character strings, and unsigned numbers */
#include "Python.h"
+#include "structseq.h"
+#include "structmember.h"
#include <ctype.h>
-PyDoc_STRVAR(struct__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.");
+
+/* compatibility macros */
+#if (PY_VERSION_HEX < 0x02050000)
+typedef int Py_ssize_t;
+#endif
+
+
+
+/* The translation function for each format character is table driven */
+
+typedef struct _formatdef {
+ char format;
+ int size;
+ int alignment;
+ PyObject* (*unpack)(const char *,
+ const struct _formatdef *);
+ int (*pack)(char *, PyObject *,
+ const struct _formatdef *);
+} formatdef;
+
+typedef struct _formatcode {
+ const struct _formatdef *fmtdef;
+ int offset;
+ int repeat;
+} formatcode;
+
+/* Struct object interface */
+
+typedef struct {
+ PyObject_HEAD
+ int s_size;
+ int s_len;
+ formatcode *s_codes;
+ PyObject *s_format;
+ PyObject *weakreflist; /* List of weak references */
+} PyStructObject;
+
+PyAPI_DATA(PyTypeObject) PyStruct_Type;
+
+#define PyStruct_Check(op) PyObject_TypeCheck(op, &PyStruct_Type)
+#define PyStruct_CheckExact(op) ((op)->ob_type == &PyStruct_Type)
/* Exception */
}
-/* The translation function for each format character is table driven */
-
-typedef struct _formatdef {
- char format;
- int size;
- int alignment;
- PyObject* (*unpack)(const char *,
- const struct _formatdef *);
- int (*pack)(char *, PyObject *,
- const struct _formatdef *);
-} formatdef;
-
/* A large number of small routines follow, with names of the form
[bln][up]_TYPE
/* calculate the size of a format string */
static int
-calcsize(const char *fmt, const formatdef *f)
+prepare_s(PyStructObject *self)
{
+ const formatdef *f;
const formatdef *e;
+ formatcode *codes;
+
const char *s;
+ const char *fmt;
char c;
- int size, num, itemsize, x;
+ int size, len, numcodes, num, itemsize, x;
+ fmt = PyString_AS_STRING(self->s_format);
+
+ f = whichtable((char **)&fmt);
+
s = fmt;
size = 0;
+ len = 0;
+ numcodes = 0;
while ((c = *s++) != '\0') {
if (isspace(Py_CHARMASK(c)))
continue;
e = getentry(c, f);
if (e == NULL)
return -1;
+
+ switch (c) {
+ case 's': /* fall through */
+ case 'p': len++; break;
+ case 'x': break;
+ default: len += num; break;
+ }
+ if (c != 'x') numcodes++;
+
itemsize = e->size;
size = align(size, c, e);
x = num * itemsize;
}
}
- return size;
-}
-
-
-PyDoc_STRVAR(calcsize__doc__,
-"calcsize(fmt) -> int\n\
-Return size of C struct described by format string fmt.\n\
-See struct.__doc__ for more on format strings.");
-
-static PyObject *
-struct_calcsize(PyObject *self, PyObject *args)
-{
- char *fmt;
- const formatdef *f;
- int size;
-
- if (!PyArg_ParseTuple(args, "s:calcsize", &fmt))
- return NULL;
- f = whichtable(&fmt);
- size = calcsize(fmt, f);
- if (size < 0)
- return NULL;
- return PyInt_FromLong((long)size);
-}
-
-
-PyDoc_STRVAR(pack__doc__,
-"pack(fmt, v1, v2, ...) -> string\n\
-Return string containing values v1, v2, ... packed according to fmt.\n\
-See struct.__doc__ for more on format strings.");
-
-static PyObject *
-struct_pack(PyObject *self, PyObject *args)
-{
- const formatdef *f, *e;
- PyObject *format, *result, *v;
- char *fmt;
- int size, num;
- Py_ssize_t i, n;
- char *s, *res, *restart, *nres;
- char c;
-
- if (args == NULL || !PyTuple_Check(args) ||
- (n = PyTuple_Size(args)) < 1)
- {
- PyErr_SetString(PyExc_TypeError,
- "struct.pack requires at least one argument");
- return NULL;
+ self->s_size = size;
+ self->s_len = len;
+ codes = PyMem_MALLOC((numcodes + 1) * sizeof(formatcode));
+ if (codes == NULL) {
+ PyErr_NoMemory();
+ return -1;
}
- format = PyTuple_GetItem(args, 0);
- fmt = PyString_AsString(format);
- if (!fmt)
- return NULL;
- f = whichtable(&fmt);
- size = calcsize(fmt, f);
- if (size < 0)
- return NULL;
- result = PyString_FromStringAndSize((char *)NULL, size);
- if (result == NULL)
- return NULL;
-
+ self->s_codes = codes;
+
s = fmt;
- i = 1;
- res = restart = PyString_AsString(result);
-
+ size = 0;
while ((c = *s++) != '\0') {
if (isspace(Py_CHARMASK(c)))
continue;
if ('0' <= c && c <= '9') {
num = c - '0';
while ('0' <= (c = *s++) && c <= '9')
- num = num*10 + (c - '0');
+ num = num*10 + (c - '0');
if (c == '\0')
break;
}
num = 1;
e = getentry(c, f);
- if (e == NULL)
- goto fail;
- nres = restart + align((int)(res-restart), c, e);
- /* Fill padd bytes with zeros */
- while (res < nres)
- *res++ = '\0';
- if (num == 0 && c != 's')
- continue;
- do {
- if (c == 'x') {
- /* doesn't consume arguments */
- memset(res, '\0', num);
- res += num;
- break;
- }
- if (i >= n) {
- PyErr_SetString(StructError,
- "insufficient arguments to pack");
+
+ size = align(size, c, e);
+ if (c != 'x') {
+ codes->offset = size;
+ codes->repeat = num;
+ codes->fmtdef = e;
+ codes++;
+ }
+ size += num * e->size;
+ }
+ codes->fmtdef = NULL;
+ codes->offset = -1;
+ codes->repeat = -1;
+
+ return 0;
+}
+
+static PyObject *
+s_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+ PyObject *self;
+ static PyObject *not_yet_string;
+
+ assert(type != NULL && type->tp_alloc != NULL);
+
+ self = type->tp_alloc(type, 0);
+ if (self != NULL) {
+ PyStructObject *s = (PyStructObject*)self;
+ Py_INCREF(Py_None);
+ s->s_format = Py_None;
+ s->s_codes = NULL;
+ s->s_size = -1;
+ s->s_len = -1;
+ }
+ return self;
+}
+
+static int
+s_init(PyObject *self, PyObject *args, PyObject *kwds)
+{
+ PyStructObject *soself = (PyStructObject *)self;
+ PyObject *o_format = NULL;
+ int ret = 0;
+ static char *kwlist[] = {"format", 0};
+
+ assert(PyStruct_Check(self));
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwds, "S:Struct", kwlist,
+ &o_format))
+ return -1;
+
+ Py_INCREF(o_format);
+ Py_XDECREF(soself->s_format);
+ soself->s_format = o_format;
+
+ ret = prepare_s(soself);
+ return ret;
+}
+
+static void
+s_dealloc(PyStructObject *s)
+{
+ int sts = 0;
+ if (s->weakreflist != NULL)
+ PyObject_ClearWeakRefs((PyObject *)s);
+ if (s->s_codes != NULL) {
+ PyMem_FREE(s->s_codes);
+ }
+ Py_XDECREF(s->s_format);
+ s->ob_type->tp_free((PyObject *)s);
+}
+
+PyDoc_STRVAR(s_unpack__doc__,
+"unpack(str) -> (v1, v2, ...)\n\
+\n\
+Return tuple containing values unpacked according to this Struct's format.\n\
+Requires len(str) == self.size. See struct.__doc__ for more on format\n\
+strings.");
+
+static PyObject *
+s_unpack(PyObject *self, PyObject *inputstr)
+{
+ PyStructObject *soself;
+ PyObject *result;
+ char *restart;
+ formatcode *code;
+ Py_ssize_t i;
+
+ soself = (PyStructObject *)self;
+ assert(PyStruct_Check(self));
+ assert(soself->s_codes != NULL);
+ if (inputstr == NULL || !PyString_Check(inputstr) ||
+ PyString_GET_SIZE(inputstr) != soself->s_size) {
+ PyErr_Format(StructError,
+ "unpack requires a string argument of length %d", soself->s_size);
+ return NULL;
+ }
+ result = PyTuple_New(soself->s_len);
+ if (result == NULL)
+ return NULL;
+
+
+ restart = PyString_AS_STRING(inputstr);
+ i = 0;
+ for (code = soself->s_codes; code->fmtdef != NULL; code++) {
+ Py_ssize_t n;
+ PyObject *v;
+ const formatdef *e = code->fmtdef;
+ const char *res = restart + code->offset;
+ if (e->format == 's') {
+ v = PyString_FromStringAndSize(res, code->repeat);
+ if (v == NULL)
goto fail;
- }
- v = PyTuple_GetItem(args, i++);
+ PyTuple_SET_ITEM(result, i++, v);
+ } else if (e->format == 'p') {
+ n = *(unsigned char*)res;
+ if (n >= code->repeat)
+ n = code->repeat - 1;
+ v = PyString_FromStringAndSize(res + 1, n);
if (v == NULL)
goto fail;
