Function AddInt64ToValue

pg_documentdb_core/src/io/pgbson_utils.c:817–863

* Adds an Int64 to the current value. If the current value is an double * applies the sum as an double. If the value overflows, applies * the sum as a double * @overflowedFromInt64: Set if overflow from Int64 occurs, unset otherwise. */

 * @overflowedFromInt64: Set if overflow from Int64 occurs, unset otherwise.
 */
static void
AddInt64ToValue(bson_value_t *current, int64_t value, bool *overflowedFromInt64)
{
	if (current->value_type == BSON_TYPE_DOUBLE)
	{
		/* current is already double - just do double add. */
		AddDoubleToValue(current, (double) value);

		*overflowedFromInt64 = false;
		return;
	}
	else if (current->value_type == BSON_TYPE_DECIMAL128)
	{
		bson_value_t valueToAdd;
		valueToAdd.value.v_int64 = value;
		valueToAdd.value_type = BSON_TYPE_INT64;

		valueToAdd.value.v_decimal128 = GetBsonValueAsDecimal128Quantized(&valueToAdd);
		valueToAdd.value_type = BSON_TYPE_DECIMAL128;
		AddDecimal128Numbers(current, &valueToAdd, current);

		*overflowedFromInt64 = false;
		return;
	}

	/* current is int64 or int32. */
	int64_t currentSum = BsonValueAsInt64(current);

	/* check for overflow: */
	/* if current + value > INT64_MAX -> current > INT64_MAX - value */
	/* if current + (-value) < INT64_MIN -> current < INT64_MIN - (-value) */
	if ((value > 0 && currentSum > INT64_MAX - value) ||
		(value < 0 && currentSum < INT64_MIN - value))
	{
		*overflowedFromInt64 = true;

		/* coerce to double. */
		AddDoubleToValue(current, (double) value);
	}
	else
	{
		*overflowedFromInt64 = false;

		current->value.v_int64 = currentSum + value;
		current->value_type = BSON_TYPE_INT64;
	}
}


/*