Change TABLE->alias to String for less memory reallocation

Changed some String.ptr() -> String.c_ptr() for String that are not guaranteed to end with \0
Removed some c_ptr() usage from parameters to functions that takes ptr & length
Use preallocate buffers to avoid calling malloc() for most operations. 


sql/event_db_repository.cc:
  alias is now a String
sql/event_scheduler.cc:
  c_ptr -> c_ptr_safe() to avoid warnings from valgrind.
sql/events.cc:
  c_ptr -> c_ptr_safe() to avoid warnings from valgrind.
  c_ptr -> ptr() as function takes ptr & length
sql/field.cc:
  alias is now a String
sql/field.h:
  alias is now a String
sql/ha_partition.cc:
  alias is now a String
sql/handler.cc:
  alias is now a String
  ptr() -> c_ptr() as string is not guaranteed to be \0 terminated
sql/item.cc:
  Store error parameter in separarte buffer to ensure correct error message
sql/item_func.cc:
  ptr() -> c_ptr_safe() as string is not guaranteed to be \0 terminated
sql/item_sum.h:
  Use my_strtod() instead of my_atof() to not have to make string \0 terminated
sql/lock.cc:
  alias is now a String
sql/log.cc:
  c_ptr() -> ptr() as function takes ptr & length
sql/log_event.cc:
  c_ptr_quick() -> ptr() as we only want to get the pointer to String buffer
sql/opt_range.cc:
  ptr() -> c_ptr() as string is not guaranteed to be \0 terminated
sql/opt_table_elimination.cc:
  alias is now a String
sql/set_var.cc:
  ptr() -> c_ptr() as string is not guaranteed to be \0 terminated
  c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
  c_ptr() -> ptr() as function takes ptr & length
  Simplify some code.
sql/sp.cc:
  c_ptr() -> ptr() as function takes ptr & length
sql/sp_rcontext.cc:
  alias is now a String
sql/sql_base.cc:
  alias is now a String.
  Here we win a realloc() for most alias usage.
sql/sql_class.cc:
  Use size descriptor for printf() to avoid accessing bytes outside of buffer
sql/sql_insert.cc:
  Change allocation of TABLE as it's now contains a String
  _ptr() -> ptr() as function takes ptr & length
sql/sql_load.cc:
  Use preallocate buffers to avoid calling malloc() for most operations.
sql/sql_parse.cc:
  Use c_ptr_safe() to ensure string is \0 terminated.
sql/sql_plugin.cc:
  c_ptr_quick() -> ptr() as function takes ptr & length
sql/sql_select.cc:
  alias is now a String
sql/sql_show.cc:
  alias is now a String
sql/sql_string.h:
  Added move() function to change who owns the string (owner does the free)
sql/sql_table.cc:
  alias is now a String
  c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
sql/sql_test.cc:
  c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
  alias is now a String
sql/sql_trigger.cc:
  c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
  Use field->init() to setup pointers to alias.
sql/sql_update.cc:
  alias is now a String
sql/sql_view.cc:
  ptr() -> c_ptr_safe() as string is not guaranteed to be \0 terminated
sql/sql_yacc.yy:
  r() -> c_ptr() as string is not guaranteed to be \0 terminated
sql/table.cc:
  alias is now a String
sql/table.h:
  alias is now a String
storage/federatedx/ha_federatedx.cc:
  Remove extra 1 byte alloc that is automaticly done by strmake()
  Ensure that error message ends with \0
storage/maria/ha_maria.cc:
  alias is now a String
storage/myisam/ha_myisam.cc:
  alias is now a String

sql/sql_string.h

@@ -274,6 +274,14 @@ 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);
@@ -304,6 +312,7 @@ 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);