Weird bug in draw_tree

Seems near the 100,000 node mark, the vector craps itself?  I keep
getting "heap use after free" errors here when trying to access the
allocator vector.  Disabling fsan just leads to a segment fault near
the same point.

I think we might need to introduce our own vector :)

build.sh

@@ -2,9 +2,15 @@
 
 set -xe
 
+OUT="cw_tree.out"
 GFLAGS="-Wall -Wextra -Wswitch-enum -std=c++17"
 DFLAGS="-ggdb -fsanitize=address -fsanitize=undefined"
 CFLAGS="$GFLAGS $DFLAGS"
 LIBS="-lraylib -lm"
 
-c++ $CFLAGS -o cw_tree.out src/numerics.cpp src/main.cpp $LIBS
+c++ $CFLAGS -o $OUT src/node.cpp src/state.cpp src/worker.cpp src/main.cpp $LIBS
+
+if [ "$1" = "run" ]
+then
+    ./$OUT
+fi

src/base.hpp

@@ -0,0 +1,57 @@
+/* base.hpp: Basic definitions
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef BASE_HPP
+#define BASE_HPP
+
+#include <cassert>
+#include <cstdint>
+#include <optional>
+
+#define MIN(A, B) ((A) < (B) ? (A) : (B))
+#define MAX(A, B) ((B) < (A) ? (A) : (B))
+
+using u8  = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+
+using i8  = int8_t;
+using i16 = int16_t;
+using i32 = int32_t;
+using i64 = int64_t;
+
+static_assert(sizeof(float) == 4, "f32 requires 4 byte floats");
+static_assert(sizeof(double) == 8, "f64 requires 8 byte doubles");
+using f32 = float;
+using f64 = double;
+
+inline u64 gcd(u64 a, u64 b)
+{
+  if (a == b)
+    return a;
+  else if (a <= 1 || b <= 1)
+    return 1;
+  for (u64 r = b % a; r != 0; b = a, a = r, r = b % a)
+    continue;
+  return a;
+}
+
+#endif
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */

src/main.cpp

@@ -5,18 +5,21 @@
  * Commentary: 2024-07-25
  */
 
-#include "./numerics.hpp"
-
 #include <chrono>
 #include <cmath>
 #include <cstdio>
 #include <iostream>
 #include <sstream>
 #include <stack>
+#include <thread>
 #include <tuple>
 
 #include <raylib.h>
 
+#include "base.hpp"
+#include "node.hpp"
+#include "worker.hpp"
+
 #define WIDTH       1024
 #define HEIGHT      1024
 #define FONT_SIZE   20
@@ -24,14 +27,17 @@
 #define LINE_TOP    (7 * HEIGHT / 16)
 #define LINE_BOTTOM (9 * HEIGHT / 16)
 
-std::pair<std::string, int> fraction_to_string(Fraction f)
+using cw::state::DrawState;
+using cw::state::State;
+
+std::pair<std::string, int> fraction_to_string(cw::node::Fraction f)
 {
   std::string s{to_string(f)};
   int width = MeasureText(s.c_str(), FONT_SIZE);
   return std::make_pair(s, width);
 }
 
-void draw_fraction(Fraction f, word_t x, word_t y)
+void draw_fraction(cw::node::Fraction f, u64 x, u64 y)
 {
   std::string s;
   int width;
@@ -40,6 +46,133 @@ void draw_fraction(Fraction f, word_t x, word_t y)
   DrawText(s.c_str(), x - width / 2, y - FONT_SIZE, FONT_SIZE, WHITE);
 }
 
