1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA */
/*
Radixsort for pointers to fixed length strings.
A very quick sort for not to long (< 20 char) strings.
Neads a extra buffers of number_of_elements pointers but is
2-3 times faster than quicksort
*/
#include "mysys_priv.h"
#include <m_string.h>
/* Radixsort */
void radixsort_for_str_ptr(uchar **base, uint number_of_elements, size_s size_of_element, uchar **buffer)
{
uchar **end,**ptr,**buffer_ptr;
uint32 *count_ptr,*count_end,count[256];
int pass;
end=base+number_of_elements; count_end=count+256;
for (pass=(int) size_of_element-1 ; pass >= 0 ; pass--)
{
bzero((gptr) count,sizeof(uint32)*256);
for (ptr= base ; ptr < end ; ptr++)
count[ptr[0][pass]]++;
if (count[0] == number_of_elements)
goto next;
for (count_ptr=count+1 ; count_ptr < count_end ; count_ptr++)
{
if (*count_ptr == number_of_elements)
goto next;
(*count_ptr)+= *(count_ptr-1);
}
for (ptr= end ; ptr-- != base ;)
buffer[--count[ptr[0][pass]]]= *ptr;
for (ptr=base, buffer_ptr=buffer ; ptr < end ;)
(*ptr++) = *buffer_ptr++;
next:;
}
}
|
