def getCircHeaderSize():
align = getAlign()
return (
(8 + 4 + 4 + 4 + 2 + 1 + 1 + 4 + 2 * 4 + 4 + 8 + 4 + 4 + 4 + 4 + 4 +
utils.pthread_sizeof_mutexcond()[0] +
utils.pthread_sizeof_mutexcond()[1] + align - 1) / align
) * align #header contains buffer size (int64), last written to (int32), freq (int32), nstore (int32), forcewriteall(int8),ndim (int8), dtype (int8), forcewrite (int8), shape (6*int32) pid (int32), circhdrsize (int32) circsignal (int8), 3 spare (int24), mutex size(int32), cond size(int32), mutex, cond
def __init__(self,
shmname,
owner=0,
dims=None,
dtype=None,
nstore=None,
raw=0,
dirname="/dev/shm"):
self.align = getAlign()
self.shmname = shmname
self.dirname = dirname
self.owner = owner
self.freqcnt = 0
self.framecnt = 0
self.dtypeSave = None
self.ndimSave = None
self.shapeArrSave = None
self.nstoreSave = None
self.raw = raw
self.lastReceived = -1 #last frame received...
self.lastReceivedFrame = -1
if owner == 1:
self.hdrsize = getCircHeaderSize()
if dims == None or dtype == None or nstore == None:
raise Exception(
"Owner of circular buffer must specify dims, dtype and nstore"
)
#self.timesize=((8*nstore+self.align-1)/self.align)*self.align#size of the timestamp (float 64 for each entry)
#self.frameNoSize=((4*nstore+self.align-1)/self.align)*self.align#size of the frameno (int32 for each entry)
#self.dtype=dtype
#self.dims=dims
self.datasize = reduce(lambda x, y: x * y, dims)
self.frameSize = ((self.datasize * numpy.zeros(
(1, ), dtype).itemsize + 32 + self.align - 1) /
self.align) * self.align
self.size = self.hdrsize + self.frameSize * nstore #self.frameNoSize+self.timesize+nstore*self.datasize*numpy.zeros((1,),dtype).itemsize
mode = "w+"
else:
#first open the header to see what size it is, then open the full array.
#buf=utils.open((self.hdrsize,),"b",shmname,owner)
mode = "r+"
self.size = os.stat(self.dirname + shmname).st_size
if self.size == 0:
time.sleep(0.1)
self.size = os.stat(self.dirname + shmname).st_size
if self.size == 0:
raise Exception("Zero size array %s" % shmname)
#utils.unmap(buf)
#self.buffer=utils.open((self.size,),"b",shmname,owner)
self.buffer = numpy.memmap(self.dirname + shmname,
"b",
mode,
shape=(self.size, ))
#now get the hdrsize
self.circsignal = self.buffer[56:57]
if owner:
self.buffer[:] = 0
self.buffer[60:68].view(
numpy.int32)[:] = utils.pthread_sizeof_mutexcond()
self.buffer[52:56].view(numpy.int32)[0] = self.hdrsize
self.buffer[48:52].view(numpy.int32)[0] = os.getpid()
else:
#if not the owner, wait until the buffer has been initialised properly... one of the last things to be done is that the writer will set ndim...
i = 0
while i < 1000 and int(self.buffer[21:22]) == 0:
i += 1
time.sleep(0.001)
if i == 1000:
print "ERROR - buffer ndim not initialised - buffer %s, ndim=%d" % (
shmname, int(self.buffer[21:22]))
raise Exception(
"ERROR - buffer ndim not initialised - buffer %s, ndim=%d"
% (shmname, int(self.buffer[21:22])))
self.hdrsize = int(self.buffer[52:56].view(numpy.int32)[0])
msize = int(self.buffer[60:64].view(numpy.int32)[0])
self.futex = self.buffer[64:64 + msize]
self.ownerPid = self.buffer[48:52].view(numpy.int32)
#self.semid=utils.newsemid("/dev/shm"+shmname,98,1,1,owner)
#get the header arrays
self.bufsize = self.buffer[0:8].view(numpy.int64)
self.lastWritten = self.buffer[8:12].view("i")
self.freq = self.buffer[12:16].view("i")
self.nstore = self.buffer[16:20].view("i")
self.forcewriteall = self.buffer[20:21]
self.ndim = self.buffer[21:22] #.view("h")
self.dtype = self.buffer[22:23].view("c")
self.forcewrite = self.buffer[23:24]
self.shapeArr = self.buffer[24:48].view("i")
if owner:
self.bufsize[0] = self.size #this should never change now...
self.lastWritten[0] = -1
self.freq[0] = 0
self.nstore[0] = nstore
self.ndim[0] = len(dims)
self.dtype[0] = dtype
self.forcewrite[0] = 0
self.circsignal[0] = 0
self.shapeArr[:] = -1
self.shapeArr[:self.ndim[0]] = dims
utils.darc_futex_init(self.futex)
#utils.initSemaphore(self.semid,0,1)#initialise so that something can block on it waiting for a zero.
else:
#If is possible that the array isn't initialised yet - which might manifest itself with ndim==0. So wait to see if this is the case.
n = 0
while self.ndim[0] == 0 and n < 100:
n += 1
time.sleep(0.01)
self.makeDataArrays()
def __init__(self, shmname, create=0, size=64 * 1024 * 1024, nhdr=128):
self.shmname = shmname
self.unlinkOnDel = 0
self.create = 0
#self.nhdr=nhdr
if shmname != None:
mode = "w+"
if create:
if os.path.exists("/dev/shm" + shmname):
create = 0
else:
#create the shm and initialise it.
self.arr = numpy.memmap("/dev/shm" + shmname,
"c",
mode,
shape=(size, ))
self.arr.view("b")[:] = 0
#write the hdrsize, number of entries etc.
self.arr[4:8].view(numpy.int32)[0] = nhdr
msize, csize = utils.pthread_sizeof_mutexcond()
self.arr[12:16].view(numpy.int32)[0] = msize
self.arr[16:20].view(numpy.int32)[0] = csize
utils.pthread_cond_init(
self.arr[20 + msize:20 + msize + csize], 1)
utils.pthread_mutex_init(self.arr[20:20 + msize], 1)
hdrsize = 4 + 4 + 4 + 4 + 4 + msize + csize
#make it nicely aligned.
hdrsize += (16 - (
(self.arr.__array_interface__["data"][0] + hdrsize)
& 0xf)) % 16
self.arr[:4].view(numpy.int32)[0] = hdrsize
if create == 0: #get the buffer size...
mode = "r+"
size = os.stat("/dev/shm" + shmname).st_size #[stat.ST_SIZE]
print "Opening buffer of size %d bytes" % size
self.arr = numpy.memmap("/dev/shm" + shmname,
"c",
mode,
shape=(size, ))
#buffer has a info header with hdrsize(4),nhdr(4),flags(4),mutexsize(4),condsize(4),mutex(N),cond(N)
hdrsize = int(self.arr[:4].view(numpy.int32)[0])
while hdrsize == 0:
print "Waiting to get hdrsize of parambuf"
hdrsize = int(self.arr[:4].view(numpy.int32)[0])
time.sleep(0.1)
#pointer to the main part of the array.
print "Got buffer header size of %d" % hdrsize
self.buffer = self.arr[hdrsize:]
#get the number of entries.
self.nhdr = self.arr[4:8].view(numpy.int32)
while self.nhdr[0] == 0:
print "Waiting to get number of header entries..."
#self.nhdr[0]=int(self.arr[4:8].view(numpy.int32)[0])
time.sleep(0.1)
print "Got max number of entries (nhdr) %d" % self.nhdr[0]
msize = int(self.arr[12:16].view(numpy.int32)[0])
self.flags = self.arr[8:12].view(numpy.int32)
csize = int(self.arr[16:20].view(numpy.int32)[0])
while msize == 0 or csize == 0:
msize = int(self.arr[12:16].view(numpy.int32)[0])
csize = int(self.arr[16:20].view(numpy.int32)[0])
print "Waiting to get mutex/cond size"
time.sleep(0.1)
#get the memory occupied by the condition variable and mutex.
self.condmutex = self.arr[20:20 + msize]
self.cond = self.arr[20 + msize:20 + msize + csize]
#self.semid=utils.newsemid("/dev/shm"+shmname,98,1,1,owner)
else:
hdrsize = 20
self.arr = numpy.zeros((max(size, hdrsize), ), "c")
self.arr[:4].view(numpy.int32)[0] = hdrsize
self.arr[4:8].view(numpy.int32)[0] = nhdr
self.nhdr = self.arr[4:8].view(numpy.int32)
self.flags = self.arr[8:12].view(numpy.int32)
self.buffer = self.arr[hdrsize:]
self.condmutex = None
self.cond = None
self.arrhdrsize = self.arr[:4].view(numpy.int32)
self.bufferSize = size
self.align = 64 #align data to this byte boundaries...
self.hdrsize = 57 #the size of an individual entry in the header. See setNhdr() for why...
self.setNhdr(self.nhdr[0])
self.tmpname = numpy.zeros((16, ), "c")
self.create = create