bk commit into 5.0 tree (gkodinov:1.2202) BUG#20569

[kgeorge]

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ChangeSet
  1.2202 06/07/05 16:38:27 gkodinov@stripped +3 -0
  Bug #20569 Garbage in DECIMAL results from some mathematical functions
    Adding decimal "digits" in multiplication resulted in signed overflow and
  producing wrong results.
  
    Fixed by using large enough buffers and intermediary result types :
  dec2 (currently longlong) to hold result of adding decimal "digits" 
  (currently int32). 

  strings/decimal.c
    1.69 06/07/05 16:38:17 gkodinov@stripped +4 -4
    Bug #20569 Garbage in DECIMAL results from some mathematical functions
      * fixed the overflow in adding decimal "digits"

  mysql-test/t/select.test
    1.107 06/07/05 16:38:16 gkodinov@stripped +5 -0
    Bug #20569 Garbage in DECIMAL results from some mathematical functions
      * test suite for the bug

  mysql-test/r/select.result
    1.131 06/07/05 16:38:15 gkodinov@stripped +3 -0
    Bug #20569 Garbage in DECIMAL results from some mathematical functions
      * test suite for the bug

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	gkodinov
# Host:	ws243.gmz
# Root:	/Users/kgeorge/mysql/5.0/test

--- 1.130/mysql-test/r/select.result	2006-06-21 00:04:31 +03:00
+++ 1.131/mysql-test/r/select.result	2006-07-05 16:38:15 +03:00
@@ -3395,3 +3395,6 @@
 1	0	1	1	0	1	NULL
 2	0	1	NULL	NULL	NULL	NULL
 drop table t1,t2;
+SELECT 0.9888889889 * 1.011111411911;
+0.9888889889 * 1.011111411911
+0.9998769417899202067879

--- 1.106/mysql-test/t/select.test	2006-06-21 00:04:14 +03:00
+++ 1.107/mysql-test/t/select.test	2006-07-05 16:38:16 +03:00
@@ -2901,3 +2901,8 @@
 where t1.b <> 1 order by t1.a;
 
 drop table t1,t2;
+
+#
+# Bug #20569: Garbage in DECIMAL results from some mathematical functions
+#
+SELECT 0.9888889889 * 1.011111411911;

--- 1.68/strings/decimal.c	2006-05-12 19:58:54 +03:00
+++ 1.69/strings/decimal.c	2006-07-05 16:38:17 +03:00
@@ -170,16 +170,16 @@
 #define ADD(to, from1, from2, carry)  /* assume carry <= 1 */           \
         do                                                              \
         {                                                               \
-          dec1 a=(from1)+(from2)+(carry);                               \
+          dec2 a=((dec2)(from1))+(from2)+(carry);                       \
           if (((carry)= a >= DIG_BASE)) /* no division here! */         \
             a-=DIG_BASE;                                                \
-          (to)=a;                                                       \
+          (to)=(dec1)a;                                                 \
         } while(0)
 
 #define ADD2(to, from1, from2, carry)                                   \
         do                                                              \
         {                                                               \
-          dec1 a=(from1)+(from2)+(carry);                               \
+          dec2 a=((dec2)(from1))+(from2)+(carry);                       \
           if (((carry)= a >= DIG_BASE))                                 \
             a-=DIG_BASE;                                                \
           if (unlikely(a >= DIG_BASE))                                  \
@@ -187,7 +187,7 @@
             a-=DIG_BASE;                                                \
             carry++;                                                    \
           }                                                             \
-          (to)=a;                                                       \
+          (to)=(dec1) a;                                                \
         } while(0)
 
 #define SUB(to, from1, from2, carry) /* to=from1-from2 */               \