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cimport posix.fcntl
cimport posix.unistd
from posix.unistd cimport off_t
cdef extern from "sys/mman.h":
void *mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
int munmap(void *addr, size_t len)
enum:
PROT_READ
enum:
MAP_FILE
MAP_SHARED
cdef extern from "sys/stat.h":
cdef struct stat:
off_t st_size
int fstat(int fildes, stat *buf)
cdef class MemoryMap:
def __init__(self, filename):
self.fd = posix.fcntl.open(filename, posix.fcntl.O_RDONLY)
assert self.fd >= 0
# Get file size
cdef stat statbuf
fstat(self.fd, &statbuf)
self.fs = statbuf.st_size
# Memory map file
self.map_start = mmap(NULL, self.fs, PROT_READ, MAP_FILE|MAP_SHARED, self.fd, 0)
self.map_ptr = self.map_start
def __dealloc__(self):
posix.unistd.close(self.fd)
munmap(self.map_start, self.fs)
cdef int read_int(self):
cdef int v = (<int*> self.map_ptr)[0]
self.map_ptr = &(<int*> self.map_ptr)[1]
return v
cdef int* read_int_array(self, int size):
cdef int* v = <int*> self.map_ptr
self.map_ptr = &(<int*> self.map_ptr)[size]
return v
cdef char* read_char_array(self, int size):
cdef char* v = <char*> self.map_ptr
self.map_ptr = &(<char*> self.map_ptr)[size]
return v
cdef float* read_float_array(self, int size):
cdef float* v = <float*> self.map_ptr
self.map_ptr = &(<float*> self.map_ptr)[size]
return v
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