1 files changed, 39 insertions, 0 deletions
diff --git a/src/user/include/cxx/structs/map.h b/src/user/include/cxx/structs/map.h
new file mode 100644
index 0000000..f9c477f
--- /dev/null
+++ b/src/user/include/cxx/structs/map.h
@@ -0,0 +1,39 @@
+#ifndef STRUCTS_MAP_H
+#define STRUCTS_MAP_H
+
+#include <structs/alist.h>
+
+template<class type>
+bool default_equals(type a, type b) {
+  return a == b;
+}
+
+template<class key, class value, bool (*equals)(key, key) = &default_equals<key>>
+class map {
+public:
+  alist<key> keys;
+  alist<value> values;
+
+  map(uint32_t default_size=10, uint32_t expand_by=10)
+    : keys(default_size, expand_by), values(default_size, expand_by) {}
+
+  void add_pair(key k, value v) {
+    for (key *i = keys.buf; i < keys.buf + keys.n_entries; ++i)
+      if (equals(k, *i)) {
+        values.buf[i - keys.buf] = v;
+        return;
+      }
+    keys.add_back(k);
+    values.add_back(v);
+  }
+
+  __attribute__ ((pure))
+  value transform(key k, value fallback=value()) {
+    for (key *i = keys.buf; i < keys.buf + keys.n_entries; ++i)
+      if (equals(k, *i))
+        return values.buf[i - keys.buf];
+    return fallback;
+  }
+};
+
+#endif
+\ No newline at end of file