From 8b277ff53bc81b59fdf41ec3aed29e37ab96a118 Mon Sep 17 00:00:00 2001
From: randogoth <kflux@posteo.de>
Date: Sun, 5 Jan 2025 15:37:42 +0200
Subject: [PATCH] sequential & bandpass

---
 src/bin/main.rs | 17 +----------------
 src/lib.rs      | 46 +++++-----------------------------------------
 2 files changed, 6 insertions(+), 57 deletions(-)

diff --git a/src/bin/main.rs b/src/bin/main.rs
index 3668ad4..5efefcd 100644
--- a/src/bin/main.rs
+++ b/src/bin/main.rs
@@ -28,7 +28,6 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     }
 
     let quick = args.contains(&String::from("-q"));
-    let pp = args.contains(&String::from("-p"));
 
     let camera_index: usize = args[1].parse().expect("Failed to parse camera index as a number");
     let length: usize = args[2].parse().expect("Failed to parse entropy length as a number");
@@ -72,21 +71,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
         let grayscale_data = frame_to_grayscale(&data);
 
-        let entropy: Vec<u8> = if pp {
-            let mut low = 10;
-            let mut high = 245;
-
-            if ocelli.is_covered(&grayscale_data, 50) {
-                low = 3;
-                high = 252;
-            }
-
-            if let Some(last) = last_frame {
-                ocelli.whiten(&ocelli.tune_and_prune(&grayscale_data, &last, low, high))
-            } else {
-                Vec::new()
-            }
-        } else if quick {
+        let entropy: Vec<u8> = if quick {
             ocelli.whiten(&ocelli.pick_and_flip(&grayscale_data, frame_count as usize))
         } else {
             if ocelli.is_covered(&grayscale_data, 50) {
diff --git a/src/lib.rs b/src/lib.rs
index e328e9a..3fb6d22 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -50,7 +50,7 @@ impl Ocelli {
 
     }
 
-    pub fn pick_and_flip(&self, data: &[u8], current_frame_index: usize) -> Vec<u8> {
+    pub fn pick_and_flip(&self, data: &[u8], low: u8, high: u8, current_frame_index: usize) -> Vec<u8> {
         // Extracts the least significant bit (LSB) of each pixel brightness, flipping it based on the frame index.
         // Generates entropy by combining these bits into bytes.
         // Algorithm is a simplified version of R. Li, "A True Random Number Generator algorithm from 
@@ -59,7 +59,7 @@ impl Ocelli {
         let mut entropy = Vec::new();
 
         for &pixel in data {
-            if (2..=253).contains(&pixel) { // filter bias
+            if (low..=high).contains(&pixel) { // filter bias
                 let mut lsb = pixel & 1;
                 if current_frame_index % 2 == 0 { // flip bits
                     lsb ^= 1;
@@ -71,20 +71,6 @@ impl Ocelli {
         self.bits_to_bytes(&entropy)
     }
 
-    pub fn tune_and_prune(&self, current: &Vec<u8>, previous: &Vec<u8>, low: u8, high: u8) -> Vec<u8> {
-        // Extracts the least significant bit (LSB) of each pixel brightness while filtering out bias
-        // It's a combination of methods from the other two entropy extraction algorithms
-        let mut entropy = Vec::new();
-
-        for (&c, &p) in current.iter().zip(previous.iter()) {
-            if c != p && (low..=high).contains(&c) {
-                entropy.push(c & 1);
-            }
-        }
-
-        self.bits_to_bytes(&entropy)
-    }
-
     pub fn shannon(&self, data: &Vec<u8>) -> f64 {
         // Calculates the Shannon entropy of a given byte vector to measure its randomness.
         // Uses a frequency map to compute probabilities and their contributions to entropy.
@@ -178,6 +164,8 @@ pub extern "C" fn chop_and_tack(
 pub extern "C" fn pick_and_flip(
     data_ptr: *const u8,
     data_len: usize,
+    low: u8,
+    high: u8,
     current_frame_index: usize,
     result_ptr: *mut u8,
     result_len: &mut usize,
@@ -185,31 +173,7 @@ pub extern "C" fn pick_and_flip(
     let data = unsafe { slice::from_raw_parts(data_ptr, data_len) };
 
     let ocelli = Ocelli;
-    let result = ocelli.pick_and_flip(data, current_frame_index);
-
-    unsafe {
-        let result_slice = slice::from_raw_parts_mut(result_ptr, result.len());
-        result_slice.copy_from_slice(&result);
-        *result_len = result.len();
-    }
-}
-
-#[no_mangle]
-pub extern "C" fn tune_and_prune(
-    current_ptr: *const u8,
-    current_len: usize,
-    previous_ptr: *const u8,
-    previous_len: usize,
-    low: u8,
-    high: u8,
-    result_ptr: *mut u8,
-    result_len: &mut usize,
-) {
-    let current = unsafe { slice::from_raw_parts(current_ptr, current_len) };
-    let previous = unsafe { slice::from_raw_parts(previous_ptr, previous_len) };
-
-    let ocelli = Ocelli;
-    let result = ocelli.tune_and_prune(&current.to_vec(), &previous.to_vec(), low, high);
+    let result = ocelli.pick_and_flip(data, low, high, current_frame_index);
 
     unsafe {
         let result_slice = slice::from_raw_parts_mut(result_ptr, result.len());