_search.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:25k
- /* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
- (at your option) any later version.
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- /* S|ker efter positionen f|r en nyckel samt d{rmedh|rande funktioner */
- #include "isamdef.h"
- #include "m_ctype.h"
- #define CMP(a,b) (a<b ? -1 : a == b ? 0 : 1)
- /* Check index */
- int _nisam_check_index(N_INFO *info, int inx)
- {
- if (inx == -1) /* Use last index */
- inx=info->lastinx;
- if (inx >= (int) info->s->state.keys || inx < 0)
- {
- my_errno=HA_ERR_WRONG_INDEX;
- return -1;
- }
- if (info->lastinx != inx) /* Index changed */
- {
- info->lastinx = inx;
- info->lastpos = NI_POS_ERROR;
- info->update= ((info->update & (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED)) |
- HA_STATE_NEXT_FOUND | HA_STATE_PREV_FOUND);
- }
- if (info->opt_flag & WRITE_CACHE_USED && flush_io_cache(&info->rec_cache))
- return(-1);
- return(inx);
- } /* ni_check_index */
- /* S|ker reda p} positionen f|r ett record p} basen av en nyckel */
- /* Positionen l{ggs i info->lastpos */
- /* Returns -1 if not found and 1 if search at upper levels */
- int _nisam_search(register N_INFO *info, register N_KEYDEF *keyinfo, uchar *key, uint key_len, uint nextflag, register ulong pos)
- {
- int error,flag;
- uint nod_flag;
- uchar *keypos,*maxpos;
- uchar lastkey[N_MAX_KEY_BUFF],*buff;
- DBUG_ENTER("_nisam_search");
- DBUG_PRINT("enter",("pos: %ld nextflag: %d lastpos: %ld",
- pos,nextflag,info->lastpos));
- if (pos == NI_POS_ERROR)
- {
- my_errno=HA_ERR_KEY_NOT_FOUND; /* Didn't find key */
- info->lastpos= NI_POS_ERROR;
- if (!(nextflag & (SEARCH_SMALLER | SEARCH_BIGGER | SEARCH_LAST)))
- DBUG_RETURN(-1); /* Not found ; return error */
- DBUG_RETURN(1); /* Search at upper levels */
- }
- if (!(buff=_nisam_fetch_keypage(info,keyinfo,pos,info->buff,
- test(!(nextflag & SEARCH_SAVE_BUFF)))))
- goto err;
- DBUG_DUMP("page",(byte*) buff,getint(buff));
- flag=(*keyinfo->bin_search)(info,keyinfo,buff,key,key_len,nextflag,
- &keypos,lastkey);
- nod_flag=test_if_nod(buff);
- maxpos=buff+getint(buff)-1;
- if (flag)
- {
- if ((error=_nisam_search(info,keyinfo,key,key_len,nextflag,
- _nisam_kpos(nod_flag,keypos))) <= 0)
- DBUG_RETURN(error);
- if (flag >0)
- {
- if ((nextflag & (SEARCH_SMALLER | SEARCH_LAST)) &&
- keypos == buff+2+nod_flag)
- DBUG_RETURN(1); /* Bigger than key */
- }
- else if (nextflag & SEARCH_BIGGER && keypos >= maxpos)
- DBUG_RETURN(1); /* Smaller than key */
- }
- else
- {
- if (nextflag & SEARCH_FIND && (!(keyinfo->base.flag & HA_NOSAME)
- || key_len) && nod_flag)
- {
- if ((error=_nisam_search(info,keyinfo,key,key_len,SEARCH_FIND,
- _nisam_kpos(nod_flag,keypos))) >= 0 ||
- my_errno != HA_ERR_KEY_NOT_FOUND)
- DBUG_RETURN(error);
- info->int_pos= NI_POS_ERROR; /* Buffer not in memory */
- }
- }
- if (pos != info->int_pos)
- {
- uchar *old_buff=buff;
- if (!(buff=_nisam_fetch_keypage(info,keyinfo,pos,info->buff,
