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Kaydet (Commit) 2f6621cc authored tarafından Raymond Hettinger's avatar Raymond Hettinger
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Finish-up the struct module optimizations started at the Iceland NFS sprint.

üst 076d9eef
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Lib/struct.py
Dosyayı görüntüle @ 2f6621cc
"""
Functions to convert between Python values and C structs.
Python strings are used to hold the data representing the C struct
and also as format strings to describe the layout of data in the C struct.
The optional first format char indicates byte order, size and alignment:
@: native order, size & alignment (default)
=: native order, std. size & alignment
<: little-endian, std. size & alignment
>: big-endian, std. size & alignment
!: same as >
The remaining chars indicate types of args and must match exactly;
these can be preceded by a decimal repeat count:
x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;
h:short; H:unsigned short; i:int; I:unsigned int;
l:long; L:unsigned long; f:float; d:double.
Special cases (preceding decimal count indicates length):
s:string (array of char); p: pascal string (with count byte).
Special case (only available in native format):
P:an integer type that is wide enough to hold a pointer.
Special case (not in native mode unless 'long long' in platform C):
q:long long; Q:unsigned long long
Whitespace between formats is ignored.
The variable struct.error is an exception raised on errors.
"""
__version__ = '0.1'
from _struct import Struct, error
_MAXCACHE = 100
_cache = {}
def _compile(fmt):
# Internal: compile struct pattern
if len(_cache) >= _MAXCACHE:
_cache.clear()
s = Struct(fmt)
_cache[fmt] = s
return s
def calcsize(fmt):
"""
Return size of C struct described by format string fmt.
See struct.__doc__ for more on format strings.
"""
try:
o = _cache[fmt]
except KeyError:
o = _compile(fmt)
return o.size
def pack(fmt, *args):
"""
Return string containing values v1, v2, ... packed according to fmt.
See struct.__doc__ for more on format strings.
"""
try:
o = _cache[fmt]
except KeyError:
o = _compile(fmt)
return o.pack(*args)
def pack_into(fmt, buf, offset, *args):
"""
Pack the values v1, v2, ... according to fmt, write
the packed bytes into the writable buffer buf starting at offset.
See struct.__doc__ for more on format strings.
"""
try:
o = _cache[fmt]
except KeyError:
o = _compile(fmt)
return o.pack_into(buf, offset, *args)
def unpack(fmt, s):
"""
Unpack the string, containing packed C structure data, according
to fmt. Requires len(string)==calcsize(fmt).
See struct.__doc__ for more on format strings.
"""
try:
o = _cache[fmt]
except KeyError:
o = _compile(fmt)
return o.unpack(s)
def unpack_from(fmt, buf, offset=0):
"""
Unpack the buffer, containing packed C structure data, according to
fmt starting at offset. Requires len(buffer[offset:]) >= calcsize(fmt).
See struct.__doc__ for more on format strings.
"""
try:
o = _cache[fmt]
except KeyError:
o = _compile(fmt)
return o.unpack_from(buf, offset)
from _struct import *
Modules/_struct.c
Dosyayı görüntüle @ 2f6621cc
......@@ -1847,12 +1847,214 @@ PyTypeObject PyStructType = {
PyObject_Del, /* tp_free */
};
/* ---- Standalone functions ---- */
#define MAXCACHE 100
static PyObject *
cache_struct(PyObject *fmt)
{
static PyObject *cache = NULL;
PyObject * s_object;
if (cache == NULL) {
cache = PyDict_New();
if (cache == NULL)
return NULL;
}
s_object = PyDict_GetItem(cache, fmt);
if (s_object != NULL) {
Py_INCREF(s_object);
return s_object;
}
s_object = PyObject_CallFunctionObjArgs((PyObject *)(&PyStructType), fmt, NULL);
if (s_object != NULL) {
if (PyDict_Size(cache) >= MAXCACHE)
PyDict_Clear(cache);
/* Attempt to cache the result */
if (PyDict_SetItem(cache, fmt, s_object) == -1)
PyErr_Clear();
}
return s_object;
}
PyDoc_STRVAR(calcsize_doc,
"Return size of C struct described by format string fmt.");
static PyObject *
calcsize(PyObject *self, PyObject *fmt)
{
Py_ssize_t n;
PyObject *s_object = cache_struct(fmt);
if (s_object == NULL)
return NULL;
n = ((PyStructObject *)s_object)->s_size;
Py_DECREF(s_object);
return PyInt_FromSsize_t(n);
}
PyDoc_STRVAR(pack_doc,
"Return string containing values v1, v2, ... packed according to fmt.");
static PyObject *
pack(PyObject *self, PyObject *args)
{
PyObject *s_object, *fmt, *newargs, *result;
Py_ssize_t n = PyTuple_GET_SIZE(args);
if (n == 0) {
PyErr_SetString(PyExc_TypeError, "missing format argument");
