I give up. SUM() now throws an error on integer overflow. Those of us

who think this is goofy can use TOTAL() instead.
Tickets #1664, #1669, #1670, #1674. (CVS 3084)

FossilOrigin-Name: 1c3e6002cd9fd5d30e197448c4d98cdd59163cac

1 files changed, 23 insertions, 14 deletions

diff --git a/src/func.c b/src/func.c
index 0e050f80a..6d1195961 100644
--- a/src/func.c
+++ b/src/func.c
@@ -16,7 +16,7 @@
 ** sqliteRegisterBuildinFunctions() found at the bottom of the file.
 ** All other code has file scope.
 **
-** $Id: func.c,v 1.121 2006/02/09 22:13:42 drh Exp $
+** $Id: func.c,v 1.122 2006/02/11 17:34:00 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -817,9 +817,11 @@ static void test_error(
 */
 typedef struct SumCtx SumCtx;
 struct SumCtx {
-  LONGDOUBLE_TYPE sum;    /* Sum of terms */
-  i64 cnt;                /* Number of elements summed */
-  u8 approx;              /* True if sum is approximate */
+  double rSum;      /* Floating point sum */
+  i64 iSum;         /* Integer sum */   
+  i64 cnt;          /* Number of elements summed */
+  u8 overflow;      /* True if integer overflow seen */
+  u8 approx;        /* True if non-integer value was input to the sum */
 };
 
 /*
@@ -849,13 +851,18 @@ static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
   if( p && type!=SQLITE_NULL ){
     p->cnt++;
     if( type==SQLITE_INTEGER ){
-      p->sum += sqlite3_value_int64(argv[0]);
-      if( !p->approx ){
-        i64 iVal;
-        p->approx = p->sum!=(LONGDOUBLE_TYPE)(iVal = (i64)p->sum);
+      i64 v = sqlite3_value_int64(argv[0]);
+      p->rSum += v;
+      if( (p->approx|p->overflow)==0 ){
+        i64 iNewSum = p->iSum + v;
+        int s1 = p->iSum >> (sizeof(i64)*8-1);
+        int s2 = v       >> (sizeof(i64)*8-1);
+        int s3 = iNewSum >> (sizeof(i64)*8-1);
+        p->overflow = (s1&s2&~s3) | (~s1&~s2&s3);
+        p->iSum = iNewSum;
       }
     }else{
-      p->sum += sqlite3_value_double(argv[0]);
+      p->rSum += sqlite3_value_double(argv[0]);
       p->approx = 1;
     }
   }
@@ -864,10 +871,12 @@ static void sumFinalize(sqlite3_context *context){
   SumCtx *p;
   p = sqlite3_aggregate_context(context, 0);
   if( p && p->cnt>0 ){
-    if( p->approx ){
-      sqlite3_result_double(context, p->sum);
+    if( p->overflow ){
+      sqlite3_result_error(context,"integer overflow",-1);
+    }else if( p->approx ){
+      sqlite3_result_double(context, p->rSum);
     }else{
-      sqlite3_result_int64(context, (i64)p->sum);
+      sqlite3_result_int64(context, p->iSum);
     }
   }
 }
@@ -875,13 +884,13 @@ static void avgFinalize(sqlite3_context *context){
   SumCtx *p;
   p = sqlite3_aggregate_context(context, 0);
   if( p && p->cnt>0 ){
-    sqlite3_result_double(context, p->sum/(double)p->cnt);
+    sqlite3_result_double(context, p->rSum/(double)p->cnt);
   }
 }
 static void totalFinalize(sqlite3_context *context){
   SumCtx *p;
   p = sqlite3_aggregate_context(context, 0);
-  sqlite3_result_double(context, p ? p->sum : 0.0);
+  sqlite3_result_double(context, p ? p->rSum : 0.0);
 }
 
 /*