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ctype-mb.c
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/* Copyright (c) 2002, 2016, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include <my_global.h>
#include "m_ctype.h"
#include "m_string.h"
size_t my_caseup_str_mb(const CHARSET_INFO *cs, char *str)
{
uint32 l;
const uchar *map= cs->to_upper;
char *str_orig= str;
while (*str)
{
/* Pointing after the '\0' is safe here. */
if ((l= my_ismbchar(cs, str, str + cs->mbmaxlen)))
str+= l;
else
{
*str= (char) map[(uchar)*str];
str++;
}
}
return (size_t) (str - str_orig);
}
size_t my_casedn_str_mb(const CHARSET_INFO *cs, char *str)
{
uint32 l;
const uchar *map= cs->to_lower;
char *str_orig= str;
while (*str)
{
/* Pointing after the '\0' is safe here. */
if ((l= my_ismbchar(cs, str, str + cs->mbmaxlen)))
str+= l;
else
{
*str= (char) map[(uchar)*str];
str++;
}
}
return (size_t) (str - str_orig);
}
static inline const MY_UNICASE_CHARACTER*
get_case_info_for_ch(const CHARSET_INFO *cs, uint page, uint offs)
{
const MY_UNICASE_CHARACTER *p;
return cs->caseinfo ? ((p= cs->caseinfo->page[page]) ? &p[offs] : NULL) : NULL;
}
/*
For character sets which don't change octet length in case conversion.
*/
size_t my_caseup_mb(const CHARSET_INFO *cs, char *src, size_t srclen,
char *dst MY_ATTRIBUTE((unused)),
size_t dstlen MY_ATTRIBUTE((unused)))
{
uint32 l;
char *srcend= src + srclen;
const uchar *map= cs->to_upper;
DBUG_ASSERT(cs->caseup_multiply == 1);
DBUG_ASSERT(src == dst && srclen == dstlen);
DBUG_ASSERT(cs->mbmaxlen == 2);
while (src < srcend)
{
if ((l=my_ismbchar(cs, src, srcend)))
{
const MY_UNICASE_CHARACTER *ch;
if ((ch= get_case_info_for_ch(cs, (uchar) src[0], (uchar) src[1])))
{
*src++= ch->toupper >> 8;
*src++= ch->toupper & 0xFF;
}
else
src+= l;
}
else
{
*src=(char) map[(uchar) *src];
src++;
}
}
return srclen;
}
size_t my_casedn_mb(const CHARSET_INFO *cs, char *src, size_t srclen,
char *dst MY_ATTRIBUTE((unused)),
size_t dstlen MY_ATTRIBUTE((unused)))
{
uint32 l;
char *srcend= src + srclen;
const uchar *map=cs->to_lower;
DBUG_ASSERT(cs->casedn_multiply == 1);
DBUG_ASSERT(src == dst && srclen == dstlen);
DBUG_ASSERT(cs->mbmaxlen == 2);
while (src < srcend)
{
if ((l= my_ismbchar(cs, src, srcend)))
{
const MY_UNICASE_CHARACTER *ch;
if ((ch= get_case_info_for_ch(cs, (uchar) src[0], (uchar) src[1])))
{
*src++= ch->tolower >> 8;
*src++= ch->tolower & 0xFF;
}
else
src+= l;
}
else
{
*src= (char) map[(uchar)*src];
src++;
}
}
return srclen;
}
/*
Case folding functions for character set
where case conversion can change string octet length.
For example, in EUCKR,
_euckr 0xA9A5 == "LATIN LETTER DOTLESS I" (Turkish letter)
is upper-cased to to
_euckr 0x49 "LATIN CAPITAL LETTER I" ('usual' letter I)
Length is reduced in this example from two bytes to one byte.
