Migrate ff to rand_core 0.3 (used by rand 0.5)

Cargo.lock

@@ -186,7 +186,7 @@ version = "0.4.0"
 dependencies = [
  "byteorder 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "ff_derive 0.3.0",
- "rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -424,6 +424,19 @@ dependencies = [
  "winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "redox_syscall"
 version = "0.1.40"
@@ -623,6 +636,8 @@ dependencies = [
 "checksum quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)" = "dd636425967c33af890042c483632d33fa7a18f19ad1d7ea72e8998c6ef8dea5"
 "checksum rand 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "15a732abf9d20f0ad8eeb6f909bf6868722d9a06e1e50802b6a70351f40b4eb1"
 "checksum rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "eba5f8cb59cc50ed56be8880a5c7b496bfd9bd26394e176bc67884094145c2c5"
+"checksum rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
+"checksum rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d0e7a549d590831370895ab7ba4ea0c1b6b011d106b5ff2da6eee112615e6dc0"
 "checksum redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "c214e91d3ecf43e9a4e41e578973adeb14b474f2bee858742d127af75a0112b1"
 "checksum rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)" = "f76d05d3993fd5f4af9434e8e436db163a12a9d40e1a58a726f27a01dfd12a2a"
 "checksum rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)" = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"

ff/Cargo.toml

@@ -10,7 +10,7 @@ repository = "https://github.com/ebfull/ff"
 
 [dependencies]
 byteorder = "1"
-rand = "0.4"
+rand_core = "0.3"
 ff_derive = { version = "0.3.0", path = "ff_derive", optional = true }
 
 [features]

ff/ff_derive/src/lib.rs

@@ -136,13 +136,6 @@ fn prime_field_repr_impl(repr: &syn::Ident, limbs: usize) -> proc_macro2::TokenS
             }
         }
 
-        impl ::rand::Rand for #repr {
-            #[inline(always)]
-            fn rand<R: ::rand::Rng>(rng: &mut R) -> Self {
-                #repr(rng.gen())
-            }
-        }
-
         impl ::std::fmt::Display for #repr {
             fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
                 try!(write!(f, "0x"));
@@ -839,22 +832,6 @@ fn prime_field_impl(
             }
         }
 
-        impl ::rand::Rand for #name {
-            /// Computes a uniformly random element using rejection sampling.
-            fn rand<R: ::rand::Rng>(rng: &mut R) -> Self {
-                loop {
-                    let mut tmp = #name(#repr::rand(rng));
-
-                    // Mask away the unused bits at the beginning.
-                    tmp.0.as_mut()[#top_limb_index] &= 0xffffffffffffffff >> REPR_SHAVE_BITS;
-
-                    if tmp.is_valid() {
-                        return tmp
-                    }
-                }
-            }
-        }
-
         impl From<#name> for #repr {
             fn from(e: #name) -> #repr {
                 e.into_repr()
@@ -904,6 +881,26 @@ fn prime_field_impl(
         }
 
         impl ::ff::Field for #name {
+            /// Computes a uniformly random element using rejection sampling.
+            fn random<R: ::rand_core::RngCore>(rng: &mut R) -> Self {
+                loop {
+                    let mut tmp = {
+                        let mut repr = [0u64; #limbs];
+                        for i in 0..#limbs {
+                            repr[i] = rng.next_u64();
+                        }
+                        #name(#repr(repr))
+                    };
+
+                    // Mask away the unused bits at the beginning.
+                    tmp.0.as_mut()[#top_limb_index] &= 0xffffffffffffffff >> REPR_SHAVE_BITS;
+
+                    if tmp.is_valid() {
+                        return tmp
+                    }
+                }
+            }
+
             #[inline]
             fn zero() -> Self {
                 #name(#repr::from(0))

ff/src/lib.rs

@@ -1,7 +1,7 @@
 #![allow(unused_imports)]
 
 extern crate byteorder;
-extern crate rand;
+extern crate rand_core;
 
 #[cfg(feature = "derive")]
 #[macro_use]
@@ -10,14 +10,18 @@ extern crate ff_derive;
 #[cfg(feature = "derive")]
 pub use ff_derive::*;
 
+use rand_core::RngCore;
 use std::error::Error;
 use std::fmt;
 use std::io::{self, Read, Write};
 
 /// This trait represents an element of a field.
 pub trait Field:
-    Sized + Eq + Copy + Clone + Send + Sync + fmt::Debug + fmt::Display + 'static + rand::Rand
+    Sized + Eq + Copy + Clone + Send + Sync + fmt::Debug + fmt::Display + 'static
 {
+    /// Returns an element chosen uniformly at random using a user-provided RNG.
+    fn random<R: RngCore>(rng: &mut R) -> Self;
+
     /// Returns the zero element of the field, the additive identity.
     fn zero() -> Self;
 
@@ -100,7 +104,6 @@ pub trait PrimeFieldRepr:
     + fmt::Debug
     + fmt::Display
     + 'static
-    + rand::Rand
     + AsRef<[u64]>
     + AsMut<[u64]>
     + From<u64>