def load_buffer(handle, size):
if find_library('c') is None:
if platform.system() == "Windows":
assert "IPC uses POSIX shared memory, which is not supported \
on Windows"
else:
# libc should be available by default on linux/darwin systems
assert "ctypes.find_library('c') did not find libc, which is \
required for IPC"
# OmniSci passes struct as bytes, convert to int
shmkey = struct.unpack('<L', handle)[0]
# Take key from OmniSci, get identifier of shared memory segment
# If shmid is -1, an error has occured
shmid = shmget(shmkey, size, 0)
if shmid == -1:
raise ValueError("Invalid shared memory key {}".format(shmkey))
# With id of shared memory segment, attach to Python process
# None lets system choose suitable unused address
ptr = shmat(shmid, None, 0)
# With ptr as shared memory segment's start address, make arrow buffer
pabuff = pa.foreign_buffer(ptr, size, None)
# Return the ptr value as well as the buffer, as its too early here
# to release shared memory from Python
return (pabuff, ptr)
def to_pandas(self, schema_only=False):
if schema_only:
return pd.Series([], dtype=pd.StringDtype())
# Recover a contiguous bitmask
new_self = self.repartition(1).as_string_column()
rect = new_self.offsets.ispace.get_bounds()
num_elements = rect.hi[0] - rect.lo[0]
if num_elements <= 0:
return pd.Series([], dtype=pd.StringDtype())
# Convert ranges back to offsets
# XXX: We should keep this reference to the result of export_offsets
# to avoid it being collected
offsets = new_self.offsets.data.to_raw_address()
offsets_size = new_self.offsets.dtype.itemsize * (num_elements + 1)
chars = new_self.chars.data.to_raw_address()
char_rect = new_self.chars.ispace.get_bounds()
char_size = char_rect.hi[0] - char_rect.lo[0] + 1
bitmask_buf = None
null_count = 0
if new_self.nullable:
null_count = new_self.bitmask.count_nulls()
if null_count > 0:
bitmask = new_self.bitmask.compact_bitmask.to_raw_address()
bitmask_size = (num_elements + 7) // 8
bitmask_buf = pa.foreign_buffer(bitmask, bitmask_size)
offsets_buf = pa.foreign_buffer(offsets, offsets_size)
chars_buf = pa.foreign_buffer(chars, char_size)
array = pa.StringArray.from_buffers(
num_elements,
offsets_buf,
chars_buf,
bitmask_buf,
null_count,
)
return array.to_pandas().astype(pd.StringDtype())
def xnd_xnd_cuda(cbuf):
"""Return xnd.xnd view of a pyarrow.cuda.CudaBuffer [EXPERIMENTAL].
"""
import xnd
import pyarrow as pa
#addr = cbuf.context.get_device_address(cbuf.address) # requires arrow>=0.12.1
addr = cbuf.address
# device = cbuf.context.device_number
buf = pa.foreign_buffer(addr, cbuf.size, cbuf)
return xnd.xnd.from_buffer(buf)
def test_foreign_buffer():
obj = np.array([1, 2], dtype=np.int32)
addr = obj.__array_interface__["data"][0]
size = obj.nbytes
buf = pa.foreign_buffer(addr, size, obj)
wr = weakref.ref(obj)
del obj
assert np.frombuffer(buf, dtype=np.int32).tolist() == [1, 2]
assert wr() is not None
del buf
assert wr() is None
def test_foreign_buffer():
obj = np.array([1, 2], dtype=np.int32)
addr = obj.__array_interface__["data"][0]
size = obj.nbytes
buf = pa.foreign_buffer(addr, size, obj)
wr = weakref.ref(obj)
del obj
assert np.frombuffer(buf, dtype=np.int32).tolist() == [1, 2]
assert wr() is not None
del buf
assert wr() is None
def jvm_buffer(arrowbuf):
"""
Construct an Arrow buffer from io.netty.buffer.ArrowBuf
Parameters
----------
arrowbuf: io.netty.buffer.ArrowBuf
Arrow Buffer representation on the JVM
Returns
-------
pyarrow.Buffer
Python Buffer that references the JVM memory
"""
address = arrowbuf.memoryAddress()
size = arrowbuf.capacity()
return pa.foreign_buffer(address, size, arrowbuf.asNettyBuffer())
def jvm_buffer(arrowbuf):
"""
Construct an Arrow buffer from io.netty.buffer.ArrowBuf
Parameters
----------
arrowbuf: io.netty.buffer.ArrowBuf
Arrow Buffer representation on the JVM
Returns
-------
pyarrow.Buffer
Python Buffer that references the JVM memory
"""
address = arrowbuf.memoryAddress()
size = arrowbuf.capacity()
return pa.foreign_buffer(address, size, arrowbuf.asNettyBuffer())
def jvm_buffer(jvm_buf):
"""
Construct an Arrow buffer from org.apache.arrow.memory.ArrowBuf
Parameters
----------
jvm_buf: org.apache.arrow.memory.ArrowBuf
Arrow Buffer representation on the JVM.
Returns
-------
pyarrow.Buffer
Python Buffer that references the JVM memory.
"""
nanny = _JvmBufferNanny(jvm_buf)
address = jvm_buf.memoryAddress()
size = jvm_buf.capacity()
return pa.foreign_buffer(address, size, base=nanny)
