call graph

2 files changed, 143 insertions, 1 deletions

diff --git a/src/2015/day7/aoc.h b/src/2015/day7/aoc.h
index af98330..7d76546 100644
--- a/src/2015/day7/aoc.h
+++ b/src/2015/day7/aoc.h
@@ -1,5 +1,143 @@
 #pragma once
+#include <functional>
+#include <map>
+
+#include "common.h"
 
 namespace aoc2015 {
 
-}
+struct result {
+  enum {
+    c_unknown,
+    c_value,
+  } type;
+  uint16_t value;
+
+  result op_and(result other) {
+    if (type == c_value && other.type == c_value) {
+      return result{c_value, uint16_t(value & other.value)};
+    }
+    return {c_unknown, 0};
+  }
+
+  result op_or(result other) {
+    if (type == c_value && other.type == c_value) {
+      return result{c_value, uint16_t(value | other.value)};
+    }
+    return {c_unknown, 0};
+  }
+
+  result op_leftshift(result other) {
+    if (type == c_value && other.type == c_value) {
+      return result{c_value, uint16_t(value << other.value)};
+    }
+    return {c_unknown, 0};
+  }
+
+  result op_rightshift(result other) {
+    if (type == c_value && other.type == c_value) {
+      return result{c_value, uint16_t(value >> other.value)};
+    }
+    return {c_unknown, 0};
+  }
+
+  result op_not() {
+    if (type == c_value) {
+      return result{c_value, uint16_t(~value)};
+    }
+    return {c_unknown, 0};
+  }
+};
+
+struct cals {
+  std::map<line_view, std::function<result()>> calls;
+
+  bool is_value(line_view v, uint16_t* x) const noexcept {
+    const char* p = v.line;
+    while (p != v.line + v.length) {
+      if (*p >= '0' && *p <= '9') {
+        *x = *x * 10 + *p - '0';
+        p++;
+      } else {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  result compute(line_view w) const noexcept {
+    uint16_t x = 0;
+    if (is_value(w, &x)) {
+      return {result::c_value, x};
+    } else {
+      auto it = calls.find(w);
+      return it != calls.end() ? it->second() : result{result::c_unknown, 0};
+    }
+  }
+
+  std::function<result()> op_and(line_view x, line_view y) {
+    return [&x, &y, this]() -> result { return compute(x).op_and(compute(y)); };
+  }
+
+  std::function<result()> op_or(line_view x, line_view y) {
+    return [&x, &y, this]() -> result { return compute(x).op_or(compute(y)); };
+  }
+
+  std::function<result()> op_leftshift(line_view x, line_view y) {
+    return [&x, &y, this]() -> result { return compute(x).op_leftshift(compute(y)); };
+  }
+
+  std::function<result()> op_rightshift(line_view x, line_view y) {
+    return [&x, &y, this]() -> result { return compute(x).op_rightshift(compute(y)); };
+  }
+
+  std::function<result()> op_not(line_view x, line_view y) {
+    return [&x, this]() -> result { return compute(x).op_not(); };
+  }
+
+  std::function<result()> op_value(line_view x, line_view y) {
+    return [&x, this]() -> result { return compute(x); };
+  }
+
+  std::function<result()> parse(line_view line, line_view* x, line_view* y, line_view* w) {
+    struct _ {
+      std::function<result()> (cals::*op)(line_view, line_view);
+      const char* label;
+    } ops[] = {
+        {&cals::op_and, "AND"},
+        {&cals::op_or, "OR"},
+        {&cals::op_leftshift, "LSHIFT"},
+        {&cals::op_rightshift, "RSHIFT"},
+    };
+    const char* arrow = line.contains("->");
+    *w = line_view(arrow + 3, line.line + line.length);
+
+    for (auto op : ops) {
+      const char* p = line.contains(op.label);
+      if (p != nullptr) {
+        *x = line_view(line.line, p - 1);
+        *y = line_view(p + strlen(op.label) + 1, arrow - 1);
+        return (this->*op.op)(*x, *y);
+      }
+    }
+
+    const char* p = line.contains("NOT");
+    if (p != nullptr) {
+      *x = line_view(p + 4, arrow - 1);
+      return op_not(*x, *y);
+    }
+
+    *x = line_view(line.line, arrow - 1);
+    return op_value(*x, *y);
+  }
+
+  void parse(line_view line) {
+    line_view* x = new line_view();
+    line_view* y = new line_view();
+    line_view* w = new line_view();
+    auto f = parse(line, x, y, w);
+    calls.insert({*w, f});
+  }
+};
+
+} // namespace aoc2015
diff --git a/src/common.h b/src/common.h
index 8d358cb..a88e16e 100644
--- a/src/common.h
+++ b/src/common.h
@@ -21,6 +21,10 @@ struct line_view {
     return o;
   }
 
+  bool operator<(const line_view& lv) const noexcept {
+    return std::string(line, length) < std::string(lv.line, lv.length);
+  }
+
   bool operator==(const line_view& lv) const noexcept {
     const char* p1 = line;
     const char* p2 = lv.line;