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import binascii
from cffi import FFI
from ssdeep.__about__ import __version__
cdef = """
static const long FUZZY_FLAG_ELIMSEQ;
static const long FUZZY_FLAG_NOTRUNC;
static const long FUZZY_MAX_RESULT;
struct fuzzy_state;
struct fuzzy_state *fuzzy_new(void);
int fuzzy_update(
struct fuzzy_state *,
const unsigned char *,
size_t
);
int fuzzy_digest(
const struct fuzzy_state *,
char *,
unsigned int
);
void fuzzy_free(struct fuzzy_state *);
int fuzzy_hash_buf(
const unsigned char *,
uint32_t,
char *
);
int fuzzy_hash_file(
FILE *,
char *
);
int fuzzy_hash_stream(
FILE *,
char *
);
int fuzzy_hash_filename(
const char *,
char *
);
int fuzzy_compare(
const char *,
const char *
);
static const long ssdeep_HAS_STATEFUL_HASHING;
"""
source = """
#include "fuzzy.h"
#ifndef FUZZY_FLAG_ELIMSEQ
static const long ssdeep_HAS_STATEFUL_HASHING = 0;
struct fuzzy_state {};
const long FUZZY_FLAG_ELIMSEQ = 0;
const long FUZZY_FLAG_NOTRUNC = 0;
int (*fuzzy_digest)(
const struct fuzzy_state *,
char *,
unsigned int
) = NULL;
int (*fuzzy_free)(struct fuzzy_state *) = NULL;
int (*fuzzy_new)(void) = NULL;
int (*fuzzy_update)(
struct fuzzy_state *,
const unsigned char *,
size_t
) = NULL;
int (*fuzzy_hash_stream)(
FILE *,
char *
) = NULL;
#else
static const long ssdeep_HAS_STATEFUL_HASHING = 1;
#endif
"""
CONDITIONAL_NAMES = {
"ssdeep_HAS_STATEFUL_HASHING": (
"FUZZY_FLAG_ELIMSEQ",
"FUZZY_FLAG_NOTRUNC",
"fuzzy_digest",
"fuzzy_free",
"fuzzy_new",
"fuzzy_update",
"fuzzy_hash_stream"
)
}
class Binding(object):
def __init__(self, extra_objects=None, include_dirs=None, libraries=None):
self.ffi = FFI()
self.ffi.cdef(cdef)
self._lib = None
if extra_objects is None:
extra_objects = []
self._extra_objects = extra_objects
if include_dirs is None:
include_dirs = []
self._include_dirs = include_dirs
if libraries is None:
libraries = ["fuzzy"]
self._libraries = libraries
def verify(self):
self._lib = self.ffi.verify(
source,
ext_package="ssdeep",
extra_objects=self._extra_objects,
include_dirs=self._include_dirs,
modulename=_create_modulename(cdef, source, __version__),
libraries=self._libraries,
)
for condition, names in CONDITIONAL_NAMES.items():
if getattr(self._lib, condition):
continue
for name in names:
delattr(self._lib, name)
@property
def lib(self):
if self._lib is None:
self.verify()
return self._lib
def _create_modulename(cdef, source, sys_version):
key = "\x00".join([sys_version[:3], source, cdef])
key = key.encode("utf-8")
k1 = hex(binascii.crc32(key[0::2]) & 0xffffffff)
k1 = k1.lstrip("0x").rstrip("L")
k2 = hex(binascii.crc32(key[1::2]) & 0xffffffff)
k2 = k2.lstrip("0").rstrip("L")
return "_ssdeep_cffi_{0}{1}".format(k1, k2)
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