+constexpr u64 clamp_to_width(const DrawState &ds, f64 val)
+{
+  return (WIDTH / (ds.bounds.upper_val - ds.bounds.lower_val)) *
+         (val - ds.bounds.lower_val);
+}
+
+void draw_tree(const DrawState &ds, const State &state)
+{
+  // Number line
+  DrawLine(0, HEIGHT / 2, WIDTH, HEIGHT / 2, WHITE);
+
+  // Bounds
+  u64 lower_x = clamp_to_width(ds, ds.bounds.leftmost.value.norm);
+  u64 upper_x = clamp_to_width(ds, ds.bounds.rightmost.value.norm);
+  DrawLine(lower_x, LINE_TOP, lower_x, LINE_BOTTOM, WHITE);
+  DrawLine(upper_x, LINE_TOP, upper_x, LINE_BOTTOM, WHITE);
+
+  std::stack<std::pair<u64, f64>> stack;
+  cw::node::Node n = state.allocator.get_val(0);
+  stack.push(std::make_pair(0, n.value.norm));
+  while (!stack.empty())
+  {
+    u64 node_index;
+    f64 norm;
+    std::tie(node_index, norm) = stack.top();
+    stack.pop();
+    u64 x = clamp_to_width(ds, norm);
+    DrawLine(x, LINE_TOP, x, LINE_BOTTOM, RED);
+
+    cw::node::Node n = state.allocator.get_val(node_index);
+    if (n.left >= 0)
+    {
+      cw::node::Node left = state.allocator.get_val(n.left);
+      stack.push(std::make_pair(n.left, left.value.norm));
+    }
+    if (n.right >= 0)
+    {
+      cw::node::Node right = state.allocator.get_val(n.right);
+      stack.push(std::make_pair(n.right, right.value.norm));
+    }
+  }
+}
+
+using Clock = std::chrono::steady_clock;
+using Ms    = std::chrono::milliseconds;
+
+int main(void)
+{
+  // Init timer
+  auto time_current         = Clock::now();
+  auto time_previous        = time_current;
+  constexpr auto time_delta = 0;
+
+  // Init general state
+  cw::state::State state;
+  state.stop_work  = false;
+  state.pause_work = false;
+  state.allocator.alloc(cw::node::Node{{1, 1}, -1, -1});
+  state.queue.push(0);
+
+  cw::state::DrawState draw_state{state};
+
+  // Init meta text (counter, iterations, etc)
+  u64 count = 1, prev_count = 0;
+  std::stringstream format_stream;
+  std::string format_str;
+  u64 format_str_width = 0;
+
+  // Init threads
+  std::thread threads[] = {
+      std::thread(cw::worker::worker, std::ref(state)),
+      std::thread(cw::worker::worker, std::ref(state)),
+      std::thread(cw::worker::worker, std::ref(state)),
+      std::thread(cw::worker::worker, std::ref(state)),
+  };
+
+  // Setup raylib window
+  InitWindow(WIDTH, HEIGHT, "Calkin-Wilf tree");
+  SetTargetFPS(60);
+
+  while (!WindowShouldClose())
+  {
+    // Update
+    time_current = Clock::now();
+    if (!state.pause_work &&
+        std::chrono::duration_cast<Ms>(time_current - time_previous).count() >=
+            time_delta)
+    {
+      time_previous = time_current;
+      count         = state.allocator.vec.size();
+    }
+
+    if (prev_count != count)
+    {
+      draw_state.compute_bounds();
+      prev_count = count;
+      format_stream << "Count=" << count << "\n\n"
+                    << "Iterations=" << (count - 1) / 2 << "\n\n"
+                    << "Lower=" << to_string(draw_state.bounds.leftmost.value)
+                    << "\n\n"
+                    << "Upper=" << to_string(draw_state.bounds.rightmost.value);
+      format_str = format_stream.str();
+      format_stream.str("");
+      format_str_width = MeasureText(format_str.c_str(), FONT_SIZE * 2);
+    }
+
+    // Draw
+
+    ClearBackground(BLACK);
+    BeginDrawing();
+    draw_tree(draw_state, state);
+    DrawText(format_str.c_str(), WIDTH / 2 - format_str_width / 2, HEIGHT / 8,
+             FONT_SIZE, WHITE);
+    EndDrawing();
+  }
+
+  CloseWindow();
+
+  state.stop_work = true;
+  for (auto &thread : threads)
+  {
+    thread.join();
+  }
+  return 0;
+}
+
+#if 0
 struct State
 {
   NodeAllocator allocator;
@@ -209,6 +342,7 @@ int main(void)
   CloseWindow();
   return 0;
 }
+#endif
 
