WIP HyphaeVM

This commit is a WORK IN PROGRESS for the base implementation of the
HyphaeVM. This will be squashed into a larger commit eventually when
the work of implementing the HyphaeVM is finished.

Do note the in progress number package implementation in snippets

Signed-off-by: Ava Affine <ava@sunnypup.io>

hyphae/src/hmap.rs

@@ -0,0 +1,211 @@
+/* Mycelium Scheme
+ * Copyright (C) 2025 Ava Affine
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+use alloc::slice;
+use alloc::vec::Vec;
+use alloc::vec;
+use alloc::boxed::Box;
+use alloc::string::String;
+
+/* Use a prime number so that the modulus operation
+ * provides better avalanche effect
+ */
+const INDEXED_BUCKETS: u8 = 199;
+
+/* This only has to work to make quasi unique indexes from
+ * variable names. Any given program will not have so many
+ * symbols that this becomes a bottleneck in runtime.
+ *
+ * Priorities:
+ *   - SPEED in embedded code
+ *   - avalanche effect
+ *
+ * Not a priority: minimal collisions
+ *
+ * Just to make sure this is not misused I keep it private.
+ * And yes, I am sure a B-Tree would be better.
+ *
+ * TODO: Make sure that the obvious timing attacks
+ *     dont create risk for scheme crypto libraries...
+ *     or more likely rip and replace with a better nostd hashmap
+ */
+#[inline]
+fn string_hash(input: &str) -> u8 {
+    input
+        .chars()
+        // each letter and number get a digit
+        .map(|c| c.to_digit(36)
+            // all else is 0
+            .or_else(|| Some(0))
+            .unwrap())
+        // modulo reduction
+        .reduce(|acc, i| (acc + i) % INDEXED_BUCKETS as u32)
+        // TODO: some analysis on which cases end up here
+        .or_else(|| Some(0))
+        .unwrap() as u8
+}
+
+#[derive(Clone)]
+pub struct Bucket<T: Clone>(Vec<(String, T)>);
+#[derive(Clone)]
+pub struct QuickMap<T: Clone>(Box<[Bucket<T>; INDEXED_BUCKETS as usize]>);
+
+impl<'a, T: Clone> QuickMap<T> {
+    const ARRAY_REPEAT_VALUE: Bucket<T> = Bucket(vec![]);
+
+    pub fn new() -> QuickMap<T> {
+        QuickMap(Box::new([QuickMap::ARRAY_REPEAT_VALUE; INDEXED_BUCKETS as usize]))
+    }
+
+    pub fn get(&self, arg: &String) -> Option<&T> {
+        let idx = string_hash(&arg);
+        for kv in self.0[idx as usize].0.iter() {
+            if &kv.0 == arg {
+                return Some(&kv.1);
+            }
+        }
+
+        return None;
+    }
+
+    pub fn remove(&mut self, arg: &str) -> Option<T> {
+        let idx = string_hash(&arg);
+        let len = self.0[idx as usize].0.len();
+        for i in 0..len {
+            if &self
+                .0[idx as usize]
+                .0[i as usize]
+                .0 == arg {
+                    return Some(self.0[idx as usize].0.swap_remove(i).1);
+            }
+        }
+
+        return None;
+    }
+
+    pub fn contains_key(&self, arg: &str) -> bool {
+        let idx = string_hash(arg);
+        for kv in self.0[idx as usize].0.iter() {
+            if &kv.0 == arg {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    pub fn insert(&mut self, k: String, v: T) -> Option<T> {
+        let idx = string_hash(&k);
+        for kv in self.0[idx as usize].0.iter_mut() {
+            if kv.0 == k {
+                let tmp = kv.1.clone();
+                kv.1 = v;
+                return Some(tmp);
+            }
+        }
+
+        self.0[idx as usize].0.push((k, v));
+        return None
+    }
+
+    pub fn iter(&'a self) -> QuickMapIter<'a, T> {
+        QuickMapIter::<'a, T>{
+            buckets: &self.0,
+            bucket_cursor: 0,
+            vec_iter: self.0[0].0.iter(),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct QuickMapIter<'a, T: Clone> {
+    buckets: &'a [Bucket<T>; INDEXED_BUCKETS as usize],
+    bucket_cursor: usize,
+    vec_iter: slice::Iter<'a, (String, T)>,
+}
+
+impl<'a, T: Clone> Iterator for QuickMapIter<'a, T> {
+    type Item = &'a (String, T);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.vec_iter
+            .next()
+            .or_else(|| {
+                self.bucket_cursor += 1;
+                if self.bucket_cursor == INDEXED_BUCKETS as usize{
+                    None
+                } else {
+                    self.vec_iter = self.buckets[self.bucket_cursor].0.iter();
+                    self.next()
+                }
+            })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn add_fetch_and_remove_simple() {
+        let mut q = QuickMap::<u8>::new();
+        let key = String::from("test");
+        q.insert(String::from("test"), 1);
+        assert_eq!(*q.get(&key).unwrap(), 1);
+        assert!(q.contains_key(&key));
+        assert_eq!(
+            q.remove(&key),
+            Some(1),
+        );
+        assert_eq!(q.contains_key(&key), false);
+        assert_eq!(q.get(&key), None);
+    }
+
+    #[test]
+    fn iter_test() {
+        let mut q = QuickMap::<u8>::new();
+        let k1 = String::from("test1");
+        let k2 = String::from("test1@"); // will be in same bucket
+        let k3 = String::from("test2");
+        let k4 = String::from("test2--"); // will be in same bucket
+        q.insert(k1.clone(), 1);
+        q.insert(k2.clone(), 2);
+        q.insert(k3.clone(), 3);
+        q.insert(k4.clone(), 4);
+
+        // test k1 and k2 in same bucket but that other keys are not
+        assert_eq!(q.0[string_hash(&k1) as usize].0.len(), 2);
+        // test k3 and k4 in same bucket but that other keys are not
+        assert_eq!(q.0[string_hash(&k3) as usize].0.len(), 2);
+
+        let mut i = q.iter();
+        let entry1 = i.next().unwrap();
+        let entry2 = i.next().unwrap();
+        let entry3 = i.next().unwrap();
+        let entry4 = i.next().unwrap();
+
+        assert_eq!(i.next(), None);
+        assert_eq!(entry1.0, k1);
+        assert_eq!(entry1.1, 1);
+        assert_eq!(entry2.0, k2);
+        assert_eq!(entry2.1, 2);
+        assert_eq!(entry3.0, k3);
+        assert_eq!(entry3.1, 3);
+        assert_eq!(entry4.0, k4);
+        assert_eq!(entry4.1, 4);
+    }
+}