queue.c

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/* queue.c -- generic list handling routines
 *  
 * This file is part of 'netcast' program, released under BSD License. 
 * (c) 2001-2002 Stanis砤w Pa秌o <[e-mail]>. All rights reserved.   
 */

#include <stdlib.h>
#include <string.h>
#include "queue.h"

/* Append message at queue end */
void qappend (struct mmsgq *q,void *msg,long size) {
  if (!q) return;
  if (!q->head) {
    q->head=q->tail=(struct mmsg *) malloc(sizeof(struct mmsg)); 
  } else {
    q->tail->next=(struct mmsg *) malloc(sizeof(struct mmsg)); 
    q->tail=q->tail->next;
  }
  q->tail->next=0;
  q->tail->data=msg;
  q->tail->size=size;
  q->size+=size;
  q->count++;
}

/* Insert message at queue start */ 
void qinsert (struct mmsgq *q,void *msg,long size) {
  if (!q) return;
  if (!q->head) {
    q->head=q->tail=(struct mmsg *) malloc(sizeof(struct mmsg)); 
  } else {
    q->tail->next=(struct mmsg *) malloc(sizeof(struct mmsg)); 
    q->tail->next->next=q->head;
    q->head=q->tail->next;
  }
  q->tail->next=0;
  q->head->data=msg;
  q->head->size=size;
  q->size+=size;
  q->count++;
}

/* Fetch first message */
void* qfetch (struct mmsgq *q, long *size) {
  void *res=0;
  struct mmsg *tmp;
  if (q && q->head) {
    res=q->head->data;
    *size=q->head->size;
    tmp=q->head;
    q->head=q->head->next;
    free(tmp);   
    q->count--;
    q->size-=*size;
  }
  return res;
}

/* Just return first elements data */
void *qfirst (struct mmsgq *q,long *size) {
  if (q && q->head) return q->head->data;
  return 0;
}

/* Clear structures, _including_ data pointers */
void qempty (struct mmsgq *q) {
  if (!q) return;
  while (q->head) {
    q->tail=q->head->next;
    free(q->head->data);
    free(q->head);
    q->head=q->tail;
  }
  qblank(q);
} 

/* Initialize queue struct, this plainly assigns NULL pointers */
struct mmsgq *qinit () {
  struct mmsgq *q = malloc (sizeof(struct mmsgq)); 
  qblank(q);
  return q;
}

/* Empty queue struct, this plainly assigns NULL pointers */
void qblank (struct mmsgq *q) {
  q->count=q->size=0;
  q->head=q->tail=0;
}

void* qflat (struct mmsgq *q) {
  void *tmp;
  long offs=0;
  if (!q || q->count==0) return 0;
  tmp = malloc (q->size);
  while (q->head) {
    memcpy(tmp+offs,q->head->data,q->head->size);
    offs+=q->head->size;
    q->tail=q->head->next;
    free(q->head->data);
    free(q->head);
    q->head=q->tail;
  }
  qempty(q);
  return tmp; 
}