source/python/py_tdbpack.c

   1 /* -*- c-file-style: "python"; indent-tabs-mode: nil; -*-
   2
   3    Python wrapper for Samba tdb pack/unpack functions
   4    Copyright (C) Martin Pool 2002, 2003
   5
   6
   7    NOTE PYTHON STYLE GUIDE
   8    http://www.python.org/peps/pep-0007.html
   9
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 2 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program; if not, write to the Free Software
  23    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24 */
  25
  26 #include "Python.h"
  27
  28 /* This symbol is used in both config.h and Python.h which causes an
  29    annoying compiler warning. */
  30
  31 #ifdef HAVE_FSTAT
  32 #undef HAVE_FSTAT
  33 #endif
  34
  35 /* This module is supposed to be standalone, however for portability
  36    it would be good to use the FUNCTION_MACRO preprocessor define. */
  37
  38 #include "include/config.h"
  39
  40 #ifdef HAVE_FUNCTION_MACRO
  41 #define FUNCTION_MACRO  (__FUNCTION__)
  42 #else
  43 #define FUNCTION_MACRO  (__FILE__)
  44 #endif
  45
  46 static PyObject * pytdbpack_number(char ch, PyObject *val_iter, PyObject *packed_list);
  47 static PyObject * pytdbpack_str(char ch,
  48                                 PyObject *val_iter, PyObject *packed_list,
  49                                 const char *encoding);
  50 static PyObject * pytdbpack_buffer(PyObject *val_iter, PyObject *packed_list);
  51
  52 static PyObject *pytdbunpack_item(char, char **pbuf, int *plen, PyObject *);
  53
  54 static PyObject *pytdbpack_data(const char *format_str,
  55                                      PyObject *val_seq,
  56                                      PyObject *val_list);
  57
  58 static PyObject *
  59 pytdbunpack_string(char **pbuf, int *plen, const char *encoding);
  60
  61 static void pack_le_uint32(unsigned long val_long, unsigned char *pbuf);
  62
  63
  64 static PyObject *pytdbpack_bad_type(char ch,
  65                                     const char *expected,
  66                                     PyObject *val_obj);
  67
  68 static const char * pytdbpack_docstring =
  69 "Convert between Python values and Samba binary encodings.\n"
  70 "\n"
  71 "This module is conceptually similar to the standard 'struct' module, but it\n"
  72 "uses both a different binary format and a different description string.\n"
  73 "\n"
  74 "Samba's encoding is based on that used inside DCE-RPC and SMB: a\n"
  75 "little-endian, unpadded, non-self-describing binary format.  It is intended\n"
  76 "that these functions be as similar as possible to the routines in Samba's\n"
  77 "tdb/tdbutil module, with appropriate adjustments for Python datatypes.\n"
  78 "\n"
  79 "Python strings are used to specify the format of data to be packed or\n"
  80 "unpacked.\n"
  81 "\n"
  82 "String encodings are implied by the database format: they may be either DOS\n"
  83 "codepage (currently hardcoded to 850), or Unix codepage (currently hardcoded\n"
  84 "to be the same as the default Python encoding).\n"
  85 "\n"
  86 "tdbpack format strings:\n"
  87 "\n"
  88 "    'f': NUL-terminated string in codepage iso8859-1\n"
  89 "   \n"
  90 "    'P': same as 'f'\n"
  91 "\n"
  92 "    'F': NUL-terminated string in iso-8859-1\n"
  93 "\n"
  94 "    'd':  4 byte little-endian unsigned number\n"
  95 "\n"
  96 "    'w':  2 byte little-endian unsigned number\n"
  97 "\n"
  98 "    'P': \"Pointer\" value -- in the subset of DCERPC used by Samba, this is\n"
  99 "          really just an \"exists\" or \"does not exist\" flag.  The boolean\n"
 100 "          value of the Python object is used.\n"
 101 "    \n"
 102 "    'B': 4-byte LE length, followed by that many bytes of binary data.\n"
 103 "         Corresponds to a Python integer giving the length, followed by a byte\n"
 104 "         string of the appropriate length.\n"
 105 "\n"
 106 "    '$': Special flag indicating that the preceding format code should be\n"
 107 "         repeated while data remains.  This is only supported for unpacking.\n"
 108 "\n"
 109 "    Every code corresponds to a single Python object, except 'B' which\n"
 110 "    corresponds to two values (length and contents), and '$', which produces\n"
 111 "    however many make sense.\n";
