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MySQL 5.1: Item_func_case Class Reference

Item_func_case Class Reference

#include <item_cmpfunc.h>

Inheritance diagram for Item_func_case:

[legend]Collaboration diagram for Item_func_case:

[legend]List of all members.


Public Member Functions
	Item_func_case (List< Item > &list, Item first_expr_arg, Item else_expr_arg)
double	val_real ()
longlong	val_int ()
String *	val_str (String *)
my_decimal *	val_decimal (my_decimal *)
bool	fix_fields (THD thd, Item *ref)
void	fix_length_and_dec ()
uint	decimal_precision () const
table_map	not_null_tables () const
enum Item_result	result_type () const
const char *	func_name () const
void	print (String *str)
Item *	find_item (String *str)
CHARSET_INFO *	compare_collation ()
bool	check_partition_func_processor (byte *bool_arg)
Private Attributes
int	first_expr_num
int	else_expr_num
enum Item_result	cached_result_type
String	tmp_value
uint	ncases
Item_result	cmp_type
DTCollation	cmp_collation

Detailed Description

Definition at line 591 of file item_cmpfunc.h.

Constructor & Destructor Documentation

Item_func_case::Item_func_case	(	List< Item > &	list,
		Item *	first_expr_arg,
		Item *	else_expr_arg
	)			`[inline]`

Definition at line 600 of file item_cmpfunc.h.

References else_expr_num, first_expr_num, list(), ncases, and Item_func::set_arguments().

00601     :Item_func(), first_expr_num(-1), else_expr_num(-1),
00602     cached_result_type(INT_RESULT)
00603   {
00604     ncases= list.elements;
00605     if (first_expr_arg)
00606     {
00607       first_expr_num= list.elements;
00608       list.push_back(first_expr_arg);
00609     }
00610     if (else_expr_arg)
00611     {
00612       else_expr_num= list.elements;
00613       list.push_back(else_expr_arg);
00614     }
00615     set_arguments(list);
00616   }

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Member Function Documentation

bool Item_func_case::check_partition_func_processor ( byte * bool_arg ) [inline, virtual]

Reimplemented from Item.

Definition at line 630 of file item_cmpfunc.h.

00630 { return 0;}

CHARSET_INFO* Item_func_case::compare_collation ( ) [inline, virtual]

Reimplemented from Item.

Definition at line 629 of file item_cmpfunc.h.

References cmp_collation, and DTCollation::collation.

00629 { return cmp_collation.collation; }

uint Item_func_case::decimal_precision ( ) const [virtual]

Reimplemented from Item.

Definition at line 1932 of file item_cmpfunc.cc.

References Item_func::args, Item::decimal_int_part(), DECIMAL_MAX_PRECISION, Item::decimals, else_expr_num, min, ncases, and set_if_bigger.

01933 {
01934   int max_int_part=0;
01935   for (uint i=0 ; i < ncases ; i+=2)
01936     set_if_bigger(max_int_part, args[i+1]->decimal_int_part());
01937 
01938   if (else_expr_num != -1) 
01939     set_if_bigger(max_int_part, args[else_expr_num]->decimal_int_part());
01940   return min(max_int_part + decimals, DECIMAL_MAX_PRECISION);
01941 }

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Item * Item_func_case::find_item ( String * str )

Definition at line 1688 of file item_cmpfunc.cc.

References Item_func::args, cmp_collation, cmp_type, DTCollation::collation, DBUG_ASSERT, DECIMAL_RESULT, Item::default_charset(), else_expr_num, first_expr_num, INT_RESULT, LINT_INIT, MAX_FIELD_WIDTH, my_decimal_cmp(), ncases, Item::null_value, REAL_RESULT, ROW_RESULT, sortcmp(), STRING_RESULT, Item::val_bool(), val_decimal(), Item::val_decimal(), val_int(), Item::val_int(), val_real(), Item::val_real(), val_str(), and value.

Referenced by val_decimal(), val_int(), val_real(), and val_str().