*/
static size_t
my_casefold_mb_varlen(const CHARSET_INFO *cs,
char *src, size_t srclen,
char *dst, size_t dstlen MY_ATTRIBUTE((unused)),
const uchar *map,
size_t is_upper)
{
char *srcend= src + srclen, *dst0= dst;
DBUG_ASSERT(cs->mbmaxlen == 2);
while (src < srcend)
{
size_t mblen= my_ismbchar(cs, src, srcend);
if (mblen)
{
const MY_UNICASE_CHARACTER *ch;
if ((ch= get_case_info_for_ch(cs, (uchar) src[0], (uchar) src[1])))
{
int code= is_upper ? ch->toupper : ch->tolower;
src+= 2;
if (code > 0xFF)
*dst++= code >> 8;
*dst++= code & 0xFF;
}
else
{
*dst++= *src++;
*dst++= *src++;
}
}
else
{
*dst++= (char) map[(uchar) *src++];
}
}
return (size_t) (dst - dst0);
}
size_t
my_casedn_mb_varlen(const CHARSET_INFO *cs, char *src, size_t srclen,
char *dst, size_t dstlen)
{
DBUG_ASSERT(dstlen >= srclen * cs->casedn_multiply);
DBUG_ASSERT(src != dst || cs->casedn_multiply == 1);
return my_casefold_mb_varlen(cs, src, srclen, dst, dstlen, cs->to_lower, 0);
}
size_t
my_caseup_mb_varlen(const CHARSET_INFO *cs, char *src, size_t srclen,
char *dst, size_t dstlen)
{
DBUG_ASSERT(dstlen >= srclen * cs->caseup_multiply);
DBUG_ASSERT(src != dst || cs->caseup_multiply == 1);
return my_casefold_mb_varlen(cs, src, srclen, dst, dstlen, cs->to_upper, 1);
}
/*
my_strcasecmp_mb() returns 0 if strings are equal, non-zero otherwise.
*/
int my_strcasecmp_mb(const CHARSET_INFO *cs,const char *s, const char *t)
{
uint32 l;
const uchar *map=cs->to_upper;
while (*s && *t)
{
/* Pointing after the '\0' is safe here. */
if ((l=my_ismbchar(cs, s, s + cs->mbmaxlen)))
{
while (l--)
if (*s++ != *t++)
return 1;
}
else if (my_mbcharlen(cs, *t) != 1 ||
map[(uchar) *s++] != map[(uchar) *t++])
return 1;
}
/* At least one of '*s' and '*t' is zero here. */
DBUG_ASSERT(!*t || !*s);
return (*t != *s);
}
/*
** Compare string against string with wildcard
** 0 if matched
** -1 if not matched with wildcard
** 1 if matched with wildcard
*/
#define INC_PTR(cs,A,B) A+=(my_ismbchar(cs,A,B) ? my_ismbchar(cs,A,B) : 1)
#define likeconv(s,A) (uchar) (s)->sort_order[(uchar) (A)]
static
int my_wildcmp_mb_impl(const CHARSET_INFO *cs,
const char *str,const char *str_end,
const char *wildstr,const char *wildend,
int escape, int w_one, int w_many, int recurse_level)
{
int result= -1; /* Not found, using wildcards */
if (my_string_stack_guard && my_string_stack_guard(recurse_level))
return 1;
while (wildstr != wildend)
{
while (*wildstr != w_many && *wildstr != w_one)
{
int l;
if (*wildstr == escape && wildstr+1 != wildend)
wildstr++;
if ((l = my_ismbchar(cs, wildstr, wildend)))
{
if (str+l > str_end || memcmp(str, wildstr, l) != 0)
return 1;
str += l;
wildstr += l;
}
else
if (str == str_end || likeconv(cs,*wildstr++) != likeconv(cs,*str++))
return(1); /* No match */
if (wildstr == wildend)
return (str != str_end); /* Match if both are at end */
result=1; /* Found an anchor char */
}
if (*wildstr == w_one)
{
do
{
if (str == str_end) /* Skip one char if possible */
return (result);
INC_PTR(cs,str,str_end);
} while (++wildstr < wildend && *wildstr == w_one);
if (wildstr == wildend)
break;
}
if (*wildstr == w_many)
{ /* Found w_many */
uchar cmp;
const char* mb = wildstr;
int mb_len=0;
wildstr++;
/* Remove any '%' and '_' from the wild search string */
for (; wildstr != wildend ; wildstr++)
