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1 /* struct module -- pack values into and (out of) strings */
2
3 /* New version supporting byte order, alignment and size options,
4 character strings, and unsigned numbers */
5
6 #define PY_SSIZE_T_CLEAN
7
8 #include "Python.h"
9 #include "structseq.h"
10 #include "structmember.h"
11 #include <ctype.h>
12
13 static PyTypeObject PyStructType;
14
15 /* compatibility macros */
16 #if (PY_VERSION_HEX < 0x02050000)
17 typedef int Py_ssize_t;
18 #endif
19
20 /* warning messages */
21 #define FLOAT_COERCE_WARN "integer argument expected, got float"
22 #define NON_INTEGER_WARN "integer argument expected, got non-integer " \
23 "(implicit conversion using __int__ is deprecated)"
24
25
26 /* The translation function for each format character is table driven */
27 typedef struct _formatdef {
28 char format;
29 Py_ssize_t size;
30 Py_ssize_t alignment;
31 PyObject* (*unpack)(const char *,
32 const struct _formatdef *);
33 int (*pack)(char *, PyObject *,
34 const struct _formatdef *);
35 } formatdef;
36
37 typedef struct _formatcode {
38 const struct _formatdef *fmtdef;
39 Py_ssize_t offset;
40 Py_ssize_t size;
41 } formatcode;
42
43 /* Struct object interface */
44
45 typedef struct {
46 PyObject_HEAD
47 Py_ssize_t s_size;
48 Py_ssize_t s_len;
49 formatcode *s_codes;
50 PyObject *s_format;
51 PyObject *weakreflist; /* List of weak references */
52 } PyStructObject;
53
54
55 #define PyStruct_Check(op) PyObject_TypeCheck(op, &PyStructType)
56 #define PyStruct_CheckExact(op) (Py_TYPE(op) == &PyStructType)
57
58
59 /* Exception */
60
61 static PyObject *StructError;
62
63
64 /* Define various structs to figure out the alignments of types */
65
66
67 typedef struct { char c; short x; } st_short;
68 typedef struct { char c; int x; } st_int;
69 typedef struct { char c; long x; } st_long;
70 typedef struct { char c; float x; } st_float;
71 typedef struct { char c; double x; } st_double;
72 typedef struct { char c; void *x; } st_void_p;
73
74 #define SHORT_ALIGN (sizeof(st_short) - sizeof(short))
75 #define INT_ALIGN (sizeof(st_int) - sizeof(int))
76 #define LONG_ALIGN (sizeof(st_long) - sizeof(long))
77 #define FLOAT_ALIGN (sizeof(st_float) - sizeof(float))
78 #define DOUBLE_ALIGN (sizeof(st_double) - sizeof(double))
79 #define VOID_P_ALIGN (sizeof(st_void_p) - sizeof(void *))
80
81 /* We can't support q and Q in native mode unless the compiler does;
82 in std mode, they're 8 bytes on all platforms. */
83 #ifdef HAVE_LONG_LONG
84 typedef struct { char c; PY_LONG_LONG x; } s_long_long;
85 #define LONG_LONG_ALIGN (sizeof(s_long_long) - sizeof(PY_LONG_LONG))
86 #endif
87
88 #ifdef HAVE_C99_BOOL
89 #define BOOL_TYPE _Bool
90 typedef struct { char c; _Bool x; } s_bool;
91 #define BOOL_ALIGN (sizeof(s_bool) - sizeof(BOOL_TYPE))
92 #else
93 #define BOOL_TYPE char
94 #define BOOL_ALIGN 0
95 #endif
96
97 #define STRINGIFY(x) #x
98
99 #ifdef __powerc
100 #pragma options align=reset
101 #endif
102
103 static char *integer_codes = "bBhHiIlLqQ";
104
105 /* Helper to get a PyLongObject by hook or by crook. Caller should decref. */
106
107 static PyObject *
108 get_pylong(PyObject *v)
109 {
110 PyObject *r, *w;
111 int converted = 0;
112 assert(v != NULL);
113 if (!PyInt_Check(v) && !PyLong_Check(v)) {
114 PyNumberMethods *m;
115 /* Not an integer; first try to use __index__ to
116 convert to an integer. If the __index__ method
117 doesn't exist, or raises a TypeError, try __int__.
118 Use of the latter is deprecated, and will fail in
119 Python 3.x. */
120
121 m = Py_TYPE(v)->tp_as_number;
122 if (PyIndex_Check(v)) {
123 w = PyNumber_Index(v);
124 if (w != NULL) {
125 v = w;
126 /* successfully converted to an integer */
127 converted = 1;
128 }
129 else if (PyErr_ExceptionMatches(PyExc_TypeError)) {
130 PyErr_Clear();
131 }
132 else
133 return NULL;
134 }
135 if (!converted && m != NULL && m->nb_int != NULL) {
136 /* Special case warning message for floats, for
137 backwards compatibility. */
138 if (PyFloat_Check(v)) {
139 if (PyErr_WarnEx(
140 PyExc_DeprecationWarning,
141 FLOAT_COERCE_WARN, 1))
142 return NULL;
143 }
144 else {
145 if (PyErr_WarnEx(
146 PyExc_DeprecationWarning,
147 NON_INTEGER_WARN, 1))
148 return NULL;
149 }
150 v = m->nb_int(v);
151 if (v == NULL)
152 return NULL;
153 if (!PyInt_Check(v) && !PyLong_Check(v)) {
154 PyErr_SetString(PyExc_TypeError,
155 "__int__ method returned "
156 "non-integer");
157 return NULL;
158 }
159 converted = 1;
160 }
161 if (!converted) {
162 PyErr_SetString(StructError,
163 "cannot convert argument "
164 "to integer");
165 return NULL;
166 }
167 }
168 else
169 /* Ensure we own a reference to v. */
170 Py_INCREF(v);
171
172 assert(PyInt_Check(v) || PyLong_Check(v));
173 if (PyInt_Check(v)) {
174 r = PyLong_FromLong(PyInt_AS_LONG(v));
175 Py_DECREF(v);
176 }
177 else if (PyLong_Check(v)) {
178 assert(PyLong_Check(v));
179 r = v;
180 }
181 else {
182 r = NULL; /* silence compiler warning about
183 possibly uninitialized variable */
184 assert(0); /* shouldn't ever get here */
185 }
186
187 return r;
188 }
189
190 /* Helper to convert a Python object to a C long. Sets an exception
191 (struct.error for an inconvertible type, OverflowError for
192 out-of-range values) and returns -1 on error. */
193
194 static int
195 get_long(PyObject *v, long *p)
196 {
197 long x;
198
199 v = get_pylong(v);
200 if (v == NULL)
201 return -1;
202 assert(PyLong_Check(v));
203 x = PyLong_AsLong(v);
204 Py_DECREF(v);
205 if (x == (long)-1 && PyErr_Occurred())
206 return -1;
207 *p = x;
208 return 0;
209 }
210
211 /* Same, but handling unsigned long */
212
213 static int
214 get_ulong(PyObject *v, unsigned long *p)
215 {
216 unsigned long x;
217
218 v = get_pylong(v);
219 if (v == NULL)
220 return -1;
221 assert(PyLong_Check(v));
222 x = PyLong_AsUnsignedLong(v);
223 Py_DECREF(v);
224 if (x == (unsigned long)-1 && PyErr_Occurred())
225 return -1;
226 *p = x;
227 return 0;
228 }
229
230 #ifdef HAVE_LONG_LONG
231
232 /* Same, but handling native long long. */
233
234 static int
235 get_longlong(PyObject *v, PY_LONG_LONG *p)
236 {
237 PY_LONG_LONG x;
238
239 v = get_pylong(v);
240 if (v == NULL)
241 return -1;
242 assert(PyLong_Check(v));
243 x = PyLong_AsLongLong(v);
244 Py_DECREF(v);
245 if (x == (PY_LONG_LONG)-1 && PyErr_Occurred())
246 return -1;
247 *p = x;
248 return 0;
249 }
250
251 /* Same, but handling native unsigned long long. */
252
253 static int
254 get_ulonglong(PyObject *v, unsigned PY_LONG_LONG *p)
255 {
256 unsigned PY_LONG_LONG x;
257
258 v = get_pylong(v);
259 if (v == NULL)
260 return -1;
261 assert(PyLong_Check(v));
262 x = PyLong_AsUnsignedLongLong(v);
263 Py_DECREF(v);
264 if (x == (unsigned PY_LONG_LONG)-1 && PyErr_Occurred())
265 return -1;
266 *p = x;
267 return 0;
268 }
269
270 #endif
271
272 /* Floating point helpers */
273
274 static PyObject *
275 unpack_float(const char *p, /* start of 4-byte string */
276 int le) /* true for little-endian, false for big-endian */
277 {
278 double x;
279
280 x = _PyFloat_Unpack4((unsigned char *)p, le);
281 if (x == -1.0 && PyErr_Occurred())
282 return NULL;
283 return PyFloat_FromDouble(x);
284 }
285
286 static PyObject *
287 unpack_double(const char *p, /* start of 8-byte string */
288 int le) /* true for little-endian, false for big-endian */
289 {
290 double x;
291
292 x = _PyFloat_Unpack8((unsigned char *)p, le);
293 if (x == -1.0 && PyErr_Occurred())
294 return NULL;
295 return PyFloat_FromDouble(x);
296 }
297
298 /* Helper to format the range error exceptions */
299 static int
300 _range_error(const formatdef *f, int is_unsigned)
301 {
302 /* ulargest is the largest unsigned value with f->size bytes.
