Replace TreeVector with a more generic Vector struct

src/runtime/vector.h

@@ -0,0 +1,67 @@
+#ifndef RUNTIME_VECTOR_H_
+#define RUNTIME_VECTOR_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+
+typedef struct {
+  void *contents;
+  size_t size;
+  size_t capacity;
+  size_t element_size;
+} Vector;
+
+static inline Vector vector_new(size_t element_size, size_t capacity) {
+  return (Vector){
+    .contents = malloc(capacity * element_size),
+    .size = 0,
+    .capacity = capacity,
+    .element_size = element_size,
+  };
+}
+
+static inline void vector_push(Vector *self, void *entry) {
+  if (self->size == self->capacity) {
+    self->capacity += 4;
+    self->contents =
+      realloc(self->contents, self->capacity * self->element_size);
+  }
+
+  char *contents = (char *)self->contents;
+  memcpy(contents + (self->size * self->element_size), (char *)entry,
+         self->element_size);
+  self->size++;
+}
+
+static inline void vector_reverse(Vector *self) {
+  char swap[self->element_size];
+  char *contents = (char *)self->contents;
+  size_t limit = self->size / 2;
+  for (size_t i = 0; i < limit; i++) {
+    size_t offset = i * self->element_size;
+    size_t reverse_offset = (self->size - 1 - i) * self->element_size;
+    memcpy(&swap, contents + offset, self->element_size);
+    memcpy(contents + offset, contents + reverse_offset, self->element_size);
+    memcpy(contents + reverse_offset, &swap, self->element_size);
+  }
+}
+
+static inline Vector vector_copy(Vector *self) {
+  return (Vector){
+    .contents = memcpy(malloc(self->capacity * self->element_size),
+                       self->contents, self->size * self->element_size),
+    .size = self->size,
+    .capacity = self->capacity,
+    .element_size = self->element_size,
+  };
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // RUNTIME_VECTOR_H_