{
if (*wildstr == w_many)
continue;
if (*wildstr == w_one)
{
if (str == str_end)
return (-1);
INC_PTR(cs,str,str_end);
continue;
}
break; /* Not a wild character */
}
if (wildstr == wildend)
return(0); /* Ok if w_many is last */
if (str == str_end)
return -1;
if ((cmp= *wildstr) == escape && wildstr+1 != wildend)
cmp= *++wildstr;
mb=wildstr;
mb_len= my_ismbchar(cs, wildstr, wildend);
INC_PTR(cs,wildstr,wildend); /* This is compared trough cmp */
cmp=likeconv(cs,cmp);
do
{
for (;;)
{
if (str >= str_end)
return -1;
if (mb_len)
{
if (str+mb_len <= str_end && memcmp(str, mb, mb_len) == 0)
{
str += mb_len;
break;
}
}
else if (!my_ismbchar(cs, str, str_end) &&
likeconv(cs,*str) == cmp)
{
str++;
break;
}
INC_PTR(cs,str, str_end);
}
{
int tmp=my_wildcmp_mb_impl(cs,str,str_end,
wildstr,wildend,escape,w_one,
w_many, recurse_level + 1);
if (tmp <= 0)
return (tmp);
}
} while (str != str_end && wildstr[0] != w_many);
return(-1);
}
}
return (str != str_end ? 1 : 0);
}
int my_wildcmp_mb(const CHARSET_INFO *cs,
const char *str,const char *str_end,
const char *wildstr,const char *wildend,
int escape, int w_one, int w_many)
{
return my_wildcmp_mb_impl(cs, str, str_end,
wildstr, wildend,
escape, w_one, w_many, 1);
}
size_t my_numchars_mb(const CHARSET_INFO *cs MY_ATTRIBUTE((unused)),
const char *pos, const char *end)
{
size_t count= 0;
while (pos < end)
{
uint mb_len;
pos+= (mb_len= my_ismbchar(cs,pos,end)) ? mb_len : 1;
count++;
}
return count;
}
size_t my_charpos_mb(const CHARSET_INFO *cs MY_ATTRIBUTE((unused)),
const char *pos, const char *end, size_t length)
{
const char *start= pos;
while (length && pos < end)
{
uint mb_len;
pos+= (mb_len= my_ismbchar(cs, pos, end)) ? mb_len : 1;
length--;
}
return (size_t) (length ? end+2-start : pos-start);
}
size_t my_well_formed_len_mb(const CHARSET_INFO *cs, const char *b,
const char *e, size_t pos, int *error)
{
const char *b_start= b;
*error= 0;
while (pos)
{
my_wc_t wc;
int mb_len;
if ((mb_len= cs->cset->mb_wc(cs, &wc, (uchar*) b, (uchar*) e)) <= 0)
{
*error= b < e ? 1 : 0;
break;
}
b+= mb_len;
pos--;
}
return (size_t) (b - b_start);
}
uint my_instr_mb(const CHARSET_INFO *cs,
const char *b, size_t b_length,
const char *s, size_t s_length,
my_match_t *match, uint nmatch)
{
const char *end, *b0;
int res= 0;
if (s_length <= b_length)
{
if (!s_length)
{
if (nmatch)
{
match->beg= 0;
match->end= 0;
match->mb_len= 0;
}
return 1; /* Empty string is always found */
}
b0= b;
end= b+b_length-s_length+1;
while (b < end)
{
int mb_len;
if (!cs->coll->strnncoll(cs, (uchar*) b, s_length,
(uchar*) s, s_length, 0))
{
if (nmatch)
{
match[0].beg= 0;
match[0].end= (uint) (b-b0);
match[0].mb_len= res;
if (nmatch > 1)
{
match[1].beg= match[0].end;
match[1].end= match[0].end + (uint)s_length;
match[1].mb_len= 0; /* Not computed */
}
}
return 2;
}
mb_len= (mb_len= my_ismbchar(cs, b, end)) ? mb_len : 1;
b+= mb_len;
b_length-= mb_len;
res++;
}
}
return 0;
}
/* BINARY collations handlers for MB charsets */
int
my_strnncoll_mb_bin(const CHARSET_INFO *cs MY_ATTRIBUTE((unused)),
const uchar *s, size_t slen,
const uchar *t, size_t tlen,
my_bool t_is_prefix)
{
size_t len= MY_MIN(slen,tlen);
int cmp= memcmp(s,t,len);
return cmp ? cmp : (int) ((t_is_prefix ? len : slen) - tlen);
}
/*
Compare two strings.
