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Diffstat (limited to 'include/my_compare.h')
| -rw-r--r-- | include/my_compare.h | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/include/my_compare.h b/include/my_compare.h new file mode 100644 index 00000000..048e679e --- /dev/null +++ b/include/my_compare.h @@ -0,0 +1,286 @@ +/* Copyright (c) 2011, Oracle and/or its affiliates. + Copyright (c) 1991, 2021, MariaDB Corporation. + + 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)(((uint) ptr[1]) << 8); + return (uchar) ((val >> ofs) & ((1 << len) - 1)); +} + +static inline void set_rec_bits(uint16 bits, uchar *ptr, uchar ofs, uint len) +{ + ptr[0]= (uchar) ((ptr[0] & ~(((1 << len) - 1) << ofs)) | (bits << ofs)); + if (ofs + len > 8) + ptr[1]= (uchar) ((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) + + +/* + Compare two VARCHAR values. + @param charset_info - The character set and collation + @param a - The pointer to the first string + @param a_length - The length of the first string + @param b - The pointer to the second string + @param b_length - The length of the second string + @param b_is_prefix - Whether "b" is a prefix of "a", + e.g. in a prefix key (partial length key). + @returns - The result of comparison + + - If "b_is_prefix" is FALSE, then the two strings are compared + taking into account the PAD SPACE/NO PAD attribute of the collation. + + - If "b_is_prefix" is TRUE, then trailing spaces are compared in NO PAD style. + This is done e.g. when we compare a column value to its prefix key value + (the value of "a" to the value of "key_a"): + CREATE TABLE t1 (a VARCHAR(10), KEY(key_a(5)); +*/ +static inline int ha_compare_char_varying(CHARSET_INFO *charset_info, + const uchar *a, size_t a_length, + const uchar *b, size_t b_length, + my_bool b_is_prefix) +{ + if (!b_is_prefix) + return charset_info->coll->strnncollsp(charset_info, a, a_length, + b, b_length); + return charset_info->coll->strnncoll(charset_info, + a, a_length, + b, b_length, TRUE/*prefix*/); +} + + +/* + Compare two CHAR values of the same declared character length, + e.g. CHAR(5) to CHAR(5). + + @param charset_info - The character set and collation + @param a - The pointer to the first string + @param a_length - The length of the first string + @param b - The pointer to the second string + @param b_length - The length of the second string + @param nchars - The declared length (in characters) + @param b_is_prefix - Whether "b" is a prefix of "a", + e.g. in a prefix key (partial length key). + @returns - The result of comparison + + - If "b_is_prefix" is FALSE, then the two strings are compared + taking into account the PAD SPACE/NO PAD attribute of the collation. + Additionally, this function assumes that the underlying storage could + optionally apply trailing space compression, so values can come into this + comparison function in different states: + - all trailing spaces removed + - some trailing spaced removed + - no trailing spaces removed (exactly "nchars" characters on the two sides) + This function virtually reconstructs trailing spaces up to the defined + length specified in "nchars". + If either of the sides have more than "nchar" characters, + then only leftmost "nchar" characters are compared. + + - If "b_is_prefix" is TRUE, then trailing spaces are compared in NO PAD style. + This is done e.g. when we compare a column value to its prefix key value + (the value of "a" to the value of "key_a"): + CREATE TABLE t1 (a CHAR(10), KEY(key_a(5)); +*/ +static inline int ha_compare_char_fixed(CHARSET_INFO *charset_info, + const uchar *a, size_t a_length, + const uchar *b, size_t b_length, + size_t nchars, + my_bool b_is_prefix) +{ + if (!b_is_prefix) + return charset_info->coll->strnncollsp_nchars(charset_info, + a, a_length, + b, b_length, + nchars, + MY_STRNNCOLLSP_NCHARS_EMULATE_TRIMMED_TRAILING_SPACES); + return charset_info->coll->strnncoll(charset_info, + a, a_length, + b, b_length, TRUE/*prefix*/); +} + + +/* + A function to compare words of a text. + This is a common operation in full-text search: + SELECT MATCH (title) AGAINST ('word') FROM t1; +*/ +static inline int ha_compare_word(CHARSET_INFO *charset_info, + const uchar *a, size_t a_length, + const uchar *b, size_t b_length) +{ + return charset_info->coll->strnncollsp(charset_info, + a, a_length, + b, b_length); +} + + +/* + A function to compare a word of a text to a word prefix. + This is a common operation in full-text search: + SELECT MATCH (title) AGAINST ('wor*' IN BOOLEAN MODE) FROM t1; +*/ +static inline int ha_compare_word_prefix(CHARSET_INFO *charset_info, + const uchar *a, size_t a_length, + const uchar *b, size_t b_length) +{ + return charset_info->coll->strnncoll(charset_info, + a, a_length, + b, b_length, + TRUE/*b_is_prefix*/); +} + + +/* + Compare words (full match or prefix match), e.g. for full-text search. +*/ +static inline int ha_compare_word_or_prefix(CHARSET_INFO *charset_info, + const uchar *a, size_t a_length, + const uchar *b, size_t b_length, + my_bool b_is_prefix) +{ + if (!b_is_prefix) + return ha_compare_word(charset_info, a, a_length, b, b_length); + return ha_compare_word_prefix(charset_info, a, a_length, b, b_length); +} + + +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 for pushed index condition or rowid filter check functions. + + 0=CHECK_NEG - The filter is not satisfied. The engine should discard this + index tuple and continue the scan. + 1=CHECK_POS - The filter is satisfied. Current index tuple should be + returned to the SQL layer. + 2=CHECK_OUT_OF_RANGE - the index tuple is outside of the range that we're + scanning. (Example: if we're scanning "t.key BETWEEN 10 AND + 20" and got a "t.key=21" tuple) Tthe engine should stop + scanning and return HA_ERR_END_OF_FILE right away). + 3=CHECK_ABORTED_BY_USER - the engine must stop scanning and should return + HA_ERR_ABORTED_BY_USER right away + -1=CHECK_ERROR - Reserved for internal errors in engines. Should not be + returned by ICP or rowid filter check functions. +*/ + +typedef enum check_result { + CHECK_ERROR=-1, + CHECK_NEG=0, + CHECK_POS=1, + CHECK_OUT_OF_RANGE=2, + CHECK_ABORTED_BY_USER=3 +} check_result_t; + +typedef check_result_t (*index_cond_func_t)(void *param); +typedef check_result_t (*rowid_filter_func_t)(void *param); +typedef int (*rowid_filter_is_active_func_t)(void *param); + +#endif /* _my_compare_h */ |