303 * Note that the simpler:
304 * ((size_t)1 << (f->size * 8)) - 1
305 * doesn't work when f->size == sizeof(size_t) because C doesn't
306 * define what happens when a left shift count is >= the number of
307 * bits in the integer being shifted; e.g., on some boxes it doesn't
308 * shift at all when they're equal.
309 */
310 const size_t ulargest = (size_t)-1 >> ((SIZEOF_SIZE_T - f->size)*8);
311 assert(f->size >= 1 && f->size <= SIZEOF_SIZE_T);
312 if (is_unsigned)
313 PyErr_Format(StructError,
314 "'%c' format requires 0 <= number <= %zu",
315 f->format,
316 ulargest);
317 else {
318 const Py_ssize_t largest = (Py_ssize_t)(ulargest >> 1);
319 PyErr_Format(StructError,
320 "'%c' format requires %zd <= number <= %zd",
321 f->format,
322 ~ largest,
323 largest);
324 }
325 return -1;
326 }
327
328
329
330 /* A large number of small routines follow, with names of the form
331
332 [bln][up]_TYPE
333
334 [bln] distiguishes among big-endian, little-endian and native.
335 [pu] distiguishes between pack (to struct) and unpack (from struct).
336 TYPE is one of char, byte, ubyte, etc.
337 */
338
339 /* Native mode routines. ****************************************************/
340 /* NOTE:
341 In all n[up]_<type> routines handling types larger than 1 byte, there is
342 *no* guarantee that the p pointer is properly aligned for each type,
343 therefore memcpy is called. An intermediate variable is used to
344 compensate for big-endian architectures.
345 Normally both the intermediate variable and the memcpy call will be
346 skipped by C optimisation in little-endian architectures (gcc >= 2.91
347 does this). */
348
349 static PyObject *
350 nu_char(const char *p, const formatdef *f)
351 {
352 return PyString_FromStringAndSize(p, 1);
353 }
354
355 static PyObject *
356 nu_byte(const char *p, const formatdef *f)
357 {
358 return PyInt_FromLong((long) *(signed char *)p);
359 }
360
361 static PyObject *
362 nu_ubyte(const char *p, const formatdef *f)
363 {
364 return PyInt_FromLong((long) *(unsigned char *)p);
365 }
366
367 static PyObject *
368 nu_short(const char *p, const formatdef *f)
369 {
370 short x;
371 memcpy((char *)&x, p, sizeof x);
372 return PyInt_FromLong((long)x);
373 }
374
375 static PyObject *
376 nu_ushort(const char *p, const formatdef *f)
377 {
378 unsigned short x;
379 memcpy((char *)&x, p, sizeof x);
380 return PyInt_FromLong((long)x);
381 }
382
383 static PyObject *
384 nu_int(const char *p, const formatdef *f)
385 {
386 int x;
387 memcpy((char *)&x, p, sizeof x);
388 return PyInt_FromLong((long)x);
389 }
390
391 static PyObject *
392 nu_uint(const char *p, const formatdef *f)
393 {
394 unsigned int x;
395 memcpy((char *)&x, p, sizeof x);
396 #if (SIZEOF_LONG > SIZEOF_INT)
397 return PyInt_FromLong((long)x);
398 #else
399 if (x <= ((unsigned int)LONG_MAX))
400 return PyInt_FromLong((long)x);
401 return PyLong_FromUnsignedLong((unsigned long)x);
402 #endif
403 }
404
405 static PyObject *
406 nu_long(const char *p, const formatdef *f)
407 {
408 long x;
409 memcpy((char *)&x, p, sizeof x);
410 return PyInt_FromLong(x);
411 }
412
413 static PyObject *
414 nu_ulong(const char *p, const formatdef *f)
415 {
416 unsigned long x;
417 memcpy((char *)&x, p, sizeof x);
418 if (x <= LONG_MAX)
419 return PyInt_FromLong((long)x);
420 return PyLong_FromUnsignedLong(x);
421 }
422
423 /* Native mode doesn't support q or Q unless the platform C supports
424 long long (or, on Windows, __int64). */
425
426 #ifdef HAVE_LONG_LONG
427
428 static PyObject *
429 nu_longlong(const char *p, const formatdef *f)
430 {
431 PY_LONG_LONG x;
432 memcpy((char *)&x, p, sizeof x);
433 if (x >= LONG_MIN && x <= LONG_MAX)
434 return PyInt_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long));
435 return PyLong_FromLongLong(x);
436 }
437
438 static PyObject *
439 nu_ulonglong(const char *p, const formatdef *f)
440 {
441 unsigned PY_LONG_LONG x;
442 memcpy((char *)&x, p, sizeof x);
443 if (x <= LONG_MAX)
444 return PyInt_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long));
445 return PyLong_FromUnsignedLongLong(x);
446 }
447
448 #endif
449
450 static PyObject *
451 nu_bool(const char *p, const formatdef *f)
452 {
453 BOOL_TYPE x;
454 memcpy((char *)&x, p, sizeof x);
455 return PyBool_FromLong(x != 0);
456 }
457
458
459 static PyObject *
460 nu_float(const char *p, const formatdef *f)
461 {
462 float x;
463 memcpy((char *)&x, p, sizeof x);
464 return PyFloat_FromDouble((double)x);
465 }
466
467 static PyObject *
468 nu_double(const char *p, const formatdef *f)
469 {
470 double x;
471 memcpy((char *)&x, p, sizeof x);
472 return PyFloat_FromDouble(x);
473 }
474
475 static PyObject *
476 nu_void_p(const char *p, const formatdef *f)
477 {
478 void *x;
479 memcpy((char *)&x, p, sizeof x);
480 return PyLong_FromVoidPtr(x);
481 }
482
483 static int
484 np_byte(char *p, PyObject *v, const formatdef *f)
485 {
486 long x;
487 if (get_long(v, &x) < 0)
488 return -1;
489 if (x < -128 || x > 127){
490 PyErr_SetString(StructError,
491 "byte format requires -128 <= number <= 127");
492 return -1;
493 }
494 *p = (char)x;
495 return 0;
496 }
497
498 static int
499 np_ubyte(char *p, PyObject *v, const formatdef *f)
500 {
501 long x;
502 if (get_long(v, &x) < 0)
503 return -1;
504 if (x < 0 || x > 255){
505 PyErr_SetString(StructError,
506 "ubyte format requires 0 <= number <= 255");
507 return -1;
508 }
509 *p = (char)x;
510 return 0;
511 }
512
513 static int
514 np_char(char *p, PyObject *v, const formatdef *f)
515 {
516 if (!PyString_Check(v) || PyString_Size(v) != 1) {
517 PyErr_SetString(StructError,
518 "char format require string of length 1");
519 return -1;
520 }
521 *p = *PyString_AsString(v);
522 return 0;
523 }
524
525 static int
526 np_short(char *p, PyObject *v, const formatdef *f)
527 {
528 long x;
529 short y;
530 if (get_long(v, &x) < 0)
531 return -1;
532 if (x < SHRT_MIN || x > SHRT_MAX){
533 PyErr_SetString(StructError,
534 "short format requires " STRINGIFY(SHRT_MIN)
535 " <= number <= " STRINGIFY(SHRT_MAX));
536 return -1;
537 }
538 y = (short)x;
539 memcpy(p, (char *)&y, sizeof y);
540 return 0;
541 }
542
543 static int
544 np_ushort(char *p, PyObject *v, const formatdef *f)
545 {
546 long x;
