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-rw-r--r--Lib/struct.py12
-rw-r--r--Lib/test/test_struct.py41
-rw-r--r--Modules/_struct.c170
3 files changed, 161 insertions, 62 deletions
diff --git a/Lib/struct.py b/Lib/struct.py
index ee5ddc2..648e39c 100644
--- a/Lib/struct.py
+++ b/Lib/struct.py
@@ -73,3 +73,15 @@ def unpack(fmt, s):
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) \ No newline at end of file
diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
index 9332466..40fbde1 100644
--- a/Lib/test/test_struct.py
+++ b/Lib/test/test_struct.py
@@ -437,3 +437,44 @@ def test_705836():
TestFailed("expected OverflowError")
test_705836()
+
+def test_unpack_from():
+ test_string = 'abcd01234'
+ fmt = '4s'
+ s = struct.Struct(fmt)
+ for cls in (str, buffer):
+ data = cls(test_string)
+ assert s.unpack_from(data) == ('abcd',)
+ assert s.unpack_from(data, 2) == ('cd01',)
+ assert s.unpack_from(data, 4) == ('0123',)
+ for i in xrange(6):
+ assert s.unpack_from(data, i) == (data[i:i+4],)
+ for i in xrange(6, len(test_string) + 1):
+ simple_err(s.unpack_from, data, i)
+ for cls in (str, buffer):
+ data = cls(test_string)
+ assert struct.unpack_from(fmt, data) == ('abcd',)
+ assert struct.unpack_from(fmt, data, 2) == ('cd01',)
+ assert struct.unpack_from(fmt, data, 4) == ('0123',)
+ for i in xrange(6):
+ assert struct.unpack_from(fmt, data, i) == (data[i:i+4],)
+ for i in xrange(6, len(test_string) + 1):
+ simple_err(struct.unpack_from, fmt, data, i)
+
+test_unpack_from()
+
+def test_1229380():
+ for endian in ('', '>', '<'):
+ for cls in (int, long):
+ for fmt in ('B', 'H', 'I', 'L'):
+ any_err(struct.pack, endian + fmt, cls(-1))
+
+ any_err(struct.pack, endian + 'B', cls(300))
+ any_err(struct.pack, endian + 'H', cls(70000))
+
+ any_err(struct.pack, endian + 'I', sys.maxint * 4L)
+ any_err(struct.pack, endian + 'L', sys.maxint * 4L)
+
+if 0:
+ # TODO: bug #1229380
+ test_1229380()
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 7d0467d..627ac50 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -32,7 +32,7 @@ typedef struct _formatdef {
typedef struct _formatcode {
const struct _formatdef *fmtdef;
int offset;
- int repeat;
+ int size;
} formatcode;
/* Struct object interface */
@@ -46,6 +46,7 @@ typedef struct {
PyObject *weakreflist; /* List of weak references */
} PyStructObject;
+
#define PyStruct_Check(op) PyObject_TypeCheck(op, &PyStructType)
#define PyStruct_CheckExact(op) ((op)->ob_type == &PyStructType)
@@ -962,7 +963,7 @@ prepare_s(PyStructObject *self)
const char *s;
const char *fmt;
char c;
- int size, len, numcodes, num, itemsize, x;
+ int size, len, num, itemsize, x;
fmt = PyString_AS_STRING(self->s_format);
@@ -971,7 +972,6 @@ prepare_s(PyStructObject *self)
s = fmt;
size = 0;
len = 0;
- numcodes = 0;
while ((c = *s++) != '\0') {
if (isspace(Py_CHARMASK(c)))
continue;
@@ -1003,7 +1003,6 @@ prepare_s(PyStructObject *self)
case 'x': break;
default: len += num; break;
}
- if (c != 'x') numcodes++;
itemsize = e->size;
size = align(size, c, e);
@@ -1018,7 +1017,7 @@ prepare_s(PyStructObject *self)
self->s_size = size;
self->s_len = len;
- codes = PyMem_MALLOC((numcodes + 1) * sizeof(formatcode));
+ codes = PyMem_MALLOC((len + 1) * sizeof(formatcode));
if (codes == NULL) {
PyErr_NoMemory();
return -1;
@@ -1043,17 +1042,27 @@ prepare_s(PyStructObject *self)
e = getentry(c, f);
size = align(size, c, e);
- if (c != 'x') {
+ if (c == 's' || c == 'p') {
codes->offset = size;
- codes->repeat = num;
+ codes->size = num;
codes->fmtdef = e;
codes++;
+ size += num;
+ } else if (c == 'x') {
+ size += num;
+ } else {
+ while (--num >= 0) {
+ codes->offset = size;
+ codes->size = e->size;
+ codes->fmtdef = e;
+ codes++;
+ size += e->size;
+ }
}
- size += num * e->size;
}
codes->fmtdef = NULL;
- codes->offset = -1;