01689 {
01690   String *first_expr_str, *tmp;
01691   my_decimal *first_expr_dec, first_expr_dec_val;
01692   longlong first_expr_int;
01693   double   first_expr_real;
01694   char buff[MAX_FIELD_WIDTH];
01695   String buff_str(buff,sizeof(buff),default_charset());
01696 
01697   /* These will be initialized later */
01698   LINT_INIT(first_expr_str);
01699   LINT_INIT(first_expr_int);
01700   LINT_INIT(first_expr_real);
01701   LINT_INIT(first_expr_dec);
01702 
01703   if (first_expr_num != -1)
01704   {
01705     switch (cmp_type)
01706     {
01707       case STRING_RESULT:
01708         // We can't use 'str' here as this may be overwritten
01709         if (!(first_expr_str= args[first_expr_num]->val_str(&buff_str)))
01710           return else_expr_num != -1 ? args[else_expr_num] : 0; // Impossible
01711         break;
01712       case INT_RESULT:
01713         first_expr_int= args[first_expr_num]->val_int();
01714         if (args[first_expr_num]->null_value)
01715           return else_expr_num != -1 ? args[else_expr_num] : 0;
01716         break;
01717       case REAL_RESULT:
01718         first_expr_real= args[first_expr_num]->val_real();
01719         if (args[first_expr_num]->null_value)
01720           return else_expr_num != -1 ? args[else_expr_num] : 0;
01721         break;
01722       case DECIMAL_RESULT:
01723         first_expr_dec= args[first_expr_num]->val_decimal(&first_expr_dec_val);
01724         if (args[first_expr_num]->null_value)
01725           return else_expr_num != -1 ? args[else_expr_num] : 0;
01726         break;
01727       case ROW_RESULT:
01728       default:
01729         // This case should never be chosen
01730         DBUG_ASSERT(0);
01731         break;
01732     }
01733   }
01734 
01735   // Compare every WHEN argument with it and return the first match
01736   for (uint i=0 ; i < ncases ; i+=2)
01737   {
01738     if (first_expr_num == -1)
01739     {
01740       // No expression between CASE and the first WHEN
01741       if (args[i]->val_bool())
01742         return args[i+1];
01743       continue;
01744     }
01745     switch (cmp_type) {
01746     case STRING_RESULT:
01747       if ((tmp=args[i]->val_str(str)))          // If not null
01748         if (sortcmp(tmp,first_expr_str,cmp_collation.collation)==0)
01749           return args[i+1];
01750       break;
01751     case INT_RESULT:
01752       if (args[i]->val_int()==first_expr_int && !args[i]->null_value) 
01753         return args[i+1];
01754       break;
01755     case REAL_RESULT: 
01756       if (args[i]->val_real() == first_expr_real && !args[i]->null_value)
01757         return args[i+1];
01758       break;
01759     case DECIMAL_RESULT:
01760     {
01761       my_decimal value;
01762       if (my_decimal_cmp(args[i]->val_decimal(&value), first_expr_dec) == 0)
01763         return args[i+1];
01764       break;
01765     }
01766     case ROW_RESULT:
01767     default:
01768       // This case should never be chosen
01769       DBUG_ASSERT(0);
01770       break;
01771     }
01772   }
01773   // No, WHEN clauses all missed, return ELSE expression
01774   return else_expr_num != -1 ? args[else_expr_num] : 0;
01775 }

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bool Item_func_case::fix_fields	(	THD *	thd,
		Item **	ref
	)			`[virtual]`

Reimplemented from Item_func.

Definition at line 1853 of file item_cmpfunc.cc.

References check_stack_overrun(), Item_func::fix_fields(), MAX_FIELD_WIDTH, STACK_MIN_SIZE, and TRUE.

