#include "libnazgul.h"

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

	//récuperer l'ID du BufferInfoTab;
	strcpy(bufferInfoTabId, poolDataTabAddr[poolIndex].bufferInfoTabId);

	bufferInfoTabFd = shm_open(bufferInfoTabId, O_RDWR, SHM_DEFAULT_MODE);
	if (bufferInfoTabFd < 0) {
		NZG_ERROR("shm_open", bufferInfoTabId);
		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);

	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) {
		NZG_ERROR("munmap", bufferInfoTabId);
		return -1;
	}

	return bufferFreeIndex;
}