 112
 113 static char const pytdbpack_doc[] =
 114 "pack(format, values) -> buffer\n"
 115 "Pack Python objects into Samba binary format according to format string.\n"
 116 "\n"
 117 "arguments:\n"
 118 "    format -- string of tdbpack format characters\n"
 119 "    values -- sequence of value objects corresponding 1:1 to format characters\n"
 120 "\n"
 121 "returns:\n"
 122 "    buffer -- string containing packed data\n"
 123 "\n"
 124 "raises:\n"
 125 "    IndexError -- if there are too few values for the format\n"
 126 "    ValueError -- if any of the format characters is illegal\n"
 127 "    TypeError  -- if the format is not a string, or values is not a sequence,\n"
 128 "        or any of the values is of the wrong type for the corresponding\n"
 129 "        format character\n"
 130 "\n"
 131 "notes:\n"
 132 "    For historical reasons, it is not an error to pass more values than are consumed\n"
 133 "    by the format.\n";
 134
 135
 136 static char const pytdbunpack_doc[] =
 137 "unpack(format, buffer) -> (values, rest)\n"
 138 "Unpack Samba binary data according to format string.\n"
 139 "\n"
 140 "arguments:\n"
 141 "    format -- string of tdbpack characters\n"
 142 "    buffer -- string of packed binary data\n"
 143 "\n"
 144 "returns:\n"
 145 "    2-tuple of:\n"
 146 "        values -- sequence of values corresponding 1:1 to format characters\n"
 147 "        rest -- string containing data that was not decoded, or '' if the\n"
 148 "            whole string was consumed\n"
 149 "\n"
 150 "raises:\n"
 151 "    IndexError -- if there is insufficient data in the buffer for the\n"
 152 "        format (or if the data is corrupt and contains a variable-length\n"
 153 "        field extending past the end)\n"
 154 "    ValueError -- if any of the format characters is illegal\n"
 155 "\n"
 156 "notes:\n"
 157 "    Because unconsumed data is returned, you can feed it back in to the\n"
 158 "    unpacker to extract further fields.  Alternatively, if you wish to modify\n"
 159 "    some fields near the start of the data, you may be able to save time by\n"
 160 "    only unpacking and repacking the necessary part.\n";
 161
 162
 163 const char *pytdb_dos_encoding = "cp850";
 164
 165 /* NULL, meaning that the Samba default encoding *must* be the same as the
 166    Python default encoding. */
 167 const char *pytdb_unix_encoding = NULL;
 168
 169
 170 /*
 171   * Pack objects to bytes.
 172   *
 173   * All objects are first individually encoded onto a list, and then the list
 174   * of strings is concatenated.  This is faster than concatenating strings,
 175   * and reasonably simple to code.
 176   */
 177 static PyObject *
 178 pytdbpack(PyObject *self,
 179                PyObject *args)
 180 {
 181         char *format_str;
 182         PyObject *val_seq, *val_iter = NULL,
 183                 *packed_list = NULL, *packed_str = NULL,
 184                 *empty_str = NULL;
 185
 186         /* TODO: Test passing wrong types or too many arguments */
 187         if (!PyArg_ParseTuple(args, "sO", &format_str, &val_seq))
 188                 return NULL;
 189
 190         if (!(val_iter = PyObject_GetIter(val_seq)))
 191                 goto out;
 192
 193         /* Create list to hold strings until we're done, then join them all. */
 194         if (!(packed_list = PyList_New(0)))
 195                 goto out;
 196
 197         if (!pytdbpack_data(format_str, val_iter, packed_list))
 198                 goto out;
 199
 200         /* this function is not officially documented but it works */
 201         if (!(empty_str = PyString_InternFromString("")))
 202                 goto out;
 203
 204         packed_str = _PyString_Join(empty_str, packed_list);
 205
 206   out:
 207         Py_XDECREF(empty_str);
 208         Py_XDECREF(val_iter);
 209         Py_XDECREF(packed_list);
 210
 211         return packed_str;
 212 }
 213
 214
 215 /*
 216   Pack data according to FORMAT_STR from the elements of VAL_SEQ into
 217   PACKED_BUF.
 218
 219   The string has already been checked out, so we know that VAL_SEQ is large
 220   enough to hold the packed data, and that there are enough value items.
 221   (However, their types may not have been thoroughly checked yet.)