- if (c == 's') {
- /* num is string size, not repeat count */
- Py_ssize_t n;
- if (!PyString_Check(v)) {
- PyErr_SetString(StructError,
- "argument for 's' must be a string");
- goto fail;
- }
- n = PyString_Size(v);
- if (n > num)
- n = num;
- if (n > 0)
- memcpy(res, PyString_AsString(v), n);
- if (n < num)
- memset(res+n, '\0', num-n);
- res += num;
- break;
- }
- else if (c == 'p') {
- /* num is string size + 1,
- to fit in the count byte */
- Py_ssize_t n;
- num--; /* now num is max string size */
- if (!PyString_Check(v)) {
- PyErr_SetString(StructError,
- "argument for 'p' must be a string");
- goto fail;
- }
- n = PyString_Size(v);
- if (n > num)
- n = num;
- if (n > 0)
- memcpy(res+1, PyString_AsString(v), n);
- if (n < num)
- /* no real need, just to be nice */
- memset(res+1+n, '\0', num-n);
- if (n > 255)
- n = 255;
- /* store the length byte */
- *res++ = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
- res += num;
- break;
- }
- else {
- if (e->pack(res, v, e) < 0)
+ PyTuple_SET_ITEM(result, i++, v);
+ } else {
+ for (n = 0; n < code->repeat; n++) {
+ v = e->unpack(res, e);
+ if (v == NULL)
goto fail;
+ PyTuple_SET_ITEM(result, i++, v);
res += e->size;
}
- } while (--num > 0);
- }
-
- if (i < n) {
- PyErr_SetString(StructError,
- "too many arguments for pack format");
- goto fail;
+ }
}
return result;
-
- fail:
+fail:
Py_DECREF(result);
return NULL;
-}
+};
-PyDoc_STRVAR(unpack__doc__,
-"unpack(fmt, string) -> (v1, v2, ...)\n\
-Unpack the string, containing packed C structure data, according\n\
-to fmt. Requires len(string)==calcsize(fmt).\n\
-See struct.__doc__ for more on format strings.");
+PyDoc_STRVAR(s_pack__doc__,
+"pack(v1, v2, ...) -> string\n\
+\n\
+Return a string containing values v1, v2, ... packed according to this\n\
+Struct's format. See struct.__doc__ for more on format strings.");
static PyObject *
-struct_unpack(PyObject *self, PyObject *args)
-{
- const formatdef *f, *e;
- char *str, *start, *fmt, *s;
- char c;
- int len, size, num;
- PyObject *res, *v;
-
- if (!PyArg_ParseTuple(args, "ss#:unpack", &fmt, &start, &len))
- return NULL;
- f = whichtable(&fmt);
- size = calcsize(fmt, f);
- if (size < 0)
- return NULL;
- if (size != len) {
- PyErr_SetString(StructError,
- "unpack str size does not match format");
+s_pack(PyObject *self, PyObject *args)
+{
+ PyStructObject *soself;
+ PyObject *result;
+ char *restart;
+ formatcode *code;
+ Py_ssize_t i;
+
+ soself = (PyStructObject *)self;
+ assert(PyStruct_Check(self));
+ assert(soself->s_codes != NULL);
+ if (args == NULL || !PyTuple_Check(args) ||
+ PyTuple_GET_SIZE(args) != soself->s_len)
+ {
+ PyErr_Format(StructError,
+ "pack requires exactly %d arguments", soself->s_len);
return NULL;
}
- res = PyList_New(0);
- if (res == NULL)
+
+ result = PyString_FromStringAndSize((char *)NULL, soself->s_size);
+ if (result == NULL)
return NULL;
- str = start;
- s = fmt;
- while ((c = *s++) != '\0') {
- if (isspace(Py_CHARMASK(c)))
- continue;
- if ('0' <= c && c <= '9') {
- num = c - '0';
- while ('0' <= (c = *s++) && c <= '9')
- num = num*10 + (c - '0');
- if (c == '\0')
- break;
- }
- else
- num = 1;
-
- e = getentry(c, f);
- if (e == NULL)
- goto fail;
- str = start + align((int)(str-start), c, e);
- if (num == 0 && c != 's')
- continue;
-
- do {
- if (c == 'x') {
- str += num;
- break;
- }
- if (c == 's') {
- /* num is string size, not repeat count */
- v = PyString_FromStringAndSize(str, num);
- if (v == NULL)
- goto fail;
- str += num;
- num = 0;
+
+ restart = PyString_AS_STRING(result);
+ memset(restart, '\0', soself->s_size);
+ i = 0;
+ for (code = soself->s_codes; code->fmtdef != NULL; code++) {
+ Py_ssize_t n;
+ PyObject *v;