- test(!(nextflag & SEARCH_SAVE_BUFF)))))
- goto err;
- keypos=buff+(keypos-old_buff);
- maxpos=buff+(maxpos-old_buff);
- }
- if ((nextflag & (SEARCH_SMALLER | SEARCH_LAST)) && flag != 0)
- {
- keypos=_nisam_get_last_key(info,keyinfo,buff,lastkey,keypos);
- if (!(nextflag & SEARCH_SMALLER) &&
- _nisam_key_cmp(keyinfo->seg, lastkey, key, key_len, SEARCH_FIND))
- {
- my_errno=HA_ERR_KEY_NOT_FOUND; /* Didn't find key */
- goto err;
- }
- }
- VOID((*keyinfo->get_key)(keyinfo,nod_flag,&keypos,lastkey));
- VOID(_nisam_move_key(keyinfo,info->lastkey,lastkey));
- info->lastpos=_nisam_dpos(info,nod_flag,keypos);
- info->int_keypos=info->buff+ (keypos-buff);
- info->int_maxpos=info->buff+ (maxpos-buff);
- info->page_changed=0;
- info->buff_used= (info->buff != buff);
- info->last_search_keypage=info->int_pos;
- DBUG_PRINT("exit",("found key at %ld",info->lastpos));
- DBUG_RETURN(0);
- err:
- DBUG_PRINT("exit",("Error: %d",my_errno));
- info->lastpos= NI_POS_ERROR;
- DBUG_RETURN (-1);
- } /* _nisam_search */
- /* Search after key in page-block */
- /* If packed key puts smaller or identical key in buff */
- /* ret_pos point to where find or bigger key starts */
- /* ARGSUSED */
- int _nisam_bin_search(N_INFO *info, register N_KEYDEF *keyinfo, uchar *page,
- uchar *key, uint key_len, uint comp_flag, uchar **ret_pos,
- uchar *buff __attribute__((unused)))
- {
- reg4 int start,mid,end;
- int flag;
- uint totlength,nod_flag;
- DBUG_ENTER("_nisam_bin_search");
- LINT_INIT(flag);
- totlength=keyinfo->base.keylength+(nod_flag=test_if_nod(page));
- start=0; mid=1;
- end= (int) ((getint(page)-2-nod_flag)/totlength-1);
- DBUG_PRINT("test",("getint: %d end: %d",getint(page),end));
- page+=2+nod_flag;
- while (start != end)
- {
- mid= (start+end)/2;
- if ((flag=_nisam_key_cmp(keyinfo->seg,page+(uint) mid*totlength,key,key_len,
- comp_flag))
- >= 0)
- end=mid;
- else
- start=mid+1;
- }
- if (mid != start)
- flag=_nisam_key_cmp(keyinfo->seg,page+(uint) start*totlength,key,key_len,
- comp_flag);
- if (flag < 0)
- start++; /* point at next, bigger key */
- *ret_pos=page+(uint) start*totlength;
- DBUG_PRINT("exit",("flag: %d keypos: %d",flag,start));
- DBUG_RETURN(flag);
- } /* _nisam_bin_search */
- /* Used instead of _nisam_bin_search() when key is packed */
- /* Puts smaller or identical key in buff */
- /* Key is searched sequentially */
- int _nisam_seq_search(N_INFO *info, register N_KEYDEF *keyinfo, uchar *page, uchar *key, uint key_len, uint comp_flag, uchar **ret_pos, uchar *buff)
- {
- int flag;
- uint nod_flag,length;
- uchar t_buff[N_MAX_KEY_BUFF],*end;
- DBUG_ENTER("_nisam_seq_search");
- LINT_INIT(flag); LINT_INIT(length);
- end= page+getint(page);
- nod_flag=test_if_nod(page);
- page+=2+nod_flag;
- *ret_pos=page;
- while (page < end)
- {
- length=(*keyinfo->get_key)(keyinfo,nod_flag,&page,t_buff);
- if ((flag=_nisam_key_cmp(keyinfo->seg,t_buff,key,key_len,comp_flag)) >= 0)
- break;
- #ifdef EXTRA_DEBUG
- DBUG_PRINT("loop",("page: %lx key: '%s' flag: %d",page,t_buff,flag));