 /* Copyright (C) 2024, 2025 Aryadev Chavali
 

src/node.cpp

@@ -0,0 +1,133 @@
+/* node.cpp: Implementations of various functions for fractions and nodes
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#include <sstream>
+
+#include "node.hpp"
+
+namespace cw::node
+{
+  /**************************************/
+  /*  ___            _   _              */
+  /* | __| _ __ _ __| |_(_)___ _ _  ___ */
+  /* | _| '_/ _` / _|  _| / _ \ ' \(_-< */
+  /* |_||_| \__,_\__|\__|_\___/_||_/__/ */
+  /*                                    */
+  /**************************************/
+  Fraction::Fraction(u64 numerator, u64 denominator)
+      : numerator{numerator}, denominator{denominator},
+        norm{numerator / ((f64)denominator)}
+  {
+    u64 hcf = gcd(MIN(numerator, denominator), MAX(numerator, denominator));
+    numerator /= hcf;
+    denominator /= hcf;
+  }
+
+  bool Fraction::operator<(const Fraction other)
+  {
+    if (other.denominator == denominator)
+      return numerator < other.numerator;
+    return (numerator * other.denominator) < (other.numerator * denominator);
+  }
+
+  bool Fraction::operator==(const Fraction &other)
+  {
+    return numerator == other.numerator && denominator == other.denominator;
+  }
+
+  std::string to_string(const Fraction &f)
+  {
+    std::stringstream ss;
+    ss << f.numerator << "/" << f.denominator;
+    return ss.str();
+  }
+
+  /***************************/
+  /*  _  _         _         */
+  /* | \| |___  __| |___ ___ */
+  /* | .` / _ \/ _` / -_|_-< */
+  /* |_|\_\___/\__,_\___/__/ */
+  /*                         */
+  /***************************/
+  Node::Node(const Fraction &&val, i64 left, i64 right)
+      : value{val}, left{left}, right{right}
+  {
+  }
+
+  NodeAllocator::NodeAllocator(u64 capacity)
+  {
+    vec.reserve(capacity);
+  }
+
+  u64 NodeAllocator::alloc(Node n)
+  {
+    u64 ind = vec.size();
+    vec.push_back(n);
+    return ind;
+  }
+
+  // FIXME: This is annoying.  DRY?
+  Node &NodeAllocator::get_ref(u64 n)
+  {
+    if (n >= vec.size())
+      return vec[0];
+    return vec[n];
+  }
+
+  Node NodeAllocator::get_val(u64 n) const
+  {
+    if (n >= vec.size())
+      return vec[0];
+    return vec[n];
+  }
+
+  void indent_depth(int depth, std::stringstream &ss)
+  {
+    for (int i = 0; i < depth; ++i)
+      ss << "  ";
+  }
+
+  std::string to_string(const NodeAllocator &allocator, const i64 n, int depth)
+  {
+    if (n < 0)
+      return "NIL";
+
+    std::stringstream ss;
+    Node x = allocator.get_val(n);
+    ss << "(" << to_string(x.value) << "\n";
+
+    indent_depth(depth, ss);
+    if (x.left == -1)
+      ss << "NIL";
+    else
+      ss << to_string(allocator, x.left, depth + 1);
+    ss << "\n";
+
+    indent_depth(depth, ss);
+    if (x.right == -1)
+      ss << "NIL";
+    else
+      ss << to_string(allocator, x.right, depth + 1);
+
+    ss << ")";
+    return ss.str();
+  }
+
+} // namespace cw::node
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */

src/node.hpp

@@ -0,0 +1,66 @@
+/* node.hpp: Definition of fractions and nodes on the Calkin-Wilf tree
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef NODE_HPP
+#define NODE_HPP
+
+#include <string>
+#include <vector>
+
+#include "base.hpp"
+
+namespace cw::node
+{
+  struct Fraction
+  {
+    u64 numerator, denominator; // always simplified
+    f64 norm;
+
+    Fraction(u64 numerator = 0, u64 denominator = 1);
+
+    // Complete ordering on Fractions
+    bool operator<(const Fraction other);
+    bool operator==(const Fraction &other);
+  };
+
+  std::string to_string(const Fraction &);
+
+  struct Node
+  {
+    Fraction value;
+    i64 left, right;
+
+    Node(const Fraction &&val = {}, i64 left = -1, i64 right = -1);
+  };
+
+  struct NodeAllocator
+  {
+    std::vector<Node> vec;
+
+    NodeAllocator(u64 capacity = 256);
+    u64 alloc(Node n);
+    Node get_val(u64 n) const;
+    Node &get_ref(u64 n);
+  };
+
+  std::string to_string(const NodeAllocator &, const i64, int depth = 1);
+} // namespace cw::node
+
+#endif
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */

src/numerics.cpp

@@ -1,153 +0,0 @@
-/* numerics.cpp: Implementation of numerics
- * Created: 2024-07-26
- * Author: Aryadev Chavali
- * License: See end of file
- * Commentary:
- */
-
-#include "./numerics.hpp"
-
-#include <sstream>
-
-Fraction::Fraction(word_t numerator, word_t denominator)
-    : numerator{numerator}, denominator{denominator},
-      norm{numerator / ((long double)denominator)}
-{
-  word_t hcf = gcd(MIN(numerator, denominator), MAX(numerator, denominator));
-  numerator /= hcf;
-  denominator /= hcf;
-}
-
-// floating point arithmetic inaccuracies blah blah blah better to use
-// simplified fractions here
-
-bool Fraction::operator<(const Fraction other)
-{
-  if (other.denominator == denominator)
-    return numerator < other.numerator;
-  // TODO: Is it better to use the GCD?
-  return (numerator * other.denominator) < (other.numerator * denominator);
-}
-
-bool Fraction::operator==(const Fraction &other)
-{
-  return numerator == other.numerator && denominator == other.denominator;
-}
-
-Node::Node(Fraction val, index_t left, index_t right)
-    : value{val}, left{left}, right{right}
-{
-}
-
-NodeAllocator::NodeAllocator(word_t capacity)
-{
-  vec.reserve(capacity);
-}
-
-word_t NodeAllocator::alloc(Node n)
-{
-  word_t ind = vec.size();
-  vec.push_back(n);
-  return ind;
-}
-
-// WHY DO I NEED TO DO IT TWICE REEEEEEE
-Node &NodeAllocator::getRef(word_t n)
-{
-  if (n >= vec.size())
-    return vec[0];
-  return vec[n];
-}
-
-Node NodeAllocator::getVal(word_t n) const
-{
-  if (n >= vec.size())
-    return vec[0];
-  return vec[n];
-}
-
-word_t gcd(word_t a, word_t b)
-{
-  if (a == b)
-    return a;
-  else if (a <= 1 || b <= 1)
-    return 1;
-  for (word_t r = b % a; r != 0; b = a, a = r, r = b % a)
-    continue;
-  return a;
-}
-
-std::tuple<Fraction, Fraction, Fraction> iterate(std::queue<word_t> &queue,
-                                                 NodeAllocator &allocator)
-{
-  if (queue.empty())
-    return {};
-  word_t index = queue.front();
-  Node node    = allocator.getVal(index);
-  if (!node.left.has_value())
-  {
-    allocator.getRef(index).left = allocator.alloc(Fraction{
-        node.value.numerator, node.value.numerator + node.value.denominator});
-  }
-  if (!node.right.has_value())
-  {
-    allocator.getRef(index).right = allocator.alloc(Fraction{
-        node.value.numerator + node.value.denominator, node.value.denominator});
-  }
-  queue.pop();
-  queue.push(allocator.getVal(index).left.value());
-  queue.push(allocator.getVal(index).right.value());
-  node = allocator.getVal(index);
-  // NOTE: We can be assured that left and right DO have values
-  return std::tuple(allocator.getVal(node.left.value()).value, node.value,
-                    allocator.getVal(node.right.value()).value);
-}
-
-std::string to_string(const Fraction &f)
-{
-  std::stringstream ss;
-  ss << f.numerator << "/" << f.denominator;
-  return ss.str();
-}
-
-void indent_depth(int depth, std::stringstream &ss)
-{
-  for (int i = 0; i < depth; ++i)
-    ss << "  ";
-}
-
-std::string to_string(const NodeAllocator &allocator, const index_t n,
-                      int depth)
-{
-  if (!n.has_value())
-    return "NIL";
-  std::stringstream ss;
-  Node x = allocator.getVal(n.value());
-  ss << "(" << to_string(x.value) << "\n";
-  indent_depth(depth, ss);
-  if (x.left == -1)
-    ss << "NIL";
-  else
-    ss << to_string(allocator, x.left, depth + 1);
-  ss << "\n";
-  indent_depth(depth, ss);
-  if (x.right == -1)
-    ss << "NIL";
-  else
-    ss << to_string(allocator, x.right, depth + 1);
-  ss << ")";
-  return ss.str();
-}
-
-/* Copyright (C) 2024, 2025 Aryadev Chavali
-
- * 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 Version 2 for
- * details.
-
- * You may distribute and modify this code under the terms of the GNU General
- * Public License Version 2, which you should have received a copy of along with
- * this program.  If not, please go to <https://www.gnu.org/licenses/>.
-
- */

