loop:
|
|
cmp(0);
|
|
cmp(1);
|
|
cmp(2);
|
|
cmp(3);
|
|
if ((length-=4))
|
|
{
|
|
first+=4;
|
|
last+=4;
|
|
goto loop;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int ptr_compare_3(a,b)
|
|
uchar **a,**b;
|
|
{
|
|
reg3 int length= compare_length-3;
|
|
reg1 uchar *first,*last;
|
|
|
|
first= *a +3 ; last= *b +3;
|
|
cmp(-3);
|
|
cmp(-2);
|
|
cmp(-1);
|
|
loop:
|
|
cmp(0);
|
|
cmp(1);
|
|
cmp(2);
|
|
cmp(3);
|
|
if ((length-=4))
|
|
{
|
|
first+=4;
|
|
last+=4;
|
|
goto loop;
|
|
}
|
|
return (0);
|
|
}
|