SYNOPSIS
my_strnncollsp_mb_bin()
cs Chararacter set
s String to compare
slen Length of 's'
t String to compare
tlen Length of 't'
diff_if_only_endspace_difference
Set to 1 if the strings should be regarded as different
if they only difference in end space
NOTE
This function is used for character strings with binary collations.
The shorter string is extended with end space to be as long as the longer
one.
RETURN
A negative number if s < t
A positive number if s > t
0 if strings are equal
*/
int
my_strnncollsp_mb_bin(const CHARSET_INFO *cs MY_ATTRIBUTE((unused)),
const uchar *a, size_t a_length,
const uchar *b, size_t b_length,
my_bool diff_if_only_endspace_difference)
{
const uchar *end;
size_t length;
int res;
#ifndef VARCHAR_WITH_DIFF_ENDSPACE_ARE_DIFFERENT_FOR_UNIQUE
diff_if_only_endspace_difference= 0;
#endif
end= a + (length= MY_MIN(a_length, b_length));
while (a < end)
{
if (*a++ != *b++)
return ((int) a[-1] - (int) b[-1]);
}
res= 0;
if (a_length != b_length)
{
int swap= 1;
if (diff_if_only_endspace_difference)
res= 1; /* Assume 'a' is bigger */
/*
Check the next not space character of the longer key. If it's < ' ',
then it's smaller than the other key.
*/
if (a_length < b_length)
{
/* put shorter key in s */
a_length= b_length;
a= b;
swap= -1; /* swap sign of result */
res= -res;
}
for (end= a + a_length-length; a < end ; a++)
{
if (*a != ' ')
return (*a < ' ') ? -swap : swap;
}
}
return res;
}
/*
Copy one non-ascii character.
"dst" must have enough room for the character.
Note, we don't use sort_order[] in this macros.
This is correct even for case insensitive collations:
- basic Latin letters are processed outside this macros;
- for other characters sort_order[x] is equal to x.
*/
#define my_strnxfrm_mb_non_ascii_char(cs, dst, src, se) \
{ \
switch (cs->cset->ismbchar(cs, (const char*) src, (const char*) se)) { \
case 4: \
*dst++= *src++; \
/* fall through */ \
case 3: \
*dst++= *src++; \
/* fall through */ \
case 2: \
*dst++= *src++; \
/* fall through */ \
case 0: \
*dst++= *src++; /* byte in range 0x80..0xFF which is not MB head */ \
} \
}
/*
For character sets with two or three byte multi-byte
characters having multibyte weights *equal* to their codes:
cp932, euckr, gb2312, sjis, eucjpms, ujis.
*/
size_t
my_strnxfrm_mb(const CHARSET_INFO *cs,
uchar *dst, size_t dstlen, uint nweights,
const uchar *src, size_t srclen, uint flags)
{
uchar *d0= dst;
uchar *de= dst + dstlen;
const uchar *se= src + srclen;
const uchar *sort_order= cs->sort_order;
DBUG_ASSERT(cs->mbmaxlen <= 4);
/*
If "srclen" is smaller than both "dstlen" and "nweights"
then we can run a simplified loop -
without checking "nweights" and "de".
