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-rw-r--r--src/util.c37
1 files changed, 11 insertions, 26 deletions
diff --git a/src/util.c b/src/util.c
index db6163c3c..e18b84757 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1305,36 +1305,21 @@ int sqlite3SubInt64(i64 *pA, i64 iB){
return sqlite3AddInt64(pA, -iB);
}
}
-#define TWOPOWER32 (((i64)1)<<32)
-#define TWOPOWER31 (((i64)1)<<31)
int sqlite3MulInt64(i64 *pA, i64 iB){
i64 iA = *pA;
- i64 iA1, iA0, iB1, iB0, r;
-
- iA1 = iA/TWOPOWER32;
- iA0 = iA % TWOPOWER32;
- iB1 = iB/TWOPOWER32;
- iB0 = iB % TWOPOWER32;
- if( iA1==0 ){
- if( iB1==0 ){
- *pA *= iB;
- return 0;
+ if( iB>0 ){
+ if( iA>LARGEST_INT64/iB ) return 1;
+ if( iA<SMALLEST_INT64/iB ) return 1;
+ }else if( iB<0 ){
+ if( iA>0 ){
+ if( iB<SMALLEST_INT64/iA ) return 1;
+ }else if( iA<0 ){
+ if( iB==SMALLEST_INT64 ) return 1;
+ if( iA==SMALLEST_INT64 ) return 1;
+ if( -iA>LARGEST_INT64/-iB ) return 1;
}
- r = iA0*iB1;
- }else if( iB1==0 ){
- r = iA1*iB0;
- }else{
- /* If both iA1 and iB1 are non-zero, overflow will result */
- return 1;
}
- testcase( r==(-TWOPOWER31)-1 );
- testcase( r==(-TWOPOWER31) );
- testcase( r==TWOPOWER31 );
- testcase( r==TWOPOWER31-1 );
- if( r<(-TWOPOWER31) || r>=TWOPOWER31 ) return 1;
- r *= TWOPOWER32;
- if( sqlite3AddInt64(&r, iA0*iB0) ) return 1;
- *pA = r;
+ *pA = iA*iB;
return 0;
}