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-rw-r--r--sql/sql_string.h57
1 files changed, 39 insertions, 18 deletions
diff --git a/sql/sql_string.h b/sql/sql_string.h
index 0b521eb6f49..5da0d38f24d 100644
--- a/sql/sql_string.h
+++ b/sql/sql_string.h
@@ -53,23 +53,24 @@ uint convert_to_printable(char *to, size_t to_len,
class String
{
char *Ptr;
- uint32 str_length,Alloced_length;
+ uint32 str_length,Alloced_length, extra_alloc;
bool alloced;
CHARSET_INFO *str_charset;
public:
String()
{
- Ptr=0; str_length=Alloced_length=0; alloced=0;
+ Ptr=0; str_length=Alloced_length=extra_alloc=0; alloced=0;
str_charset= &my_charset_bin;
}
String(uint32 length_arg)
{
- alloced=0; Alloced_length=0; (void) real_alloc(length_arg);
+ alloced=0; Alloced_length= extra_alloc= 0; (void) real_alloc(length_arg);
str_charset= &my_charset_bin;
}
String(const char *str, CHARSET_INFO *cs)
{
- Ptr=(char*) str; str_length=(uint) strlen(str); Alloced_length=0; alloced=0;
+ Ptr=(char*) str; str_length= (uint32) strlen(str);
+ Alloced_length= extra_alloc= 0; alloced=0;
str_charset=cs;
}
/*
@@ -79,18 +80,18 @@ public:
*/
String(const char *str,uint32 len, CHARSET_INFO *cs)
{
- Ptr=(char*) str; str_length=len; Alloced_length=0; alloced=0;
+ Ptr=(char*) str; str_length=len; Alloced_length= extra_alloc=0; alloced=0;
str_charset=cs;
}
String(char *str,uint32 len, CHARSET_INFO *cs)
{
- Ptr=(char*) str; Alloced_length=str_length=len; alloced=0;
+ Ptr=(char*) str; Alloced_length=str_length=len; extra_alloc= 0; alloced=0;
str_charset=cs;
}
String(const String &str)
{
Ptr=str.Ptr ; str_length=str.str_length ;
- Alloced_length=str.Alloced_length; alloced=0;
+ Alloced_length=str.Alloced_length; extra_alloc= 0; alloced=0;
str_charset=str.str_charset;
}
static void *operator new(size_t size, MEM_ROOT *mem_root) throw ()
@@ -110,8 +111,10 @@ public:
inline CHARSET_INFO *charset() const { return str_charset; }
inline uint32 length() const { return str_length;}
inline uint32 alloced_length() const { return Alloced_length;}
+ inline uint32 extra_allocation() const { return extra_alloc;}
inline char& operator [] (uint32 i) const { return Ptr[i]; }
inline void length(uint32 len) { str_length=len ; }
+ inline void extra_allocation(uint32 len) { extra_alloc= len; }
inline bool is_empty() const { return (str_length == 0); }
inline void mark_as_const() { Alloced_length= 0;}
inline const char *ptr() const { return Ptr; }
@@ -140,23 +143,21 @@ public:
{
DBUG_ASSERT(&str != this);
free();
- Ptr=(char*) str.ptr()+offset; str_length=arg_length; alloced=0;
+ Ptr=(char*) str.ptr()+offset; str_length=arg_length;
if (str.Alloced_length)
Alloced_length=str.Alloced_length-offset;
- else
- Alloced_length=0;
str_charset=str.str_charset;
}
inline void set(char *str,uint32 arg_length, CHARSET_INFO *cs)
{
free();
- Ptr=(char*) str; str_length=Alloced_length=arg_length ; alloced=0;
+ Ptr=(char*) str; str_length=Alloced_length=arg_length;
str_charset=cs;
}
inline void set(const char *str,uint32 arg_length, CHARSET_INFO *cs)
{
free();
- Ptr=(char*) str; str_length=arg_length; Alloced_length=0 ; alloced=0;
+ Ptr=(char*) str; str_length=arg_length;
str_charset=cs;
}
bool set_ascii(const char *str, uint32 arg_length);
@@ -207,11 +208,11 @@ public:
if (alloced)
{
alloced=0;
- Alloced_length=0;
my_free(Ptr,MYF(0));
- Ptr=0;
- str_length=0; /* Safety */
}
+ Alloced_length= extra_alloc= 0;
+ Ptr=0;
+ str_length=0; /* Safety */
}
inline bool alloc(uint32 arg_length)
{
@@ -221,9 +222,21 @@ public:
}
bool real_alloc(uint32 arg_length); // Empties old string
bool realloc(uint32 arg_length);
- inline void shrink(uint32 arg_length) // Shrink buffer
+ bool realloc_with_extra(uint32 arg_length)
+ {
+ if (extra_alloc < 4096)
+ extra_alloc= extra_alloc*2+128;
+ return realloc(arg_length + extra_alloc);
+ }
+ bool realloc_with_extra_if_needed(uint32 arg_length)
{
if (arg_length < Alloced_length)
+ return 0;
+ return realloc_with_extra(arg_length);
+ }
+ inline void shrink(uint32 arg_length) // Shrink buffer
+ {
+ if (ALIGN_SIZE(arg_length+1) < Alloced_length)
{
char *new_ptr;
if (!(new_ptr=(char*) my_realloc(Ptr,arg_length,MYF(0))))
@@ -250,7 +263,6 @@ public:
DBUG_ASSERT(!s.uses_buffer_owned_by(this));
free();
Ptr=s.Ptr ; str_length=s.str_length ; Alloced_length=s.Alloced_length;
- alloced=0;
}
return *this;
}
@@ -266,6 +278,14 @@ public:
bool set_or_copy_aligned(const char *s, uint32 arg_length, CHARSET_INFO *cs);
bool copy(const char*s,uint32 arg_length, CHARSET_INFO *csfrom,
CHARSET_INFO *csto, uint *errors);
+ void move(String &s)
+ {
+ free();
+ Ptr=s.Ptr ; str_length=s.str_length ; Alloced_length=s.Alloced_length;
+ extra_alloc= s.extra_alloc;
+ alloced= s.alloced;
+ s.alloced= 0;
+ }
bool append(const String &s);
bool append(const char *s);
bool append(const char *s,uint32 arg_length);
@@ -285,7 +305,7 @@ public:
}
else
{
- if (realloc(str_length+1))
+ if (realloc_with_extra(str_length + 1))
return 1;
Ptr[str_length++]=chr;
}
@@ -296,6 +316,7 @@ public:
friend int sortcmp(const String *a,const String *b, CHARSET_INFO *cs);
friend int stringcmp(const String *a,const String *b);
friend String *copy_if_not_alloced(String *a,String *b,uint32 arg_length);
+ friend class Field;
uint32 numchars();
int charpos(int i,uint32 offset=0);