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DCCPktQ.c
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DCCPktQ.c
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#include "DCCPktQ.h"
#include <stdlib.h>
#include <stdio.h>
#define FREECOUNT 10
typedef struct dccpktelem {
DCCPacket pkt;
struct dccpktelem *next;
struct dccpktelem *prev;
} DCCPktElem;
typedef struct dccpktq {
DCCPktElem *read; /* read pointer, rotates around linked list */
DCCPktElem *lastRead; /* remember last packet read, use for repeat removal */
DCCPktElem *freeList; /* free list to store removed elements */
int size;
int count;
int freeCount;
} DCCPktQ;
/* Linked-List help functions */
void link(DCCPktElem *before, DCCPktElem *e, DCCPktElem *after) {
before->next = e;
e->prev = before;
after->prev = e;
e->next = after;
}
void unlink(DCCPktElem *e) {
e->prev->next = e->next;
e->next->prev = e->prev;
}
void remove(DCCPktQ *q, DCCPktElem *e) {
if (q->read == e) {
if (e != e->next) q->read = e->next;
else q->read = NULL;
}
unlink(e);
q->count--;
if (q->freeCount < FREECOUNT) {
e->next = q->freeList;
e->prev = NULL;
q->freeList = e;
q->freeCount++;
}
else free(e);
}
int remove_addr_pkt(DCCPktQ *q, uint16_t addr) {
DCCPktElem *e;
int n, succ = 0;
for (n = 0, e = q->read; n < q->count && e->pkt.addr != addr; e = e->next, n++)
; /* Loop through queue to find packet matching address */
if (e->pkt.addr == addr) {
remove(q, e);
succ = 1;
}
return succ;
}
/**********************/
DCCPktQ *dccpktq_create(int size) {
DCCPktQ *q = (DCCPktQ *) malloc(sizeof(DCCPktQ));
if (q == NULL) return NULL;
q->size = size;
q->count = q->freeCount = 0;
q->read = NULL;
return q;
}
int dccpktq_insert(DCCPktQ *q, DCCPacket *pkt) {
DCCPktElem *e = NULL;
cli(); /* Disable interrupts to prevent packet removal from interfering */
if (q->count == q->size) return 0;
if (q->freeCount){
e = q->freeList;
q->freeList = e->next;
q->freeCount--;
}
else {
e = (DCCPktElem *) malloc(sizeof(DCCPktElem));
if (e == NULL) return 0;
}
memcpy(&(e->pkt), pkt, sizeof(DCCPacket));
q->count++;
if (q->read == NULL) {
q->read = e;
e->next = e->prev = e;
}
else {
link(q->read->prev, e, q->read);
q->read = e;
}
sei();
return 1;
}
int dccpktq_hasNext(DCCPktQ *q) {
int exists = 0;
exists = (q->read != NULL);
return exists;
}
int dccpktq_next(DCCPktQ *q, DCCPacket **pkt) {
if (q->read == NULL) {
return 0;
}
*pkt = &(q->read->pkt);
(*pkt)->repeat--;
q->lastRead = q->read;
q->read = q->read->next;
if (q->lastRead->pkt.repeat == 0)
remove(q, q->lastRead); /* Remove last packet read if finished repeating */
return (*pkt)->size;
}
int dccpktq_remove(DCCPktQ *q, uint16_t addr) {
int succ = 0;
cli();
succ = remove_addr_pkt(q, addr);
sei();
return succ;
}
void dccpktq_clear(DCCPktQ *q) {
DCCPktElem *e;
cli();
while((e = q->read) != NULL) remove(q, e);
sei();
}
void dccpktq_destroy(DCCPktQ *q) {
DCCPktElem *e;
cli();
if (q == NULL) return;
while((e = q->read) != NULL) remove(q, e);
while((e = q->freeList) != NULL) free(e);
free(q);
sei();
}