01854 {
01855   /*
01856     buff should match stack usage from
01857     Item_func_case::val_int() -> Item_func_case::find_item()
01858   */
01859   char buff[MAX_FIELD_WIDTH*2+sizeof(String)*2+sizeof(String*)*2+sizeof(double)*2+sizeof(longlong)*2];
01860   bool res= Item_func::fix_fields(thd, ref);
01861   /*
01862     Call check_stack_overrun after fix_fields to be sure that stack variable
01863     is not optimized away
01864   */
01865   if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
01866     return TRUE;                                // Fatal error flag is set!
01867   return res;
01868 }

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void Item_func_case::fix_length_and_dec ( ) [virtual]

Implements Item_result_field.

Definition at line 1872 of file item_cmpfunc.cc.

References Item_func::agg_arg_charsets(), agg_cmp_type(), agg_result_type(), Item_func::args, cached_result_type, cmp_collation, cmp_type, Item::collation, current_thd, Item::decimals, else_expr_num, first_expr_num, Item::max_length, Item::maybe_null, MY_COLL_ALLOW_CONV, MY_COLL_CMP_CONV, ncases, set_if_bigger, sql_alloc(), and STRING_RESULT.

01873 {
01874   Item **agg;
01875   uint nagg;
01876   THD *thd= current_thd;
01877   
01878   if (!(agg= (Item**) sql_alloc(sizeof(Item*)*(ncases+1))))
01879     return;
01880   
01881   /*
01882     Aggregate all THEN and ELSE expression types
01883     and collations when string result
01884   */
01885   
01886   for (nagg= 0 ; nagg < ncases/2 ; nagg++)
01887     agg[nagg]= args[nagg*2+1];
01888   
01889   if (else_expr_num != -1)
01890     agg[nagg++]= args[else_expr_num];
01891   
01892   agg_result_type(&cached_result_type, agg, nagg);
01893   if ((cached_result_type == STRING_RESULT) &&
01894       agg_arg_charsets(collation, agg, nagg, MY_COLL_ALLOW_CONV, 1))
01895     return;
01896   
01897   
01898   /*
01899     Aggregate first expression and all THEN expression types
01900     and collations when string comparison
01901   */
01902   if (first_expr_num != -1)
01903   {
01904     agg[0]= args[first_expr_num];
01905     for (nagg= 0; nagg < ncases/2 ; nagg++)
01906       agg[nagg+1]= args[nagg*2];
01907     nagg++;
01908     agg_cmp_type(thd, &cmp_type, agg, nagg);
01909     if ((cmp_type == STRING_RESULT) &&
01910         agg_arg_charsets(cmp_collation, agg, nagg, MY_COLL_CMP_CONV, 1))
01911       return;
01912   }
01913   
01914   if (else_expr_num == -1 || args[else_expr_num]->maybe_null)
01915     maybe_null=1;
01916   
01917   max_length=0;
01918   decimals=0;
01919   for (uint i=0 ; i < ncases ; i+=2)
01920   {
01921     set_if_bigger(max_length,args[i+1]->max_length);
01922     set_if_bigger(decimals,args[i+1]->decimals);
01923   }
01924   if (else_expr_num != -1) 
01925   {
01926     set_if_bigger(max_length,args[else_expr_num]->max_length);
01927     set_if_bigger(decimals,args[else_expr_num]->decimals);
01928   }
01929 }

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const char* Item_func_case::func_name ( ) const [inline, virtual]

Implements Item_func.

Definition at line 626 of file item_cmpfunc.h.

00626 { return "case"; }

table_map Item_func_case::not_null_tables ( ) const [inline, virtual]

Reimplemented from Item_func.

Definition at line 624 of file item_cmpfunc.h.

00624 { return 0; }

void Item_func_case::print ( String * str ) [virtual]

Reimplemented from Item_func.

Definition at line 1946 of file item_cmpfunc.cc.

References String::append(), Item_func::args, else_expr_num, first_expr_num, ncases, Item::print(), and STRING_WITH_LEN.