 222
 223   In addition, val_seq is a Python Fast sequence.
 224
 225   Returns NULL for error (with exception set), or None.
 226 */
 227 PyObject *
 228 pytdbpack_data(const char *format_str,
 229                     PyObject *val_iter,
 230                     PyObject *packed_list)
 231 {
 232         int format_i, val_i = 0;
 233
 234         for (format_i = 0, val_i = 0; format_str[format_i]; format_i++) {
 235                 char ch = format_str[format_i];
 236
 237                 switch (ch) {
 238                         /* dispatch to the appropriate packer for this type,
 239                            which should pull things off the iterator, and
 240                            append them to the packed_list */
 241                 case 'w':
 242                 case 'd':
 243                 case 'p':
 244                         if (!(packed_list = pytdbpack_number(ch, val_iter, packed_list)))
 245                                 return NULL;
 246                         break;
 247
 248                 case 'f':
 249                 case 'P':
 250                         if (!(packed_list = pytdbpack_str(ch, val_iter, packed_list, pytdb_unix_encoding)))
 251                                 return NULL;
 252                         break;
 253
 254                 case 'B':
 255                         if (!(packed_list = pytdbpack_buffer(val_iter, packed_list)))
 256                                 return NULL;
 257                         break;
 258
 259                 default:
 260                         PyErr_Format(PyExc_ValueError,
 261                                      "%s: format character '%c' is not supported",
 262                                      FUNCTION_MACRO, ch);
 263                         return NULL;
 264                 }
 265         }
 266
 267         return packed_list;
 268 }
 269
 270
 271 static PyObject *
 272 pytdbpack_number(char ch, PyObject *val_iter, PyObject *packed_list)
 273 {
 274         unsigned long val_long;
 275         PyObject *val_obj = NULL, *long_obj = NULL, *result_obj = NULL;
 276         PyObject *new_list = NULL;
 277         unsigned char pack_buf[4];
 278
 279         if (!(val_obj = PyIter_Next(val_iter)))
 280                 goto out;
 281
 282         if (!(long_obj = PyNumber_Long(val_obj))) {
 283                 pytdbpack_bad_type(ch, "Number", val_obj);
 284                 goto out;
 285         }
 286
 287         val_long = PyLong_AsUnsignedLong(long_obj);
 288         pack_le_uint32(val_long, pack_buf);
 289
 290         /* pack as 32-bit; if just packing a 'w' 16-bit word then only take
 291            the first two bytes. */
 292
 293         if (!(result_obj = PyString_FromStringAndSize(pack_buf, ch == 'w' ? 2 : 4)))
 294                 goto out;
 295
 296         if (PyList_Append(packed_list, result_obj) != -1)
 297                 new_list = packed_list;
 298
 299   out:
 300         Py_XDECREF(val_obj);
 301         Py_XDECREF(long_obj);
 302         Py_XDECREF(result_obj);
 303
 304         return new_list;
 305 }
 306
 307
 308 /*
 309  * Take one string from the iterator val_iter, convert it to 8-bit, and return
 310  * it.
 311  *
 312  * If the input is neither a string nor Unicode, an exception is raised.
 313  *
 314  * If the input is Unicode, then it is converted to the appropriate encoding.
 315  *
 316  * If the input is a String, and encoding is not null, then it is converted to
 317  * Unicode using the default decoding method, and then converted to the
 318  * encoding.  If the encoding is NULL, then the string is written out as-is --
 319  * this is used when the default Python encoding is the same as the Samba
 320  * encoding.
 321  *
 322  * I hope this approach avoids being too fragile w.r.t. being passed either
 323  * Unicode or String objects.
