summaryrefslogtreecommitdiff
path: root/include/my_compare.h
blob: bd1a7bd1f3404984be2509ddfb47f4c15a5ee9b9 (plain)
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
/* Copyright (c) 2011, Oracle and/or its affiliates.
   Copyright (c) Monty Program Ab; 1991-2011

   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 */

#ifndef _my_compare_h
#define _my_compare_h

#include "myisampack.h"
#ifdef	__cplusplus
extern "C" {
#endif

#include "m_ctype.h"                            /* CHARSET_INFO */

/*
  There is a hard limit for the maximum number of keys as there are only
  8 bits in the index file header for the number of keys in a table.
  This means that 0..255 keys can exist for a table. The idea of
  HA_MAX_POSSIBLE_KEY is to ensure that one can use myisamchk & tools on
  a MyISAM table for which one has more keys than MyISAM is normally
  compiled for. If you don't have this, you will get a core dump when
  running myisamchk compiled for 128 keys on a table with 255 keys.
*/

#define HA_MAX_POSSIBLE_KEY         255         /* For myisamchk */
/*
  The following defines can be increased if necessary.
  But beware the dependency of MI_MAX_POSSIBLE_KEY_BUFF and HA_MAX_KEY_LENGTH.
*/

#define HA_MAX_KEY_LENGTH           1000        /* Max length in bytes */
#define HA_MAX_KEY_SEG              32          /* Max segments for key */

#define HA_MAX_POSSIBLE_KEY_BUFF    (HA_MAX_KEY_LENGTH + 24+ 6+6)
#define HA_MAX_KEY_BUFF  (HA_MAX_KEY_LENGTH+HA_MAX_KEY_SEG*6+8+8)

typedef struct st_HA_KEYSEG		/* Key-portion */
{
  CHARSET_INFO *charset;
  uint32 start;				/* Start of key in record */
  uint32 null_pos;			/* position to NULL indicator */
  uint16 bit_pos;                       /* Position to bit part */
  uint16 flag;
  uint16 length;			/* Keylength */
  uint16 language;
  uint8  type;				/* Type of key (for sort) */
  uint8  null_bit;			/* bitmask to test for NULL */
  uint8  bit_start;
  uint8  bit_length;                    /* Length of bit part */
} HA_KEYSEG;

#define get_key_length(length,key) \
{ if (*(const uchar*) (key) != 255) \
    length= (uint) *(const uchar*) ((key)++); \
  else \
  { length= mi_uint2korr((key)+1); (key)+=3; } \
}

#define get_key_length_rdonly(length,key) \
{ if (*(const uchar*) (key) != 255) \
    length= ((uint) *(const uchar*) ((key))); \
  else \
  { length= mi_uint2korr((key)+1); } \
}

#define get_key_pack_length(length,length_pack,key) \
{ if (*(const uchar*) (key) != 255) \
  { length= (uint) *(const uchar*) ((key)++); length_pack= 1; }\
  else \
  { length=mi_uint2korr((key)+1); (key)+= 3; length_pack= 3; } \
}

#define store_key_length_inc(key,length) \
{ if ((length) < 255) \
  { *(key)++= (uchar)(length); } \
  else \
  { *(key)=255; mi_int2store((key)+1,(length)); (key)+=3; } \
}

#define size_to_store_key_length(length) ((length) < 255 ? 1 : 3)

static inline uchar get_rec_bits(const uchar *ptr, uchar ofs, uint len)
{
  uint16 val= ptr[0];
  if (ofs + len > 8)
    val|= (uint16)(ptr[1]) << 8;
  return (val >> ofs) & ((1 << len) - 1);
}

static inline void set_rec_bits(uint16 bits, uchar *ptr, uchar ofs, uint len)
{
  ptr[0]= (ptr[0] & ~(((1 << len) - 1) << ofs)) | (bits << ofs);
  if (ofs + len > 8)
    ptr[1]= (ptr[1] & ~((1 << (len - 8 + ofs)) - 1)) | (bits >> (8 - ofs));
}

#define clr_rec_bits(bit_ptr, bit_ofs, bit_len) \
  set_rec_bits(0, bit_ptr, bit_ofs, bit_len)

extern int ha_compare_text(CHARSET_INFO *, const uchar *, size_t,
                           const uchar *, size_t , my_bool);
extern int ha_key_cmp(HA_KEYSEG *keyseg, const uchar *a,
		      const uchar *b, uint key_length, uint nextflag,
		      uint *diff_pos);
extern HA_KEYSEG *ha_find_null(HA_KEYSEG *keyseg, const uchar *a);

/*
  Inside an in-memory data record, memory pointers to pieces of the
  record (like BLOBs) are stored in their native byte order and in
  this amount of bytes.
*/
#define portable_sizeof_char_ptr 8
#ifdef	__cplusplus
}
#endif

/**
  Return values of index_cond_func_xxx functions.

  0=ICP_NO_MATCH  - index tuple doesn't satisfy the pushed index condition (the
                    engine should discard the tuple and go to the next one)
  1=ICP_MATCH     - index tuple satisfies the pushed index condition (the
                    engine should fetch and return the record)
  2=ICP_OUT_OF_RANGE - index tuple is out range that we're scanning, e.g. this
                      if we're scanning "t.key BETWEEN 10 AND 20" and got a
                      "t.key=21" tuple (the engine should stop scanning and
                      return HA_ERR_END_OF_FILE right away).
  3=ICP_ABORTED_BY_USER - engine must stop scanning and should return 
                         HA_ERR_ABORTED_BY_USER right away
 -1= ICP_ERROR    - Reserved for internal errors in engines. Should not be
                    returned by index_cond_func_xxx
*/

typedef enum icp_result {
  ICP_ERROR=-1,
  ICP_NO_MATCH=0,
  ICP_MATCH=1,
  ICP_OUT_OF_RANGE=2,
  ICP_ABORTED_BY_USER=3
} ICP_RESULT;

typedef ICP_RESULT (*index_cond_func_t)(void *param);

#endif /* _my_compare_h */