547 unsigned short y;
548 if (get_long(v, &x) < 0)
549 return -1;
550 if (x < 0 || x > USHRT_MAX){
551 PyErr_SetString(StructError,
552 "ushort format requires 0 <= number <= " STRINGIFY(USHRT_MAX));
553 return -1;
554 }
555 y = (unsigned short)x;
556 memcpy(p, (char *)&y, sizeof y);
557 return 0;
558 }
559
560 static int
561 np_int(char *p, PyObject *v, const formatdef *f)
562 {
563 long x;
564 int y;
565 if (get_long(v, &x) < 0)
566 return -1;
567 #if (SIZEOF_LONG > SIZEOF_INT)
568 if ((x < ((long)INT_MIN)) || (x > ((long)INT_MAX)))
569 return _range_error(f, 0);
570 #endif
571 y = (int)x;
572 memcpy(p, (char *)&y, sizeof y);
573 return 0;
574 }
575
576 static int
577 np_uint(char *p, PyObject *v, const formatdef *f)
578 {
579 unsigned long x;
580 unsigned int y;
581 if (get_ulong(v, &x) < 0)
582 return -1;
583 y = (unsigned int)x;
584 #if (SIZEOF_LONG > SIZEOF_INT)
585 if (x > ((unsigned long)UINT_MAX))
586 return _range_error(f, 1);
587 #endif
588 memcpy(p, (char *)&y, sizeof y);
589 return 0;
590 }
591
592 static int
593 np_long(char *p, PyObject *v, const formatdef *f)
594 {
595 long x;
596 if (get_long(v, &x) < 0)
597 return -1;
598 memcpy(p, (char *)&x, sizeof x);
599 return 0;
600 }
601
602 static int
603 np_ulong(char *p, PyObject *v, const formatdef *f)
604 {
605 unsigned long x;
606 if (get_ulong(v, &x) < 0)
607 return -1;
608 memcpy(p, (char *)&x, sizeof x);
609 return 0;
610 }
611
612 #ifdef HAVE_LONG_LONG
613
614 static int
615 np_longlong(char *p, PyObject *v, const formatdef *f)
616 {
617 PY_LONG_LONG x;
618 if (get_longlong(v, &x) < 0)
619 return -1;
620 memcpy(p, (char *)&x, sizeof x);
621 return 0;
622 }
623
624 static int
625 np_ulonglong(char *p, PyObject *v, const formatdef *f)
626 {
627 unsigned PY_LONG_LONG x;
628 if (get_ulonglong(v, &x) < 0)
629 return -1;
630 memcpy(p, (char *)&x, sizeof x);
631 return 0;
632 }
633 #endif
634
635
636 static int
637 np_bool(char *p, PyObject *v, const formatdef *f)
638 {
639 int y;
640 BOOL_TYPE x;
641 y = PyObject_IsTrue(v);
642 if (y < 0)
643 return -1;
644 x = y;
645 memcpy(p, (char *)&x, sizeof x);
646 return 0;
647 }
648
649 static int
650 np_float(char *p, PyObject *v, const formatdef *f)
651 {
652 float x = (float)PyFloat_AsDouble(v);
653 if (x == -1 && PyErr_Occurred()) {
654 PyErr_SetString(StructError,
655 "required argument is not a float");
656 return -1;
657 }
658 memcpy(p, (char *)&x, sizeof x);
659 return 0;
660 }
661
662 static int
663 np_double(char *p, PyObject *v, const formatdef *f)
664 {
665 double x = PyFloat_AsDouble(v);
666 if (x == -1 && PyErr_Occurred()) {
667 PyErr_SetString(StructError,
668 "required argument is not a float");
669 return -1;
670 }
671 memcpy(p, (char *)&x, sizeof(double));
672 return 0;
673 }
674
675 static int
676 np_void_p(char *p, PyObject *v, const formatdef *f)
677 {
678 void *x;
679
680 v = get_pylong(v);
681 if (v == NULL)
682 return -1;
683 assert(PyLong_Check(v));
684 x = PyLong_AsVoidPtr(v);
685 Py_DECREF(v);
686 if (x == NULL && PyErr_Occurred())
687 return -1;
688 memcpy(p, (char *)&x, sizeof x);
689 return 0;
690 }
691
692 static formatdef native_table[] = {
693 {'x', sizeof(char), 0, NULL},
694 {'b', sizeof(char), 0, nu_byte, np_byte},
695 {'B', sizeof(char), 0, nu_ubyte, np_ubyte},
696 {'c', sizeof(char), 0, nu_char, np_char},
697 {'s', sizeof(char), 0, NULL},
698 {'p', sizeof(char), 0, NULL},
699 {'h', sizeof(short), SHORT_ALIGN, nu_short, np_short},
700 {'H', sizeof(short), SHORT_ALIGN, nu_ushort, np_ushort},
701 {'i', sizeof(int), INT_ALIGN, nu_int, np_int},
702 {'I', sizeof(int), INT_ALIGN, nu_uint, np_uint},
703 {'l', sizeof(long), LONG_ALIGN, nu_long, np_long},
704 {'L', sizeof(long), LONG_ALIGN, nu_ulong, np_ulong},
705 #ifdef HAVE_LONG_LONG
706 {'q', sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_longlong, np_longlong},
707 {'Q', sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_ulonglong,np_ulonglong},
708 #endif
709 {'?', sizeof(BOOL_TYPE), BOOL_ALIGN, nu_bool, np_bool},
710 {'f', sizeof(float), FLOAT_ALIGN, nu_float, np_float},
711 {'d', sizeof(double), DOUBLE_ALIGN, nu_double, np_double},
712 {'P', sizeof(void *), VOID_P_ALIGN, nu_void_p, np_void_p},
713 {0}
714 };
715
716 /* Big-endian routines. *****************************************************/
717
718 static PyObject *
719 bu_int(const char *p, const formatdef *f)
720 {
721 long x = 0;
722 Py_ssize_t i = f->size;
723 const unsigned char *bytes = (const unsigned char *)p;
724 do {
725 x = (x<<8) | *bytes++;
726 } while (--i > 0);
727 /* Extend the sign bit. */
728 if (SIZEOF_LONG > f->size)
729 x |= -(x & (1L << ((8 * f->size) - 1)));
730 return PyInt_FromLong(x);
731 }
732
733 static PyObject *
734 bu_uint(const char *p, const formatdef *f)
735 {
736 unsigned long x = 0;
737 Py_ssize_t i = f->size;
738 const unsigned char *bytes = (const unsigned char *)p;
739 do {
740 x = (x<<8) | *bytes++;
741 } while (--i > 0);
742 if (x <= LONG_MAX)
743 return PyInt_FromLong((long)x);
744 return PyLong_FromUnsignedLong(x);
745 }
746
747 static PyObject *
748 bu_longlong(const char *p, const formatdef *f)
749 {
750 #ifdef HAVE_LONG_LONG
751 PY_LONG_LONG x = 0;
752 Py_ssize_t i = f->size;
753 const unsigned char *bytes = (const unsigned char *)p;
754 do {
755 x = (x<<8) | *bytes++;
756 } while (--i > 0);
757 /* Extend the sign bit. */
758 if (SIZEOF_LONG_LONG > f->size)
759 x |= -(x & ((PY_LONG_LONG)1 << ((8 * f->size) - 1)));
760 if (x >= LONG_MIN && x <= LONG_MAX)
761 return PyInt_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long));
762 return PyLong_FromLongLong(x);
763 #else
764 return _PyLong_FromByteArray((const unsigned char *)p,
765 8,
766 0, /* little-endian */
767 1 /* signed */);
768 #endif
769 }
770
771 static PyObject *
772 bu_ulonglong(const char *p, const formatdef *f)
773 {
774 #ifdef HAVE_LONG_LONG
775 unsigned PY_LONG_LONG x = 0;
776 Py_ssize_t i = f->size;
777 const unsigned char *bytes = (const unsigned char *)p;
778 do {
779 x = (x<<8) | *bytes++;
780 } while (--i > 0);
781 if (x <= LONG_MAX)
782 return PyInt_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long));
783 return PyLong_FromUnsignedLongLong(x);
784 #else
785 return _PyLong_FromByteArray((const unsigned char *)p,