*/
if (dstlen >= srclen && nweights >= srclen)
{
if (sort_order)
{
/* Optimized version for a case insensitive collation */
for (; src < se; nweights--)
{
if (*src < 128) /* quickly catch ASCII characters */
*dst++= sort_order[*src++];
else
my_strnxfrm_mb_non_ascii_char(cs, dst, src, se);
}
}
else
{
/* Optimized version for a case sensitive collation (no sort_order) */
for (; src < se; nweights--)
{
if (*src < 128) /* quickly catch ASCII characters */
*dst++= *src++;
else
my_strnxfrm_mb_non_ascii_char(cs, dst, src, se);
}
}
goto pad;
}
/*
A thourough loop, checking all possible limits:
"se", "nweights" and "de".
*/
for (; src < se && nweights && dst < de; nweights--)
{
int chlen;
if (*src < 128 ||
!(chlen= cs->cset->ismbchar(cs, (const char*) src, (const char*) se)))
{
/* Single byte character */
*dst++= sort_order ? sort_order[*src++] : *src++;
}
else
{
/* Multi-byte character */
size_t len= (dst + chlen <= de) ? chlen : de - dst;
memcpy(dst, src, len);
dst+= len;
src+= len;
}
}
pad:
return my_strxfrm_pad_desc_and_reverse(cs, d0, dst, de, nweights, flags, 0);
}
int
my_strcasecmp_mb_bin(const CHARSET_INFO *cs MY_ATTRIBUTE((unused)),
const char *s, const char *t)
{
return strcmp(s,t);
}
void
my_hash_sort_mb_bin(const CHARSET_INFO *cs MY_ATTRIBUTE((unused)),
const uchar *key, size_t len,ulong *nr1, ulong *nr2)
{
const uchar *pos = key;
/*
Remove trailing spaces. We have to do this to be able to compare
'A ' and 'A' as identical
*/
key= skip_trailing_space(key, len);
for (; pos < (uchar*) key ; pos++)
{
nr1[0]^=(ulong) ((((uint) nr1[0] & 63)+nr2[0]) *
((uint)*pos)) + (nr1[0] << 8);
nr2[0]+=3;
}
}
/*
Fill the given buffer with 'maximum character' for given charset
SYNOPSIS
pad_max_char()
cs Character set
str Start of buffer to fill
end End of buffer to fill
DESCRIPTION
Write max key:
- for non-Unicode character sets:
just memset using max_sort_char if max_sort_char is one byte.
In case when max_sort_char is two bytes, fill with double-byte pairs
and optionally pad with a single space character.
- for Unicode character set (utf-8):
create a buffer with multibyte representation of the max_sort_char
character, and copy it into max_str in a loop.
*/
static void pad_max_char(const CHARSET_INFO *cs, char *str, char *end)
{
char buf[10];
char buflen;
if (!(cs->state & MY_CS_UNICODE))
{
if (cs->max_sort_char <= 255)
{
memset(str, cs->max_sort_char, end - str);
return;
}
else if (cs->max_sort_char <= 0xFFFF)
{
buf[0]= (char)(cs->max_sort_char >> 8);
buf[1]= cs->max_sort_char & 0xFF;
buflen= 2;
}
else
{
/* Currently, it's only for GB18030, so it must be a 4-byte char */
DBUG_ASSERT(cs->max_sort_char > 0xFFFFFF);
buf[0]= cs->max_sort_char >> 24 & 0xFF;
buf[1]= cs->max_sort_char >> 16 & 0xFF;
buf[2]= cs->max_sort_char >> 8 & 0xFF;
buf[3]= cs->max_sort_char & 0xFF;
buflen= 4;
}
}
else
{
buflen= cs->cset->wc_mb(cs, cs->max_sort_char, (uchar*) buf,
(uchar*) buf + sizeof(buf));
}
DBUG_ASSERT(buflen > 0);
do
{
if ((str + buflen) <= end)
{
/* Enough space for the characer */
memcpy(str, buf, buflen);
str+= buflen;
}
else
{
/*
There is no space for whole multibyte
character, then add trailing spaces.
