mirror of
https://github.com/python/cpython.git
synced 2025-10-31 13:41:24 +00:00
Finish-up the struct module optimizations started at the Iceland NFS sprint.
This commit is contained in:
Raymond Hettinger
parent
076d9eef7b
commit
2f6621cce7
2 changed files with 206 additions and 100 deletions
100
Lib/struct.py
100
Lib/struct.py
|
|
@ -1,99 +1 @@
|
|||
"""
|
||||
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 *
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue