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Change to representing buffers ('B') as (LEN, STRING) in Python,

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rather than as just a string.  Makes the code more messy, but needed
for compatibility with existing PSA Python code which seems to be too
knotty to separate out.
This commit is contained in:
Martin Pool
-
parent 631945a03a
commit 20d88a7d1e
1 changed files with 113 additions and 131 deletions
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244
source/python/py_tdbpack.c
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@@ -31,18 +31,20 @@ static int pytdbpack_calc_reqd_len(char *format_str,
PyObject *val_seq);
static PyObject *pytdbpack_unpack_item(char,
char **pbuf,
int *plen);
static int
pytdbpack_calc_item_len(char format_ch,
PyObject *val_obj);
char **pbuf,
int *plen);
static PyObject *pytdbpack_pack_data(const char *format_str,
PyObject *val_seq,
unsigned char *buf);
static PyObject *pytdbpack_bad_type(char ch,
const char *expected,
PyObject *val_obj);
static const char * pytdbpack_docstring =
"Convert between Python values and Samba binary encodings.
@@ -76,7 +78,8 @@ tdbpack format strings:
value of the Python object is used.
'B': 4-byte LE length, followed by that many bytes of binary data.
Corresponds to a Python byte string of the appropriate length.
Corresponds to a Python integer giving the length, followed by a byte
string of the appropriate length.
'$': Special flag indicating that the preceding format code should be
repeated while data remains. This is only supported for unpacking.
@@ -253,7 +256,7 @@ pytdbpack_unpack(PyObject *self,
last_format = format;
}
/* put leftovers in box for lunch tomorrow */
/* save leftovers for next time */
rest_string = PyString_FromStringAndSize(ppacked, packed_len);
if (!rest_string)
goto failed;
@@ -302,8 +305,6 @@ pytdbpack_calc_reqd_len(char *format_str,
for (p = format_str, val_i = 0; *p; p++, val_i++) {
char ch = *p;
PyObject *val_obj;
int item_len;
if (val_i >= val_len) {
PyErr_Format(PyExc_IndexError,
@@ -313,15 +314,57 @@ pytdbpack_calc_reqd_len(char *format_str,
}
/* borrow a reference to the item */
val_obj = PySequence_GetItem(val_seq, val_i);
if (!val_obj)
return -1;
if (ch == 'd' || ch == 'p')
len += 4;
else if (ch == 'w')
len += 2;
else if (ch == 'f' || ch == 'P') {
/* nul-terminated 8-bit string */
int item_len;
PyObject *str_obj;
item_len = pytdbpack_calc_item_len(ch, val_obj);
if (item_len == -1)
return -1;
else
str_obj = PySequence_GetItem(val_seq, val_i);
if (!str_obj)
return -1;
item_len = PyString_Size(str_obj);
if (item_len == -1) {
pytdbpack_bad_type(ch, "String", str_obj);
return -1;
}
len += item_len;
}
else if (ch == 'B') {
/* length-preceded byte buffer: n bytes, plus a preceding
* word */
PyObject *len_obj;
long len_val;
len_obj = PySequence_GetItem(val_seq, val_i);
val_i++; /* skip over buffer */
if (!PyNumber_Check(len_obj)) {
pytdbpack_bad_type(ch, "Number", len_obj);
return -1;
}
len_val = PyInt_AsLong(len_obj);
if (len_val < 0) {
PyErr_Format(PyExc_ValueError,
"%s: format 'B' requires positive integer", __FUNCTION__);
return -1;
}
len += 4 + len_val;
}
else {
PyErr_Format(PyExc_ValueError,
"%s: format character '%c' is not supported",
__FUNCTION__, ch);
return -1;
}
}
return len;
@@ -343,56 +386,6 @@ static PyObject *pytdbpack_bad_type(char ch,
}
/*
* Calculate the number of bytes required to pack a single value. While doing
* this, also conduct some initial checks that the argument types are
* reasonable.
*
* Returns -1 on exception.
*/
static int
pytdbpack_calc_item_len(char ch,
PyObject *val_obj)
{
if (ch == 'd' || ch == 'w') {
if (!PyInt_Check(val_obj)) {
pytdbpack_bad_type(ch, "Int", val_obj);
return -1;
}
if (ch == 'w')
return 2;
else
return 4;
} else if (ch == 'p') {
return 4;
}
else if (ch == 'f' || ch == 'P' || ch == 'B') {
/* nul-terminated 8-bit string */
if (!PyString_Check(val_obj)) {
pytdbpack_bad_type(ch, "String", val_obj);
return -1;
}
if (ch == 'B') {
/* byte buffer; just use Python string's length, plus
a preceding word */
return 4 + PyString_GET_SIZE(val_obj);
}
else {
/* one nul character */
return 1 + PyString_GET_SIZE(val_obj);
}
}
else {
PyErr_Format(PyExc_ValueError,
"tdbpack: format character '%c' is not supported",
ch);
return -1;
}
}
/*
XXX: glib and Samba have quicker macro for doing the endianness conversions,
but I don't know of one in plain libc, and it's probably not a big deal. I
@@ -566,63 +559,6 @@ static PyObject *pytdbpack_unpack_item(char ch,
/*
Pack a single item VAL_OBJ, encoded using format CH, into a buffer at *PBUF,
and advance the pointer. Buffer length has been pre-calculated so we are
sure that there is enough space.
*/
static PyObject *
pytdbpack_pack_item(char ch,
PyObject *val_obj,
unsigned char **pbuf)
{
if (ch == 'w') {
unsigned long val_long = PyInt_AsLong(val_obj);
(*pbuf)[0] = val_long & 0xff;
(*pbuf)[1] = (val_long >> 8) & 0xff;
(*pbuf) += 2;
}
else if (ch == 'd') {
/* 4-byte LE number */
pack_int32(PyInt_AsLong(val_obj), pbuf);
}
else if (ch == 'p') {
/* "Pointer" value -- in the subset of DCERPC used by Samba,
this is really just an "exists" or "does not exist"
flag. */
pack_int32(PyObject_IsTrue(val_obj), pbuf);
}
else if (ch == 'f' || ch == 'P') {
int size;
char *sval;
size = PyString_GET_SIZE(val_obj);
sval = PyString_AS_STRING(val_obj);
pack_bytes(size+1, sval, pbuf); /* include nul */
}
else if (ch == 'B') {
int size;
char *sval;
size = PyString_GET_SIZE(val_obj);
pack_int32(size, pbuf);
sval = PyString_AS_STRING(val_obj);
pack_bytes(size, sval, pbuf); /* do not include nul */
}
else {
/* this ought to be caught while calculating the length, but
just in case. */
PyErr_Format(PyExc_ValueError,
"%s: format character '%c' is not supported",
__FUNCTION__, ch);
return NULL;
}
return Py_None;
}
/*
Pack data according to FORMAT_STR from the elements of VAL_SEQ into
@@ -639,7 +575,7 @@ pytdbpack_pack_item(char ch,
PyObject *
pytdbpack_pack_data(const char *format_str,
PyObject *val_seq,
unsigned char *packed_buf)
unsigned char *packed)
{
int i;
@@ -648,21 +584,67 @@ pytdbpack_pack_data(const char *format_str,
PyObject *val_obj;
/* borrow a reference to the item */
val_obj = PySequence_Fast_GET_ITEM(val_seq, i);
val_obj = PySequence_GetItem(val_seq, i);
if (!val_obj)
return NULL;
if (!pytdbpack_pack_item(ch, val_obj, &packed_buf))
return NULL;
}
if (ch == 'w') {
unsigned long val_long = PyInt_AsLong(val_obj);
(packed)[0] = val_long & 0xff;
(packed)[1] = (val_long >> 8) & 0xff;
(packed) += 2;
}
else if (ch == 'd') {
/* 4-byte LE number */
pack_int32(PyInt_AsLong(val_obj), &packed);
}
else if (ch == 'p') {
/* "Pointer" value -- in the subset of DCERPC used by Samba,
this is really just an "exists" or "does not exist"
flag. */
pack_int32(PyObject_IsTrue(val_obj), &packed);
}
else if (ch == 'f' || ch == 'P') {
int size;
char *sval;
size = PyString_GET_SIZE(val_obj);
sval = PyString_AS_STRING(val_obj);
pack_bytes(size+1, sval, &packed); /* include nul */
}
else if (ch == 'B') {
long size;
char *sval;
size = PyInt_AsLong(val_obj);
pack_int32(size, &packed);
val_obj = PySequence_GetItem(val_seq, ++i);
if (!val_obj)
return NULL;
sval = PyString_AsString(val_obj);
if (!sval)
return NULL;
pack_bytes(size, sval, &packed); /* do not include nul */
}
else {
/* this ought to be caught while calculating the length, but
just in case. */
PyErr_Format(PyExc_ValueError,
"%s: format character '%c' is not supported",
__FUNCTION__, ch);
return NULL;
}
}
return Py_None;
}
static PyMethodDef pytdbpack_methods[] = {
{ "pack", pytdbpack_pack, METH_VARARGS, (char *) pytdbpack_pack_doc },
{ "unpack", pytdbpack_unpack, METH_VARARGS, (char *) pytdbpack_unpack_doc },