786 8,
787 0, /* little-endian */
788 0 /* signed */);
789 #endif
790 }
791
792 static PyObject *
793 bu_float(const char *p, const formatdef *f)
794 {
795 return unpack_float(p, 0);
796 }
797
798 static PyObject *
799 bu_double(const char *p, const formatdef *f)
800 {
801 return unpack_double(p, 0);
802 }
803
804 static PyObject *
805 bu_bool(const char *p, const formatdef *f)
806 {
807 char x;
808 memcpy((char *)&x, p, sizeof x);
809 return PyBool_FromLong(x != 0);
810 }
811
812 static int
813 bp_int(char *p, PyObject *v, const formatdef *f)
814 {
815 long x;
816 Py_ssize_t i;
817 if (get_long(v, &x) < 0)
818 return -1;
819 i = f->size;
820 if (i != SIZEOF_LONG) {
821 if ((i == 2) && (x < -32768 || x > 32767))
822 return _range_error(f, 0);
823 #if (SIZEOF_LONG != 4)
824 else if ((i == 4) && (x < -2147483648L || x > 2147483647L))
825 return _range_error(f, 0);
826 #endif
827 }
828 do {
829 p[--i] = (char)x;
830 x >>= 8;
831 } while (i > 0);
832 return 0;
833 }
834
835 static int
836 bp_uint(char *p, PyObject *v, const formatdef *f)
837 {
838 unsigned long x;
839 Py_ssize_t i;
840 if (get_ulong(v, &x) < 0)
841 return -1;
842 i = f->size;
843 if (i != SIZEOF_LONG) {
844 unsigned long maxint = 1;
845 maxint <<= (unsigned long)(i * 8);
846 if (x >= maxint)
847 return _range_error(f, 1);
848 }
849 do {
850 p[--i] = (char)x;
851 x >>= 8;
852 } while (i > 0);
853 return 0;
854 }
855
856 static int
857 bp_longlong(char *p, PyObject *v, const formatdef *f)
858 {
859 int res;
860 v = get_pylong(v);
861 if (v == NULL)
862 return -1;
863 res = _PyLong_AsByteArray((PyLongObject *)v,
864 (unsigned char *)p,
865 8,
866 0, /* little_endian */
867 1 /* signed */);
868 Py_DECREF(v);
869 return res;
870 }
871
872 static int
873 bp_ulonglong(char *p, PyObject *v, const formatdef *f)
874 {
875 int res;
876 v = get_pylong(v);
877 if (v == NULL)
878 return -1;
879 res = _PyLong_AsByteArray((PyLongObject *)v,
880 (unsigned char *)p,
881 8,
882 0, /* little_endian */
883 0 /* signed */);
884 Py_DECREF(v);
885 return res;
886 }
887
888 static int
889 bp_float(char *p, PyObject *v, const formatdef *f)
890 {
891 double x = PyFloat_AsDouble(v);
892 if (x == -1 && PyErr_Occurred()) {
893 PyErr_SetString(StructError,
894 "required argument is not a float");
895 return -1;
896 }
897 return _PyFloat_Pack4(x, (unsigned char *)p, 0);
898 }
899
900 static int
901 bp_double(char *p, PyObject *v, const formatdef *f)
902 {
903 double x = PyFloat_AsDouble(v);
904 if (x == -1 && PyErr_Occurred()) {
905 PyErr_SetString(StructError,
906 "required argument is not a float");
907 return -1;
908 }
909 return _PyFloat_Pack8(x, (unsigned char *)p, 0);
910 }
911
912 static int
913 bp_bool(char *p, PyObject *v, const formatdef *f)
914 {
915 int y;
916 y = PyObject_IsTrue(v);
917 if (y < 0)
918 return -1;
919 *p = (char)y;
920 return 0;
921 }
922
923 static formatdef bigendian_table[] = {
924 {'x', 1, 0, NULL},
925 {'b', 1, 0, nu_byte, np_byte},
926 {'B', 1, 0, nu_ubyte, np_ubyte},
927 {'c', 1, 0, nu_char, np_char},
928 {'s', 1, 0, NULL},
929 {'p', 1, 0, NULL},
930 {'h', 2, 0, bu_int, bp_int},
931 {'H', 2, 0, bu_uint, bp_uint},
932 {'i', 4, 0, bu_int, bp_int},
933 {'I', 4, 0, bu_uint, bp_uint},
934 {'l', 4, 0, bu_int, bp_int},
935 {'L', 4, 0, bu_uint, bp_uint},
936 {'q', 8, 0, bu_longlong, bp_longlong},
937 {'Q', 8, 0, bu_ulonglong, bp_ulonglong},
938 {'?', 1, 0, bu_bool, bp_bool},
939 {'f', 4, 0, bu_float, bp_float},
940 {'d', 8, 0, bu_double, bp_double},
941 {0}
942 };
943
944 /* Little-endian routines. *****************************************************/
945
946 static PyObject *
947 lu_int(const char *p, const formatdef *f)
948 {
949 long x = 0;
950 Py_ssize_t i = f->size;
951 const unsigned char *bytes = (const unsigned char *)p;
952 do {
953 x = (x<<8) | bytes[--i];
954 } while (i > 0);
955 /* Extend the sign bit. */
956 if (SIZEOF_LONG > f->size)
957 x |= -(x & (1L << ((8 * f->size) - 1)));
958 return PyInt_FromLong(x);
959 }
960
961 static PyObject *
962 lu_uint(const char *p, const formatdef *f)
963 {
964 unsigned long x = 0;
965 Py_ssize_t i = f->size;
966 const unsigned char *bytes = (const unsigned char *)p;
967 do {
968 x = (x<<8) | bytes[--i];
969 } while (i > 0);
970 if (x <= LONG_MAX)
971 return PyInt_FromLong((long)x);
972 return PyLong_FromUnsignedLong((long)x);
973 }
974
975 static PyObject *
976 lu_longlong(const char *p, const formatdef *f)
977 {
978 #ifdef HAVE_LONG_LONG
979 PY_LONG_LONG x = 0;
980 Py_ssize_t i = f->size;
981 const unsigned char *bytes = (const unsigned char *)p;
982 do {
983 x = (x<<8) | bytes[--i];
984 } while (i > 0);
985 /* Extend the sign bit. */
986 if (SIZEOF_LONG_LONG > f->size)
987 x |= -(x & ((PY_LONG_LONG)1 << ((8 * f->size) - 1)));
988 if (x >= LONG_MIN && x <= LONG_MAX)
989 return PyInt_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long));
990 return PyLong_FromLongLong(x);
991 #else
992 return _PyLong_FromByteArray((const unsigned char *)p,
993 8,
994 1, /* little-endian */
995 1 /* signed */);
996 #endif
997 }
998
999 static PyObject *
1000 lu_ulonglong(const char *p, const formatdef *f)
1001 {
1002 #ifdef HAVE_LONG_LONG
1003 unsigned PY_LONG_LONG x = 0;
1004 Py_ssize_t i = f->size;
1005 const unsigned char *bytes = (const unsigned char *)p;
1006 do {
1007 x = (x<<8) | bytes[--i];
1008 } while (i > 0);
1009 if (x <= LONG_MAX)
1010 return PyInt_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long));
1011 return PyLong_FromUnsignedLongLong(x);
1012 #else
1013 return _PyLong_FromByteArray((const unsigned char *)p,
1014 8,
1015 1, /* little-endian */
1016 0 /* signed */);
1017 #endif
1018 }
1019
1020 static PyObject *
1021 lu_float(const char *p, const formatdef *f)
1022 {
1023 return unpack_float(p, 1);
1024 }
1025
1026 static PyObject *
1027 lu_double(const char *p, const formatdef *f)
1028 {
1029 return unpack_double(p, 1);
1030 }
1031
1032 static int
1033 lp_int(char *p, PyObject *v, const formatdef *f)
1034 {
1035 long x;
1036 Py_ssize_t i;
1037 if (get_long(v, &x) < 0)
1038 return -1;
1039 i = f->size;
1040 if (i != SIZEOF_LONG) {
1041 if ((i == 2) && (x < -32768 || x > 32767))
1042 return _range_error(f, 0);
1043 #if (SIZEOF_LONG != 4)
