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mariadb/mysys/my_compare.c
Magne Mahre 517c5c247c Bug#11933945 REMOVE LGPL LICENSED FILES IN MYSQL 5.5 
The LGPL license is used in some legacy code, and to
adhere to current licensing polity, we remove those
files that are no longer used, and reorganize the
remaining LGPL code so it will be GPL licensed from
now on.
            
Note:  This patch only removed LGPL licensed files
       in MySQL 5.5 and later, and is the third of a 
       set of patches to remove LGPL from all trees.
       (See Bug# 11840513 for details)
2011-03-29 14:43:49 +02:00

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/* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <my_global.h>
#include <m_ctype.h>
#include <my_base.h>
#include <my_compare.h>
#include <my_sys.h>
#define CMP_NUM(a,b) (((a) < (b)) ? -1 : ((a) == (b)) ? 0 : 1)
int ha_compare_text(CHARSET_INFO *charset_info, uchar *a, uint a_length,
uchar *b, uint b_length, my_bool part_key,
my_bool skip_end_space)
{
if (!part_key)
return charset_info->coll->strnncollsp(charset_info, a, a_length,
b, b_length, (my_bool)!skip_end_space);
return charset_info->coll->strnncoll(charset_info, a, a_length,
b, b_length, part_key);
}
static int compare_bin(uchar *a, uint a_length, uchar *b, uint b_length,
my_bool part_key, my_bool skip_end_space)
{
uint length= min(a_length,b_length);
uchar *end= a+ length;
int flag;
while (a < end)
if ((flag= (int) *a++ - (int) *b++))
return flag;
if (part_key && b_length < a_length)
return 0;
if (skip_end_space && a_length != b_length)
{
int swap= 1;
/*
We are using space compression. We have to check if longer key
has next character < ' ', in which case it's less than the shorter
key that has an implicite space afterwards.
This code is identical to the one in
strings/ctype-simple.c:my_strnncollsp_simple
*/
if (a_length < b_length)
{
/* put shorter key in a */
a_length= b_length;
a= b;
swap= -1; /* swap sign of result */
}
for (end= a + a_length-length; a < end ; a++)
{
if (*a != ' ')
return (*a < ' ') ? -swap : swap;
}
return 0;
}
return (int) (a_length-b_length);
}
/*
Compare two keys
SYNOPSIS
ha_key_cmp()
keyseg Array of key segments of key to compare
a First key to compare, in format from _mi_pack_key()
This is normally key specified by user
b Second key to compare. This is always from a row
key_length Length of key to compare. This can be shorter than
a to just compare sub keys
next_flag How keys should be compared
If bit SEARCH_FIND is not set the keys includes the row
position and this should also be compared
diff_pos OUT Number of first keypart where values differ, counting
from one.
diff_pos[1] OUT (b + diff_pos[1]) points to first value in tuple b
that is different from corresponding value in tuple a.
EXAMPLES
Example1: if the function is called for tuples
('aaa','bbb') and ('eee','fff'), then
diff_pos[0] = 1 (as 'aaa' != 'eee')
diff_pos[1] = 0 (offset from beggining of tuple b to 'eee' keypart).
Example2: if the index function is called for tuples
('aaa','bbb') and ('aaa','fff'),
diff_pos[0] = 2 (as 'aaa' != 'eee')
diff_pos[1] = 3 (offset from beggining of tuple b to 'fff' keypart,
here we assume that first key part is CHAR(3) NOT NULL)
NOTES
Number-keys can't be splited
RETURN VALUES
<0 If a < b
0 If a == b
>0 If a > b
*/
#define FCMP(A,B) ((int) (A) - (int) (B))
int ha_key_cmp(register HA_KEYSEG *keyseg, register uchar *a,
register uchar *b, uint key_length, uint nextflag,
uint *diff_pos)
{
int flag;
int16 s_1,s_2;
int32 l_1,l_2;
uint32 u_1,u_2;
float f_1,f_2;
double d_1,d_2;
uint next_key_length;
uchar *orig_b= b;
*diff_pos=0;
for ( ; (int) key_length >0 ; key_length=next_key_length, keyseg++)
{
uchar *end;
uint piks=! (keyseg->flag & HA_NO_SORT);
(*diff_pos)++;
diff_pos[1]= (uint)(b - orig_b);
/* Handle NULL part */
if (keyseg->null_bit)
{
key_length--;
if (*a != *b && piks)
{
flag = (int) *a - (int) *b;
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
}
b++;
if (!*a++) /* If key was NULL */
{
if (nextflag == (SEARCH_FIND | SEARCH_UPDATE))
nextflag=SEARCH_SAME; /* Allow duplicate keys */
else if (nextflag & SEARCH_NULL_ARE_NOT_EQUAL)
{
/*
This is only used from mi_check() to calculate cardinality.