- codes->repeat = -1;
+ codes->offset = size;
+ codes->size = 0;
return 0;
}
@@ -1111,64 +1120,36 @@ s_dealloc(PyStructObject *s)
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;
+s_unpack_internal(PyStructObject *soself, char *startfrom) {
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);
+ Py_ssize_t i = 0;
+ PyObject *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;
+ const char *res = startfrom + code->offset;
if (e->format == 's') {
- v = PyString_FromStringAndSize(res, code->repeat);
+ v = PyString_FromStringAndSize(res, code->size);
if (v == NULL)
goto fail;
PyTuple_SET_ITEM(result, i++, v);
} else if (e->format == 'p') {
- n = *(unsigned char*)res;
- if (n >= code->repeat)
- n = code->repeat - 1;
+ Py_ssize_t n = *(unsigned char*)res;
+ if (n >= code->size)
+ n = code->size - 1;
v = PyString_FromStringAndSize(res + 1, n);
if (v == NULL)
goto fail;
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;
- }
+ v = e->unpack(res, e);
+ if (v == NULL)
+ goto fail;
+ PyTuple_SET_ITEM(result, i++, v);
}
}
@@ -1179,6 +1160,73 @@ fail:
};
+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 = (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;
+ }
+ return s_unpack_internal(soself, PyString_AS_STRING(inputstr));
+}
+
+PyDoc_STRVAR(s_unpack_from__doc__,
+"unpack_from(buffer[, offset]) -> (v1, v2, ...)\n\
+\n\
+Return tuple containing values unpacked according to this Struct's format.\n\
+Unlike unpack, unpack_from can unpack values from any object supporting\n\
+the buffer API, not just str. Requires len(buffer[offset:]) >= self.size.\n\
+See struct.__doc__ for more on format strings.");
+
+static PyObject *
+s_unpack_from(PyObject *self, PyObject *args, PyObject *kwds)
+{
+ static char *kwlist[] = {"buffer", "offset", 0};
+#if (PY_VERSION_HEX < 0x02050000)
+ static char *fmt = "z#|i:unpack_from";
+#else
+ static char *fmt = "z#|n:unpack_from";
+#endif
+ Py_ssize_t buffer_len = 0, offset = 0;
+ char *buffer = NULL;
+ PyStructObject *soself = (PyStructObject *)self;
+ assert(PyStruct_Check(self));
+ assert(soself->s_codes != NULL);
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwds, fmt, kwlist,
+ &buffer, &buffer_len, &offset))
+ return NULL;
+
+ if (buffer == NULL) {
+ PyErr_Format(StructError,
+ "unpack_from requires a buffer argument");
+ return NULL;
+ }
+
+ if (offset < 0)
+ offset += buffer_len;
+
+ if (offset < 0 || (buffer_len - offset) < soself->s_size) {
+ PyErr_Format(StructError,
+ "unpack_from requires a buffer of at least %d bytes",
+ soself->s_size);
+ return NULL;
+ }
+ return s_unpack_internal(soself, buffer + offset);
+}
+
PyDoc_STRVAR(s_pack__doc__,
"pack(v1, v2, ...) -> string\n\
\n\
@@ -1225,8 +1273,8 @@ s_pack(PyObject *self, PyObject *args)
goto fail;
}
n = PyString_GET_SIZE(v);
- if (n > code->repeat)
- n = code->repeat;
+ if (n > code->size)
+ n = code->size;
if (n > 0)
memcpy(res, PyString_AS_STRING(v), n);
} else if (e->format == 'p') {
@@ -1237,20 +1285,17 @@ s_pack(PyObject *self, PyObject *args)
goto fail;
}
n = PyString_GET_SIZE(v);
- if (n > (code->repeat - 1))
- n = code->repeat - 1;
+ if (n > (code->size - 1))
+ n = code->size - 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;
- res += e->size;
- }
+ v = PyTuple_GET_ITEM(args, i++);
+ if (e->pack(res, v, e) < 0)
+ goto fail;
}
}
@@ -1266,8 +1311,9 @@ fail:
/* List of functions */
static struct PyMethodDef s_methods[] = {
- {"pack", s_pack, METH_VARARGS, s_pack__doc__},
- {"unpack", s_unpack, METH_O, s_unpack__doc__},
+ {"pack", (PyCFunction)s_pack, METH_VARARGS, s_pack__doc__},
+ {"unpack", (PyCFunction)s_unpack, METH_O, s_unpack__doc__},
+ {"unpack_from", (PyCFunction)s_unpack_from, METH_KEYWORDS, s_unpack_from__doc__},
{NULL, NULL} /* sentinel */
};
generated by cgit v0.12 at 2025-04-28 05:30:48 (GMT)