points.rs

use std::num::pow;

pub struct Point { x: int, y: int }
struct Line  { p1: Point, p2: Point }

impl Line {
  pub fn length(&self) -> f64 {
    let xdiff = self.p1.x - self.p2.x;
    let ydiff = self.p1.y - self.p2.y;
    ((pow(xdiff, 2) + pow(ydiff, 2)) as f64).sqrt()
  }
}

#[no_mangle]
pub extern "C" fn make_point(x: int, y: int) -> Box<Point> {
    box Point { x: x, y: y }
}


#[no_mangle]
pub extern "C" fn get_distance(p1: &Point, p2: &Point) -> f64 {
    Line { p1: *p1, p2: *p2 }.length()
}

rust_cffi.py

#!/usr/bin/env python
"""
Consumer example to use the shared object created in Rust.
Ref: http://blog.skylight.io/bending-the-curve-writing-safe-fast-native-gems-with-rust/

"""
from cffi import FFI
import os, sys

RUST_SO_PATH = os.path.join(os.path.dirname(__file__), "libpoints.%s" % ('dylib' if sys.platform == 'darwin' else 'so'))

ffi = FFI()
ffi.cdef("""
    typedef struct {
        int x, y;
    } Point;
""")
ffi.cdef("double get_distance(Point* p1, Point* p2);")
ffi.cdef("Point* make_point(int x, int y);")

api = ffi.dlopen(RUST_SO_PATH)
make_point, get_distance = api.make_point, api.get_distance

p1 = make_point(10, 10)
p2 = make_point(20, 20)

print get_distance(p1, p2)

rust_ctypes.py

#!/usr/bin/env python
"""
Consumer example to use the shared object created in Rust.
Ref: http://blog.skylight.io/bending-the-curve-writing-safe-fast-native-gems-with-rust/

"""
from ctypes import CDLL, Structure, c_int, c_void_p
from ctypes import c_double, CFUNCTYPE
import os, sys

RUST_SO_PATH = os.path.join(os.path.dirname(__file__), "libpoints.%s" % ('dylib' if sys.platform == 'darwin' else 'so'))


class Point (Structure):
    _fields_ = [
        ("x", c_int),
        ("y", c_int)
    ]

api = CDLL(RUST_SO_PATH)

make_point = CFUNCTYPE(c_void_p, c_int, c_int)(('make_point', api))
get_distance = CFUNCTYPE(c_double, c_void_p, c_void_p)(('get_distance', api))

p1 = make_point(10, 10)
p2 = make_point(20, 20)

print get_distance(p1, p2)