1044 else if ((i == 4) && (x < -2147483648L || x > 2147483647L))
1045 return _range_error(f, 0);
1046 #endif
1047 }
1048 do {
1049 *p++ = (char)x;
1050 x >>= 8;
1051 } while (--i > 0);
1052 return 0;
1053 }
1054
1055 static int
1056 lp_uint(char *p, PyObject *v, const formatdef *f)
1057 {
1058 unsigned long x;
1059 Py_ssize_t i;
1060 if (get_ulong(v, &x) < 0)
1061 return -1;
1062 i = f->size;
1063 if (i != SIZEOF_LONG) {
1064 unsigned long maxint = 1;
1065 maxint <<= (unsigned long)(i * 8);
1066 if (x >= maxint)
1067 return _range_error(f, 1);
1068 }
1069 do {
1070 *p++ = (char)x;
1071 x >>= 8;
1072 } while (--i > 0);
1073 return 0;
1074 }
1075
1076 static int
1077 lp_longlong(char *p, PyObject *v, const formatdef *f)
1078 {
1079 int res;
1080 v = get_pylong(v);
1081 if (v == NULL)
1082 return -1;
1083 res = _PyLong_AsByteArray((PyLongObject*)v,
1084 (unsigned char *)p,
1085 8,
1086 1, /* little_endian */
1087 1 /* signed */);
1088 Py_DECREF(v);
1089 return res;
1090 }
1091
1092 static int
1093 lp_ulonglong(char *p, PyObject *v, const formatdef *f)
1094 {
1095 int res;
1096 v = get_pylong(v);
1097 if (v == NULL)
1098 return -1;
1099 res = _PyLong_AsByteArray((PyLongObject*)v,
1100 (unsigned char *)p,
1101 8,
1102 1, /* little_endian */
1103 0 /* signed */);
1104 Py_DECREF(v);
1105 return res;
1106 }
1107
1108 static int
1109 lp_float(char *p, PyObject *v, const formatdef *f)
1110 {
1111 double x = PyFloat_AsDouble(v);
1112 if (x == -1 && PyErr_Occurred()) {
1113 PyErr_SetString(StructError,
1114 "required argument is not a float");
1115 return -1;
1116 }
1117 return _PyFloat_Pack4(x, (unsigned char *)p, 1);
1118 }
1119
1120 static int
1121 lp_double(char *p, PyObject *v, const formatdef *f)
1122 {
1123 double x = PyFloat_AsDouble(v);
1124 if (x == -1 && PyErr_Occurred()) {
1125 PyErr_SetString(StructError,
1126 "required argument is not a float");
1127 return -1;
1128 }
1129 return _PyFloat_Pack8(x, (unsigned char *)p, 1);
1130 }
1131
1132 static formatdef lilendian_table[] = {
1133 {'x', 1, 0, NULL},
1134 {'b', 1, 0, nu_byte, np_byte},
1135 {'B', 1, 0, nu_ubyte, np_ubyte},
1136 {'c', 1, 0, nu_char, np_char},
1137 {'s', 1, 0, NULL},
1138 {'p', 1, 0, NULL},
1139 {'h', 2, 0, lu_int, lp_int},
1140 {'H', 2, 0, lu_uint, lp_uint},
1141 {'i', 4, 0, lu_int, lp_int},
1142 {'I', 4, 0, lu_uint, lp_uint},
1143 {'l', 4, 0, lu_int, lp_int},
1144 {'L', 4, 0, lu_uint, lp_uint},
1145 {'q', 8, 0, lu_longlong, lp_longlong},
1146 {'Q', 8, 0, lu_ulonglong, lp_ulonglong},
1147 {'?', 1, 0, bu_bool, bp_bool}, /* Std rep not endian dep,
1148 but potentially different from native rep -- reuse bx_bool funcs. */
1149 {'f', 4, 0, lu_float, lp_float},
1150 {'d', 8, 0, lu_double, lp_double},
1151 {0}
1152 };
1153
1154
1155 static const formatdef *
1156 whichtable(char **pfmt)
1157 {
1158 const char *fmt = (*pfmt)++; /* May be backed out of later */
1159 switch (*fmt) {
1160 case '<':
1161 return lilendian_table;
1162 case '>':
1163 case '!': /* Network byte order is big-endian */
1164 return bigendian_table;
1165 case '=': { /* Host byte order -- different from native in alignment! */
1166 int n = 1;
1167 char *p = (char *) &n;
1168 if (*p == 1)
1169 return lilendian_table;
1170 else
1171 return bigendian_table;
1172 }
1173 default:
1174 --*pfmt; /* Back out of pointer increment */
1175 /* Fall through */
1176 case '@':
1177 return native_table;
1178 }
1179 }
1180
1181
1182 /* Get the table entry for a format code */
1183
1184 static const formatdef *
1185 getentry(int c, const formatdef *f)
1186 {
1187 for (; f->format != '\0'; f++) {
1188 if (f->format == c) {
1189 return f;
1190 }
1191 }
1192 PyErr_SetString(StructError, "bad char in struct format");
1193 return NULL;
1194 }
1195
1196
1197 /* Align a size according to a format code. Return -1 on overflow. */
1198
1199 static Py_ssize_t
1200 align(Py_ssize_t size, char c, const formatdef *e)
1201 {
1202 Py_ssize_t extra;
1203
1204 if (e->format == c) {
1205 if (e->alignment && size > 0) {
1206 extra = (e->alignment - 1) - (size - 1) % (e->alignment);
1207 if (extra > PY_SSIZE_T_MAX - size)
1208 return -1;
1209 size += extra;
1210 }
1211 }
1212 return size;
1213 }
1214
1215
1216 /* calculate the size of a format string */
1217
1218 static int
1219 prepare_s(PyStructObject *self)
1220 {
1221 const formatdef *f;
1222 const formatdef *e;
1223 formatcode *codes;
1224
1225 const char *s;
1226 const char *fmt;
1227 char c;
1228 Py_ssize_t size, len, num, itemsize;
1229
1230 fmt = PyString_AS_STRING(self->s_format);
1231
1232 f = whichtable((char **)&fmt);
1233
1234 s = fmt;
1235 size = 0;
1236 len = 0;
1237 while ((c = *s++) != '\0') {
1238 if (isspace(Py_CHARMASK(c)))
1239 continue;
1240 if ('0' <= c && c <= '9') {
1241 num = c - '0';
1242 while ('0' <= (c = *s++) && c <= '9') {
1243 /* overflow-safe version of
1244 if (num*10 + (c - '0') > PY_SSIZE_T_MAX) { ... } */
1245 if (num >= PY_SSIZE_T_MAX / 10 && (
1246 num > PY_SSIZE_T_MAX / 10 ||
1247 (c - '0') > PY_SSIZE_T_MAX % 10))
1248 goto overflow;
1249 num = num*10 + (c - '0');
1250 }
1251 if (c == '\0')
1252 break;
1253 }
1254 else
1255 num = 1;
1256
1257 e = getentry(c, f);
1258 if (e == NULL)
1259 return -1;
1260
1261 switch (c) {
1262 case 's': /* fall through */
1263 case 'p': len++; break;
1264 case 'x': break;
1265 default: len += num; break;
1266 }
1267
1268 itemsize = e->size;
1269 size = align(size, c, e);
1270 if (size == -1)
1271 goto overflow;
1272
1273 /* if (size + num * itemsize > PY_SSIZE_T_MAX) { ... } */
1274 if (num > (PY_SSIZE_T_MAX - size) / itemsize)
1275 goto overflow;
1276 size += num * itemsize;
1277 }
1278
1279 /* check for overflow */
1280 if ((len + 1) > (PY_SSIZE_T_MAX / sizeof(formatcode))) {
1281 PyErr_NoMemory();
1282 return -1;
1283 }
1284
1285 self->s_size = size;
1286 self->s_len = len;
1287 codes = PyMem_MALLOC((len + 1) * sizeof(formatcode));
1288 if (codes == NULL) {
1289 PyErr_NoMemory();
1290 return -1;
1291 }
1292 /* Free any s_codes value left over from a previous initialization. */
1293 if (self->s_codes != NULL)
1294 PyMem_FREE(self->s_codes);
1295 self->s_codes = codes;
1296
1297 s = fmt;
1298 size = 0;
1299 while ((c = *s++) != '\0') {
1300 if (isspace(Py_CHARMASK(c)))
