diff options
Diffstat (limited to 'sql/key.cc')
| -rw-r--r-- | sql/key.cc | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/sql/key.cc b/sql/key.cc new file mode 100644 index 00000000000..df3f0fe25d5 --- /dev/null +++ b/sql/key.cc @@ -0,0 +1,266 @@ +/* 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 */ + + +/* Functions to handle keys and fields in forms */ + +#include "mysql_priv.h" + + /* + ** Search after with key field is. If no key starts with field test + ** if field is part of some key. + ** + ** returns number of key. keylength is set to length of key before + ** (not including) field + ** Used when calculating key for NEXT_NUMBER + */ + +int find_ref_key(TABLE *table,Field *field, uint *key_length) +{ + reg2 int i; + reg3 KEY *key_info; + uint fieldpos; + + fieldpos= field->offset(); + + /* Test if some key starts as fieldpos */ + + for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++) + { + if (key_info->key_part[0].offset == fieldpos) + { /* Found key. Calc keylength */ + *key_length=0; + return(i); /* Use this key */ + } + } + /* Test if some key contains fieldpos */ + + for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++) + { + uint j; + KEY_PART_INFO *key_part; + *key_length=0; + for (j=0, key_part=key_info->key_part ; + j < key_info->key_parts ; + j++, key_part++) + { + if (key_part->offset == fieldpos) + return(i); /* Use this key */ + *key_length+=key_part->length; + } + } + return(-1); /* No key is ok */ +} + + + /* Copy a key from record to some buffer */ + /* if length == 0 then copy hole key */ + +void key_copy(byte *key,TABLE *table,uint idx,uint key_length) +{ + uint length; + KEY *key_info=table->key_info+idx; + KEY_PART_INFO *key_part; + + if (key_length == 0) + key_length=key_info->key_length+key_info->extra_length; + for (key_part=key_info->key_part; + (int) key_length > 0 ; + key_part++) + { + if (key_part->null_bit) + { + *key++= test(table->record[0][key_part->null_offset] & + key_part->null_bit); + key_length--; + } + if (key_part->key_part_flag & HA_BLOB_PART) + { + char *pos; + ulong blob_length=((Field_blob*) key_part->field)->get_length(); + key_length-=2; + ((Field_blob*) key_part->field)->get_ptr(&pos); + length=min(key_length,key_part->length); + set_if_smaller(blob_length,length); + int2store(key,(uint) blob_length); + key+=2; // Skipp length info + memcpy(key,pos,blob_length); + } + else + { + length=min(key_length,key_part->length); + memcpy(key,table->record[0]+key_part->offset,(size_t) length); + } + key+=length; + key_length-=length; + } +} /* key_copy */ + + + /* restore a key from some buffer to record */ + +void key_restore(TABLE *table,byte *key,uint idx,uint key_length) +{ + uint length; + KEY *key_info=table->key_info+idx; + KEY_PART_INFO *key_part; + + if (key_length == 0) + { + if (idx == (uint) -1) + return; + key_length=key_info->key_length+key_info->extra_length; + } + for (key_part=key_info->key_part; + (int) key_length > 0 ; + key_part++) + { + if (key_part->null_bit) + { + if (*key++) + table->record[0][key_part->null_offset]|= key_part->null_bit; + else + table->record[0][key_part->null_offset]&= ~key_part->null_bit; + key_length--; + } + if (key_part->key_part_flag & HA_BLOB_PART) + { + uint blob_length=uint2korr(key); + key+=2; + key_length-=2; + ((Field_blob*) key_part->field)->set_ptr((ulong) blob_length, + (char*) key); + length=key_part->length; + } + else + { + length=min(key_length,key_part->length); + memcpy(table->record[0]+key_part->offset,key,(size_t) length); + } + key+=length; + key_length-=length; + } +} /* key_restore */ + + + /* Compare if a key has changed */ + +int key_cmp(TABLE *table,const byte *key,uint idx,uint key_length) +{ + uint length; + KEY_PART_INFO *key_part; + + for (key_part=table->key_info[idx].key_part; + (int) key_length > 0; + key_part++, key+=length, key_length-=length) + { + if (key_part->null_bit) + { + key_length--; + if (*key != test(table->record[0][key_part->null_offset] & + key_part->null_bit)) + return 1; + if (*key) + { + length=key_part->store_length; + continue; + } + key++; + } + if (key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH)) + { + if (key_part->field->key_cmp(key, key_part->length+2)) + return 1; + length=key_part->length+2; + } + else + { + length=min(key_length,key_part->length); + if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+ + FIELDFLAG_PACK))) + { + if (my_sortcmp((char*) key,(char*) table->record[0]+key_part->offset, + length)) + return 1; + } + else if (memcmp(key,table->record[0]+key_part->offset,length)) + return 1; + } + } + return 0; +} + + /* unpack key-fields from record to some buffer */ + /* This is used to get a good error message */ + +void key_unpack(String *to,TABLE *table,uint idx) +{ + KEY_PART_INFO *key_part,*key_part_end; + Field *field; + String tmp; + DBUG_ENTER("key_unpack"); + + to->length(0); + for (key_part=table->key_info[idx].key_part,key_part_end=key_part+ + table->key_info[idx].key_parts ; + key_part < key_part_end; + key_part++) + { + if (to->length()) + to->append('-'); + if (key_part->null_bit) + { + if (table->record[0][key_part->null_offset] & key_part->null_bit) + { + to->append("NULL"); + continue; + } + } + if ((field=key_part->field)) + { + field->val_str(&tmp,&tmp); + if (key_part->length < field->pack_length()) + tmp.length(min(tmp.length(),key_part->length)); + to->append(tmp); + } + else + to->append("???"); + } + DBUG_VOID_RETURN; +} + + +/* Return 1 if any field in a list is part of key */ + +bool check_if_key_used(TABLE *table, uint idx, List<Item> &fields) +{ + List_iterator<Item> f(fields); + KEY_PART_INFO *key_part,*key_part_end; + for (key_part=table->key_info[idx].key_part,key_part_end=key_part+ + table->key_info[idx].key_parts ; + key_part < key_part_end; + key_part++) + { + Item_field *field; + f.rewind(); + while ((field=(Item_field*) f++)) + { + if (key_part->field == field->field) + return 1; + } + } + return 0; +} |