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/* Copyright (C) 2002-2006 MySQL AB
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; version 2
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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#include "myisampack.h"
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There is a hard limit for the maximum number of keys as there are only
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8 bits in the index file header for the number of keys in a table.
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This means that 0..255 keys can exist for a table. The idea of
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HA_MAX_POSSIBLE_KEY is to ensure that one can use myisamchk & tools on
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a MyISAM table for which one has more keys than MyISAM is normally
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compiled for. If you don't have this, you will get a core dump when
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running myisamchk compiled for 128 keys on a table with 255 keys.
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#define HA_MAX_POSSIBLE_KEY 255 /* For myisamchk */
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The following defines can be increased if necessary.
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But beware the dependency of MI_MAX_POSSIBLE_KEY_BUFF and HA_MAX_KEY_LENGTH.
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#define HA_MAX_KEY_LENGTH 1000 /* Max length in bytes */
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#define HA_MAX_KEY_SEG 16 /* Max segments for key */
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#define HA_MAX_POSSIBLE_KEY_BUFF (HA_MAX_KEY_LENGTH + 24+ 6+6)
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#define HA_MAX_KEY_BUFF (HA_MAX_KEY_LENGTH+HA_MAX_KEY_SEG*6+8+8)
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typedef struct st_HA_KEYSEG /* Key-portion */
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CHARSET_INFO *charset;
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uint32 start; /* Start of key in record */
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uint32 null_pos; /* position to NULL indicator */
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uint16 bit_pos; /* Position to bit part */
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uint16 length; /* Keylength */
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uint8 type; /* Type of key (for sort) */
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uint8 null_bit; /* bitmask to test for NULL */
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uint8 bit_start,bit_end; /* if bit field */
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uint8 bit_length; /* Length of bit part */
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#define get_key_length(length,key) \
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{ if (*(uchar*) (key) != 255) \
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length= (uint) *(uchar*) ((key)++); \
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{ length= mi_uint2korr((key)+1); (key)+=3; } \
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#define get_key_length_rdonly(length,key) \
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{ if (*(uchar*) (key) != 255) \
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length= ((uint) *(uchar*) ((key))); \
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{ length= mi_uint2korr((key)+1); } \
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#define get_key_pack_length(length,length_pack,key) \
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{ if (*(uchar*) (key) != 255) \
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{ length= (uint) *(uchar*) ((key)++); length_pack= 1; }\
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{ length=mi_uint2korr((key)+1); (key)+= 3; length_pack= 3; } \
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#define store_key_length_inc(key,length) \
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{ if ((length) < 255) \
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{ *(key)++= (length); } \
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{ *(key)=255; mi_int2store((key)+1,(length)); (key)+=3; } \
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#define size_to_store_key_length(length) ((length) < 255 ? 1 : 3)
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#define get_rec_bits(bit_ptr, bit_ofs, bit_len) \
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(((((uint16) (bit_ptr)[1] << 8) | (uint16) (bit_ptr)[0]) >> (bit_ofs)) & \
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((1 << (bit_len)) - 1))
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#define set_rec_bits(bits, bit_ptr, bit_ofs, bit_len) \
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(bit_ptr)[0]= ((bit_ptr)[0] & ~(((1 << (bit_len)) - 1) << (bit_ofs))) | \
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((bits) << (bit_ofs)); \
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if ((bit_ofs) + (bit_len) > 8) \
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(bit_ptr)[1]= ((bit_ptr)[1] & ~((1 << ((bit_len) - 8 + (bit_ofs))) - 1)) | \
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((bits) >> (8 - (bit_ofs))); \
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#define clr_rec_bits(bit_ptr, bit_ofs, bit_len) \
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set_rec_bits(0, bit_ptr, bit_ofs, bit_len)
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extern int ha_compare_text(CHARSET_INFO *, uchar *, uint, uchar *, uint ,
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extern int ha_key_cmp(register HA_KEYSEG *keyseg, register uchar *a,
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register uchar *b, uint key_length, uint nextflag,
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extern HA_KEYSEG *ha_find_null(HA_KEYSEG *keyseg, uchar *a);
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extern void my_handler_error_register(void);
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extern void my_handler_error_unregister(void);
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Inside an in-memory data record, memory pointers to pieces of the
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record (like BLOBs) are stored in their native byte order and in
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this amount of bytes.
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#define portable_sizeof_char_ptr 8
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#endif /* _my_handler_h */
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include/my_handler.h