It can't be used when searching for a key as this would cause
compare of (a,b) and (b,a) to return the same value.
*/
return -1;
}
next_key_length=key_length;
continue; /* To next key part */
}
}
end= a+ min(keyseg->length,key_length);
next_key_length=key_length-keyseg->length;
switch ((enum ha_base_keytype) keyseg->type) {
case HA_KEYTYPE_TEXT: /* Ascii; Key is converted */
if (keyseg->flag & HA_SPACE_PACK)
{
int a_length,b_length,pack_length;
get_key_length(a_length,a);
get_key_pack_length(b_length,pack_length,b);
next_key_length=key_length-b_length-pack_length;
if (piks &&
(flag=ha_compare_text(keyseg->charset,a,a_length,b,b_length,
(my_bool) ((nextflag & SEARCH_PREFIX) &&
next_key_length <= 0),
(my_bool)!(nextflag & SEARCH_PREFIX))))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a+=a_length;
b+=b_length;
break;
}
else
{
uint length=(uint) (end-a), a_length=length, b_length=length;
if (piks &&
(flag= ha_compare_text(keyseg->charset, a, a_length, b, b_length,
(my_bool) ((nextflag & SEARCH_PREFIX) &&
next_key_length <= 0),
(my_bool)!(nextflag & SEARCH_PREFIX))))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a=end;
b+=length;
}
break;
case HA_KEYTYPE_BINARY:
case HA_KEYTYPE_BIT:
if (keyseg->flag & HA_SPACE_PACK)
{
int a_length,b_length,pack_length;
get_key_length(a_length,a);
get_key_pack_length(b_length,pack_length,b);
next_key_length=key_length-b_length-pack_length;
if (piks &&
(flag=compare_bin(a,a_length,b,b_length,
(my_bool) ((nextflag & SEARCH_PREFIX) &&
next_key_length <= 0),1)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a+=a_length;
b+=b_length;
break;
}
else
{
uint length=keyseg->length;
if (piks &&
(flag=compare_bin(a,length,b,length,
(my_bool) ((nextflag & SEARCH_PREFIX) &&
next_key_length <= 0),0)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a+=length;
b+=length;
}
break;
case HA_KEYTYPE_VARTEXT1:
case HA_KEYTYPE_VARTEXT2:
{
int a_length,b_length,pack_length;
get_key_length(a_length,a);
get_key_pack_length(b_length,pack_length,b);
next_key_length=key_length-b_length-pack_length;
if (piks &&
(flag= ha_compare_text(keyseg->charset,a,a_length,b,b_length,
(my_bool) ((nextflag & SEARCH_PREFIX) &&
next_key_length <= 0),
(my_bool) ((nextflag & (SEARCH_FIND |
SEARCH_UPDATE)) ==
SEARCH_FIND &&
! (keyseg->flag &
HA_END_SPACE_ARE_EQUAL)))))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a+= a_length;
b+= b_length;
break;
}
break;
case HA_KEYTYPE_VARBINARY1:
case HA_KEYTYPE_VARBINARY2:
{
int a_length,b_length,pack_length;
get_key_length(a_length,a);
get_key_pack_length(b_length,pack_length,b);
next_key_length=key_length-b_length-pack_length;
if (piks &&
(flag=compare_bin(a,a_length,b,b_length,
(my_bool) ((nextflag & SEARCH_PREFIX) &&
next_key_length <= 0), 0)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a+=a_length;
b+=b_length;
}
break;
case HA_KEYTYPE_INT8:
{
int i_1= (int) *((signed char*) a);
int i_2= (int) *((signed char*) b);
if (piks && (flag = CMP_NUM(i_1,i_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b++;
break;
}
case HA_KEYTYPE_SHORT_INT:
s_1= mi_sint2korr(a);
s_2= mi_sint2korr(b);
if (piks && (flag = CMP_NUM(s_1,s_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 2; /* sizeof(short int); */
break;
case HA_KEYTYPE_USHORT_INT:
{
uint16 us_1,us_2;
us_1= mi_sint2korr(a);
us_2= mi_sint2korr(b);
if (piks && (flag = CMP_NUM(us_1,us_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+=2; /* sizeof(short int); */
break;
}
case HA_KEYTYPE_LONG_INT:
l_1= mi_sint4korr(a);
l_2= mi_sint4korr(b);
