Integer expressions in IDL

Support

Support for KasperskyOS

KasperskyOS Community Edition

Developing security policies

Formal specifications of KasperskyOS-based solution components

IDL description

Integer expressions in IDL

May 21, 2024

ID ice_idl_int_expres

Get as PDF

Integer expressions in IDL are composed of named integer constants, integer literals, operators (see the table below), and grouping parentheses.

Example use of integer expressions:

const UInt8 itemHeaderLen = 2;

const UInt8 itemBlockLen = 4;

const UInt8 maxItemCount = 0X10;

const UInt64 maxLen = (2 << 3) + (itemHeaderLen + itemBlockLen * 4) * maxItemCount;

interface {

CopyPage(in array<UInt8, 4 * maxLen> page);

}

If an integer overflow occurs when computing an expression, the source code generator using the IDL file will terminate with an error.

Details on operators of integer expressions in IDL

Syntax	Operation	Precedence	Associativity	Special considerations
`-a`	Sign change	1	No	N/A
`~a`	Bitwise negation	1	No	N/A
`a ** b`	Exponentiation	2	No	Special considerations: Due to the lack of associativity, you must use parentheses when specifying multiple consecutive operators to define the order of operations. Example: `(a b) c` `a (b c)` The power exponent cannot be negative.
`a * b`	Multiplication	3	Left	N/A
`a / b`	Integer division	3	Left	Special considerations: The result of the operation is a value obtained by rounding the real quotient down to the next lower integer. For example, 4 / 3 = 1, -4 / 3 = -2. The divisor cannot be zero.
`a % b`	Modulo	3	Left	Special considerations: The sign of the operation result matches the sign of the divisor. For example, -5 % 2 = 1, 5 % -2 = -1. The divisor cannot be zero.
`a + b`	Addition	4	Left	N/A
`a - b`	Subtraction	4	Left	N/A
`a << b`	Bit shift left	2*	No	Special considerations: The precedence is lower than with unary operations but incomparable to the precedences of binary arithmetic operations. Therefore, in expressions with binary arithmetic operations, you must use parentheses to define the order of operations. Example: `a << (b + c)` `(a << b) ** c` Due to the lack of associativity, you must use parentheses when specifying multiple consecutive operators to define the order of operations. Example: `(a << b) << c` `a << (b << c)` The shift value must be within the interval [0; 63].
`a >> b`	Bit shift right	2*	No	Special considerations: The precedence is lower than with unary operations but incomparable to the precedences of binary arithmetic operations. Therefore, in expressions with binary arithmetic operations, you must use parentheses to define the order of operations. Example: `a >> (b * c)` `(a >> b) / c` Due to the lack of associativity, you must use parentheses when specifying multiple consecutive operators to define the order of operations. Example: `(a >> b) >> c` `a >> (b >> c)` The shift value must be within the interval [0; 63].

Did you find this article helpful?

What can we do better?

Thank you for your feedback! You're helping us improve.