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//------------------------------------------------------------------------------
// GB_int64_multiply: multiply two integers and guard against overflow
//------------------------------------------------------------------------------
// SuiteSparse:GraphBLAS, Timothy A. Davis, (c) 2017-2025, All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
//------------------------------------------------------------------------------
// c = a*b where c is uint64_t, and a and b are int64_t.
// Check for overflow. Requires a >= 0 and b >= 0.
#ifndef GB_INT64_MULTIPLY_H
#define GB_INT64_MULTIPLY_H
GB_STATIC_INLINE bool GB_int64_multiply // true if ok, false if overflow
(
uint64_t *restrict c, // c = a*b, or zero if overflow occurs
const int64_t a,
const int64_t b
)
{
ASSERT (c != NULL) ;
(*c) = 0 ;
if (a == 0 || b == 0) return (true) ;
if (a < 0 || b < 0 || a > GB_NMAX || b > GB_NMAX) return (false) ;
uint64_t x ;
bool ok = GB_uint64_multiply (&x, (uint64_t) a, (uint64_t) b) ;
(*c) = ok ? x : 0 ;
return (ok) ;
}
#endif
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