01947 {
01948   str->append(STRING_WITH_LEN("(case "));
01949   if (first_expr_num != -1)
01950   {
01951     args[first_expr_num]->print(str);
01952     str->append(' ');
01953   }
01954   for (uint i=0 ; i < ncases ; i+=2)
01955   {
01956     str->append(STRING_WITH_LEN("when "));
01957     args[i]->print(str);
01958     str->append(STRING_WITH_LEN(" then "));
01959     args[i+1]->print(str);
01960     str->append(' ');
01961   }
01962   if (else_expr_num != -1)
01963   {
01964     str->append(STRING_WITH_LEN("else "));
01965     args[else_expr_num]->print(str);
01966     str->append(' ');
01967   }
01968   str->append(STRING_WITH_LEN("end)"));
01969 }

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enum Item_result Item_func_case::result_type ( ) const [inline, virtual]

Reimplemented from Item.

Definition at line 625 of file item_cmpfunc.h.

References cached_result_type.

00625 { return cached_result_type; }

my_decimal * Item_func_case::val_decimal ( my_decimal * ) [virtual]

Reimplemented from Item_func.

Definition at line 1833 of file item_cmpfunc.cc.

References DBUG_ASSERT, Item::default_charset(), find_item(), Item::fixed, MAX_FIELD_WIDTH, Item::null_value, and Item::val_decimal().

Referenced by find_item().

01834 {
01835   DBUG_ASSERT(fixed == 1);
01836   char buff[MAX_FIELD_WIDTH];
01837   String dummy_str(buff, sizeof(buff), default_charset());
01838   Item *item= find_item(&dummy_str);
01839   my_decimal *res;
01840 
01841   if (!item)
01842   {
01843     null_value=1;
01844     return 0;
01845   }
01846 
01847   res= item->val_decimal(decimal_value);
01848   null_value= item->null_value;
01849   return res;
01850 }

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longlong Item_func_case::val_int ( ) [virtual]

Implements Item.

Definition at line 1796 of file item_cmpfunc.cc.

References DBUG_ASSERT, Item::default_charset(), find_item(), Item::fixed, MAX_FIELD_WIDTH, Item::null_value, and Item::val_int().

Referenced by find_item().

01797 {
01798   DBUG_ASSERT(fixed == 1);
01799   char buff[MAX_FIELD_WIDTH];
01800   String dummy_str(buff,sizeof(buff),default_charset());
01801   Item *item=find_item(&dummy_str);
01802   longlong res;
01803 
01804   if (!item)
01805   {
01806     null_value=1;
01807     return 0;
01808   }
01809   res=item->val_int();
01810   null_value=item->null_value;
01811   return res;
01812 }

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double Item_func_case::val_real ( ) [virtual]

Implements Item.

Definition at line 1814 of file item_cmpfunc.cc.

References DBUG_ASSERT, Item::default_charset(), find_item(), Item::fixed, MAX_FIELD_WIDTH, Item::null_value, and Item::val_real().

Referenced by find_item().

01815 {
01816   DBUG_ASSERT(fixed == 1);
01817   char buff[MAX_FIELD_WIDTH];
01818   String dummy_str(buff,sizeof(buff),default_charset());
01819   Item *item=find_item(&dummy_str);
01820   double res;
01821 
01822   if (!item)
01823   {
01824     null_value=1;
01825     return 0;
01826   }
01827   res= item->val_real();
01828   null_value=item->null_value;
01829   return res;
01830 }

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String * Item_func_case::val_str ( String * ) [virtual]

Implements Item.

Definition at line 1778 of file item_cmpfunc.cc.

References DBUG_ASSERT, find_item(), Item::fixed, Item::null_value, and Item::val_str().

Referenced by find_item().

01779 {
01780   DBUG_ASSERT(fixed == 1);
01781   String *res;
01782   Item *item=find_item(str);
01783 
01784   if (!item)
01785   {
01786     null_value=1;
01787     return 0;
01788   }
01789   null_value= 0;
01790   if (!(res=item->val_str(str)))
01791     null_value= 1;
01792   return res;
01793 }