 324  */
 325 static PyObject *
 326 pytdbpack_str(char ch,
 327               PyObject *val_iter, PyObject *packed_list, const char *encoding)
 328 {
 329         PyObject *val_obj = NULL;
 330         PyObject *unicode_obj = NULL;
 331         PyObject *coded_str = NULL;
 332         PyObject *nul_str = NULL;
 333         PyObject *new_list = NULL;
 334
 335         if (!(val_obj = PyIter_Next(val_iter)))
 336                 goto out;
 337
 338         if (PyUnicode_Check(val_obj)) {
 339                 if (!(coded_str = PyUnicode_AsEncodedString(val_obj, encoding, NULL)))
 340                         goto out;
 341         }
 342         else if (PyString_Check(val_obj) && !encoding) {
 343                 /* For efficiency, we assume that the Python interpreter has
 344                    the same default string encoding as Samba's native string
 345                    encoding.  On the PSA, both are always 8859-1. */
 346                 coded_str = val_obj;
 347                 Py_INCREF(coded_str);
 348         }
 349         else if (PyString_Check(val_obj)) {
 350                 /* String, but needs to be converted */
 351                 if (!(unicode_obj = PyString_AsDecodedObject(val_obj, NULL, NULL)))
 352                         goto out;
 353                 if (!(coded_str = PyUnicode_AsEncodedString(unicode_obj, encoding, NULL)))
 354                         goto out;
 355         }
 356         else {
 357                 pytdbpack_bad_type(ch, "String or Unicode", val_obj);
 358                 goto out;
 359         }
 360
 361         if (!nul_str)
 362                 /* this is constant and often-used; hold it forever */
 363                 if (!(nul_str = PyString_FromStringAndSize("", 1)))
 364                         goto out;
 365
 366         if ((PyList_Append(packed_list, coded_str) != -1)
 367             && (PyList_Append(packed_list, nul_str) != -1))
 368                 new_list = packed_list;
 369
 370   out:
 371         Py_XDECREF(val_obj);
 372         Py_XDECREF(unicode_obj);
 373         Py_XDECREF(coded_str);
 374
 375         return new_list;
 376 }
 377
 378
 379 /*
 380  * Pack (LENGTH, BUFFER) pair onto the list.
 381  *
 382  * The buffer must already be a String, not Unicode, because it contains 8-bit
 383  * untranslated data.  In some cases it will actually be UTF_16_LE data.
 384  */
 385 static PyObject *
 386 pytdbpack_buffer(PyObject *val_iter, PyObject *packed_list)
 387 {
 388         PyObject *val_obj;
 389         PyObject *new_list = NULL;
 390
 391         /* pull off integer and stick onto list */
 392         if (!(packed_list = pytdbpack_number('d', val_iter, packed_list)))
 393                 return NULL;
 394
 395         /* this assumes that the string is the right length; the old code did
 396            the same. */
 397         if (!(val_obj = PyIter_Next(val_iter)))
 398                 return NULL;
 399
 400         if (!PyString_Check(val_obj)) {
 401                 pytdbpack_bad_type('B', "String", val_obj);
 402                 goto out;
 403         }
 404
 405         if (PyList_Append(packed_list, val_obj) != -1)
 406                 new_list = packed_list;
 407
 408   out:
 409         Py_XDECREF(val_obj);
 410         return new_list;
 411 }
 412
 413
 414 static PyObject *pytdbpack_bad_type(char ch,
 415                                     const char *expected,
 416                                     PyObject *val_obj)
 417 {
 418         PyObject *r = PyObject_Repr(val_obj);
 419         if (!r)
 420                 return NULL;
 421         PyErr_Format(PyExc_TypeError,
 422                      "tdbpack: format '%c' requires %s, not %s",
 423                      ch, expected, PyString_AS_STRING(r));
 424         Py_DECREF(r);
 425         return val_obj;
 426 }
 427
 428
 429 /*
 430   XXX: glib and Samba have quicker macro for doing the endianness conversions,
 431   but I don't know of one in plain libc, and it's probably not a big deal.  I
 432   realize this is kind of dumb because we'll almost always be on x86, but
 433   being safe is important.
