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ctype-utf8.c:

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A faster UTF8 null-terminated string implementation.
  It is used for identifier comparison, so it's quite critical.


strings/ctype-utf8.c:
  A faster UTF8 null-terminated string implementation.
  It is used for identifier comparison, so it's quite critical.
This commit is contained in:
unknown 2004-10-20 18:07:59 +05:00
parent 6d3e14a1c6
commit 9eb596fb2e
1 changed files with 85 additions and 31 deletions
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116
strings/ctype-utf8.c
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@ -2103,49 +2103,103 @@ static int my_strnncollsp_utf8(CHARSET_INFO *cs,
}
static int my_strncasecmp_utf8(CHARSET_INFO *cs,
const char *s, const char *t, uint len)
/*
Compare 0-terminated UTF8 strings.
SYNOPSIS
my_strcasecmp_utf8()
cs character set handler
s First 0-terminated string to compare
t Second 0-terminated string to compare
IMPLEMENTATION
RETURN
- negative number if s < t
- positive number if s > t
- 0 is the strings are equal
*/
static
int my_strcasecmp_utf8(CHARSET_INFO *cs, const char *s, const char *t)
{
int s_res,t_res;
my_wc_t s_wc,t_wc;
const char *se=s+len;
const char *te=t+len;
while ( s < se && t < te )
while (s[0] && t[0])
{
int plane;
my_wc_t s_wc,t_wc;
s_res=my_utf8_uni(cs,&s_wc, (const uchar*)s, (const uchar*)se);
t_res=my_utf8_uni(cs,&t_wc, (const uchar*)t, (const uchar*)te);
if ( s_res <= 0 || t_res <= 0 )
if (s[0] >= 0)
{
/* Incorrect string, compare byte by byte value */
return bincmp(s, se, t, te);
/*
s[0] is between 0 and 127.
It represents a single byte character.
Convert it into weight according to collation.
*/
s_wc= plane00[(uchar) s[0]].tolower;
s++;
}
else
{
int plane, res;
/*
Scan a multibyte character.
plane=(s_wc>>8) & 0xFF;
s_wc = uni_plane[plane] ? uni_plane[plane][s_wc & 0xFF].tolower : s_wc;
plane=(t_wc>>8) & 0xFF;
t_wc = uni_plane[plane] ? uni_plane[plane][t_wc & 0xFF].tolower : t_wc;
In the future it is worth to write a special version of my_utf8_uni()
for 0-terminated strings which will not take in account length. Now
we call the regular version of my_utf8_uni() with s+3 in the
last argument. s+3 is enough to scan any multibyte sequence.
Calling the regular version of my_utf8_uni is safe for 0-terminated
strings: we will never lose the end of the string:
If we have 0 character in the middle of a multibyte sequence,
then my_utf8_uni will always return a negative number, so the
loop with finish.
*/
res= my_utf8_uni(cs,&s_wc, (const uchar*)s, (const uchar*) s + 3);
/*
In the case of wrong multibyte sequence we will
call strcmp() for byte-to-byte comparison.
*/
if (res <= 0)
return strcmp(s, t);
s+= res;
/* Convert Unicode code into weight according to collation */
plane=(s_wc>>8) & 0xFF;
s_wc = uni_plane[plane] ? uni_plane[plane][s_wc & 0xFF].tolower : s_wc;
}
/* Do the same for the second string */
if (t[0] >= 0)
{
/* Convert single byte character into weight */
t_wc= plane00[(uchar) t[0]].tolower;
t++;
}
else
{
int plane;
int res=my_utf8_uni(cs,&t_wc, (const uchar*)t, (const uchar*) t + 3);
if (res <= 0)
return strcmp(s, t);
t+= res;
/* Convert code into weight */
plane=(t_wc>>8) & 0xFF;
t_wc = uni_plane[plane] ? uni_plane[plane][t_wc & 0xFF].tolower : t_wc;
}
/* Now we have two weights, let's compare them */
if ( s_wc != t_wc )
return ((int) s_wc) - ((int) t_wc);
s+=s_res;
t+=t_res;
}
return ( (se-s) - (te-t) );
return ((int)(uchar)s[0]) - ((int) (uchar) t[0]);
}
static int my_strcasecmp_utf8(CHARSET_INFO *cs, const char *s, const char *t)
{
uint s_len=strlen(s);
uint t_len=strlen(t);
uint len = (s_len > t_len) ? s_len : t_len;
return my_strncasecmp_utf8(cs, s, t, len);
}
static
int my_wildcmp_utf8(CHARSET_INFO *cs,