*/
*str++= ' ';
}
} while (str < end);
}
/*
** Calculate min_str and max_str that ranges a LIKE string.
** Arguments:
** ptr Pointer to LIKE string.
** ptr_length Length of LIKE string.
** escape Escape character in LIKE. (Normally '\').
** All escape characters should be removed from min_str and max_str
** res_length Length of min_str and max_str.
** min_str Smallest case sensitive string that ranges LIKE.
** Should be space padded to res_length.
** max_str Largest case sensitive string that ranges LIKE.
** Normally padded with the biggest character sort value.
**
** The function should return 0 if ok and 1 if the LIKE string can't be
** optimized !
*/
my_bool my_like_range_mb(const CHARSET_INFO *cs,
const char *ptr,size_t ptr_length,
pbool escape, pbool w_one, pbool w_many,
size_t res_length,
char *min_str,char *max_str,
size_t *min_length,size_t *max_length)
{
uint mb_len;
const char *end= ptr + ptr_length;
char *min_org= min_str;
char *min_end= min_str + res_length;
char *max_end= max_str + res_length;
size_t maxcharlen= res_length / cs->mbmaxlen;
const MY_CONTRACTIONS *contractions= my_charset_get_contractions(cs, 0);
for (; ptr != end && min_str != min_end && maxcharlen ; maxcharlen--)
{
/* We assume here that escape, w_any, w_namy are one-byte characters */
if (*ptr == escape && ptr+1 != end)
ptr++; /* Skip escape */
else if (*ptr == w_one || *ptr == w_many) /* '_' and '%' in SQL */
{
fill_max_and_min:
/*
Calculate length of keys:
'a\0\0... is the smallest possible string when we have space expand
a\ff\ff... is the biggest possible string
*/
*min_length= ((cs->state & MY_CS_BINSORT) ? (size_t) (min_str - min_org) :
res_length);
*max_length= res_length;
/* Create min key */
do
{
*min_str++= (char) cs->min_sort_char;
} while (min_str != min_end);
/*
Write max key: create a buffer with multibyte
representation of the max_sort_char character,
and copy it into max_str in a loop.
*/
*max_length= res_length;
pad_max_char(cs, max_str, max_end);
return 0;
}
if ((mb_len= my_ismbchar(cs, ptr, end)) > 1)
{
if (ptr+mb_len > end || min_str+mb_len > min_end)
break;
while (mb_len--)
*min_str++= *max_str++= *ptr++;
}
else
{
/*
Special case for collations with contractions.
For example, in Chezh, 'ch' is a separate letter
which is sorted between 'h' and 'i'.
If the pattern 'abc%', 'c' at the end can mean:
- letter 'c' itself,
- beginning of the contraction 'ch'.
If we simply return this LIKE range:
'abc\min\min\min' and 'abc\max\max\max'
then this query: SELECT * FROM t1 WHERE a LIKE 'abc%'
will only find values starting from 'abc[^h]',
but won't find values starting from 'abch'.
We must ignore contraction heads followed by w_one or w_many.
('Contraction head' means any letter which can be the first
letter in a contraction)
For example, for Czech 'abc%', we will return LIKE range,
which is equal to LIKE range for 'ab%':
'ab\min\min\min\min' and 'ab\max\max\max\max'.
*/
if (contractions && ptr + 1 < end &&
my_uca_can_be_contraction_head(contractions, (uchar) *ptr))
{
/* Ptr[0] is a contraction head. */
if (ptr[1] == w_one || ptr[1] == w_many)
{
/* Contraction head followed by a wildcard, quit. */
goto fill_max_and_min;
}
/*
Some letters can be both contraction heads and contraction tails.