- #endif
- memcpy(buff,t_buff,length);
- *ret_pos=page;
- }
- if (flag == 0)
- memcpy(buff,t_buff,length); /* Result is first key */
- DBUG_PRINT("exit",("flag: %d ret_pos: %lx",flag,*ret_pos));
- DBUG_RETURN(flag);
- } /* _nisam_seq_search */
- /* Get pos to a key_block */
- ulong _nisam_kpos(uint nod_flag, uchar *after_key)
- {
- after_key-=nod_flag;
- switch (nod_flag) {
- case 3:
- return uint3korr(after_key)*512L;
- case 2:
- return uint2korr(after_key)*512L;
- case 1:
- return (uint) (*after_key)*512L;
- case 0: /* At leaf page */
- default: /* Impossible */
- return(NI_POS_ERROR);
- }
- } /* _kpos */
- /* Save pos to a key_block */
- void _nisam_kpointer(register N_INFO *info, register uchar *buff, ulong pos)
- {
- pos/=512L;
- switch (info->s->base.key_reflength) {
- case 3: int3store(buff,pos); break;
- case 2: int2store(buff,(uint) pos); break;
- case 1: buff[0]= (uchar) pos; break;
- default: abort(); /* impossible */
- }
- } /* _nisam_kpointer */
- /* Calc pos to a data-record */
- ulong _nisam_dpos(N_INFO *info, uint nod_flag, uchar *after_key)
- {
- ulong pos;
- after_key-=(nod_flag + info->s->rec_reflength);
- switch (info->s->rec_reflength) {
- case 4:
- pos= (ulong) uint4korr(after_key);
- break;
- case 3:
- pos= (ulong) uint3korr(after_key);
- break;
- case 2:
- pos= (ulong) uint2korr(after_key);
- break;
- default:
- pos=0L; /* Shut compiler up */
- }
- return (info->s->base.options &
- (HA_OPTION_PACK_RECORD | HA_OPTION_COMPRESS_RECORD)) ? pos :
- pos*info->s->base.reclength;
- }
- /* save pos to record */
- void _nisam_dpointer(N_INFO *info, uchar *buff, ulong pos)
- {
- if (!(info->s->base.options &
- (HA_OPTION_PACK_RECORD | HA_OPTION_COMPRESS_RECORD)))
- pos/=info->s->base.reclength;
- switch (info->s->rec_reflength) {
- case 4: int4store(buff,pos); break;
- case 3: int3store(buff,pos); break;
- case 2: int2store(buff,(uint) pos); break;
- default: abort(); /* Impossible */
- }
- } /* _nisam_dpointer */
- /*
- ** Compare two keys with is bigger
- ** Returns <0, 0, >0 acording to with is bigger
- ** Key_length specifies length of key to use. Number-keys can't
- ** be splitted
- ** If flag <> SEARCH_FIND compare also position
- */
- int _nisam_key_cmp(register N_KEYSEG *keyseg, register uchar *a, register uchar *b, uint key_length, uint nextflag)
- {
- reg4 int flag,length_diff;
- int16 s_1,s_2;
- int32 l_1,l_2;
- uint32 u_1,u_2;
- float f_1,f_2;
- double d_1,d_2;
- reg5 uchar *end;
- if (!(nextflag & (SEARCH_FIND | SEARCH_NO_FIND | SEARCH_LAST))
- || key_length == 0)
- key_length=N_MAX_KEY_BUFF*2;
- for ( ; (int) key_length >0 ; key_length-= (keyseg++)->base.length)
- {
- end= a+ min(keyseg->base.length,key_length);
- switch ((enum ha_base_keytype) keyseg->base.type) {
- case HA_KEYTYPE_TEXT: /* Ascii; Key is converted */
- case HA_KEYTYPE_BINARY:
- if (keyseg->base.flag & HA_SPACE_PACK)
- {
- uchar *as, *bs;
- int length,b_length;
- as=a++; bs=b++;
- length= (length_diff= ((int) *as - (b_length= (int) *bs))) < 0 ?