if (piks && (flag = CMP_NUM(l_1,l_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 4; /* sizeof(long int); */
break;
case HA_KEYTYPE_ULONG_INT:
u_1= mi_sint4korr(a);
u_2= mi_sint4korr(b);
if (piks && (flag = CMP_NUM(u_1,u_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 4; /* sizeof(long int); */
break;
case HA_KEYTYPE_INT24:
l_1=mi_sint3korr(a);
l_2=mi_sint3korr(b);
if (piks && (flag = CMP_NUM(l_1,l_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 3;
break;
case HA_KEYTYPE_UINT24:
l_1=mi_uint3korr(a);
l_2=mi_uint3korr(b);
if (piks && (flag = CMP_NUM(l_1,l_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 3;
break;
case HA_KEYTYPE_FLOAT:
mi_float4get(f_1,a);
mi_float4get(f_2,b);
/*
The following may give a compiler warning about floating point
comparison not being safe, but this is ok in this context as
we are bascily doing sorting
*/
if (piks && (flag = CMP_NUM(f_1,f_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 4; /* sizeof(float); */
break;
case HA_KEYTYPE_DOUBLE:
mi_float8get(d_1,a);
mi_float8get(d_2,b);
/*
The following may give a compiler warning about floating point
comparison not being safe, but this is ok in this context as
we are bascily doing sorting
*/
if (piks && (flag = CMP_NUM(d_1,d_2)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 8; /* sizeof(double); */
break;
case HA_KEYTYPE_NUM: /* Numeric key */
{
int swap_flag= 0;
int alength,blength;
if (keyseg->flag & HA_REVERSE_SORT)
{
swap_variables(uchar*, a, b);
swap_flag=1; /* Remember swap of a & b */
end= a+ (int) (end-b);
}
if (keyseg->flag & HA_SPACE_PACK)
{
alength= *a++; blength= *b++;
end=a+alength;
next_key_length=key_length-blength-1;
}
else
{
alength= (int) (end-a);
blength=keyseg->length;
/* remove pre space from keys */
for ( ; alength && *a == ' ' ; a++, alength--) ;
for ( ; blength && *b == ' ' ; b++, blength--) ;
}
if (piks)
{
if (*a == '-')
{
if (*b != '-')
return -1;
a++; b++;
swap_variables(uchar*, a, b);
swap_variables(int, alength, blength);
swap_flag=1-swap_flag;
alength--; blength--;
end=a+alength;
}
else if (*b == '-')
return 1;
while (alength && (*a == '+' || *a == '0'))
{
a++; alength--;
}
while (blength && (*b == '+' || *b == '0'))
{
b++; blength--;
}
if (alength != blength)
return (alength < blength) ? -1 : 1;
while (a < end)
if (*a++ != *b++)
return ((int) a[-1] - (int) b[-1]);
}
else
{
b+=(end-a);
a=end;
}
if (swap_flag) /* Restore pointers */
swap_variables(uchar*, a, b);
break;
}
#ifdef HAVE_LONG_LONG
case HA_KEYTYPE_LONGLONG:
{
longlong ll_a,ll_b;
ll_a= mi_sint8korr(a);
ll_b= mi_sint8korr(b);
if (piks && (flag = CMP_NUM(ll_a,ll_b)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 8;
break;
}
case HA_KEYTYPE_ULONGLONG:
{
ulonglong ll_a,ll_b;
ll_a= mi_uint8korr(a);
ll_b= mi_uint8korr(b);
if (piks && (flag = CMP_NUM(ll_a,ll_b)))
return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
a= end;
b+= 8;
break;
}
#endif
case HA_KEYTYPE_END: /* Ready */
goto end; /* diff_pos is incremented */
}
}
(*diff_pos)++;
end:
if (!(nextflag & SEARCH_FIND))
{
uint i;
if (nextflag & (SEARCH_NO_FIND | SEARCH_LAST)) /* Find record after key */
return (nextflag & (SEARCH_BIGGER | SEARCH_LAST)) ? -1 : 1;
flag=0;
for (i=keyseg->length ; i-- > 0 ; )
{
if (*a++ != *b++)
{
flag= FCMP(a[-1],b[-1]);
break;
}
}
if (nextflag & SEARCH_SAME)
return (flag); /* read same */
if (nextflag & SEARCH_BIGGER)
return (flag <= 0 ? -1 : 1); /* read next */
return (flag < 0 ? -1 : 1); /* read previous */
}
return 0;
} /* ha_key_cmp */
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