--- src/libs/zbxserver/evalfunc.c	2010-08-16 08:19:31.000000000 +0000
+++ src/libs/zbxserver/evalfunc.c.new	2010-08-17 08:22:24.000000000 +0000
@@ -862,67 +862,92 @@
 	else
 		goto clean;
 
-	if (time_shift == 0 && arg1 == 1)
-	{
-		if (1 != item->lastvalue_null)
+	if (ITEM_VALUE_TYPE_TEXT != item->value_type) {
+		if (time_shift == 0 && arg1 == 1)
 		{
-			switch (item->value_type) {
-			case ITEM_VALUE_TYPE_FLOAT:
-				zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_DBL, item->lastvalue_dbl);
-				break;
-			case ITEM_VALUE_TYPE_UINT64:
-				zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_UI64, item->lastvalue_uint64);
-				break;
-			default:
-				zbx_snprintf(value, MAX_STRING_LEN, "%s", item->lastvalue_str);
-				break;
+			if (1 != item->lastvalue_null)
+			{
+				switch (item->value_type) {
+				case ITEM_VALUE_TYPE_FLOAT:
+					zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_DBL, item->lastvalue_dbl);
+					break;
+				case ITEM_VALUE_TYPE_UINT64:
+					zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_UI64, item->lastvalue_uint64);
+					break;
+				default:
+					zbx_snprintf(value, MAX_STRING_LEN, "%s", item->lastvalue_str);
+					break;
+				}
+				res = SUCCEED;
 			}
-			res = SUCCEED;
 		}
-	}
-	else if (time_shift == 0 && arg1 == 2)
-	{
-		if (1 != item->prevvalue_null)
+		else if (time_shift == 0 && arg1 == 2)
 		{
-			switch (item->value_type) {
-			case ITEM_VALUE_TYPE_FLOAT:
-				zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_DBL, item->prevvalue_dbl);
-				break;
-			case ITEM_VALUE_TYPE_UINT64:
-				zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_UI64, item->prevvalue_uint64);
-				break;
-			default:
-				zbx_snprintf(value, MAX_STRING_LEN, "%s", item->prevvalue_str);
-				break;
+			if (1 != item->prevvalue_null)
+			{
+				switch (item->value_type) {
+				case ITEM_VALUE_TYPE_FLOAT:
+					zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_DBL, item->prevvalue_dbl);
+					break;
+				case ITEM_VALUE_TYPE_UINT64:
+					zbx_snprintf(value, MAX_STRING_LEN, ZBX_FS_UI64, item->prevvalue_uint64);
+					break;
+				default:
+					zbx_snprintf(value, MAX_STRING_LEN, "%s", item->prevvalue_str);
+					break;
+				}
+				res = SUCCEED;
 			}
-			res = SUCCEED;
 		}
-	}
-	else
-	{
-		zbx_snprintf(sql, sizeof(sql),
-				"select value,clock"
-				" from %s"
-				" where itemid=" ZBX_FS_UI64
-					" and clock<=%d"
-				" order by %s desc",
-				get_table_by_value_type(item->value_type),
-				item->itemid,
-				now,
-				get_key_by_value_type(item->value_type));
-
-		result = DBselectN(sql, arg1);
-
-		while (NULL != (row = DBfetch(result)))
+		else
 		{
-			if (arg1 == ++rows)
+			zbx_snprintf(sql, sizeof(sql),
+					"select value,clock"
+					" from %s"
+					" where itemid=" ZBX_FS_UI64
+						" and clock<=%d"
+					" order by %s desc",
+					get_table_by_value_type(item->value_type),
+					item->itemid,
+					now,
+					get_key_by_value_type(item->value_type));
+		
+			result = DBselectN(sql, arg1);
+	
+			while (NULL != (row = DBfetch(result)))
 			{
-				zbx_snprintf(value, MAX_STRING_LEN, "%s", row[0]);
-				res = SUCCEED;
+				if (arg1 == ++rows)
+				{
+					zbx_snprintf(value, MAX_STRING_LEN, "%s", row[0]);
+					res = SUCCEED;
+				}
 			}
+	
+			DBfree_result(result);
 		}
+	} else {
+	        zbx_snprintf(sql, sizeof(sql),
+                                "select value,clock"
+                                " from %s"
+                                " where itemid=" ZBX_FS_UI64
+                                " order by %s desc",
+                                get_table_by_value_type(item->value_type),
+                                item->itemid,
+                                get_key_by_value_type(item->value_type));
+
+		zabbix_log(LOG_LEVEL_DEBUG, "DIFFSQL: %s", sql);
+                result = DBselectN(sql, arg1);
+
+                while (NULL != (row = DBfetch(result)))
+                {
+                	if (arg1 == ++rows)
+                        {
+                        	zbx_snprintf(value, MAX_STRING_LEN, "%s", row[0]);
+                        	res = SUCCEED;
+                        }
+                }
 
-		DBfree_result(result);
+                DBfree_result(result);
 	}
 
 clean:
@@ -1496,6 +1521,7 @@
 {
 	const char	*__function_name = "evaluate_DIFF";
 	int		res = FAIL;
+	char		last_txt[MAX_STRING_LEN], prev_txt[MAX_STRING_LEN];
 
 	zabbix_log(LOG_LEVEL_DEBUG, "In %s()", __function_name);
 
@@ -1515,6 +1541,17 @@
 			else
 				zbx_strlcpy(value, "1", MAX_STRING_LEN);
 			break;
+		case ITEM_VALUE_TYPE_TEXT:
+			if (FAIL != evaluate_LAST(last_txt, item, "last", parameters, now))
+				res = evaluate_LAST(prev_txt, item, "prev", parameters, now);
+			
+			if (FAIL != res) {
+				if (strcmp(last_txt, prev_txt) == 0)
+					zbx_strlcpy(value, "0", MAX_STRING_LEN);
+				else
+					zbx_strlcpy(value, "1", MAX_STRING_LEN);
+			}
+			break;
 		default:
 			if (0 == strcmp(item->lastvalue_str, item->prevvalue_str))
 				zbx_strlcpy(value, "0", MAX_STRING_LEN);