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#[doc = "Random number generation"];
export rng;
enum rctx {}
#[abi = "cdecl"]
native mod rustrt {
fn rand_new() -> *rctx;
fn rand_next(c: *rctx) -> u32;
fn rand_free(c: *rctx);
}
#[doc = "A random number generator"]
iface rng {
#[doc = "Return the next random integer"]
fn next() -> u32;
#[doc = "Return the next random float"]
fn next_float() -> float;
#[doc = "Return a random string composed of A-Z, a-z, 0-9."]
fn gen_str(len: uint) -> str;
#[doc = "Return a random byte string."]
fn gen_bytes(len: uint) -> [u8];
}
resource rand_res(c: *rctx) { rustrt::rand_free(c); }
#[doc = "Create a random number generator"]
fn rng() -> rng {
impl of rng for @rand_res {
fn next() -> u32 { ret rustrt::rand_next(**self); }
fn next_float() -> float {
let u1 = rustrt::rand_next(**self) as float;
let u2 = rustrt::rand_next(**self) as float;
let u3 = rustrt::rand_next(**self) as float;
let scale = u32::max_value as float;
ret ((u1 / scale + u2) / scale + u3) / scale;
}
fn gen_str(len: uint) -> str {
let charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
"abcdefghijklmnopqrstuvwxyz" +
"0123456789";
let mut s = "";
let mut i = 0u;
while (i < len) {
let n = rustrt::rand_next(**self) as uint %
str::len(charset);
s = s + str::from_char(str::char_at(charset, n));
i += 1u;
}
s
}
fn gen_bytes(len: uint) -> [u8] {
let mut v = [];
let mut i = 0u;
while i < len {
let n = rustrt::rand_next(**self) as uint;
v += [(n % (u8::max_value as uint)) as u8];
i += 1u;
}
v
}
}
@rand_res(rustrt::rand_new()) as rng
}
#[cfg(test)]
mod tests {
#[test]
fn test() {
let r1: rand::rng = rand::rng();
log(debug, r1.next());
log(debug, r1.next());
{
let r2 = rand::rng();
log(debug, r1.next());
log(debug, r2.next());
log(debug, r1.next());
log(debug, r1.next());
log(debug, r2.next());
log(debug, r2.next());
log(debug, r1.next());
log(debug, r1.next());
log(debug, r1.next());
log(debug, r2.next());
log(debug, r2.next());
log(debug, r2.next());
}
log(debug, r1.next());
log(debug, r1.next());
}
#[test]
fn genstr() {
let r: rand::rng = rand::rng();
log(debug, r.gen_str(10u));
log(debug, r.gen_str(10u));
log(debug, r.gen_str(10u));
assert(str::len(r.gen_str(10u)) == 10u);
assert(str::len(r.gen_str(16u)) == 16u);
}
}
// Local Variables:
// mode: rust;
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
|