For example, in Danish 'aa' is a separate single letter which
is sorted after 'z'. So 'a' can be both head and tail.
If ptr[0]+ptr[1] is a contraction,
then put both letters together.
If ptr[1] can be a contraction part, but ptr[0]+ptr[1]
is not a contraction, then we put only ptr[0],
and continue with ptr[1] on the next loop.
*/
if (my_uca_can_be_contraction_tail(contractions, (uchar) ptr[1]) &&
my_uca_contraction2_weight(contractions, (uchar) ptr[0], ptr[1]))
{
/* Contraction found */
if (maxcharlen == 1 || min_str + 1 >= min_end)
{
/* Both contraction parts don't fit, quit */
goto fill_max_and_min;
}
/* Put contraction head */
*min_str++= *max_str++= *ptr++;
maxcharlen--;
}
}
/* Put contraction tail, or a single character */
*min_str++= *max_str++= *ptr++;
}
}
*min_length= *max_length = (size_t) (min_str - min_org);
while (min_str != min_end)
*min_str++= *max_str++= ' '; /* Because if key compression */
return 0;
}
/**
Calculate min_str and max_str that ranges a LIKE string.
Generic function, currently used for ucs2, utf16, utf32,
but should be suitable for any other character sets with
cs->min_sort_char and cs->max_sort_char represented in
Unicode code points.
@param cs Character set and collation pointer
@param ptr Pointer to LIKE pattern.
@param ptr_length Length of LIKE pattern.
@param escape Escape character pattern, typically '\'.
@param w_one 'One character' pattern, typically '_'.
@param w_many 'Many characters' pattern, typically '%'.
@param res_length Length of min_str and max_str.
@param[out] min_str Smallest string that ranges LIKE.
@param[out] max_str Largest string that ranges LIKE.
@param[out] min_len Length of min_str
@param[out] max_len Length of max_str
@return Optimization status.
@retval FALSE if LIKE pattern can be optimized
@rerval TRUE if LIKE can't be optimized.
*/
my_bool
my_like_range_generic(const CHARSET_INFO *cs,
const char *ptr, size_t ptr_length,
pbool escape, pbool w_one, pbool w_many,
size_t res_length,
char *min_str,char *max_str,
size_t *min_length,size_t *max_length)
{
const char *end= ptr + ptr_length;
const char *min_org= min_str;
const char *max_org= max_str;
char *min_end= min_str + res_length;
char *max_end= max_str + res_length;
size_t charlen= res_length / cs->mbmaxlen;
size_t res_length_diff;
const MY_CONTRACTIONS *contractions= my_charset_get_contractions(cs, 0);
for ( ; charlen > 0; charlen--)
{
my_wc_t wc, wc2;
int res;
if ((res= cs->cset->mb_wc(cs, &wc, (uchar*) ptr, (uchar*) end)) <= 0)
{
if (res == MY_CS_ILSEQ) /* Bad sequence */
return TRUE; /* min_length and max_length are not important */
break; /* End of the string */
}
ptr+= res;
if (wc == (my_wc_t) escape)
{
if ((res= cs->cset->mb_wc(cs, &wc, (uchar*) ptr, (uchar*) end)) <= 0)
{
if (res == MY_CS_ILSEQ)
return TRUE; /* min_length and max_length are not important */
/*
End of the string: Escape is the last character.
Put escape as a normal character.
We'll will leave the loop on the next iteration.
*/
}
else
ptr+= res;
/* Put escape character to min_str and max_str */
if ((res= cs->cset->wc_mb(cs, wc,
(uchar*) min_str, (uchar*) min_end)) <= 0)
goto pad_set_lengths; /* No space */
min_str+= res;
if ((res= cs->cset->wc_mb(cs, wc,
(uchar*) max_str, (uchar*) max_end)) <= 0)
goto pad_set_lengths; /* No space */
max_str+= res;
continue;
}
else if (wc == (my_wc_t) w_one)