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MySQL 5.1: Item_func_conv_charset Class Reference

Item_func_conv_charset Class Reference

#include <item_strfunc.h>

Inheritance diagram for Item_func_conv_charset:

[legend]Collaboration diagram for Item_func_conv_charset:

[legend]List of all members.


Public Member Functions
	Item_func_conv_charset (Item a, CHARSET_INFO cs)
	Item_func_conv_charset (Item a, CHARSET_INFO cs, bool cache_if_const)
String *	val_str (String *)
void	fix_length_and_dec ()
const char *	func_name () const
void	print (String *str)
bool	check_partition_func_processor (byte *bool_arg)
Public Attributes
bool	safe
CHARSET_INFO *	conv_charset
Private Attributes
bool	use_cached_value

Detailed Description

Definition at line 697 of file item_strfunc.h.

Constructor & Destructor Documentation

Item_func_conv_charset::Item_func_conv_charset	(	Item *	a,
		CHARSET_INFO *	cs
	)			`[inline]`

Definition at line 703 of file item_strfunc.h.

References conv_charset, safe, and use_cached_value.

00703                                                     :Item_str_func(a) 
00704   { conv_charset= cs; use_cached_value= 0; safe= 0; }

Item_func_conv_charset::Item_func_conv_charset	(	Item *	a,
		CHARSET_INFO *	cs,
		bool	cache_if_const
	)			`[inline]`

Definition at line 705 of file item_strfunc.h.

References Item_func::args, String::charset(), DTCollation::collation, Item::collation, Item_func::const_item(), conv_charset, String::copy(), DBUG_ASSERT, Item::fixed, String::length(), String::mark_as_const(), my_charset_bin, MY_CS_UNICODE, Item::null_value, String::ptr(), safe, charset_info_st::state, Item::str_value, use_cached_value, and Item::val_str().

00706     :Item_str_func(a) 
00707   {
00708     DBUG_ASSERT(args[0]->fixed);
00709     conv_charset= cs;
00710     if (cache_if_const && args[0]->const_item())
00711     {
00712       uint errors= 0;
00713       String tmp, *str= args[0]->val_str(&tmp);
00714       if (!str || str_value.copy(str->ptr(), str->length(),
00715                                  str->charset(), conv_charset, &errors))
00716         null_value= 1;
00717       use_cached_value= 1;
00718       str_value.mark_as_const();
00719       safe= (errors == 0);
00720     }
00721     else
00722     {
00723       use_cached_value= 0;
00724       /*
00725         Conversion from and to "binary" is safe.
00726         Conversion to Unicode is safe.
00727         Other kind of conversions are potentially lossy.
00728       */
00729       safe= (args[0]->collation.collation == &my_charset_bin ||
00730              cs == &my_charset_bin ||
00731              (cs->state & MY_CS_UNICODE));
00732     }
00733   }

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Member Function Documentation

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

Reimplemented from Item.

Definition at line 738 of file item_strfunc.h.

00738 { return 0;}

void Item_func_conv_charset::fix_length_and_dec ( ) [virtual]

Implements Item_result_field.

Definition at line 2395 of file item_strfunc.cc.

References Item_func::args, Item::collation, conv_charset, DERIVATION_IMPLICIT, Item::max_length, charset_info_st::mbmaxlen, and DTCollation::set().

02396 {
02397   collation.set(conv_charset, DERIVATION_IMPLICIT);
02398   max_length = args[0]->max_length*conv_charset->mbmaxlen;
02399 }

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

Implements Item_func.

Definition at line 736 of file item_strfunc.h.

00736 { return "convert"; }

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

Reimplemented from Item_func.

Definition at line 2401 of file item_strfunc.cc.

References String::append(), Item_func::args, conv_charset, charset_info_st::csname, Item::print(), and STRING_WITH_LEN.

02402 {
02403   str->append(STRING_WITH_LEN("convert("));
02404   args[0]->print(str);
02405   str->append(STRING_WITH_LEN(" using "));
02406   str->append(conv_charset->csname);
02407   str->append(')');
02408 }

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

Implements Item.

Definition at line 2378 of file item_strfunc.cc.

References Item_func::args, String::charset(), Item_str_func::check_well_formed_result(), conv_charset, String::copy(), DBUG_ASSERT, Item::fixed, String::length(), Item::null_value, String::ptr(), Item::str_value, use_cached_value, and Item::val_str().

02379 {
02380   DBUG_ASSERT(fixed == 1);
02381   if (use_cached_value)
02382     return null_value ? 0 : &str_value;
02383   String *arg= args[0]->val_str(str);
02384   uint dummy_errors;
02385   if (!arg)
02386   {
02387     null_value=1;
02388     return 0;
02389   }
02390   null_value= str_value.copy(arg->ptr(),arg->length(),arg->charset(),
02391                              conv_charset, &dummy_errors);
02392   return null_value ? 0 : check_well_formed_result(&str_value);
02393 }