Package builtin

Package builtin defines MPCL built-in functions and types. This package is always imported, and the functions and types can be used in all programs.

The copy built-in function copies elements from a source slice into a destination slice. The source and destination slices may overlap. The function returns the number of elements copied, which will be the minimum of len(src) and len(dst).

The floorPow2 built-in function returns the power of 2 number that is smaller than or equal to the argument value.

The len built-in function returns the length of the argument value, according to its type:

Array:  the number of elements in the array
Slice:  the number of elements in the slice
String: the number of bytes in the string

The make built-in function creates arrays or concrete type instances. The arrays are created by specifying a concrete array type as the Type argument:

buf := make([]byte, 10)

The concrete type instances are created by specifying an inconcrete type as the Type argument, and type bit size as the Size argument:

i1024 := make(int, 1024)
var x i1024

The native built-in function loads the native circuit from the named file. The circuit must be located in the same directory as the calling MPCL program. The native built-in function supports the following circuit formats:

.circ    Bristol circuit format
.bristol Bristol circuit format
.mpclc   compiled MPCL circuit format

The panic built-in function terminates the compilation with an error message. The first argument is used as a format string, and the remaining arguments are positional arguments for the formatted message. Any extra arguments are appended to the result string, separated by a space character. The panic built-in function is a compile-time call. If any of the live execution paths contains a panic call, it will be triggered during the compilation phase and terminate the compilation. The panic function is usually used in parametrized functions to assert pre-conditions:

func CryptBlocks(data []byte) []byte {
    if len(data)%blockSize != 0 {
        panic("input not full blocks")
    }
    ...
}

The size built-in function returns the size of the argument value in bits. The argument value can be of any type.

bool is a boolean value true or false.

byte is an alias for unsigned 8-bit integer numbers.

intSize is a Size-bit signed integer number. The signed integer numbers can be instantiated in any bit sizes.

rune is an alias for int32.

stringSize defines Size-bit long string.

uintSize is a Size-bit unsigned integer number. The unsigned integer numbers can be instantiated in any bit sizes.