- (int) *as : b_length;
- end= a+ min(key_length,(uint) length);
- if (use_strnxfrm(default_charset_info)) {
- if (((enum ha_base_keytype) keyseg->base.type) == HA_KEYTYPE_BINARY)
- {
- while (a < end)
- if ((flag= (int) *a++ - (int) *b++))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- }
- else
- {
- if ((flag = my_strnncoll(default_charset_info,
- a, (int) (end-a), b, b_length)))
- return (keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag;
- b+= (uint) (end-a);
- a=end;
- }
- }
- else
- {
- while (a < end)
- if ((flag= (int) *a++ - (int) *b++))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- }
- if (key_length < (uint) keyseg->base.length)
- { /* key_part */
- if (length_diff)
- {
- if (length_diff < 0 || (uint) *as <= key_length)
- return ((keyseg->base.flag & HA_REVERSE_SORT) ?
- -length_diff : length_diff);
- for (length= (int) key_length-b_length; length-- > 0 ;)
- {
- if (*a++ != ' ')
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -1 : 1);
- }
- }
- if (nextflag & SEARCH_NO_FIND) /* Find record after key */
- return (nextflag & SEARCH_BIGGER) ? -1 : 1;
- return 0;
- }
- else
- {
- if (length_diff)
- return ((keyseg->base.flag & HA_REVERSE_SORT) ?
- -length_diff : length_diff);
- }
- a=as+ (uint) *as+1 ; b= bs+ b_length+1; /* to next key */
- }
- else
- {
- if (use_strnxfrm(default_charset_info)) {
- if (((enum ha_base_keytype) keyseg->base.type) == HA_KEYTYPE_BINARY)
- {
- while (a < end)
- if ((flag= (int) *a++ - (int) *b++))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- }
- else
- {
- if ((flag = my_strnncoll(default_charset_info,
- a, (int) (end-a), b, (int) (end-a))))
- return (keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag;
- b+= (uint) (end-a);
- a=end;
- }
- }
- else
- {
- while (a < end)
- if ((flag= (int) *a++ - (int) *b++))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- }
- }
- break;
- case HA_KEYTYPE_INT8:
- {
- int i_1= (int) *((signed char*) a);
- int i_2= (int) *((signed char*) b);
- if ((flag = CMP(i_1,i_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b++;
- break;
- }
- case HA_KEYTYPE_SHORT_INT:
- shortget(s_1,a);
- shortget(s_2,b);
- if ((flag = CMP(s_1,s_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= 2; /* sizeof(short int); */
- break;
- case HA_KEYTYPE_USHORT_INT:
- {
- uint16 us_1,us_2;
- ushortget(us_1,a);
- ushortget(us_2,b);
- if ((flag = CMP(us_1,us_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+=2; /* sizeof(short int); */
- break;
- }
- case HA_KEYTYPE_LONG_INT:
- longget(l_1,a);
- longget(l_2,b);
- if ((flag = CMP(l_1,l_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= 4; /* sizeof(long int); */
- break;
- case HA_KEYTYPE_ULONG_INT:
- ulongget(u_1,a);
- ulongget(u_2,b);
- if ((flag = CMP(u_1,u_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= 4; /* sizeof(long int); */
