std: merge rand::{Rng,RngUtil} with default methods.

Also, documentation & general clean-up:
- remove `gen_char_from`: better served by `sample` or `choose`.
- `gen_bytes` generalised to `gen_vec`.
- `gen_int_range`/`gen_uint_range` merged into `gen_integer_range` and
  made to be properly uniformly distributed. Fixes #8644.

Minor adjustments to other functions.

src/libextra/base64.rs

@@ -311,11 +311,11 @@ fn test_from_base64_invalid_padding() {
 
     #[test]
     fn test_base64_random() {
-        use std::rand::{task_rng, random, RngUtil};
+        use std::rand::{task_rng, random, Rng};
         use std::vec;
 
         do 1000.times {
-            let times = task_rng().gen_uint_range(1, 100);
+            let times = task_rng().gen_integer_range(1u, 100);
             let v = vec::from_fn(times, |_| random::<u8>());
             assert_eq!(v.to_base64(STANDARD).from_base64().unwrap(), v);
         }

src/libextra/container.rs

@@ -43,7 +43,7 @@ pub trait Deque<T> : Mutable {
 mod bench {
     use std::container::MutableMap;
     use std::{vec, rand};
-    use std::rand::RngUtil;
+    use std::rand::Rng;
     use test::BenchHarness;
 
     pub fn insert_rand_n<M:MutableMap<uint,uint>>(n: uint,

src/libextra/crypto/cryptoutil.rs

@@ -347,8 +347,7 @@ fn standard_padding(&mut self, rem: uint, func: &fn(&[u8])) {
 
 #[cfg(test)]
 mod test {
-    use std::rand::IsaacRng;
-    use std::rand::RngUtil;
+    use std::rand::{IsaacRng, Rng};
     use std::vec;
 
     use cryptoutil::{add_bytes_to_bits, add_bytes_to_bits_tuple};
@@ -365,7 +364,7 @@ pub fn test_digest_1million_random<D: Digest>(digest: &mut D, blocksize: uint, e
         digest.reset();
 
         while count < total_size {
-            let next: uint = rng.gen_uint_range(0, 2 * blocksize + 1);
+            let next: uint = rng.gen_integer_range(0, 2 * blocksize + 1);
             let remaining = total_size - count;
             let size = if next > remaining { remaining } else { next };
             digest.input(buffer.slice_to(size));

src/libextra/flate.rs

@@ -106,15 +106,15 @@ pub fn inflate_bytes_zlib(bytes: &[u8]) -> ~[u8] {
 mod tests {
     use super::*;
     use std::rand;
-    use std::rand::RngUtil;
+    use std::rand::Rng;
 
     #[test]
     fn test_flate_round_trip() {
         let mut r = rand::rng();
         let mut words = ~[];
         do 20.times {
-            let range = r.gen_uint_range(1, 10);
-            words.push(r.gen_bytes(range));
+            let range = r.gen_integer_range(1u, 10);
+            words.push(r.gen_vec::<u8>(range));
         }
         do 20.times {
             let mut input = ~[];

src/libextra/num/bigint.rs

@@ -23,7 +23,7 @@
 use std::int;
 use std::num;
 use std::num::{IntConvertible, Zero, One, ToStrRadix, FromStrRadix, Orderable};
-use std::rand::{Rng, RngUtil};
+use std::rand::Rng;
 use std::str;
 use std::uint;
 use std::vec;

src/libextra/sort.rs

@@ -909,7 +909,7 @@ fn ile(x: &(&'static str), y: &(&'static str)) -> bool
 mod test_tim_sort {
 
     use sort::tim_sort;
-    use std::rand::RngUtil;
+    use std::rand::Rng;
     use std::rand;
     use std::vec;
 
@@ -1008,7 +1008,7 @@ mod big_tests {
 
     use sort::*;
 
-    use std::rand::RngUtil;
+    use std::rand::Rng;
     use std::rand;
     use std::vec;
 
@@ -1069,8 +1069,8 @@ fn isSorted<T:Ord>(arr: &[T]) {
             isSorted(arr);
 
             do 3.times {
-                let i1 = rng.gen_uint_range(0, n);
-                let i2 = rng.gen_uint_range(0, n);
+                let i1 = rng.gen_integer_range(0u, n);
+                let i2 = rng.gen_integer_range(0u, n);
                 arr.swap(i1, i2);
             }
             tim_sort(arr); // 3sort
@@ -1088,7 +1088,7 @@ fn isSorted<T:Ord>(arr: &[T]) {
             isSorted(arr);
 
             do (n/100).times {
-                let idx = rng.gen_uint_range(0, n);
+                let idx = rng.gen_integer_range(0u, n);
                 arr[idx] = rng.gen();
             }
             tim_sort(arr);
@@ -1141,8 +1141,8 @@ fn isSorted<T:Ord>(arr: &[@T]) {
             isSorted(arr);
 
             do 3.times {
-                let i1 = rng.gen_uint_range(0, n);
-                let i2 = rng.gen_uint_range(0, n);
+                let i1 = rng.gen_integer_range(0u, n);
+                let i2 = rng.gen_integer_range(0u, n);
                 arr.swap(i1, i2);
             }
             tim_sort(arr); // 3sort
@@ -1160,7 +1160,7 @@ fn isSorted<T:Ord>(arr: &[@T]) {
             isSorted(arr);
 
             do (n/100).times {
-                let idx = rng.gen_uint_range(0, n);
+                let idx = rng.gen_integer_range(0u, n);
                 arr[idx] = @rng.gen();
             }
             tim_sort(arr);

src/libextra/tempfile.rs

@@ -12,7 +12,7 @@
 
 
 use std::os;
-use std::rand::RngUtil;
+use std::rand::Rng;
 use std::rand;
 
 /// Attempts to make a temporary directory inside of `tmpdir` whose name will
@@ -20,7 +20,7 @@
 pub fn mkdtemp(tmpdir: &Path, suffix: &str) -> Option<Path> {
     let mut r = rand::rng();
     for _ in range(0u, 1000) {
-        let p = tmpdir.push(r.gen_str(16) + suffix);
+        let p = tmpdir.push(r.gen_ascii_str(16) + suffix);
         if os::make_dir(&p, 0x1c0) { // 700
             return Some(p);
         }

src/libextra/treemap.rs

@@ -874,7 +874,7 @@ mod test_treemap {
 
     use super::*;
 
-    use std::rand::RngUtil;
+    use std::rand::Rng;
     use std::rand;
 
     #[test]
@@ -1028,7 +1028,7 @@ fn test_rand_int() {
             }
 
             do 30.times {
-                let r = rng.gen_uint_range(0, ctrl.len());
+                let r = rng.gen_integer_range(0, ctrl.len());
                 let (key, _) = ctrl.remove(r);
                 assert!(map.remove(&key));
                 check_structure(&map);

src/libextra/uuid.rs

@@ -62,7 +62,7 @@ fn main() {
 use std::container::Container;
 use std::to_str::ToStr;
 use std::rand;
-use std::rand::RngUtil;
+use std::rand::Rng;
 use std::cmp::Eq;
 use std::cast::{transmute,transmute_copy};
 
@@ -170,7 +170,7 @@ pub fn new(v: UuidVersion) -> Option<Uuid> {
     /// of random numbers. Use the rand::Rand trait to supply
     /// a custom generator if required.
     pub fn new_v4() -> Uuid {
-        let ub = rand::task_rng().gen_bytes(16);
+        let ub = rand::task_rng().gen_vec(16);
         let mut uuid = Uuid{ bytes: [0, .. 16] };
         vec::bytes::copy_memory(uuid.bytes, ub, 16);
         uuid.set_variant(VariantRFC4122);
@@ -488,7 +488,7 @@ fn equals(&self, other: &Uuid) -> bool {
 impl rand::Rand for Uuid {
     #[inline]
     fn rand<R: rand::Rng>(rng: &mut R) -> Uuid {
-        let ub = rng.gen_bytes(16);
+        let ub = rng.gen_vec(16);
         let mut uuid = Uuid{ bytes: [0, .. 16] };
         vec::bytes::copy_memory(uuid.bytes, ub, 16);
         uuid.set_variant(VariantRFC4122);

src/libstd/hashmap.rs

@@ -24,7 +24,7 @@
 use iter::{FilterMap, Chain, Repeat, Zip};
 use num;
 use option::{None, Option, Some};
-use rand::RngUtil;
+use rand::Rng;
 use rand;
 use uint;
 use util::replace;

