Arjens LOG functions changes with small changes and tests added to mysql-test

Docs/manual.texi:
  Manual changes to doccument new functions and function changes
mysql-test/r/func_math.result:
  Extend tests for LOG family functions
mysql-test/t/func_math.test:
  Extend tests for LOG family functions
sql/gen_lex_hash.cc:
  Lex hash changes
sql/item_create.cc:
  Rename old log function to ln
sql/item_create.h:
  More log functions
sql/item_func.cc:
  Implementation of new log function behavior
sql/item_func.h:
  Class definition for new functions
sql/lex.h:
  Function names
sql/sql_yacc.yy:
  Symbols for new LOG function
tests/function.res:
  One more test result change
tests/function.tst:
  One more test change
BitKeeper/etc/logging_ok:
  Logging to logging@openlogging.org accepted

1 files changed, 30 insertions, 1 deletions

diff --git a/sql/item_func.cc b/sql/item_func.cc
index 4ec4377509f..807f023b308 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -437,14 +437,43 @@ void Item_func_abs::fix_length_and_dec()
   hybrid_type= args[0]->result_type() == INT_RESULT ? INT_RESULT : REAL_RESULT;
 }
 
+/* Gateway to natural LOG function */
+double Item_func_ln::val()
+{
+  double value=args[0]->val();
+  if ((null_value=(args[0]->null_value || value <= 0.0)))
+    return 0.0;
+  return log(value);
+}
+
+/* 
+ Extended but so slower LOG function
+ We have to check if all values are > zero and first one is not one
+ as these are the cases then result is not a number.
+*/ 
 double Item_func_log::val()
 {
   double value=args[0]->val();
   if ((null_value=(args[0]->null_value || value <= 0.0)))
-    return 0.0; /* purecov: inspected */
+    return 0.0;
+  if (arg_count == 2)
+  {
+    double value2= args[1]->val();
+    if ((null_value=(args[1]->null_value || value2 <= 0.0 || value == 1.0)))
+      return 0.0;
+    return log(value2) / log(value);
+  }
   return log(value);
 }
 
+double Item_func_log2::val()
+{
+  double value=args[0]->val();
+  if ((null_value=(args[0]->null_value || value <= 0.0)))
+    return 0.0;
+  return log(value) / log(2.0);
+}
+
 double Item_func_log10::val()
 {
   double value=args[0]->val();