+ const formatdef *e = code->fmtdef;
+ char *res = restart + code->offset;
+ if (e->format == 's') {
+ v = PyTuple_GET_ITEM(args, i++);
+ if (!PyString_Check(v)) {
+ PyErr_SetString(StructError,
+ "argument for 's' must be a string");
+ goto fail;
}
- else if (c == 'p') {
- /* num is string buffer size,
- not repeat count */
- int n = *(unsigned char*)str;
- /* first byte (unsigned) is string size */
- if (n >= num)
- n = num-1;
- v = PyString_FromStringAndSize(str+1, n);
- if (v == NULL)
- goto fail;
- str += num;
- num = 0;
+ n = PyString_GET_SIZE(v);
+ if (n > code->repeat)
+ n = code->repeat;
+ if (n > 0)
+ memcpy(res, PyString_AS_STRING(v), n);
+ } else if (e->format == 'p') {
+ v = PyTuple_GET_ITEM(args, i++);
+ if (!PyString_Check(v)) {
+ PyErr_SetString(StructError,
+ "argument for 'p' must be a string");
+ goto fail;
}
- else {
- v = e->unpack(str, e);
- if (v == NULL)
+ n = PyString_GET_SIZE(v);
+ if (n > (code->repeat - 1))
+ n = code->repeat - 1;
+ if (n > 0)
+ memcpy(res + 1, PyString_AS_STRING(v), n);
+ if (n > 255)
+ n = 255;
+ *res = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
+ } else {
+ for (n = 0; n < code->repeat; n++) {
+ v = PyTuple_GET_ITEM(args, i++);
+ if (e->pack(res, v, e) < 0)
goto fail;
- str += e->size;
+ res += e->size;
}
- if (v == NULL || PyList_Append(res, v) < 0)
- goto fail;
- Py_DECREF(v);
- } while (--num > 0);
+ }
}
+
+ return result;
- v = PyList_AsTuple(res);
- Py_DECREF(res);
- return v;
-
- fail:
- Py_DECREF(res);
+fail:
+ Py_DECREF(result);
return NULL;
+
}
/* List of functions */
-static PyMethodDef struct_methods[] = {
- {"calcsize", struct_calcsize, METH_VARARGS, calcsize__doc__},
- {"pack", struct_pack, METH_VARARGS, pack__doc__},
- {"unpack", struct_unpack, METH_VARARGS, unpack__doc__},
- {NULL, NULL} /* sentinel */
+static struct PyMethodDef s_methods[] = {
+ {"pack", s_pack, METH_VARARGS, s_pack__doc__},
+ {"unpack", s_unpack, METH_O, s_unpack__doc__},
+ {NULL, NULL} /* sentinel */
};
+PyDoc_STRVAR(s__doc__, "Compiled struct object");
+
+#define OFF(x) offsetof(PyStructObject, x)
+
+static PyMemberDef s_memberlist[] = {
+ {"format", T_OBJECT, OFF(s_format), RO,
+ "struct format string"},
+ {"size", T_INT, OFF(s_size), RO,
+ "struct size in bytes"},
+ {"_len", T_INT, OFF(s_len), RO,
+ "number of items expected in tuple"},
+ {NULL} /* Sentinel */
+};
+
+
+static
+PyTypeObject PyStructType = {
+ PyObject_HEAD_INIT(&PyType_Type)
+ 0,
+ "Struct",
+ sizeof(PyStructObject),
+ 0,
+ (destructor)s_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_compare */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ PyObject_GenericSetAttr, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_WEAKREFS, /* tp_flags */
+ s__doc__, /* tp_doc */
+ 0, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ offsetof(PyStructObject, weakreflist), /* tp_weaklistoffset */
+ 0, /* tp_iter */
+ 0, /* tp_iternext */
+ s_methods, /* tp_methods */
+ s_memberlist, /* tp_members */
+ 0, /* tp_getset */
+ 0, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ 0, /* tp_dictoffset */
+ s_init, /* tp_init */
+ PyType_GenericAlloc, /* tp_alloc */
+ s_new, /* tp_new */
+ PyObject_Del, /* tp_free */
+};
/* Module initialization */
PyMODINIT_FUNC
-initstruct(void)
+init_struct(void)
{
- PyObject *m;
-
- /* Create the module and add the functions */
- m = Py_InitModule4("struct", struct_methods, struct__doc__,
- (PyObject*)NULL, PYTHON_API_VERSION);
+ PyObject *m = Py_InitModule("_struct", NULL);
if (m == NULL)
return;
}
Py_INCREF(StructError);
PyModule_AddObject(m, "error", StructError);
+ Py_INCREF((PyObject*)&PyStructType);
+ PyModule_AddObject(m, "Struct", (PyObject*)&PyStructType);
}
projects / python / commitdiff