- break;
- case HA_KEYTYPE_INT24:
- l_1=sint3korr(a);
- l_2=sint3korr(b);
- if ((flag = CMP(l_1,l_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= 3;
- break;
- case HA_KEYTYPE_UINT24:
- l_1=(long) uint3korr(a);
- l_2=(long) uint3korr(b);
- if ((flag = CMP(l_1,l_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= 3;
- break;
- case HA_KEYTYPE_FLOAT:
- bmove((byte*) &f_1,(byte*) a,(int) sizeof(float));
- bmove((byte*) &f_2,(byte*) b,(int) sizeof(float));
- if ((flag = CMP(f_1,f_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= sizeof(float);
- break;
- case HA_KEYTYPE_DOUBLE:
- doubleget(d_1,a);
- doubleget(d_2,b);
- if ((flag = CMP(d_1,d_2)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= sizeof(double);
- break;
- case HA_KEYTYPE_NUM: /* Numeric key */
- {
- int swap_flag=keyseg->base.flag & HA_REVERSE_SORT;
- if (keyseg->base.flag & HA_SPACE_PACK)
- {
- int alength,blength;
- if (swap_flag)
- swap_variables(uchar*, a, b);
- alength= *a++; blength= *b++;
- if ((flag=(int) (keyseg->base.length-key_length)) < 0)
- flag=0;
- if (alength != blength+flag)
- {
- if ((alength > blength+flag && *a != '-') ||
- (alength < blength+flag && *b == '-'))
- return 1;
- else
- return -1;
- }
- if (*a == '-' && *b == '-')
- {
- swap_flag=1;
- swap_variables(uchar*, a, b);
- }
- end=a+alength;
- while (a < end)
- if (*a++ != *b++)
- {
- a--; b--;
- if (my_isdigit(default_charset_info, (char) *a) &&
- my_isdigit(default_charset_info, (char) *b))
- return ((int) *a - (int) *b);
- if (*a == '-' || my_isdigit(default_charset_info,(char) *b))
- return (-1);
- if (*b == '-' || *b++ == ' ' ||
- my_isdigit(default_charset_info,(char) *a))
- return (1);
- if (*a++ == ' ')
- return (-1);
- }
- }
- else
- {
- for ( ; a < end && *a == ' ' && *b == ' ' ; a++, b++) ;
- if (*a == '-' && *b == '-')
- swap_flag=1;
- if (swap_flag)
- {
- end=b+(int) (end-a);
- swap_variables(uchar*, a, b);
- }
- while (a < end)
- if (*a++ != *b++)
- {
- a--; b--;
- if (my_isdigit(default_charset_info,(char) *a) &&
- my_isdigit(default_charset_info,(char) *b))
- return ((int) *a - (int) *b);
- if (*a == '-' || my_isdigit(default_charset_info,(char) *b))
- return (-1);
- if (*b == '-' || *b++ == ' ' ||
- my_isdigit(default_charset_info,(char) *a))
- return (1);
- if (*a++ == ' ')
- return -1;
- }
- }
- if (swap_flag)
- swap_variables(uchar*, a, b);
- break;
- }
- #ifdef HAVE_LONG_LONG
- case HA_KEYTYPE_LONGLONG:
- {
- longlong ll_a,ll_b;
- longlongget(ll_a,a);
- longlongget(ll_b,b);
- if ((flag = CMP(ll_a,ll_b)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= sizeof(longlong);
- break;
- }
- case HA_KEYTYPE_ULONGLONG:
- {
- ulonglong ll_a,ll_b;
- longlongget(ll_a,a);
- longlongget(ll_b,b);
- if ((flag = CMP(ll_a,ll_b)))
- return ((keyseg->base.flag & HA_REVERSE_SORT) ? -flag : flag);
- a= end;
- b+= sizeof(ulonglong);
- break;
- }
- #endif
- case HA_KEYTYPE_END: /* Ready */
- case HA_KEYTYPE_VARTEXT: /* Impossible */
- case HA_KEYTYPE_VARBINARY: /* Impossible */
- goto end;
- }
- }
- end:
- if (!(nextflag & SEARCH_FIND))
- {
- if (nextflag & (SEARCH_NO_FIND | SEARCH_LAST)) /* Find record after key */
- return (nextflag & (SEARCH_BIGGER | SEARCH_LAST)) ? -1 : 1;
- LINT_INIT(l_1); LINT_INIT(l_2);
- switch (keyseg->base.length) {
- case 4:
- u_1= (ulong) uint4korr(a);
- u_2= (ulong) uint4korr(b);
- break;
- case 3:
- u_1= (ulong) uint3korr(a);
- u_2= (ulong) uint3korr(b);
- break;
- case 2:
- u_1= (ulong) uint2korr(a);
- u_2= (ulong) uint2korr(b);
- break;
- default: abort(); /* Impossible */
- }
- flag = CMP(u_1,u_2);
- if (nextflag & SEARCH_SAME)
- return (flag); /* read same */
- if (nextflag & SEARCH_BIGGER)
- return (flag <= 0 ? -1 : 1); /* read next */
- return (flag < 0 ? -1 : 1); /* read previous */
- }
- return 0;
- } /* _nisam_key_cmp */
- /* Get key from key-block */
- /* page points at previous key; its advanced to point at next key */
- /* key should contain previous key */
- /* Returns length of found key + pointers */
- /* nod_flag is a flag if we are on nod */
- uint _nisam_get_key(register N_KEYDEF *keyinfo, uint nod_flag,
- register uchar **page, register uchar *key)
- {
- reg1 N_KEYSEG *keyseg;
- uchar *start,*start_key;
- uint length,c_length;
- LINT_INIT(start);
- start_key=key; c_length=0;
- for (keyseg=keyinfo->seg ; keyseg->base.type ;keyseg++)
- {
- if (keyseg->base.flag & (HA_SPACE_PACK | HA_PACK_KEY))
- {
- start=key;
- if (keyseg->base.flag & HA_SPACE_PACK)
- key++;
- if ((length= *(*page)++) & 128)
- {
- key+= (c_length=(length & 127));
- if (c_length == 0) /* Same key */
- {
- key+= *start; /* Same diff_key as prev */
- length=0;
- }
- else
- {
- if (keyseg->base.flag & HA_SPACE_PACK)
- length= *(*page)++;
- else
- length=keyseg->base.length-length+128; /* Rest of key */
- /* Prevent core dumps if wrong data formats */
- if (length > keyseg->base.length)
- length=0;
- }
- }
- }
- else
- length=keyseg->base.length;
- memcpy((byte*) key,(byte*) *page,(size_t) length); key+=length;
- if (keyseg->base.flag & HA_SPACE_PACK)
- *start= (uchar) ((key-start)-1);
- *page+=length;
- }
- length=keyseg->base.length+nod_flag;
- bmove((byte*) key,(byte*) *page,length);
- *page+=length;
- return((uint) (key-start_key)+keyseg->base.length);
- } /* _nisam_get_key */
- /* same as _nisam_get_key but used with fixed length keys */
- uint _nisam_get_static_key(register N_KEYDEF *keyinfo, uint nod_flag, register uchar **page, register uchar *key)
- {
- memcpy((byte*) key,(byte*) *page,
- (size_t) (keyinfo->base.keylength+nod_flag));
- *page+=keyinfo->base.keylength+nod_flag;
- return(keyinfo->base.keylength);
- } /* _nisam_get_static_key */
- /* Get last key from key-block, starting from keypos */
- /* Return pointer to where keystarts */
- uchar *_nisam_get_last_key(N_INFO *info, N_KEYDEF *keyinfo, uchar *keypos, uchar *lastkey, uchar *endpos)
- {
- uint nod_flag;
- uchar *lastpos;
- nod_flag=test_if_nod(keypos);
- if (! (keyinfo->base.flag & (HA_PACK_KEY | HA_SPACE_PACK_USED)))
- {
- lastpos=endpos-keyinfo->base.keylength-nod_flag;
- if (lastpos > keypos)
- bmove((byte*) lastkey,(byte*) lastpos,keyinfo->base.keylength+nod_flag);
- }
- else
- {
- lastpos=0 ; keypos+=2+nod_flag;
- lastkey[0]=0;
- while (keypos < endpos)
- {
- lastpos=keypos;
- VOID(_nisam_get_key(keyinfo,nod_flag,&keypos,lastkey));
- }
- }
- return lastpos;
- } /* _nisam_get_last_key */
- /* Calculate length of key */
- uint _nisam_keylength(N_KEYDEF *keyinfo, register uchar *key)
- {
- reg1 N_KEYSEG *keyseg;
- uchar *start;
- if (! (keyinfo->base.flag & HA_SPACE_PACK_USED))
- return (keyinfo->base.keylength);
- start=key;
- for (keyseg=keyinfo->seg ; keyseg->base.type ; keyseg++)
- {
- if (keyseg->base.flag & HA_SPACE_PACK)
- key+= *key+1;
- else
- key+= keyseg->base.length;
- }
- return((uint) (key-start)+keyseg->base.length);
- } /* _nisam_keylength */
- /* Move a key */
- uchar *_nisam_move_key(N_KEYDEF *keyinfo, uchar *to, uchar *from)
- {
- reg1 uint length;
- memcpy((byte*) to, (byte*) from,
- (size_t) (length=_nisam_keylength(keyinfo,from)));
- return to+length;
- }
- /* Find next/previous record with same key */
- /* This can't be used when database is touched after last read */
- int _nisam_search_next(register N_INFO *info, register N_KEYDEF *keyinfo,
- uchar *key, uint nextflag, ulong pos)
- {
- int error;
- uint nod_flag;
- uchar lastkey[N_MAX_KEY_BUFF];
- DBUG_ENTER("_nisam_search_next");
- DBUG_PRINT("enter",("nextflag: %d lastpos: %d int_keypos: %lx",
- nextflag,info->lastpos,info->int_keypos));
- DBUG_EXECUTE("key",_nisam_print_key(DBUG_FILE,keyinfo->seg,key););
- if ((nextflag & SEARCH_BIGGER && info->int_keypos >= info->int_maxpos) ||
- info->int_pos == NI_POS_ERROR || info->page_changed)
- DBUG_RETURN(_nisam_search(info,keyinfo,key,0,nextflag | SEARCH_SAVE_BUFF,
- pos));
- if (info->buff_used)
- {
- if (!_nisam_fetch_keypage(info,keyinfo,info->last_search_keypage,
- info->buff,0))
- {
- info->lastpos= NI_POS_ERROR;
- DBUG_RETURN(-1);
- }
- info->buff_used=0;
- }
- /* Last used buffer is in info->buff */
- nod_flag=test_if_nod(info->buff);
- VOID(_nisam_move_key(keyinfo,lastkey,key));
- if (nextflag & SEARCH_BIGGER) /* Next key */
- {
- ulong tmp_pos=_nisam_kpos(nod_flag,info->int_keypos);
- if (tmp_pos != NI_POS_ERROR)
- {
- if ((error=_nisam_search(info,keyinfo,key,0,nextflag | SEARCH_SAVE_BUFF,
- tmp_pos)) <=0)
- DBUG_RETURN(error);
- }
- VOID((*keyinfo->get_key)(keyinfo,nod_flag,&info->int_keypos,lastkey));
- }
- else /* Previous key */