1301 continue;
1302 if ('0' <= c && c <= '9') {
1303 num = c - '0';
1304 while ('0' <= (c = *s++) && c <= '9')
1305 num = num*10 + (c - '0');
1306 if (c == '\0')
1307 break;
1308 }
1309 else
1310 num = 1;
1311
1312 e = getentry(c, f);
1313
1314 size = align(size, c, e);
1315 if (c == 's' || c == 'p') {
1316 codes->offset = size;
1317 codes->size = num;
1318 codes->fmtdef = e;
1319 codes++;
1320 size += num;
1321 } else if (c == 'x') {
1322 size += num;
1323 } else {
1324 while (--num >= 0) {
1325 codes->offset = size;
1326 codes->size = e->size;
1327 codes->fmtdef = e;
1328 codes++;
1329 size += e->size;
1330 }
1331 }
1332 }
1333 codes->fmtdef = NULL;
1334 codes->offset = size;
1335 codes->size = 0;
1336
1337 return 0;
1338
1339 overflow:
1340 PyErr_SetString(StructError,
1341 "total struct size too long");
1342 return -1;
1343 }
1344
1345 static PyObject *
1346 s_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
1347 {
1348 PyObject *self;
1349
1350 assert(type != NULL && type->tp_alloc != NULL);
1351
1352 self = type->tp_alloc(type, 0);
1353 if (self != NULL) {
1354 PyStructObject *s = (PyStructObject*)self;
1355 Py_INCREF(Py_None);
1356 s->s_format = Py_None;
1357 s->s_codes = NULL;
1358 s->s_size = -1;
1359 s->s_len = -1;
1360 }
1361 return self;
1362 }
1363
1364 static int
1365 s_init(PyObject *self, PyObject *args, PyObject *kwds)
1366 {
1367 PyStructObject *soself = (PyStructObject *)self;
1368 PyObject *o_format = NULL;
1369 int ret = 0;
1370 static char *kwlist[] = {"format", 0};
1371
1372 assert(PyStruct_Check(self));
1373
1374 if (!PyArg_ParseTupleAndKeywords(args, kwds, "S:Struct", kwlist,
1375 &o_format))
1376 return -1;
1377
1378 Py_INCREF(o_format);
1379 Py_CLEAR(soself->s_format);
1380 soself->s_format = o_format;
1381
1382 ret = prepare_s(soself);
1383 return ret;
1384 }
1385
1386 static void
1387 s_dealloc(PyStructObject *s)
1388 {
1389 if (s->weakreflist != NULL)
1390 PyObject_ClearWeakRefs((PyObject *)s);
1391 if (s->s_codes != NULL) {
1392 PyMem_FREE(s->s_codes);
1393 }
1394 Py_XDECREF(s->s_format);
1395 Py_TYPE(s)->tp_free((PyObject *)s);
1396 }
1397
1398 static PyObject *
1399 s_unpack_internal(PyStructObject *soself, char *startfrom) {
1400 formatcode *code;
1401 Py_ssize_t i = 0;
1402 PyObject *result = PyTuple_New(soself->s_len);
1403 if (result == NULL)
1404 return NULL;
1405
1406 for (code = soself->s_codes; code->fmtdef != NULL; code++) {
1407 PyObject *v;
1408 const formatdef *e = code->fmtdef;
1409 const char *res = startfrom + code->offset;
1410 if (e->format == 's') {
1411 v = PyString_FromStringAndSize(res, code->size);
1412 } else if (e->format == 'p') {
1413 Py_ssize_t n = *(unsigned char*)res;
1414 if (n >= code->size)
1415 n = code->size - 1;
1416 v = PyString_FromStringAndSize(res + 1, n);
1417 } else {
1418 v = e->unpack(res, e);
1419 }
1420 if (v == NULL)
1421 goto fail;
1422 PyTuple_SET_ITEM(result, i++, v);
1423 }
1424
1425 return result;
1426 fail:
1427 Py_DECREF(result);
1428 return NULL;
1429 }
1430
1431
1432 PyDoc_STRVAR(s_unpack__doc__,
1433 "S.unpack(str) -> (v1, v2, ...)\n\
1434 \n\
1435 Return tuple containing values unpacked according to this Struct's format.\n\
1436 Requires len(str) == self.size. See struct.__doc__ for more on format\n\
1437 strings.");
1438
1439 static PyObject *
1440 s_unpack(PyObject *self, PyObject *inputstr)
1441 {
1442 char *start;
1443 Py_ssize_t len;
1444 PyObject *args=NULL, *result;
1445 PyStructObject *soself = (PyStructObject *)self;
1446 assert(PyStruct_Check(self));
1447 assert(soself->s_codes != NULL);
1448 if (inputstr == NULL)
1449 goto fail;
1450 if (PyString_Check(inputstr) &&
1451 PyString_GET_SIZE(inputstr) == soself->s_size) {
1452 return s_unpack_internal(soself, PyString_AS_STRING(inputstr));
1453 }
1454 args = PyTuple_Pack(1, inputstr);
1455 if (args == NULL)
1456 return NULL;
1457 if (!PyArg_ParseTuple(args, "s#:unpack", &start, &len))
1458 goto fail;
1459 if (soself->s_size != len)
1460 goto fail;
1461 result = s_unpack_internal(soself, start);
1462 Py_DECREF(args);
1463 return result;
1464
1465 fail:
1466 Py_XDECREF(args);
1467 PyErr_Format(StructError,
1468 "unpack requires a string argument of length %zd",
1469 soself->s_size);
1470 return NULL;
1471 }
1472
1473 PyDoc_STRVAR(s_unpack_from__doc__,
1474 "S.unpack_from(buffer[, offset]) -> (v1, v2, ...)\n\
1475 \n\
1476 Return tuple containing values unpacked according to this Struct's format.\n\
1477 Unlike unpack, unpack_from can unpack values from any object supporting\n\
1478 the buffer API, not just str. Requires len(buffer[offset:]) >= self.size.\n\
1479 See struct.__doc__ for more on format strings.");
1480
1481 static PyObject *
1482 s_unpack_from(PyObject *self, PyObject *args, PyObject *kwds)
1483 {
1484 static char *kwlist[] = {"buffer", "offset", 0};
1485 #if (PY_VERSION_HEX < 0x02050000)
1486 static char *fmt = "z#|i:unpack_from";
1487 #else
1488 static char *fmt = "z#|n:unpack_from";
1489 #endif
1490 Py_ssize_t buffer_len = 0, offset = 0;
1491 char *buffer = NULL;
1492 PyStructObject *soself = (PyStructObject *)self;
1493 assert(PyStruct_Check(self));
1494 assert(soself->s_codes != NULL);
1495
1496 if (!PyArg_ParseTupleAndKeywords(args, kwds, fmt, kwlist,
1497 &buffer, &buffer_len, &offset))
1498 return NULL;
1499
1500 if (buffer == NULL) {
1501 PyErr_Format(StructError,
1502 "unpack_from requires a buffer argument");
1503 return NULL;
1504 }
1505
1506 if (offset < 0)
1507 offset += buffer_len;
1508
1509 if (offset < 0 || (buffer_len - offset) < soself->s_size) {
1510 PyErr_Format(StructError,
1511 "unpack_from requires a buffer of at least %zd bytes",
1512 soself->s_size);
1513 return NULL;
1514 }
1515 return s_unpack_internal(soself, buffer + offset);
1516 }
1517
1518
1519 /*
1520 * Guts of the pack function.
1521 *
1522 * Takes a struct object, a tuple of arguments, and offset in that tuple of
1523 * argument for where to start processing the arguments for packing, and a
1524 * character buffer for writing the packed string. The caller must insure
1525 * that the buffer may contain the required length for packing the arguments.
1526 * 0 is returned on success, 1 is returned if there is an error.
1527 *
1528 */
1529 static int
1530 s_pack_internal(PyStructObject *soself, PyObject *args, int offset, char* buf)
1531 {
1532 formatcode *code;
1533 /* XXX(nnorwitz): why does i need to be a local? can we use
1534 the offset parameter or do we need the wider width? */
1535 Py_ssize_t i;
1536
1537 memset(buf, '\0', soself->s_size);
1538 i = offset;
1539 for (code = soself->s_codes; code->fmtdef != NULL; code++) {
1540 Py_ssize_t n;
1541 PyObject *v = PyTuple_GET_ITEM(args, i++);
1542 const formatdef *e = code->fmtdef;
1543 char *res = buf + code->offset;
1544 if (e->format == 's') {
1545 if (!PyString_Check(v)) {
1546 PyErr_SetString(StructError,
1547 "argument for 's' must "
1548 "be a string");
1549 return -1;
1550 }
1551 n = PyString_GET_SIZE(v);
1552 if (n > code->size)
1553 n = code->size;
1554 if (n > 0)
1555 memcpy(res, PyString_AS_STRING(v), n);
1556 } else if (e->format == 'p') {
1557 if (!PyString_Check(v)) {
1558 PyErr_SetString(StructError,
1559 "argument for 'p' must "
1560 "be a string");
1561 return -1;
1562 }
1563 n = PyString_GET_SIZE(v);
1564 if (n > (code->size - 1))
1565 n = code->size - 1;
1566 if (n > 0)
1567 memcpy(res + 1, PyString_AS_STRING(v), n);
1568 if (n > 255)
1569 n = 255;
1570 *res = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
1571 } else if (e->pack(res, v, e) < 0) {
1572 if (strchr(integer_codes, e->format) != NULL &&
1573 PyErr_ExceptionMatches(PyExc_OverflowError))
1574 PyErr_Format(StructError,
1575 "integer out of range for "
1576 "'%c' format code",
1577 e->format);
1578 return -1;
1579 }
1580 }
1581
1582 /* Success */
1583 return 0;
1584 }
1585
1586
1587 PyDoc_STRVAR(s_pack__doc__,
1588 "S.pack(v1, v2, ...) -> string\n\
1589 \n\
1590 Return a string containing values v1, v2, ... packed according to this\n\
1591 Struct's format. See struct.__doc__ for more on format strings.");
1592
1593 static PyObject *
1594 s_pack(PyObject *self, PyObject *args)
1595 {
1596 PyStructObject *soself;
1597 PyObject *result;
1598
1599 /* Validate arguments. */
1600 soself = (PyStructObject *)self;
1601 assert(PyStruct_Check(self));
1602 assert(soself->s_codes != NULL);
1603 if (PyTuple_GET_SIZE(args) != soself->s_len)
1604 {
1605 PyErr_Format(StructError,
1606 "pack requires exactly %zd arguments", soself->s_len);
1607 return NULL;
1608 }
1609
1610 /* Allocate a new string */
1611 result = PyString_FromStringAndSize((char *)NULL, soself->s_size);
1612 if (result == NULL)
1613 return NULL;
1614
1615 /* Call the guts */
1616 if ( s_pack_internal(soself, args, 0, PyString_AS_STRING(result)) != 0 ) {
1617 Py_DECREF(result);
1618 return NULL;
1619 }
1620
1621 return result;
1622 }
1623
1624 PyDoc_STRVAR(s_pack_into__doc__,
1625 "S.pack_into(buffer, offset, v1, v2, ...)\n\
1626 \n\
1627 Pack the values v1, v2, ... according to this Struct's format, write \n\
1628 the packed bytes into the writable buffer buf starting at offset. Note\n\
1629 that the offset is not an optional argument. See struct.__doc__ for \n\
1630 more on format strings.");
1631
1632 static PyObject *
1633 s_pack_into(PyObject *self, PyObject *args)
1634 {
1635 PyStructObject *soself;
1636 char *buffer;
1637 Py_ssize_t buffer_len, offset;
1638
1639 /* Validate arguments. +1 is for the first arg as buffer. */
1640 soself = (PyStructObject *)self;
1641 assert(PyStruct_Check(self));
1642 assert(soself->s_codes != NULL);
1643 if (PyTuple_GET_SIZE(args) != (soself->s_len + 2))
1644 {
1645 PyErr_Format(StructError,
1646 "pack_into requires exactly %zd arguments",
1647 (soself->s_len + 2));
1648 return NULL;
1649 }
1650
1651 /* Extract a writable memory buffer from the first argument */
1652 if ( PyObject_AsWriteBuffer(PyTuple_GET_ITEM(args, 0),
1653 (void**)&buffer, &buffer_len) == -1 ) {
1654 return NULL;
1655 }
1656 assert( buffer_len >= 0 );
1657
1658 /* Extract the offset from the first argument */
1659 offset = PyInt_AsSsize_t(PyTuple_GET_ITEM(args, 1));
1660 if (offset == -1 && PyErr_Occurred())
1661 return NULL;
1662
1663 /* Support negative offsets. */
1664 if (offset < 0)
1665 offset += buffer_len;
1666
1667 /* Check boundaries */
1668 if (offset < 0 || (buffer_len - offset) < soself->s_size) {
1669 PyErr_Format(StructError,
1670 "pack_into requires a buffer of at least %zd bytes",
1671 soself->s_size);
1672 return NULL;
1673 }
1674
1675 /* Call the guts */
1676 if ( s_pack_internal(soself, args, 2, buffer + offset) != 0 ) {
1677 return NULL;
1678 }
1679
1680 Py_RETURN_NONE;
1681 }
1682
1683 static PyObject *
1684 s_get_format(PyStructObject *self, void *unused)
1685 {
1686 Py_INCREF(self->s_format);
1687 return self->s_format;
1688 }
1689
1690 static PyObject *
1691 s_get_size(PyStructObject *self, void *unused)
1692 {
1693 return PyInt_FromSsize_t(self->s_size);
1694 }
1695
1696 /* List of functions */
1697
1698 static struct PyMethodDef s_methods[] = {
1699 {"pack", s_pack, METH_VARARGS, s_pack__doc__},
1700 {"pack_into", s_pack_into, METH_VARARGS, s_pack_into__doc__},
1701 {"unpack", s_unpack, METH_O, s_unpack__doc__},
1702 {"unpack_from", (PyCFunction)s_unpack_from, METH_VARARGS|METH_KEYWORDS,
1703 s_unpack_from__doc__},
1704 {NULL, NULL} /* sentinel */
1705 };
1706
1707 PyDoc_STRVAR(s__doc__, "Compiled struct object");
1708
1709 #define OFF(x) offsetof(PyStructObject, x)
1710
1711 static PyGetSetDef s_getsetlist[] = {
1712 {"format", (getter)s_get_format, (setter)NULL, "struct format string", NULL},
1713 {"size", (getter)s_get_size, (setter)NULL, "struct size in bytes", NULL},
1714 {NULL} /* sentinel */
1715 };
1716
1717 static
1718 PyTypeObject PyStructType = {
1719 PyVarObject_HEAD_INIT(NULL, 0)
1720 "Struct",
1721 sizeof(PyStructObject),
1722 0,
1723 (destructor)s_dealloc, /* tp_dealloc */
1724 0, /* tp_print */
1725 0, /* tp_getattr */
1726 0, /* tp_setattr */
1727 0, /* tp_compare */
1728 0, /* tp_repr */
1729 0, /* tp_as_number */
1730 0, /* tp_as_sequence */
1731 0, /* tp_as_mapping */
1732 0, /* tp_hash */
1733 0, /* tp_call */
1734 0, /* tp_str */
1735 PyObject_GenericGetAttr, /* tp_getattro */
1736 PyObject_GenericSetAttr, /* tp_setattro */
1737 0, /* tp_as_buffer */
1738 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_WEAKREFS,/* tp_flags */
1739 s__doc__, /* tp_doc */
1740 0, /* tp_traverse */
1741 0, /* tp_clear */
1742 0, /* tp_richcompare */
1743 offsetof(PyStructObject, weakreflist), /* tp_weaklistoffset */
1744 0, /* tp_iter */
1745 0, /* tp_iternext */
1746 s_methods, /* tp_methods */
1747 NULL, /* tp_members */
1748 s_getsetlist, /* tp_getset */
1749 0, /* tp_base */
1750 0, /* tp_dict */
1751 0, /* tp_descr_get */
1752 0, /* tp_descr_set */
1753 0, /* tp_dictoffset */
1754 s_init, /* tp_init */
1755 PyType_GenericAlloc,/* tp_alloc */
1756 s_new, /* tp_new */
1757 PyObject_Del, /* tp_free */
1758 };
1759
1760
1761 /* ---- Standalone functions ---- */
1762
1763 #define MAXCACHE 100
1764 static PyObject *cache = NULL;
1765
1766 static PyObject *
1767 cache_struct(PyObject *fmt)
1768 {
1769 PyObject * s_object;
1770
1771 if (cache == NULL) {
1772 cache = PyDict_New();
1773 if (cache == NULL)
1774 return NULL;
1775 }
1776
1777 s_object = PyDict_GetItem(cache, fmt);
1778 if (s_object != NULL) {
1779 Py_INCREF(s_object);
1780 return s_object;
1781 }
1782
1783 s_object = PyObject_CallFunctionObjArgs((PyObject *)(&PyStructType), fmt, NULL);
1784 if (s_object != NULL) {
1785 if (PyDict_Size(cache) >= MAXCACHE)
1786 PyDict_Clear(cache);
1787 /* Attempt to cache the result */
1788 if (PyDict_SetItem(cache, fmt, s_object) == -1)
1789 PyErr_Clear();
1790 }
1791 return s_object;
1792 }
1793
1794 PyDoc_STRVAR(clearcache_doc,
1795 "Clear the internal cache.");
1796
1797 static PyObject *
1798 clearcache(PyObject *self)
1799 {
1800 Py_CLEAR(cache);