 434 */
 435 static void pack_le_uint32(unsigned long val_long, unsigned char *pbuf)
 436 {
 437         pbuf[0] =         val_long & 0xff;
 438         pbuf[1] = (val_long >> 8)  & 0xff;
 439         pbuf[2] = (val_long >> 16) & 0xff;
 440         pbuf[3] = (val_long >> 24) & 0xff;
 441 }
 442
 443
 444 static void pack_bytes(long len, const char *from,
 445                        unsigned char **pbuf)
 446 {
 447         memcpy(*pbuf, from, len);
 448         (*pbuf) += len;
 449 }
 450
 451
 452
 453 static PyObject *
 454 pytdbunpack(PyObject *self,
 455                  PyObject *args)
 456 {
 457         char *format_str, *packed_str, *ppacked;
 458         PyObject *val_list = NULL, *ret_tuple = NULL;
 459         PyObject *rest_string = NULL;
 460         int format_len, packed_len;
 461         char last_format = '#'; /* invalid */
 462         int i;
 463
 464         /* get arguments */
 465         if (!PyArg_ParseTuple(args, "ss#", &format_str, &packed_str, &packed_len))
 466                 return NULL;
 467
 468         format_len = strlen(format_str);
 469
 470         /* Allocate list to hold results.  Initially empty, and we append
 471            results as we go along. */
 472         val_list = PyList_New(0);
 473         if (!val_list)
 474                 goto failed;
 475         ret_tuple = PyTuple_New(2);
 476         if (!ret_tuple)
 477                 goto failed;
 478
 479         /* For every object, unpack.  */
 480         for (ppacked = packed_str, i = 0; i < format_len && format_str[i] != '$'; i++) {
 481                 last_format = format_str[i];
 482                 /* packed_len is reduced in place */
 483                 if (!pytdbunpack_item(format_str[i], &ppacked, &packed_len, val_list))
 484                         goto failed;
 485         }
 486
 487         /* If the last character was '$', keep going until out of space */
 488         if (format_str[i] == '$') {
 489                 if (i == 0) {
 490                         PyErr_Format(PyExc_ValueError,
 491                                      "%s: '$' may not be first character in format",
 492                                      FUNCTION_MACRO);
 493                         return NULL;
 494                 }
 495                 while (packed_len > 0)
 496                         if (!pytdbunpack_item(last_format, &ppacked, &packed_len, val_list))
 497                                 goto failed;
 498         }
 499
 500         /* save leftovers for next time */
 501         rest_string = PyString_FromStringAndSize(ppacked, packed_len);
 502         if (!rest_string)
 503                 goto failed;
 504
 505         /* return (values, rest) tuple; give up references to them */
 506         PyTuple_SET_ITEM(ret_tuple, 0, val_list);
 507         val_list = NULL;
 508         PyTuple_SET_ITEM(ret_tuple, 1, rest_string);
 509         val_list = NULL;
 510         return ret_tuple;
 511
 512   failed:
 513         /* handle failure: deallocate anything.  XDECREF forms handle NULL
 514            pointers for objects that haven't been allocated yet. */
 515         Py_XDECREF(val_list);
 516         Py_XDECREF(ret_tuple);
 517         Py_XDECREF(rest_string);
 518         return NULL;
 519 }
 520
 521
 522 static void
 523 pytdbunpack_err_too_short(void)
 524 {
 525         PyErr_Format(PyExc_IndexError,
 526                      "%s: data too short for unpack format", FUNCTION_MACRO);
 527 }
 528
 529
 530 static PyObject *
 531 pytdbunpack_uint32(char **pbuf, int *plen)
 532 {
 533         unsigned long v;
 534         unsigned char *b;
 535
 536         if (*plen < 4) {
 537                 pytdbunpack_err_too_short();
 538                 return NULL;
 539         }
 540
 541         b = *pbuf;
 542         v = b[0] | b[1]<<8 | b[2]<<16 | b[3]<<24;
 543
 544         (*pbuf) += 4;
 545         (*plen) -= 4;
 546
 547         return PyLong_FromUnsignedLong(v);
 548 }
 549
 550
 551 static PyObject *pytdbunpack_int16(char **pbuf, int *plen)
 552 {
 553         long v;
 554         unsigned char *b;
 555
 556         if (*plen < 2) {
 557                 pytdbunpack_err_too_short();
 558                 return NULL;
 559         }
 560
 561         b = *pbuf;
 562         v = b[0] | b[1]<<8;
 563
 564         (*pbuf) += 2;
 565         (*plen) -= 2;
 566
 567         return PyInt_FromLong(v);
 568 }
 569
 570
 571 static PyObject *
 572 pytdbunpack_string(char **pbuf, int *plen, const char *encoding)
 573 {
 574         int len;
 575         char *nul_ptr, *start;
 576
 577         start = *pbuf;
 578
