#include "libnazgul.h"

int msgBufferGetFreeIndex(msgPoolData * poolDataTabAddr,int poolIndex){
  msgBufferInfoTabId bufferInfoTabId;
int bufferInfoTabFd;
msgBufferInfo * bufferInfoTabAddr;
int bufferInfoNb;  
int bufferFreeIndex;

  //récuperer l'ID du BufferInfoTab;
  strcpy(bufferInfoTabId, poolDataTabAddr[poolIndex].bufferInfoTabId);
  
  bufferInfoTabFd=shm_open(bufferInfoTabId,O_RDWR,SHM_DEFAULT_MODE);
  if (bufferInfoTabFd<0){
	perror("shm_open");
	return -1;
  }

  /** on regarde dans le tableau d'infos de buffer **/
  bufferInfoNb=poolDataTabAddr[poolIndex].bufferNb;
  bufferInfoTabAddr=mmap(NULL,bufferInfoNb*sizeof(msgBufferInfo),
	  PROT_READ,MAP_SHARED,bufferInfoTabFd,(off_t)0);

  int i=0;
  while ((i<bufferInfoNb) 
	  && (bufferInfoTabAddr[i].ownerPid != (pid_t)-1)){ i++; }
  if (i == bufferInfoNb){ return -1; }
  bufferFreeIndex=i;
  
  if (munmap(bufferInfoTabAddr,bufferInfoNb*sizeof(msgBufferInfo))< 0)
  {	perror("munmap"); return -1; }
  
  return bufferFreeIndex;
}