src/numerics.hpp

@@ -1,72 +0,0 @@
-/* numerics.hpp: Computation necessary for generating the tree
- * Created: 2024-07-26
- * Author: Aryadev Chavali
- * License: See end of file
- * Commentary:
- */
-
-#ifndef NUMERICS_HPP
-#define NUMERICS_HPP
-
-#include <cstdint>
-
-#include <optional>
-#include <queue>
-#include <string>
-#include <tuple>
-#include <vector>
-
-#define MIN(A, B) ((A) < (B) ? (A) : (B))
-#define MAX(A, B) ((B) < (A) ? (A) : (B))
-typedef uint64_t word_t;
-typedef std::optional<word_t> index_t;
-
-struct Fraction
-{
-  word_t numerator, denominator;
-  long double norm;
-
-  Fraction(word_t numerator = 0, word_t denominator = 1);
-  bool operator<(const Fraction other);
-  bool operator==(const Fraction &other);
-};
-
-struct Node
-{
-  Fraction value;
-  index_t left, right;
-
-  Node(Fraction val = {}, index_t left = std::nullopt,
-       index_t right = std::nullopt);
-};
-
-struct NodeAllocator
-{
-  std::vector<Node> vec;
-
-  NodeAllocator(word_t capacity = 0);
-  word_t alloc(Node n);
-  Node getVal(word_t n) const;
-  Node &getRef(word_t n);
-};
-
-word_t gcd(word_t a, word_t b);
-std::tuple<Fraction, Fraction, Fraction> iterate(std::queue<word_t> &queue,
-                                                 NodeAllocator &allocator);
-
-std::string to_string(const Fraction &);
-std::string to_string(const NodeAllocator &, const index_t, int depth = 1);
-
-#endif
-
-/* Copyright (C) 2024, 2025 Aryadev Chavali
-
- * 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 Version 2 for
- * details.
-
- * You may distribute and modify this code under the terms of the GNU General
- * Public License Version 2, which you should have received a copy of along with
- * this program.  If not, please go to <https://www.gnu.org/licenses/>.
- */

src/state.cpp

@@ -0,0 +1,39 @@
+/* state.cpp:
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#include "state.hpp"
+#include <cmath>
+
+namespace cw::state
+{
+  void DrawState::compute_bounds()
+  {
+    bounds.leftmost = state.allocator.get_val(0);
+    while (bounds.leftmost.left >= 0)
+      bounds.leftmost = state.allocator.get_val(bounds.leftmost.left);
+
+    bounds.rightmost = state.allocator.get_val(0);
+    while (bounds.rightmost.right >= 0)
+      bounds.rightmost = state.allocator.get_val(bounds.rightmost.right);
+
+    bounds.lower_val = std::floorl(bounds.leftmost.value.norm);
+    bounds.upper_val = std::ceill(bounds.rightmost.value.norm);
+  }
+} // namespace cw::state
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */

src/state.hpp

@@ -0,0 +1,58 @@
+/* state.hpp: General state of the simulation
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef STATE_HPP
+#define STATE_HPP
+
+#include <mutex>
+#include <queue>
+
+#include "base.hpp"
+#include "node.hpp"
+
+namespace cw::state
+{
+  struct State
+  {
+    cw::node::NodeAllocator allocator;
+    std::queue<u64> queue;
+
+    bool pause_work, stop_work;
+    std::mutex mutex;
+
+    State(void) {};
+  };
+
+  struct DrawState
+  {
+    const State &state;
+    struct Bounds
+    {
+      cw::node::Node leftmost, rightmost;
+      f64 lower_val, upper_val;
+    } bounds;
+
+    DrawState(const State &state) : state{state} {};
+
+    void compute_bounds(void);
+  };
+} // namespace cw::state
+
+#endif
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */

src/worker.cpp

@@ -0,0 +1,81 @@
+/* worker.cpp: Implementation of workers in our simulation
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#include <chrono>
+#include <thread>
+#include <tuple>
+
+#include "worker.hpp"
+
+namespace cw::worker
+{
+  using cw::node::Fraction;
+  using cw::node::Node;
+
+  void do_iteration(State &state)
+  {
+    state.mutex.lock();
+    if (state.queue.empty())
+    {
+      // Unlock since there isn't any work to be done.
+      state.mutex.unlock();
+      return;
+    }
+    u64 index = state.queue.front();
+    state.queue.pop();
+
+    Node node = state.allocator.get_val(index);
+
+    i64 left = node.left, right = node.right;
+    if (left < 0)
+    {
+      left = state.allocator.alloc(Fraction{
+          node.value.numerator, node.value.numerator + node.value.denominator});
+    }
+    if (right < 0)
+    {
+      right = state.allocator.alloc(
+          Fraction{node.value.numerator + node.value.denominator,
+                   node.value.denominator});
+    }
+
+    Node &node_ref = state.allocator.get_ref(index);
+    node_ref.left  = left;
+    node_ref.right = right;
+
+    state.queue.push(left);
+    state.queue.push(right);
+    state.mutex.unlock();
+  }
+
+  void worker(State &state)
+  {
+    while (!state.stop_work)
+    {
+      std::this_thread::sleep_for(THREAD_GENERAL_DELAY);
+      while (state.pause_work)
+      {
+        std::this_thread::sleep_for(THREAD_PAUSE_DELAY);
+      }
+
+      do_iteration(state);
+    }
+  }
+} // namespace cw::worker
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */

src/worker.hpp

@@ -0,0 +1,49 @@
+/* worker.hpp: Definition of "workers" who will generate nodes on the tree
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef WORKER_HPP
+#define WORKER_HPP
+
+#include <chrono>
+#include <tuple>
+
+#include "state.hpp"
+
+namespace cw::worker
+{
+  using cw::node::NodeAllocator;
+  using cw::state::State;
+  constexpr auto THREAD_PAUSE_DELAY   = std::chrono::milliseconds(1000);
+  constexpr auto THREAD_GENERAL_DELAY = std::chrono::milliseconds(1);
+
+  // Performs a single iteration which consists of the following:
+  // 1) pop an index off the iteration queue
+  // 2) generate the children of the node at that index
+  // 3) push the indices of the children onto the iteration queue
+  // Each step will block on the relevant mutex for the resource (1,3 will block
+  // on the queue mutex, 2 will block on the allocator mutex) so is thread safe.
+  void do_iteration(State &state);
+
+  // Steady living thread worker which performs iterations.  If state.pause_work
+  // is true, thread will pause until otherwise.
+  void worker(State &state);
+} // namespace cw::worker
+
+#endif
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */