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from cpython cimport Py_INCREF, PyBytes_FromStringAndSize, PyBytes_AsString
from cpython.bytearray cimport PyByteArray_AsString
# Using python's versions of pure c memory management functions for
# proper memory statistics count.
from cpython.mem cimport PyMem_Malloc, PyMem_Realloc, PyMem_Free
from cpython.tuple cimport PyTuple_New, PyTuple_SET_ITEM
from libc.string cimport memcpy
cdef class BufferedReader(object):
cdef public unsigned long long position, current_buffer_size
cdef public bytearray buffer
def __init__(self, bufsize):
self.buffer = bytearray(bufsize)
self.position = 0
self.current_buffer_size = 0
super(BufferedReader, self).__init__()
def read_into_buffer(self):
raise NotImplementedError
def read(self, unsigned long long unread):
# When the buffer is large enough bytes read are almost
# always hit the buffer.
cdef unsigned long long next_position = unread + self.position
if next_position < self.current_buffer_size:
t = self.position
self.position = next_position
return bytes(self.buffer[t:self.position])
cdef char* buffer_ptr = PyByteArray_AsString(self.buffer)
cdef unsigned long long read_bytes
rv = bytes()
while unread > 0:
if self.position == self.current_buffer_size:
self.read_into_buffer()
buffer_ptr = PyByteArray_AsString(self.buffer)
self.position = 0
read_bytes = min(unread, self.current_buffer_size - self.position)
rv += PyBytes_FromStringAndSize(
&buffer_ptr[self.position], read_bytes
)
self.position += read_bytes
unread -= read_bytes
return rv
def read_one(self):
if self.position == self.current_buffer_size:
self.read_into_buffer()
self.position = 0
rv = self.buffer[self.position]
self.position += 1
return rv
def read_strings(self, unsigned long long n_items, encoding=None):
"""
Python has great overhead between function calls.
We inline strings reading logic here to avoid this overhead.
"""
items = PyTuple_New(n_items)
cdef unsigned long long i
# Buffer vars
cdef char* buffer_ptr = PyByteArray_AsString(self.buffer)
cdef unsigned long long right
# String length vars
cdef unsigned long long size, shift, bytes_read
cdef unsigned long long b
# String for decode vars.
cdef char *c_string = NULL
cdef unsigned long long c_string_size = 1024
cdef char *c_encoding = NULL
if encoding:
encoding = encoding.encode('utf-8')
c_encoding = encoding
cdef object rv = object()
# String for decode vars.
if c_encoding:
c_string = <char *> PyMem_Realloc(NULL, c_string_size)
for i in range(n_items):
shift = size = 0
# Read string size
while True:
if self.position == self.current_buffer_size:
self.read_into_buffer()
# `read_into_buffer` can override buffer
buffer_ptr = PyByteArray_AsString(self.buffer)
self.position = 0
b = buffer_ptr[self.position]
self.position += 1
size |= (b & 0x7f) << shift
if b < 0x80:
break
shift += 7
right = self.position + size
if c_encoding:
if size + 1 > c_string_size:
c_string_size = size + 1
c_string = <char *> PyMem_Realloc(c_string, c_string_size)
if c_string is NULL:
raise MemoryError()
c_string[size] = 0
bytes_read = 0
# Decoding pure c strings in Cython is faster than in pure Python.
# We need to copy it into buffer for adding null symbol at the end.
# In ClickHouse block there is no null
if right > self.current_buffer_size:
if c_encoding:
memcpy(&c_string[bytes_read], &buffer_ptr[self.position],
self.current_buffer_size - self.position)
else:
rv = PyBytes_FromStringAndSize(
&buffer_ptr[self.position],
self.current_buffer_size - self.position
)
bytes_read = self.current_buffer_size - self.position
# Read the rest of the string.
while bytes_read != size:
self.position = size - bytes_read
self.read_into_buffer()
# `read_into_buffer` can override buffer
buffer_ptr = PyByteArray_AsString(self.buffer)
# There can be not enough data in buffer.
self.position = min(
self.position, self.current_buffer_size
)
if c_encoding:
memcpy(
&c_string[bytes_read], buffer_ptr, self.position
)
else:
rv += PyBytes_FromStringAndSize(
buffer_ptr, self.position
)
bytes_read += self.position
else:
if c_encoding:
memcpy(c_string, &buffer_ptr[self.position], size)
else:
rv = PyBytes_FromStringAndSize(
&buffer_ptr[self.position], size
)
self.position = right
if c_encoding:
try:
rv = c_string[:size].decode(c_encoding)
except UnicodeDecodeError:
rv = PyBytes_FromStringAndSize(c_string, size)
Py_INCREF(rv)
PyTuple_SET_ITEM(items, i, rv)
if c_string:
PyMem_Free(c_string)
return items
def read_fixed_strings_as_bytes(self, Py_ssize_t n_items,
Py_ssize_t length):
cdef Py_ssize_t i
data = self.read(length * n_items)
cdef char* data_ptr = PyBytes_AsString(data)
items = PyTuple_New(n_items)
for i in range(n_items):
item = PyBytes_FromStringAndSize(&data_ptr[i * length], length)
Py_INCREF(item)
PyTuple_SET_ITEM(items, i, item)
return items
def read_fixed_strings(self, Py_ssize_t n_items, Py_ssize_t length,
encoding=None):
if encoding is None:
return self.read_fixed_strings_as_bytes(n_items, length)
cdef Py_ssize_t i, j
encoding = encoding.encode('utf-8')
cdef char* c_encoding = encoding
data = self.read(length * n_items)
cdef char* data_ptr = PyBytes_AsString(data)
cdef char* c_string = <char *>PyMem_Malloc(length + 1)
if not c_string:
raise MemoryError()
c_string[length] = 0
items = PyTuple_New(n_items)
for i in range(n_items):
memcpy(c_string, &data_ptr[i * length], length)
# Get last non zero byte of string from the end.
j = length - 1
while j >= 0 and not c_string[j]:
j -= 1
try:
item = c_string[:j + 1].decode(c_encoding)
except UnicodeDecodeError:
item = PyBytes_FromStringAndSize(c_string, length)
Py_INCREF(item)
PyTuple_SET_ITEM(items, i, item)
PyMem_Free(c_string)
return items
cdef class BufferedSocketReader(BufferedReader):
cdef object sock
def __init__(self, sock, bufsize):
self.sock = sock
super(BufferedSocketReader, self).__init__(bufsize)
def read_into_buffer(self):
self.current_buffer_size = self.sock.recv_into(self.buffer)
if self.current_buffer_size == 0:
raise EOFError('Unexpected EOF while reading bytes')
cdef class CompressedBufferedReader(BufferedReader):
cdef object read_block
def __init__(self, read_block, bufsize):
self.read_block = read_block
super(CompressedBufferedReader, self).__init__(bufsize)
def read_into_buffer(self):
self.buffer = bytearray(self.read_block())
self.current_buffer_size = len(self.buffer)
if self.current_buffer_size == 0:
raise EOFError('Unexpected EOF while reading bytes')
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