 579         nul_ptr = memchr(start, '\0', *plen);
 580         if (!nul_ptr) {
 581                 pytdbunpack_err_too_short();
 582                 return NULL;
 583         }
 584
 585         len = nul_ptr - start;
 586
 587         *pbuf += len + 1;       /* skip \0 */
 588         *plen -= len + 1;
 589
 590         return PyString_Decode(start, len, encoding, NULL);
 591 }
 592
 593
 594 static PyObject *
 595 pytdbunpack_buffer(char **pbuf, int *plen, PyObject *val_list)
 596 {
 597         /* first get 32-bit len */
 598         long slen;
 599         unsigned char *b;
 600         unsigned char *start;
 601         PyObject *str_obj = NULL, *len_obj = NULL;
 602
 603         if (*plen < 4) {
 604                 pytdbunpack_err_too_short();
 605                 return NULL;
 606         }
 607
 608         b = *pbuf;
 609         slen = b[0] | b[1]<<8 | b[2]<<16 | b[3]<<24;
 610
 611         if (slen < 0) { /* surely you jest */
 612                 PyErr_Format(PyExc_ValueError,
 613                              "%s: buffer seems to have negative length", FUNCTION_MACRO);
 614                 return NULL;
 615         }
 616
 617         (*pbuf) += 4;
 618         (*plen) -= 4;
 619         start = *pbuf;
 620
 621         if (*plen < slen) {
 622                 PyErr_Format(PyExc_IndexError,
 623                              "%s: not enough data to unpack buffer: "
 624                              "need %d bytes, have %d", FUNCTION_MACRO,
 625                              (int) slen, *plen);
 626                 return NULL;
 627         }
 628
 629         (*pbuf) += slen;
 630         (*plen) -= slen;
 631
 632         if (!(len_obj = PyInt_FromLong(slen)))
 633                 goto failed;
 634
 635         if (PyList_Append(val_list, len_obj) == -1)
 636                 goto failed;
 637
 638         if (!(str_obj = PyString_FromStringAndSize(start, slen)))
 639                 goto failed;
 640
 641         if (PyList_Append(val_list, str_obj) == -1)
 642                 goto failed;
 643
 644         Py_DECREF(len_obj);
 645         Py_DECREF(str_obj);
 646
 647         return val_list;
 648
 649   failed:
 650         Py_XDECREF(len_obj);    /* handles NULL */
 651         Py_XDECREF(str_obj);
 652         return NULL;
 653 }
 654
 655
 656 /* Unpack a single field from packed data, according to format character CH.
 657    Remaining data is at *PBUF, of *PLEN.
 658
 659    *PBUF is advanced, and *PLEN reduced to reflect the amount of data that has
 660    been consumed.
 661
 662    Returns a reference to None, or NULL for failure.
 663 */
 664 static PyObject *pytdbunpack_item(char ch,
 665                                   char **pbuf,
 666                                   int *plen,
 667                                   PyObject *val_list)
 668 {
 669         PyObject *unpacked;
 670
 671         if (ch == 'w') {        /* 16-bit int */
 672                 unpacked = pytdbunpack_int16(pbuf, plen);
 673         }
 674         else if (ch == 'd' || ch == 'p') { /* 32-bit int */
 675                 /* pointers can just come through as integers */
 676                 unpacked = pytdbunpack_uint32(pbuf, plen);
 677         }
 678         else if (ch == 'f' || ch == 'P') { /* nul-term string  */
 679                 unpacked = pytdbunpack_string(pbuf, plen, pytdb_unix_encoding);
 680         }
 681         else if (ch == 'B') { /* length, buffer */
 682                 return pytdbunpack_buffer(pbuf, plen, val_list);
 683         }
 684         else {
 685                 PyErr_Format(PyExc_ValueError,
 686                              "%s: format character '%c' is not supported",
 687                              FUNCTION_MACRO, ch);
 688
 689                 return NULL;
 690         }
 691
 692         /* otherwise OK */
 693         if (!unpacked)
 694                 return NULL;
 695
 696         if (PyList_Append(val_list, unpacked) == -1)
 697                 val_list = NULL;
 698
 699         /* PyList_Append takes a new reference to the inserted object.
 700            Therefore, we no longer need the original reference. */
 701         Py_DECREF(unpacked);
 702
 703         return val_list;
 704 }
 705
 706
 707
 708
 709
 710
 711 static PyMethodDef pytdbpack_methods[] = {
 712         { "pack", pytdbpack, METH_VARARGS, (char *) pytdbpack_doc },
 713         { "unpack", pytdbunpack, METH_VARARGS, (char *) pytdbunpack_doc },
 714 };
 715
 716 DL_EXPORT(void)
 717 inittdbpack(void)
 718 {
 719         Py_InitModule3("tdbpack", pytdbpack_methods,
 720                        (char *) pytdbpack_docstring);
 721 }