- {
- info->int_keypos=_nisam_get_last_key(info,keyinfo,info->buff,lastkey,
- info->int_keypos);
- if (info->int_keypos == info->buff+2)
- DBUG_RETURN(_nisam_search(info,keyinfo,key,0,nextflag | SEARCH_SAVE_BUFF,
- pos));
- if ((error=_nisam_search(info,keyinfo,key,0,nextflag | SEARCH_SAVE_BUFF,
- _nisam_kpos(nod_flag,info->int_keypos))) <= 0)
- DBUG_RETURN(error);
- }
- info->int_keypos=_nisam_get_last_key(info,keyinfo,info->buff,lastkey,
- info->int_keypos);
- VOID(_nisam_move_key(keyinfo,info->lastkey,lastkey));
- VOID((*keyinfo->get_key)(keyinfo,nod_flag,&info->int_keypos,info->lastkey));
- info->lastpos=_nisam_dpos(info,nod_flag,info->int_keypos);
- DBUG_PRINT("exit",("found key at %d",info->lastpos));
- DBUG_RETURN(0);
- } /* _nisam_search_next */
- /* S|ker reda p} positionen f|r f|rsta recordet i ett index */
- /* Positionen l{ggs i info->lastpos */
- int _nisam_search_first(register N_INFO *info, register N_KEYDEF *keyinfo, register ulong pos)
- {
- uint nod_flag;
- uchar *page;
- DBUG_ENTER("_nisam_search_first");
- if (pos == NI_POS_ERROR)
- {
- my_errno=HA_ERR_KEY_NOT_FOUND;
- info->lastpos= NI_POS_ERROR;
- DBUG_RETURN(-1);
- }
- do
- {
- if (!_nisam_fetch_keypage(info,keyinfo,pos,info->buff,0))
- {
- info->lastpos= NI_POS_ERROR;
- DBUG_RETURN(-1);
- }
- nod_flag=test_if_nod(info->buff);
- page=info->buff+2+nod_flag;
- } while ((pos=_nisam_kpos(nod_flag,page)) != NI_POS_ERROR);
- VOID((*keyinfo->get_key)(keyinfo,nod_flag,&page,info->lastkey));
- info->int_keypos=page; info->int_maxpos=info->buff+getint(info->buff)-1;
- info->lastpos=_nisam_dpos(info,nod_flag,page);
- info->page_changed=info->buff_used=0;
- info->last_search_keypage=info->int_pos;
- DBUG_PRINT("exit",("found key at %d",info->lastpos));
- DBUG_RETURN(0);
- } /* _nisam_search_first */
- /* S|ker reda p} positionen f|r sista recordet i ett index */
- /* Positionen l{ggs i info->lastpos */
- int _nisam_search_last(register N_INFO *info, register N_KEYDEF *keyinfo, register ulong pos)
- {
- uint nod_flag;
- uchar *buff,*page;
- DBUG_ENTER("_nisam_search_last");
- if (pos == NI_POS_ERROR)
- {
- my_errno=HA_ERR_KEY_NOT_FOUND; /* Didn't find key */
- info->lastpos= NI_POS_ERROR;
- DBUG_RETURN(-1);
- }
- buff=info->buff;
- do
- {
- if (!_nisam_fetch_keypage(info,keyinfo,pos,buff,0))
- {
- info->lastpos= NI_POS_ERROR;
- DBUG_RETURN(-1);
- }
- page= buff+getint(buff);
- nod_flag=test_if_nod(buff);
- } while ((pos=_nisam_kpos(nod_flag,page)) != NI_POS_ERROR);
- VOID(_nisam_get_last_key(info,keyinfo,buff,info->lastkey,page));
- info->lastpos=_nisam_dpos(info,nod_flag,page);
- info->int_keypos=info->int_maxpos=page;
- info->page_changed=info->buff_used=0;
- info->last_search_keypage=info->int_pos;
- DBUG_PRINT("exit",("found key at %d",info->lastpos));
- DBUG_RETURN(0);
- } /* _nisam_search_last */