<?php

/*
  Linha de comando
  ipcs ->  mostra blocos de memoria alocados
  ipcrm -m "shmid" ->   remove o bloco de mem�ria referenciado por shmid
 */

define("SHM_SIZE", 2048);
define("SHM_ACESS_MODE_C", 'c');
define("SHM_ACESS_MODE_R", 'a');
define("SHM_ACESS_MODE_RW", 'w');
define("SHM_ACESS_PERMISSION", 0666);

function ShmGetId($file) {
    /**
     * Se for passado um id, retorna se n�o obtem a partir de um arquivo.
     */
    if (is_numeric($file)) {
        return $file;
    }

    if (!file_exists($file)) {
        touch($file);
    }

    return ftok($file, 'R');
}

function ShmOpen($key, $flags, $perms, $size) {
    $shmkey = shmop_open($key, $flags, $perms, $size);

    if (!$shmkey) {
        return false;
    }

    return $shmkey;
}

function ShmClear($shmkey, $offset, $length) {

    $shm_bytes_written = shmop_write($shmkey, str_repeat(' ', $length), $offset);

    if ($shm_bytes_written != $length) {
        return false;
    }

    return $shm_bytes_written;
}

function ShmWrite($shmkey, $data, $offset = 0) {
    $fsize = strlen($data);
    $shm_bytes_written = shmop_write($shmkey, $data, $offset);

    if ($shm_bytes_written != $fsize) {
        return false;
    }

    return $shm_bytes_written;
}

function ShmRead($shmkey, $start, $count) {
    $my_string = shmop_read($shmkey, $start, $count);
    if (!$my_string) {
        return false;
    }

    return $my_string;
}

function ShmWriteVar($shmkey, $data, $offset) {
    $fdata = serialize($data);
    $fsize = strlen($fdata);
    $shm_bytes_written = shmop_write($shmkey, $fdata, $offset);

    if ($shm_bytes_written != $fsize) {
        return false;
    }
    return $shm_bytes_written;
}

function ShmReadVar($shmkey, $start, $count) {
    $my_string = shmop_read($shmkey, $start, $count);
    if (!$my_string) {
        return false;
    }

    return unserialize($my_string);
}

function ShmDelete($shmkey) {
    if (!@shmop_delete($shmkey)) {
        return false;
    }

    return true;
}

function ShmClose($shmkey) {
    return shmop_close($shmkey);
}

function ShmExist($key) {
    return shmop_open($key, 'a', 0, 0);
}

function ShmSize($shmkey) {
    return shmop_size($shmkey);
}

?>