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
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
#ifndef STRINGS_DEF_INCLUDED
#define STRINGS_DEF_INCLUDED
/* Copyright (C) 2011 Monty Program Ab
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 Street, Fifth Floor, Boston, MA 02110-1335 USA */
/* This file is to be include first in all files in the string directory */
#undef DBUG_ASSERT_AS_PRINTF
#include <my_global.h> /* Define standard vars */
#include "m_string.h" /* Exernal definitions of string functions */
/*
We can't use the original DBUG_ASSERT() (which includes _db_flush())
in the strings library as libdbug is compiled after the the strings
library and we don't want to have strings depending on libdbug which
depends on mysys and strings.
*/
#if !defined(DBUG_OFF)
#undef DBUG_ASSERT
#define DBUG_ASSERT(A) assert(A)
#endif
#define MY_NOPAD_ID(x) ((x)+0x400)
/* SPACE_INT is a word that contains only spaces */
#if SIZEOF_INT == 4
#define SPACE_INT 0x20202020
#elif SIZEOF_INT == 8
#define SPACE_INT 0x2020202020202020
#else
#error define the appropriate constant for a word full of spaces
#endif
/**
Skip trailing space.
On most systems reading memory in larger chunks (ideally equal to the size of
the chinks that the machine physically reads from memory) causes fewer memory
access loops and hence increased performance.
This is why the 'int' type is used : it's closest to that (according to how
it's defined in C).
So when we determine the amount of whitespace at the end of a string we do
the following :
1. We divide the string into 3 zones :
a) from the start of the string (__start) to the first multiple
of sizeof(int) (__start_words)
b) from the end of the string (__end) to the last multiple of sizeof(int)
(__end_words)
c) a zone that is aligned to sizeof(int) and can be safely accessed
through an int *
2. We start comparing backwards from (c) char-by-char. If all we find is
space then we continue
3. If there are elements in zone (b) we compare them as unsigned ints to a
int mask (SPACE_INT) consisting of all spaces
4. Finally we compare the remaining part (a) of the string char by char.
This covers for the last non-space unsigned int from 3. (if any)
This algorithm works well for relatively larger strings, but it will slow
the things down for smaller strings (because of the additional calculations
and checks compared to the naive method). Thus the barrier of length 20
is added.
@param ptr pointer to the input string
@param len the length of the string
@return the last non-space character
*/
static inline const uchar *skip_trailing_space(const uchar *ptr,size_t len)
{
const uchar *end= ptr + len;
if (len > 20)
{
const uchar *end_words= (const uchar *)(intptr)
(((ulonglong)(intptr)end) / SIZEOF_INT * SIZEOF_INT);
const uchar *start_words= (const uchar *)(intptr)
((((ulonglong)(intptr)ptr) + SIZEOF_INT - 1) / SIZEOF_INT * SIZEOF_INT);
DBUG_ASSERT(((ulonglong)(intptr)ptr) >= SIZEOF_INT);
if (end_words > ptr)
{
while (end > end_words && end[-1] == 0x20)
end--;
if (end[-1] == 0x20 && start_words < end_words)
while (end > start_words && ((unsigned *)end)[-1] == SPACE_INT)
end -= SIZEOF_INT;
}
}
while (end > ptr && end[-1] == 0x20)
end--;
return (end);
}
int my_strnncollsp_nchars_generic(CHARSET_INFO *cs,
const uchar *str1, size_t len1,
const uchar *str2, size_t len2,
size_t nchars);
int my_strnncollsp_nchars_generic_8bit(CHARSET_INFO *cs,
const uchar *str1, size_t len1,
const uchar *str2, size_t len2,
size_t nchars);
uint my_8bit_charset_flags_from_data(CHARSET_INFO *cs);
uint my_8bit_collation_flags_from_data(CHARSET_INFO *cs);
/* Macros for hashing characters */
#define MY_HASH_ADD(A, B, value) \
do { A^= (((A & 63)+B)*((value)))+ (A << 8); B+=3; } while(0)
#define MY_HASH_ADD_16(A, B, value) \
do { MY_HASH_ADD(A, B, ((value) & 0xFF)) ; MY_HASH_ADD(A, B, ((value >>8 ))); } while(0)
#define my_wc_t ulong
int my_wc_to_printable_ex(CHARSET_INFO *cs, my_wc_t wc,
uchar *s, uchar *e,
uint bs, uint bslen, uint diglen);
int my_wc_to_printable_generic(CHARSET_INFO *cs, my_wc_t wc,
uchar *s, uchar *e);
int my_wc_to_printable_8bit(CHARSET_INFO *cs, my_wc_t wc,
uchar *s, uchar *e);
/* Some common character set names */
extern const char charset_name_latin2[];
#define charset_name_latin2_length 6
extern const char charset_name_utf8mb3[];
#define charset_name_utf8mb3_length 7
extern const char charset_name_utf16[];
#define charset_name_utf16_length 5
extern const char charset_name_utf32[];
#define charset_name_utf32_length 5
extern const char charset_name_ucs2[];
#define charset_name_ucs2_length 4
extern const char charset_name_utf8mb4[];
#define charset_name_utf8mb4_length 7
#endif /*STRINGS_DEF_INCLUDED */
|
