added ffi rng

.gitignore

@@ -1 +1,3 @@
 *~
+libsrng/target/
+libsrng/Cargo.lock

Makefile

@@ -0,0 +1,12 @@
+install:
+	cp -f libsrng.so /usr/local/lib/libsrng.so
+	ln -sf /usr/local/lib/libsrng.so /usr/lib/libsrng.so
+
+uninstall:
+	rm -f /usr/local/lib/libsrng.so
+	rm /usr/lib/libsrng.so
+
+build:
+	cd libsrng && cargo build --release
+	cp libsrng/target/release/libsrng.so ./
+	gpg --sign libsrng.so

README

@@ -0,0 +1,5 @@
+Prebuild binary signed with https://flanchan.moe/flanchan.asc
+
+To build dependencies yourself run:
+ make build && sudo make install
+(requires Rust)

cl-rng.asd

@@ -6,6 +6,8 @@
   :license  "None"
   :version "0.0.1"
   :serial t
+  :depends-on (:cffi)
   :components ((:file "package")
+	       (:file "ffi")
                (:file "urandom")
 	       (:file "cl-rng")))

cl-rng.lisp

@@ -2,9 +2,9 @@
 
 (in-package :cl-rng)
 
-(defparameter *default-precision* 100
+(defparameter *default-precision* 1
   "Default precision for the default RNG provider")
-(defparameter *default-randomness-provider* #'(lambda (&rest args) (apply #'urandom (append `(:precision ,*default-precision*) args)))
+(defparameter *default-randomness-provider* #'(lambda (&rest args) (apply #'crandom (append `(:precision ,*default-precision*) args)))
   "The default randomness provider used by cl-rng functions")
 
 (defun chance (fraction &key (provider *default-randomness-provider*))
@@ -58,6 +58,7 @@
 ;; Exports
 
 (export '*default-randomness-provider*)
+(export '*default-precision*)
 (defsetf within within-set)
 (export 'range)
 (export 'within)

crandom.lisp

@@ -0,0 +1,19 @@
+
+(in-package #:cl-rng)
+
+(defun crandom (&key (limit 1.0) (precision 1) (transform nil))
+  (let ((transform (or transform #'identity)))
+    (multiple-value-bind (result ok) (cl-rng-ffi:ffi-sample)
+      (and ok
+	   (funcall transform
+		    (* limit
+		       (if (< precision 2)
+			   result
+			   (/ (apply #'+ (mapcan #'(lambda (x)
+						     (and (not (null x))
+							  (list x)))
+						 (loop for x from 0 below precision collect
+						      (crandom))))
+			      precision))))))))
+
+(export 'crandom)

ffi.lisp

@@ -0,0 +1,19 @@
+
+(in-package #:cl-rng-ffi)
+
+(define-foreign-library libsrng
+  (:unix (:or "libsrng.so" "libsrng" "./libsrng.so"))
+  (t (:default "libsrng")))
+
+(use-foreign-library libsrng)
+
+(defcfun "sample" :int (to :pointer))
+
+(defun ffi-sample ()
+  (with-foreign-pointer (value 8)
+    (let ((rval (sample value)))
+      (values
+       (mem-ref value :double 0)
+       (= rval 1)))))
+
+(export 'ffi-sample)

libsrng/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "srng"
+version = "0.1.0"
+authors = ["Avril <flanchan@cumallover.me>"]
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+getrandom = "0.1"

libsrng/src/lib.rs

@@ -0,0 +1,56 @@
+extern crate getrandom;
+
+use getrandom::*;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn it_works() {
+	let mut f: f64 = 0.0;
+	assert_eq!(sample(&mut f as *mut f64), 1);
+    }
+}
+
+fn get<T: Default>() -> Result<T, Error>
+{
+    let mut value: T = Default::default();
+    unsafe {
+	let mut slice = std::slice::from_raw_parts_mut(&mut value as *mut T as *mut u8, std::mem::size_of::<T>());
+	populate(&mut slice)?;
+    }
+    
+    Ok(value)
+}
+
+fn double() -> Result<f64, Error>
+{
+    let long: i64 = get::<i64>()?;
+
+    Ok( ((long & ((1i64 << 53) - 1)) as f64) * (1_f64 / ((1_i64 << 53) as f64)))
+}
+
+fn populate(mut value: &mut [u8]) -> Result<(), Error>
+{
+    getrandom(&mut value)?;
+
+    Ok(())
+}
+
+#[no_mangle]
+pub extern "C" fn sample(value: *mut f64) -> i32
+{
+    match std::panic::catch_unwind(|| {
+	unsafe {
+	    match double() {
+		Ok(x) => *value = x,
+		Err(_) => return 0,
+	    }
+	}
+	1
+    }) {
+	Ok(v) => v,
+	Err(_) => 0,
+    }
+}
+

package.lisp

@@ -2,3 +2,6 @@
 
 (defpackage #:cl-rng
   (:use #:cl))
+
+(defpackage #:cl-rng-ffi
+  (:use :cl :cffi :cl-rng))