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MDEV-26669 Add MY_COLLATION_HANDLER functions min_str() and max_str()

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This commit is contained in:
Alexander Barkov
2021-09-23 18:46:37 +04:00
parent 7697216371
commit 0d68b0a2d6
23 changed files with 683 additions and 87 deletions
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41
strings/ctype-mb.c
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@@ -16,6 +16,7 @@
#include "strings_def.h"
#include <m_ctype.h>
#include "ctype-mb.h"
#ifdef USE_MB
@@ -640,6 +641,46 @@ my_hash_sort_mb_bin(CHARSET_INFO *cs __attribute__((unused)),
}
static inline size_t
my_repeat_char_native(CHARSET_INFO *cs,
uchar *dst, size_t dst_size, size_t nchars,
my_wc_t native_code)
{
uchar *dst0= dst;
uchar *dstend= dst + dst_size;
int chlen= my_ci_native_to_mb(cs, native_code, dst, dstend);
if (chlen < 1 /* Not enough space */ || !nchars)
return 0;
for (dst+= chlen, nchars--;
dst + chlen <= dstend && nchars > 0;
dst+= chlen, nchars--)
memcpy(dst, dst0, chlen);
return dst - dst0;
}
size_t my_min_str_mb_simple(CHARSET_INFO *cs,
uchar *dst, size_t dst_size, size_t nchars)
{
return my_repeat_char_native(cs, dst, dst_size, nchars, cs->min_sort_char);
}
size_t my_min_str_mb_simple_nopad(CHARSET_INFO *cs,
uchar *dst, size_t dst_size, size_t nchars)
{
/* For NOPAD collations, the empty string is the smallest possible */
return 0;
}
size_t my_max_str_mb_simple(CHARSET_INFO *cs,
uchar *dst, size_t dst_size, size_t nchars)
{
return my_repeat_char_native(cs, dst, dst_size, nchars, cs->max_sort_char);
}
/*
Fill the given buffer with 'maximum character' for given charset
SYNOPSIS