zeek/src/Queue.h

112 lines
3.8 KiB
C++

// $Id: Queue.h 6219 2008-10-01 05:39:07Z vern $
//
// See the file "COPYING" in the main distribution directory for copyright.
#ifndef queue_h
#define queue_h
// BaseQueue.h --
// Interface for class BaseQueue, current implementation is as an
// array of ent's. This implementation was chosen to optimize
// getting to the ent's rather than inserting and deleting.
// Also push's and pop's from the front or the end of the queue
// are very efficient. The only really expensive operation
// is resizing the list, which involves getting new space
// and moving the data. Resizing occurs automatically when inserting
// more elements than the list can currently hold. Automatic
// resizing is done one "chunk_size" of elements at a time and
// always increases the size of the list. Resizing to zero
// (or to less than the current value of num_entries)
// will decrease the size of the list to the current number of
// elements. Resize returns the new max_entries.
//
// Entries must be either a pointer to the data or nonzero data with
// sizeof(data) <= sizeof(void*).
#include "List.h"
class BaseQueue {
public:
~BaseQueue() { delete[] entry; }
int length() const { return num_entries; }
int resize(int = 0); // 0 => size to fit current number of entries
// remove all entries without delete[] entry
void clear() { head = tail = num_entries = 0; }
// helper functions for iterating over queue
int front() const { return head; }
int back() const { return tail; }
void incr(int& index) { index < max_entries ? ++index : index = 0; }
protected:
BaseQueue(int = 0);
void push_front(ent); // add in front of queue
void push_back(ent); // add at end of queue
ent pop_front(); // return and remove the front of queue
ent pop_back(); // return and remove the end of queue
// return nth *PHYSICAL* entry of queue (do not remove)
ent operator[](int i) const { return entry[i]; }
ent* entry;
int chunk_size; // increase size by this amount when necessary
int max_entries; // entry's index range: 0 .. max_entries
int num_entries;
int head; // beginning of the queue in the ring
int tail; // just beyond the end of the queue in the ring
};
// Queue.h -- interface for class Queue
// Use: to get a list of pointers to class foo you should:
// 1) declare(PQueue,foo); (declare interest in lists of foo*'s)
// 2) variables are declared like:
// PQueue(foo) bar; (bar is of type list of foo*'s)
// For queues of "type"
#define Queue(type) type ## Queue
// For queues of pointers to "type"
#define PQueue(type) type ## PQueue
#define Queuedeclare(type) \
struct Queue(type) : BaseQueue \
{ \
Queue(type)() : BaseQueue(0) {} \
Queue(type)(int sz) : BaseQueue(sz) {} \
\
void push_front(type a) { BaseQueue::push_front(ent(a)); } \
void push_back(type a) { BaseQueue::push_back(ent(a)); } \
type pop_front() { return type(BaseQueue::pop_front()); }\
type pop_back() { return type(BaseQueue::pop_back()); } \
\
type operator[](int i) const \
{ return type(BaseQueue::operator[](i)); } \
}; \
#define PQueuedeclare(type) \
struct PQueue(type) : BaseQueue \
{ \
PQueue(type)() : BaseQueue(0) {} \
PQueue(type)(int sz) : BaseQueue(sz) {} \
\
void push_front(type* a){ BaseQueue::push_front(ent(a)); } \
void push_back(type* a) { BaseQueue::push_back(ent(a)); } \
type* pop_front() \
{ return (type*)BaseQueue::pop_front(); } \
type* pop_back() \
{ return (type*)BaseQueue::pop_back(); } \
\
type* operator[](int i) const \
{ return (type*)BaseQueue::operator[](i); } \
}; \
// Macro to visit each queue element in turn.
#define loop_over_queue(queue, iterator) \
int iterator; \
for ( iterator = (queue).front(); iterator != (queue).back(); \
(queue).incr(iterator) ) \
#endif /* queue_h */