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-rw-r--r--src/func.c47
-rw-r--r--src/sqliteInt.h10
-rw-r--r--src/util.c40
3 files changed, 76 insertions, 21 deletions
diff --git a/src/func.c b/src/func.c
index f0695ac53..c505c37d6 100644
--- a/src/func.c
+++ b/src/func.c
@@ -1670,11 +1670,9 @@ static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
*/
typedef struct SumCtx SumCtx;
struct SumCtx {
- double rSum; /* Floating point sum */
- i64 iSum; /* Integer sum */
+ double rSum[2]; /* Running sum as a Dekker double-double */
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 */
+ u8 approx; /* True if any non-integer value was input to the sum */
};
/*
@@ -1695,17 +1693,17 @@ static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
p = sqlite3_aggregate_context(context, sizeof(*p));
type = sqlite3_value_numeric_type(argv[0]);
if( p && type!=SQLITE_NULL ){
+ double y[2];
p->cnt++;
if( type==SQLITE_INTEGER ){
i64 v = sqlite3_value_int64(argv[0]);
- p->rSum += v;
- if( (p->approx|p->overflow)==0 && sqlite3AddInt64(&p->iSum, v) ){
- p->approx = p->overflow = 1;
- }
+ sqlite3DDFromInt(v, y);
}else{
- p->rSum += sqlite3_value_double(argv[0]);
+ y[0] = sqlite3_value_double(argv[0]);
+ y[1] = 0.0;
p->approx = 1;
}
+ sqlite3DDAdd(p->rSum[0], p->rSum[1], y[0], y[1], p->rSum);
}
}
#ifndef SQLITE_OMIT_WINDOWFUNC
@@ -1719,16 +1717,17 @@ static void sumInverse(sqlite3_context *context, int argc, sqlite3_value**argv){
/* p is always non-NULL because sumStep() will have been called first
** to initialize it */
if( ALWAYS(p) && type!=SQLITE_NULL ){
+ double y[2];
assert( p->cnt>0 );
p->cnt--;
- assert( type==SQLITE_INTEGER || p->approx );
- if( type==SQLITE_INTEGER && p->approx==0 ){
+ if( type==SQLITE_INTEGER ){
i64 v = sqlite3_value_int64(argv[0]);
- p->rSum -= v;
- p->iSum -= v;
+ sqlite3DDFromInt(v, y);
}else{
- p->rSum -= sqlite3_value_double(argv[0]);
+ y[0] = sqlite3_value_double(argv[0]);
+ y[1] = 0.0;
}
+ sqlite3DDSub(p->rSum[0], p->rSum[1], y[0], y[1], p->rSum);
}
}
#else
@@ -1738,12 +1737,18 @@ static void sumFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
if( p && p->cnt>0 ){
- if( p->overflow ){
- sqlite3_result_error(context,"integer overflow",-1);
- }else if( p->approx ){
- sqlite3_result_double(context, p->rSum);
+ if( p->approx ){
+ sqlite3_result_double(context, p->rSum[0]+p->rSum[1]);
}else{
- sqlite3_result_int64(context, p->iSum);
+ i64 v = (i64)p->rSum[0] + (i64)p->rSum[1];
+ double y[2], z[2];
+ sqlite3DDFromInt(v, y);
+ sqlite3DDSub(y[0], y[1], p->rSum[0], p->rSum[1], z);
+ if( z[0] + z[1] != 0.0 ){
+ sqlite3_result_error(context,"integer overflow",-1);
+ }else{
+ sqlite3_result_int64(context, v);
+ }
}
}
}
@@ -1751,14 +1756,14 @@ static void avgFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
if( p && p->cnt>0 ){
- sqlite3_result_double(context, p->rSum/(double)p->cnt);
+ sqlite3_result_double(context, (p->rSum[0]+p->rSum[1])/(double)p->cnt);
}
}
static void totalFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
/* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
- sqlite3_result_double(context, p ? p->rSum : (double)0);
+ sqlite3_result_double(context, p ? p->rSum[0]+p->rSum[1] : (double)0);
}
/*
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 91b78710c..332048f43 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1234,6 +1234,7 @@ typedef struct Cte Cte;
typedef struct CteUse CteUse;
typedef struct Db Db;
typedef struct DbFixer DbFixer;
+typedef struct DblDbl DblDbl;
typedef struct Schema Schema;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
@@ -5035,6 +5036,15 @@ int sqlite3FixSrcList(DbFixer*, SrcList*);
int sqlite3FixSelect(DbFixer*, Select*);
int sqlite3FixExpr(DbFixer*, Expr*);
int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
+
+
+/* Representation of an extended precision floating point value.
+** The actual value is the sum r and rr. See the dbldbl.c file.
+*/
+void sqlite3DDFromInt(i64,double*);
+void sqlite3DDAdd(double,double,double,double,double*);
+void sqlite3DDSub(double,double,double,double,double*);
+
int sqlite3RealSameAsInt(double,sqlite3_int64);
i64 sqlite3RealToI64(double);
int sqlite3Int64ToText(i64,char*);
diff --git a/src/util.c b/src/util.c
index abd36eda8..256ec7c5c 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1750,3 +1750,43 @@ int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
|| defined(SQLITE_ENABLE_STMT_SCANSTATUS)
# include "hwtime.h"
#endif
+
+/***************************************************************************
+** Double-Double arithmetic.
+**
+** Reference:
+** T. J. Dekker, "A Floating-Point Technique for Extending the
+** Available Precision". 1971-07-26.
+*/
+
+/* Compute z = (i64)x */
+void sqlite3DDFromInt(i64 x, double *z){
+ z[0] = (double)x;
+ z[1] = (double)(x - (i64)z[0]);
+}
+
+/* Compute z = x + y */
+void sqlite3DDAdd(double x, double xx, double y, double yy, double *z){
+ double r, s;
+ r = x + y;
+ if( fabs(x)>fabs(y) ){
+ s = x - r + y + yy + xx;
+ }else{
+ s = y - r + x + xx + yy;
+ }
+ z[0] = r+s;
+ z[1] = r - z[0] + s;
+}
+
+/* Compute z = x - y */
+void sqlite3DDSub(double x, double xx, double y, double yy, double *z){
+ double r, s;
+ r = x - y;
+ if( fabs(x)>fabs(y) ){
+ s = x - r - y - yy + xx;
+ }else{
+ s = -y - r + x + xx - yy;
+ }
+ z[0] = r+s;
+ z[1] = r - z[0] + s;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-19 10:29:00 +0000