1801 Py_RETURN_NONE;
1802 }
1803
1804 PyDoc_STRVAR(calcsize_doc,
1805 "Return size of C struct described by format string fmt.");
1806
1807 static PyObject *
1808 calcsize(PyObject *self, PyObject *fmt)
1809 {
1810 Py_ssize_t n;
1811 PyObject *s_object = cache_struct(fmt);
1812 if (s_object == NULL)
1813 return NULL;
1814 n = ((PyStructObject *)s_object)->s_size;
1815 Py_DECREF(s_object);
1816 return PyInt_FromSsize_t(n);
1817 }
1818
1819 PyDoc_STRVAR(pack_doc,
1820 "Return string containing values v1, v2, ... packed according to fmt.");
1821
1822 static PyObject *
1823 pack(PyObject *self, PyObject *args)
1824 {
1825 PyObject *s_object, *fmt, *newargs, *result;
1826 Py_ssize_t n = PyTuple_GET_SIZE(args);
1827
1828 if (n == 0) {
1829 PyErr_SetString(PyExc_TypeError, "missing format argument");
1830 return NULL;
1831 }
1832 fmt = PyTuple_GET_ITEM(args, 0);
1833 newargs = PyTuple_GetSlice(args, 1, n);
1834 if (newargs == NULL)
1835 return NULL;
1836
1837 s_object = cache_struct(fmt);
1838 if (s_object == NULL) {
1839 Py_DECREF(newargs);
1840 return NULL;
1841 }
1842 result = s_pack(s_object, newargs);
1843 Py_DECREF(newargs);
1844 Py_DECREF(s_object);
1845 return result;
1846 }
1847
1848 PyDoc_STRVAR(pack_into_doc,
1849 "Pack the values v1, v2, ... according to fmt.\n\
1850 Write the packed bytes into the writable buffer buf starting at offset.");
1851
1852 static PyObject *
1853 pack_into(PyObject *self, PyObject *args)
1854 {
1855 PyObject *s_object, *fmt, *newargs, *result;
1856 Py_ssize_t n = PyTuple_GET_SIZE(args);
1857
1858 if (n == 0) {
1859 PyErr_SetString(PyExc_TypeError, "missing format argument");
1860 return NULL;
1861 }
1862 fmt = PyTuple_GET_ITEM(args, 0);
1863 newargs = PyTuple_GetSlice(args, 1, n);
1864 if (newargs == NULL)
1865 return NULL;
1866
1867 s_object = cache_struct(fmt);
1868 if (s_object == NULL) {
1869 Py_DECREF(newargs);
1870 return NULL;
1871 }
1872 result = s_pack_into(s_object, newargs);
1873 Py_DECREF(newargs);
1874 Py_DECREF(s_object);
1875 return result;
1876 }
1877
1878 PyDoc_STRVAR(unpack_doc,
1879 "Unpack the string containing packed C structure data, according to fmt.\n\
1880 Requires len(string) == calcsize(fmt).");
1881
1882 static PyObject *
1883 unpack(PyObject *self, PyObject *args)
1884 {
1885 PyObject *s_object, *fmt, *inputstr, *result;
1886
1887 if (!PyArg_UnpackTuple(args, "unpack", 2, 2, &fmt, &inputstr))
1888 return NULL;
1889
1890 s_object = cache_struct(fmt);
1891 if (s_object == NULL)
1892 return NULL;
1893 result = s_unpack(s_object, inputstr);
1894 Py_DECREF(s_object);
1895 return result;
1896 }
1897
1898 PyDoc_STRVAR(unpack_from_doc,
1899 "Unpack the buffer, containing packed C structure data, according to\n\
1900 fmt, starting at offset. Requires len(buffer[offset:]) >= calcsize(fmt).");
1901
1902 static PyObject *
1903 unpack_from(PyObject *self, PyObject *args, PyObject *kwds)
1904 {
1905 PyObject *s_object, *fmt, *newargs, *result;
1906 Py_ssize_t n = PyTuple_GET_SIZE(args);
1907
1908 if (n == 0) {
1909 PyErr_SetString(PyExc_TypeError, "missing format argument");
1910 return NULL;
1911 }
1912 fmt = PyTuple_GET_ITEM(args, 0);
1913 newargs = PyTuple_GetSlice(args, 1, n);
1914 if (newargs == NULL)
1915 return NULL;
1916
1917 s_object = cache_struct(fmt);
1918 if (s_object == NULL) {
1919 Py_DECREF(newargs);
1920 return NULL;
1921 }
1922 result = s_unpack_from(s_object, newargs, kwds);
1923 Py_DECREF(newargs);
1924 Py_DECREF(s_object);
1925 return result;
1926 }
1927
1928 static struct PyMethodDef module_functions[] = {
1929 {"_clearcache", (PyCFunction)clearcache, METH_NOARGS, clearcache_doc},
1930 {"calcsize", calcsize, METH_O, calcsize_doc},
1931 {"pack", pack, METH_VARARGS, pack_doc},
1932 {"pack_into", pack_into, METH_VARARGS, pack_into_doc},
1933 {"unpack", unpack, METH_VARARGS, unpack_doc},
1934 {"unpack_from", (PyCFunction)unpack_from,
1935 METH_VARARGS|METH_KEYWORDS, unpack_from_doc},
1936 {NULL, NULL} /* sentinel */
1937 };
1938
1939
1940 /* Module initialization */
1941
1942 PyDoc_STRVAR(module_doc,
1943 "Functions to convert between Python values and C structs represented\n\
1944 as Python strings. It uses format strings (explained below) as compact\n\
1945 descriptions of the lay-out of the C structs and the intended conversion\n\
1946 to/from Python values.\n\
1947 \n\
1948 The optional first format char indicates byte order, size and alignment:\n\
1949 @: native order, size & alignment (default)\n\
1950 =: native order, std. size & alignment\n\
1951 <: little-endian, std. size & alignment\n\
1952 >: big-endian, std. size & alignment\n\
1953 !: same as >\n\
1954 \n\
1955 The remaining chars indicate types of args and must match exactly;\n\
1956 these can be preceded by a decimal repeat count:\n\
1957 x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;\n\
1958 ?: _Bool (requires C99; if not available, char is used instead)\n\
1959 h:short; H:unsigned short; i:int; I:unsigned int;\n\
1960 l:long; L:unsigned long; f:float; d:double.\n\
1961 Special cases (preceding decimal count indicates length):\n\
1962 s:string (array of char); p: pascal string (with count byte).\n\
1963 Special case (only available in native format):\n\
1964 P:an integer type that is wide enough to hold a pointer.\n\
1965 Special case (not in native mode unless 'long long' in platform C):\n\
1966 q:long long; Q:unsigned long long\n\
1967 Whitespace between formats is ignored.\n\
1968 \n\
1969 The variable struct.error is an exception raised on errors.\n");
1970
1971 PyMODINIT_FUNC
1972 init_struct(void)
1973 {
1974 PyObject *ver, *m;
1975
1976 ver = PyString_FromString("0.2");
1977 if (ver == NULL)
1978 return;
1979
1980 m = Py_InitModule3("_struct", module_functions, module_doc);
1981 if (m == NULL)
1982 return;
1983
1984 Py_TYPE(&PyStructType) = &PyType_Type;
1985 if (PyType_Ready(&PyStructType) < 0)
1986 return;
1987
1988 /* This speed trick can't be used until overflow masking goes
1989 away, because native endian always raises exceptions
1990 instead of overflow masking. */
1991
1992 /* Check endian and swap in faster functions */
1993 {
1994 int one = 1;
1995 formatdef *native = native_table;
1996 formatdef *other, *ptr;
1997 if ((int)*(unsigned char*)&one)
1998 other = lilendian_table;
1999 else
2000 other = bigendian_table;
2001 /* Scan through the native table, find a matching
2002 entry in the endian table and swap in the
2003 native implementations whenever possible
2004 (64-bit platforms may not have "standard" sizes) */
2005 while (native->format != '\0' && other->format != '\0') {
2006 ptr = other;
2007 while (ptr->format != '\0') {
2008 if (ptr->format == native->format) {
2009 /* Match faster when formats are
2010 listed in the same order */
2011 if (ptr == other)
2012 other++;
2013 /* Only use the trick if the
2014 size matches */
2015 if (ptr->size != native->size)
2016 break;
2017 /* Skip float and double, could be
2018 "unknown" float format */
2019 if (ptr->format == 'd' || ptr->format == 'f')
2020 break;
2021 ptr->pack = native->pack;
2022 ptr->unpack = native->unpack;
2023 break;
2024 }
2025 ptr++;
2026 }
2027 native++;
2028 }
2029 }
2030
2031 /* Add some symbolic constants to the module */
2032 if (StructError == NULL) {
2033 StructError = PyErr_NewException("struct.error", NULL, NULL);
2034 if (StructError == NULL)
2035 return;
2036 }
2037
2038 Py_INCREF(StructError);
2039 PyModule_AddObject(m, "error", StructError);
2040
2041 Py_INCREF((PyObject*)&PyStructType);
2042 PyModule_AddObject(m, "Struct", (PyObject*)&PyStructType);
2043
2044 PyModule_AddObject(m, "__version__", ver);
2045
2046 PyModule_AddIntConstant(m, "_PY_STRUCT_RANGE_CHECKING", 1);
2047 PyModule_AddIntConstant(m, "_PY_STRUCT_FLOAT_COERCE", 1);
2048 }