return NULL;
}
fmt = PyTuple_GET_ITEM(args, 0);
newargs = PyTuple_GetSlice(args, 1, n);
if (newargs == NULL)
return NULL;
s_object = cache_struct(fmt);
if (s_object == NULL) {
Py_DECREF(newargs);
return NULL;
}
result = s_pack(s_object, newargs);
Py_DECREF(newargs);
Py_DECREF(s_object);
return result;
}
PyDoc_STRVAR(pack_into_doc,
"Pack the values v1, v2, ... according to fmt.\n\
Write the packed bytes into the writable buffer buf starting at offset.");
static PyObject *
pack_into(PyObject *self, PyObject *args)
{
PyObject *s_object, *fmt, *newargs, *result;
Py_ssize_t n = PyTuple_GET_SIZE(args);
if (n == 0) {
PyErr_SetString(PyExc_TypeError, "missing format argument");
return NULL;
}
fmt = PyTuple_GET_ITEM(args, 0);
newargs = PyTuple_GetSlice(args, 1, n);
if (newargs == NULL)
return NULL;
s_object = cache_struct(fmt);
if (s_object == NULL) {
Py_DECREF(newargs);
return NULL;
}
result = s_pack_into(s_object, newargs);
Py_DECREF(newargs);
Py_DECREF(s_object);
return result;
}
PyDoc_STRVAR(unpack_doc,
"Unpack the string containing packed C structure data, according to fmt.\n\
Requires len(string) == calcsize(fmt).");
static PyObject *
unpack(PyObject *self, PyObject *args)
{
PyObject *s_object, *fmt, *inputstr, *result;
if (!PyArg_UnpackTuple(args, "unpack", 2, 2, &fmt, &inputstr))
return NULL;
s_object = cache_struct(fmt);
if (s_object == NULL)
return NULL;
result = s_unpack(s_object, inputstr);
Py_DECREF(s_object);
return result;
}
PyDoc_STRVAR(unpack_from_doc,
"Unpack the buffer, containing packed C structure data, according to\n\
fmt, starting at offset. Requires len(buffer[offset:]) >= calcsize(fmt).");
static PyObject *
unpack_from(PyObject *self, PyObject *args, PyObject *kwds)
{
PyObject *s_object, *fmt, *newargs, *result;
Py_ssize_t n = PyTuple_GET_SIZE(args);
if (n == 0) {
PyErr_SetString(PyExc_TypeError, "missing format argument");
return NULL;
}
fmt = PyTuple_GET_ITEM(args, 0);
newargs = PyTuple_GetSlice(args, 1, n);
if (newargs == NULL)
return NULL;
s_object = cache_struct(fmt);
if (s_object == NULL) {
Py_DECREF(newargs);
return NULL;
}
result = s_unpack_from(s_object, newargs, kwds);
Py_DECREF(newargs);
Py_DECREF(s_object);
return result;
}
static struct PyMethodDef module_functions[] = {
{"calcsize", calcsize, METH_O, calcsize_doc},
{"pack", pack, METH_VARARGS, pack_doc},
{"pack_into", pack_into, METH_VARARGS, pack_into_doc},
{"unpack", unpack, METH_VARARGS, unpack_doc},
{"unpack_from", (PyCFunction)unpack_from,
METH_VARARGS|METH_KEYWORDS, unpack_from_doc},
{NULL, NULL} /* sentinel */
};
/* Module initialization */
PyDoc_STRVAR(module_doc,
"Functions to convert between Python values and C structs.\n\
Python strings are used to hold the data representing the C struct\n\
and also as format strings to describe the layout of data in the C struct.\n\
\n\
The optional first format char indicates byte order, size and alignment:\n\
@: native order, size & alignment (default)\n\
=: native order, std. size & alignment\n\
<: little-endian, std. size & alignment\n\
>: big-endian, std. size & alignment\n\
!: same as >\n\
\n\
The remaining chars indicate types of args and must match exactly;\n\
these can be preceded by a decimal repeat count:\n\
x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;\n\
h:short; H:unsigned short; i:int; I:unsigned int;\n\
l:long; L:unsigned long; f:float; d:double.\n\
Special cases (preceding decimal count indicates length):\n\
s:string (array of char); p: pascal string (with count byte).\n\
Special case (only available in native format):\n\
P:an integer type that is wide enough to hold a pointer.\n\
Special case (not in native mode unless 'long long' in platform C):\n\
q:long long; Q:unsigned long long\n\
Whitespace between formats is ignored.\n\
\n\
The variable struct.error is an exception raised on errors.\n");
PyMODINIT_FUNC
init_struct(void)
{
PyObject *m = Py_InitModule("_struct", NULL);
PyObject *ver, *m;
ver = PyString_FromString("0.2");
if (ver == NULL)
return;
m = Py_InitModule3("_struct", module_functions, module_doc);
if (m == NULL)
return;
......@@ -1933,6 +2135,8 @@ init_struct(void)
Py_INCREF((PyObject*)&PyStructType);
PyModule_AddObject(m, "Struct", (PyObject*)&PyStructType);
PyModule_AddObject(m, "__version__", ver);
PyModule_AddIntConstant(m, "_PY_STRUCT_RANGE_CHECKING", 1);
#ifdef PY_STRUCT_OVERFLOW_MASKING
PyModule_AddIntConstant(m, "_PY_STRUCT_OVERFLOW_MASKING", 1);
......
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