root/lang/objective-cplusplus/i3/trunk/src/mil/include/mil/Serial.h @ 36273

#pragma once
#include "Mil.h"
#include "Synchronize.h"

/**
* XXX CAST!!!
*/
namespace mil {
class Serial {
public:
    enum {
        INVALID_VALUE = -1,
    };
private:
    Mutex mutex;
    int max;
    int serial;
    void* list_; // avoid compiler's segv
public:
    Serial(int max) : max(max), serial(0) {
        list_ = reinterpret_cast<void*>(new std::list<int>());
    }

    ~Serial() {
        delete reinterpret_cast<std::list<int>*>(list_);
    }

    int retain() {
        int new_id = INVALID_VALUE;
        synchronized (mutex) {
            std::list<int>& list = *reinterpret_cast<std::list<int>*>(list_);
            try {
                if (!list.empty()) {
                    int v = list.back();
                    list.pop_back();
                    return v;
                }
            } catch (std::exception&) {
                halt << "insufficient memory";
                return INVALID_VALUE;
            }

            if (serial >= max) {
                return INVALID_VALUE;
            }
            new_id = serial;
            serial++;
        }
        return new_id;
    }

    bool release(int v) {
        synchronized (mutex) {
            std::list<int>& list = *reinterpret_cast<std::list<int>*>(list_);
            try {
                list.push_back(v);
            } catch (std::exception&) {
                return false;
            }
        }
        return true;
    }
};
}