C++ random32函数代码示例

void brodge(struct c642_pict *pict)
{
    int o;
    int at[2], m[2];
    long d;
    struct timespec ls = current_kernel_time();

    c642_esqu(pict);

    //°\\ 0: osc1 , 1: osc2 , 2: osc3
    for(o = 0; o < 2; o++) {
        d = 1L * pict->num_at * random32();
        at[o] = d >> 32;
    }
    d = 4L * random32();
    m[0] = d >> 32;
    d = 4L * random32();
    m[1] = d >> 32;

    brodge1(pict, at, m);

    pict->sig = current_kernel_time();
    d = (pict->sig.tv_nsec - ls.tv_nsec);
    if ( d < 0 ) {
        printk("Brodge  ' %lX '  taked  %ld.%lds.\n", pict->sig.tv_sec, pict->sig.tv_sec - ls.tv_sec - 1, (1000000000 - d)/1000000);
    } else {
        printk("Brodge  ' %lX '  taked  %ld.%lds.\n", pict->sig.tv_sec, pict->sig.tv_sec - ls.tv_sec, d/1000000);
    }

    // Sig

    // Export
    d = a051_data_write(pict->env, pict->picture, pict->size);
    printk("Brodge  ' %lX '  send %ld bytes\n", 0x7F1FFFFFFF & (1L * pict->sig.tv_sec * 1000L + pict->sig.tv_nsec / 1000000L), d);
}

quint64 Zobrist::random64()
{
	quint64 random1 = (quint64)random32();
	quint64 random2 = (quint64)random32();
	quint64 random3 = (quint64)random32();

	return random1 ^ (random2 << 31) ^ (random3 << 62);
}

end_point replication_app_client_base::get_read_address(read_semantic_t semantic, const partition_configuration& config)
{
    if (semantic == read_semantic_t::ReadLastUpdate)
        return config.primary;

    // readsnapshot or readoutdated, using random
    else
    {
        bool has_primary = false;
        int N = static_cast<int>(config.secondaries.size());
        if (config.primary != dsn::end_point::INVALID)
        {
            N++;
            has_primary = true;
        }

        if (0 == N) return config.primary;

        int r = random32(0, 1000) % N;
        if (has_primary && r == N - 1)
            return config.primary;
        else
            return config.secondaries[r];
    }
}

static ssize_t nasty_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 
{
	int rcount, ret; /* random bytes to write */

	/* 0 in -> 0 out, no strings attached  */
	if (count == 0) 
		return 0;

	/* end of story */
	if (*ppos >= FILE_MAX_SIZE)
		return -ENOSPC;

	/*  make sure that we write at least 1 character */
	rcount = 1 + random32() % MAX_CHUNK_SIZE; 
	
	/* ... and don't cross the borders */
	if (rcount > count)
		rcount = count;
	if (*ppos + rcount > FILE_MAX_SIZE)
		rcount = FILE_MAX_SIZE - *ppos;
	ret = copy_from_user(&content[*ppos], buf, rcount);
	if (ret != 0) {
		pr_warning("@write: copy to user failead\n");
		return -EFAULT;
	}	
	pr_debug("@write: requested %d, written %d, current pos %lld\n", 
			count, rcount, *ppos);
	*ppos += rcount;
	crt_size = max(crt_size, (int)*ppos);
	
	return rcount;
}

static ssize_t nasty_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 
{
	int rcount, ret; /* random bytes to read */

	/* end of file */
	if (*ppos >= crt_size)
		return 0;

	/*  make sure that we read at least 1 character */
	rcount = 1 + random32() % MAX_CHUNK_SIZE; 
	
	/* ... and don't cross the borders */
	if (rcount > count)
		rcount = count;
	if (*ppos + rcount > crt_size)
		rcount = crt_size - *ppos;
	ret = copy_to_user(buf, &content[*ppos], rcount);
	if (ret != 0) {
		pr_warning("@read: copy to user failed\n");
		return -EFAULT;
	}	
	pr_debug("@read: requested %d, received %d, current pos %lld\n", 
			count, rcount, *ppos);
	*ppos += rcount;

	return rcount;
}

static const HDNode *generateKeyHandle(const uint8_t app_id[], uint8_t key_handle[])
{
	uint8_t keybase[U2F_APPID_SIZE + KEY_PATH_LEN];

	// Derivation path is m/U2F'/r'/r'/r'/r'/r'/r'/r'/r'
	uint32_t key_path[KEY_PATH_ENTRIES];
	for (uint32_t i = 0; i < KEY_PATH_ENTRIES; i++) {
		// high bit for hardened keys
		key_path[i]= 0x80000000 | random32();
	}

	// First half of keyhandle is key_path
	memcpy(key_handle, key_path, KEY_PATH_LEN);

	// prepare keypair from /random data
	const HDNode *node = getDerivedNode(key_path, KEY_PATH_ENTRIES);
	if (!node)
		return NULL;

	// For second half of keyhandle
	// Signature of app_id and random data
	memcpy(&keybase[0], app_id, U2F_APPID_SIZE);
	memcpy(&keybase[U2F_APPID_SIZE], key_handle, KEY_PATH_LEN);
	hmac_sha256(node->private_key, sizeof(node->private_key),
					keybase, sizeof(keybase), &key_handle[KEY_PATH_LEN]);

	// Done!
	return node;
}

static void yam_arbitrate(struct net_device *dev)
{
	struct yam_port *yp = netdev_priv(dev);

	if (yp->magic != YAM_MAGIC || yp->tx_state != TX_OFF ||
	    skb_queue_empty(&yp->send_queue))
		return;
	/* tx_state is TX_OFF and there is data to send */

	if (yp->dupmode) {
		/* Full duplex mode, don't wait */
		yam_start_tx(dev, yp);
		return;
	}
	if (yp->dcd) {
		/* DCD on, wait slotime ... */
		yp->slotcnt = yp->slot / 10;
		return;
	}
	/* Is slottime passed ? */
	if ((--yp->slotcnt) > 0)
		return;

	yp->slotcnt = yp->slot / 10;

	/* is random > persist ? */
	if ((random32() % 256) > yp->pers)
		return;

	yam_start_tx(dev, yp);
}

void IChatHandler::_sCmd_Coin(IWorldPlayer *_player, const char *_message)
{
	FDASSERT(_player);
	FDASSERT(_message);

	_player->greenText((random32() & 1) ? "heads" : "tails");
}

/*search in cache*/
dsn::rpc_address replication_app_client_base::get_address(bool is_write, read_semantic_t semantic, const partition_configuration& config)
{
    if (is_write || semantic == read_semantic_t::ReadLastUpdate)
        return config.primary;

    // readsnapshot or readoutdated, using random
    else
    {
        bool has_primary = false;
        int N = static_cast<int>(config.secondaries.size());
        if (!config.primary.is_invalid())
        {
            N++;
            has_primary = true;
        }

        if (0 == N) return config.primary;

        int r = random32(0, 1000) % N;
        if (has_primary && r == N - 1)
            return config.primary;
        else
            return config.secondaries[r];
    }
}

static int do_operation(void)
{
	if (random32() & 1)
		return do_read();
	else
		return do_write();
}

void gravManager::addTestObject()
{
    lockSources();

    RectangleBase* obj = new RectangleBase( 0.0f, 0.0f );
    drawnObjects->push_back( obj );
    bool useRandName = false;
    if ( useRandName )
    {
        int nameLength = 10;
        std::string randName;
        for( int i = 0; i < nameLength; i++ )
        {
            int rand = ((float)random32() / (float)random32_max() * 95) + 32;
            randName += (char)rand;
        }
        obj->setName( randName );
    }
    else if ( drawnObjects->size() % 2 == 0 )
    {
        obj->setName( " " );
    }
    else
    {
        obj->setName( "TEST" );
    }
    Texture t = GLUtil::getInstance()->getTexture( "border" );
    obj->setTexture( t.ID, t.width, t.height );
    obj->setUserDeletable( true );

    unlockSources();
}

int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num,
			u32 reserved, u32 flags)
{
	int i;

	alloc->start = start;
	alloc->flags = flags;
	if (flags & C4IW_ID_TABLE_F_RANDOM)
		alloc->last = random32() % RANDOM_SKIP;
	else
		alloc->last = 0;
	alloc->max  = num;
	spin_lock_init(&alloc->lock);
	alloc->table = kmalloc(BITS_TO_LONGS(num) * sizeof(long),
				GFP_KERNEL);
	if (!alloc->table)
		return -ENOMEM;

	bitmap_zero(alloc->table, num);
	if (!(alloc->flags & C4IW_ID_TABLE_F_EMPTY))
		for (i = 0; i < reserved; ++i)
			set_bit(i, alloc->table);

	return 0;
}

DECLARE_TEST( ringbuffer, io )
{
	ringbuffer_t* buffer;
	char from[256];
	char to[256];
	unsigned int size, verify, loop, loops;
	unsigned int expected_size = 0;

	for( size = 0; size < 256; ++size )
		from[size] = (char)( random32() & 0xFF );
	
	buffer = ringbuffer_allocate( 512 );
	loops = 32;
	for( loop = 0; loop < loops; ++loop )
	{
		for( size = 0; size < 256; ++size )
		{
			ringbuffer_write( buffer, from, size );
			ringbuffer_read( buffer, to, size );

			for( verify = 0; verify < size; ++verify )
				EXPECT_EQ( to[verify], from[verify] );
		
			expected_size += size;
		}
	}
	EXPECT_EQ( ringbuffer_total_read( buffer ), expected_size );
	EXPECT_EQ( ringbuffer_total_written( buffer ), expected_size );

	ringbuffer_deallocate( buffer );
	
	return 0;
}

/**
 * Allocate a new binding. Try using the same port as on the IPv6 side.
 * If it's already in use, allocate one randomly. The binding is inserted into
 * the Binding Information Base (BIB).
 *
 * \param bkey	Initializer for the created binding.
 *
 * \return	A pointer to the created binding if successful, NULL otherwise.
 */
static struct nat64_binding *
nat64_binding_create(const struct nat64_binding *bkey)
{
	struct nat64_binding	*b;
	int			 min;
	int			 max;
	int			 first;

	b = malloc(sizeof(*b));
	if(!b) {
		if(printk_ratelimit())
			printk(KERN_DEBUG "nat64_binding_create: kmalloc failed");
		return NULL;
	}

	*b = *bkey;
	b->b_saddr4 = *(nat64_config_nat_addr());  
	b->b_sport4 = b->b_sport6;

	if (!nat64_bib_insert(b))
		return b;

	min = b->b_sport6 < 1024 ? 0 : 1024;
	max = b->b_sport6 < 1024 ? 1024 : 65536;

 	first = min + ((random32() % ((max - min) / 2) * 2) | (b->b_sport6 & 1));

	if (nat64_binding_alloc_port(b, first, max) ||
			nat64_binding_alloc_port(b, min, first))
		return b;

	kfree(b);
	return NULL;
}

/*
 * Trivial bitmap-based allocator. If the random flag is set, the
 * allocator is designed to:
 * - pseudo-randomize the id returned such that it is not trivially predictable.
 * - avoid reuse of recently used id (at the expense of predictability)
 */
u32 c4iw_id_alloc(struct c4iw_id_table *alloc)
{
	unsigned long flags;
	u32 obj;

	spin_lock_irqsave(&alloc->lock, flags);

	obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last);
	if (obj >= alloc->max)
		obj = find_first_zero_bit(alloc->table, alloc->max);

	if (obj < alloc->max) {
		if (alloc->flags & C4IW_ID_TABLE_F_RANDOM)
			alloc->last += random32() % RANDOM_SKIP;
		else
			alloc->last = obj + 1;
		if (alloc->last >= alloc->max)
			alloc->last = 0;
		set_bit(obj, alloc->table);
		obj += alloc->start;
	} else
		obj = -1;

	spin_unlock_irqrestore(&alloc->lock, flags);
	return obj;
}