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SUM never gives an error. An integer result is returned for exact results

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and a floating point result is returned for approximate results.
Tickets #1664, #1669, and #1670. (CVS 3066)

FossilOrigin-Name: 9e04f8fdf1ec0dc36effb55c05d075b3b4777fef
This commit is contained in:
drh
2006-02-09 22:13:41 +00:00
parent cf85a51c2a
commit 29d7210819
10 changed files with 121 additions and 68 deletions
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src/func.c
+23 -11
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@@ -16,7 +16,7 @@
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.120 2006/02/09 18:35:30 drh Exp $
** $Id: func.c,v 1.121 2006/02/09 22:13:42 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@@ -819,7 +819,7 @@ typedef struct SumCtx SumCtx;
struct SumCtx {
LONGDOUBLE_TYPE sum; /* Sum of terms */
i64 cnt; /* Number of elements summed */
u8 seenFloat; /* True if there has been any floating point value */
u8 approx; /* True if sum is approximate */
};
/*
@@ -830,18 +830,33 @@ struct SumCtx {
** 0.0 in that case. In addition, TOTAL always returns a float where
** SUM might return an integer if it never encounters a floating point
** value.
**
** I am told that SUM() should raise an exception if it encounters
** a integer overflow. But after pondering this, I decided that
** behavior leads to brittle programs. So instead, I have coded
** SUM() to revert to using floating point if it encounters an
** integer overflow. The answer may not be exact, but it will be
** close. If the SUM() function returns an integer, the value is
** exact. If SUM() returns a floating point value, it means the
** value might be approximated.
*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
SumCtx *p;
int type;
assert( argc==1 );
p = sqlite3_aggregate_context(context, sizeof(*p));
type = sqlite3_value_type(argv[0]);
type = sqlite3_value_numeric_type(argv[0]);
if( p && type!=SQLITE_NULL ){
p->sum += sqlite3_value_double(argv[0]);
p->cnt++;
if( type==SQLITE_FLOAT ){
p->seenFloat = 1;
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);
}
}else{
p->sum += sqlite3_value_double(argv[0]);
p->approx = 1;
}
}
}
@@ -849,13 +864,10 @@ static void sumFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
if( p && p->cnt>0 ){
i64 iVal = (i64)p->sum;
if( p->seenFloat ){
if( p->approx ){
sqlite3_result_double(context, p->sum);
}else if( p->sum==(LONGDOUBLE_TYPE)iVal ){
sqlite3_result_int64(context, iVal);
}else{
sqlite3_result_error(context, "integer overflow", -1);
sqlite3_result_int64(context, (i64)p->sum);
}
}
}