1 files changed, 119 insertions, 0 deletions
diff --git a/sql/item_buff.cc b/sql/item_buff.cc
new file mode 100644
index 00000000000..61e1f5498a9
--- /dev/null
+++ b/sql/item_buff.cc
@@ -0,0 +1,119 @@
+/* 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 */
+
+
+/* Buffers to save and compare item values */
+
+#include "mysql_priv.h"
+
+/*
+** Create right type of item_buffer for an item
+*/
+
+Item_buff *new_Item_buff(Item *item)
+{
+  if (item->type() == Item::FIELD_ITEM &&
+      !(((Item_field *) item)->field->flags & BLOB_FLAG))
+    return new Item_field_buff((Item_field *) item);
+  if (item->result_type() == STRING_RESULT)
+    return new Item_str_buff((Item_field *) item);
+  if (item->result_type() == INT_RESULT)
+    return new Item_int_buff((Item_field *) item);
+  return new Item_real_buff(item);
+}
+
+Item_buff::~Item_buff() {}
+
+/*
+** Compare with old value and replace value with new value
+** Return true if values have changed
+*/
+
+bool Item_str_buff::cmp(void)
+{
+  String *res;
+  bool tmp;
+
+  res=item->val_str(&tmp_value);
+  if (null_value != item->null_value)
+  {
+    if ((null_value= item->null_value))
+      return TRUE;				// New value was null
+    tmp=TRUE;
+  }
+  else if (null_value)
+    return 0;					// new and old value was null
+  else if (!item->binary)
+    tmp= sortcmp(&value,res) != 0;
+  else
+    tmp= stringcmp(&value,res) != 0;
+  if (tmp)
+    value.copy(*res);				// Remember for next cmp
+  return tmp;
+}
+
+Item_str_buff::~Item_str_buff()
+{
+  item=0;					// Safety
+}
+
+bool Item_real_buff::cmp(void)
+{
+  double nr=item->val();
+  if (null_value != item->null_value || nr != value)
+  {
+    null_value= item->null_value;
+    value=nr;
+    return TRUE;
+  }
+  return FALSE;
+}
+
+bool Item_int_buff::cmp(void)
+{
+  longlong nr=item->val_int();
+  if (null_value != item->null_value || nr != value)
+  {
+    null_value= item->null_value;
+    value=nr;
+    return TRUE;
+  }
+  return FALSE;
+}
+
+
+bool Item_field_buff::cmp(void)
+{
+  bool tmp= field->cmp(buff) != 0;		// This is not a blob!
+  if (tmp)
+    field->get_image(buff,length);
+  if (null_value != field->is_null())
+  {
+    null_value= !null_value;
+    tmp=TRUE;
+  }
+  return tmp;
+}
+
+
+/*****************************************************************************
+** Instansiate templates
+*****************************************************************************/
+
+#ifdef __GNUC__
+template class List<Item_buff>;
+template class List_iterator<Item_buff>;
+#endif