rust/src/rt/util/indexed_list.h

97 lines
2.3 KiB
C++

// -*- c++ -*-
#ifndef INDEXED_LIST_H
#define INDEXED_LIST_H
#include <assert.h>
#include "array_list.h"
class indexed_list_object {
public:
int32_t list_index;
};
template<typename T>
class indexed_list_element : public indexed_list_object {
public:
T value;
indexed_list_element(T value) : value(value) {
}
};
/**
* An array list of objects that are aware of their position in the list.
* Normally, objects in this list should derive from the base class
* "indexed_list_object" however because of nasty Rust compiler dependencies
* on the layout of runtime objects we cannot always derive from this
* base class, so instead we just enforce the informal protocol that any
* object inserted in this list must define a "int32_t list_index" member.
*/
template<typename T> class indexed_list {
array_list<T*> list;
public:
virtual int32_t append(T *value);
virtual bool pop(T **value);
/**
* Same as pop(), except that it returns NULL if the list is empty.
*/
virtual T* pop_value();
virtual size_t length() {
return list.size();
}
virtual bool is_empty() {
return list.is_empty();
}
virtual int32_t remove(T* value);
virtual T * operator[](int32_t index);
};
template<typename T> int32_t
indexed_list<T>::append(T *value) {
value->list_index = list.push(value);
return value->list_index;
}
/**
* Swap delete the last object in the list with the specified object.
*/
template<typename T> int32_t
indexed_list<T>::remove(T *value) {
assert (value->list_index >= 0);
assert (value->list_index < (int32_t)list.size());
int32_t removeIndex = value->list_index;
T *last = 0;
list.pop(&last);
if (last->list_index == removeIndex) {
last->list_index = -1;
return removeIndex;
} else {
value->list_index = -1;
list[removeIndex] = last;
last->list_index = removeIndex;
return removeIndex;
}
}
template<typename T> bool
indexed_list<T>::pop(T **value) {
return list.pop(value);
}
template<typename T> T*
indexed_list<T>::pop_value() {
T *value = NULL;
if (list.pop(&value)) {
return value;
}
return NULL;
}
template <typename T> T *
indexed_list<T>::operator[](int32_t index) {
T *value = list[index];
assert(value->list_index == index);
return value;
}
#endif /* INDEXED_LIST_H */