Backport my_strntod() from 5.0

Change string->float conversion to delay division as long as possible.
This gives us more exact integer->float conversion for numbers of type '123.45E+02' (Bug #7740)




client/mysql.cc:
  Fix wront usage of charset (found during review of pushed code)
include/m_string.h:
  Backported my_strtod() from 5.0
mysql-test/mysql-test-run.sh:
  Run also mysql_client_test with --debug
mysql-test/r/ps_1general.result:
  Safety fix (if mysql_client_test.test fails)
mysql-test/r/type_float.result:
  More test
mysql-test/t/mysql_client_test.test:
  Comments for what to do if this test fails
mysql-test/t/ps_1general.test:
  Safety fix (if mysql_client_test.test fails)
mysql-test/t/type_float.test:
  More test to better test new strtod() function
  Test also bug #7740 (wrong comparsion between integer and float-in-integer-range)
sql/field.cc:
  Backport my_strntod() from 5.0
sql/item.cc:
  Backport my_strntod() from 5.0
sql/item.h:
  Backport my_strntod() from 5.0
sql/item_func.h:
  Backport my_strntod() from 5.0
sql/item_strfunc.cc:
  Backport my_strntod() from 5.0
sql/item_sum.cc:
  Backport my_strntod() from 5.0
sql/item_sum.h:
  Backport my_strntod() from 5.0
sql/procedure.h:
  Backport my_strntod() from 5.0
strings/ctype-simple.c:
  Backport my_strntod() from 5.0
strings/ctype-ucs2.c:
  Backport my_strntod() from 5.0
strings/strtod.c:
  Backport my_strntod() from 5.0
  Change conversion to delay division as long as possible.
  This gives us more exact integer-> float conversion for numbers of type '123.45E+02'

1 files changed, 8 insertions, 3 deletions

diff --git a/sql/procedure.h b/sql/procedure.h
index 5365b2e1102..abe50bdc0a0 100644
--- a/sql/procedure.h
+++ b/sql/procedure.h
@@ -59,7 +59,11 @@ public:
   void set(double nr) { value=nr; }
   void set(longlong nr) { value=(double) nr; }
   void set(const char *str,uint length,CHARSET_INFO *cs)
-  { int err; value=my_strntod(cs,(char*) str,length,(char**)0,&err); }
+  {
+    int err;
+    char *end_not_used;
+    value= my_strntod(cs, (char*) str, length, &end_not_used, &err);
+  }
   double val() { return value; }
   longlong val_int() { return (longlong) value; }
   String *val_str(String *s) { s->set(value,decimals,default_charset()); return s; }
@@ -99,9 +103,10 @@ public:
   double val() 
   { 
     int err;
-    CHARSET_INFO *cs=str_value.charset();
+    CHARSET_INFO *cs= str_value.charset();
+    char *end_not_used;
     return my_strntod(cs, (char*) str_value.ptr(), str_value.length(),
-		      (char**) 0, &err);
+		      &end_not_used, &err);
   }
   longlong val_int()
   {