src/libstd/num/strconv.rs

@@ -734,7 +734,7 @@ fn from_str_issue7588() {
 #[cfg(test)]
 mod bench {
     use extra::test::BenchHarness;
-    use rand::{XorShiftRng,RngUtil};
+    use rand::{XorShiftRng, Rng};
     use float;
     use to_str::ToStr;
 

src/libstd/os.rs

@@ -1718,7 +1718,7 @@ mod tests {
     use os::{remove_file, setenv, unsetenv};
     use os;
     use path::Path;
-    use rand::RngUtil;
+    use rand::Rng;
     use rand;
     use run;
     use str::StrSlice;
@@ -1738,7 +1738,7 @@ pub fn test_args() {
 
     fn make_rand_name() -> ~str {
         let mut rng = rand::rng();
-        let n = ~"TEST" + rng.gen_str(10u);
+        let n = ~"TEST" + rng.gen_ascii_str(10u);
         assert!(getenv(n).is_none());
         n
     }

src/libstd/rt/comm.rs

@@ -1095,7 +1095,7 @@ fn shared_port_close() {
     #[test]
     fn megapipe_stress() {
         use rand;
-        use rand::RngUtil;
+        use rand::Rng;
 
         if util::limit_thread_creation_due_to_osx_and_valgrind() { return; }
 
@@ -1106,7 +1106,7 @@ fn megapipe_stress() {
             let total = stress_factor() + 10;
             let mut rng = rand::rng();
             do total.times {
-                let msgs = rng.gen_uint_range(0, 10);
+                let msgs = rng.gen_integer_range(0u, 10);
                 let pipe_clone = pipe.clone();
                 let end_chan_clone = end_chan.clone();
                 do spawntask_random {

src/libstd/rt/sched.rs

@@ -26,7 +26,7 @@
 use rt::rtio::{RemoteCallback, PausibleIdleCallback};
 use borrow::{to_uint};
 use cell::Cell;
-use rand::{XorShiftRng, RngUtil};
+use rand::{XorShiftRng, Rng};
 use iter::range;
 use vec::{OwnedVector};
 
@@ -391,7 +391,7 @@ fn find_work(&mut self) -> Option<~Task> {
     fn try_steals(&mut self) -> Option<~Task> {
         let work_queues = &mut self.work_queues;
         let len = work_queues.len();
-        let start_index = self.rng.gen_uint_range(0, len);
+        let start_index = self.rng.gen_integer_range(0, len);
         for index in range(0, len).map(|i| (i + start_index) % len) {
             match work_queues[index].steal() {
                 Some(task) => {

src/test/bench/core-std.rs

@@ -15,7 +15,7 @@
 use extra::time::precise_time_s;
 use std::io;
 use std::os;
-use std::rand::RngUtil;
+use std::rand::Rng;
 use std::rand;
 use std::str;
 use std::util;
@@ -85,7 +85,7 @@ fn vec_plus() {
     let mut v = ~[];
     let mut i = 0;
     while i < 1500 {
-        let rv = vec::from_elem(r.gen_uint_range(0, i + 1), i);
+        let rv = vec::from_elem(r.gen_integer_range(0u, i + 1), i);
         if r.gen() {
             v.push_all_move(rv);
         } else {
@@ -101,7 +101,7 @@ fn vec_append() {
     let mut v = ~[];
     let mut i = 0;
     while i < 1500 {
-        let rv = vec::from_elem(r.gen_uint_range(0, i + 1), i);
+        let rv = vec::from_elem(r.gen_integer_range(0u, i + 1), i);
         if r.gen() {
             v = vec::append(v, rv);
         }
@@ -117,7 +117,7 @@ fn vec_push_all() {
 
     let mut v = ~[];
     for i in range(0u, 1500) {
-        let mut rv = vec::from_elem(r.gen_uint_range(0, i + 1), i);
+        let mut rv = vec::from_elem(r.gen_integer_range(0u, i + 1), i);
         if r.gen() {
             v.push_all(rv);
         }

src/test/bench/noise.rs

 // Perlin noise benchmark from https://gist.github.com/1170424
 
 use std::float;
-use std::rand::{Rng, RngUtil};
+use std::rand::Rng;
 use std::rand;
 
 struct Vec2 {