2009-07-01 Paul Brook <paul@codesourcery.com>
[deliverable/binutils-gdb.git] / gdb / value.h
1 /* Definitions for values of C expressions, for GDB.
2
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
5 2008, 2009 Free Software Foundation, Inc.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22 #if !defined (VALUE_H)
23 #define VALUE_H 1
24
25 #include "doublest.h"
26 #include "frame.h" /* For struct frame_id. */
27
28 struct block;
29 struct expression;
30 struct regcache;
31 struct symbol;
32 struct type;
33 struct ui_file;
34 struct language_defn;
35 struct value_print_options;
36
37 /* The structure which defines the type of a value. It should never
38 be possible for a program lval value to survive over a call to the
39 inferior (i.e. to be put into the history list or an internal
40 variable). */
41
42 struct value;
43
44 /* Needed if another module needs to maintain its own list of values. */
45
46 void value_prepend_to_list (struct value **head, struct value *val);
47 void value_remove_from_list (struct value **head, struct value *val);
48
49 /* Values are stored in a chain, so that they can be deleted easily
50 over calls to the inferior. Values assigned to internal variables,
51 put into the value history or exposed to Python are taken off this
52 list. */
53
54 struct value *value_next (struct value *);
55
56 /* Type of the value. */
57
58 extern struct type *value_type (struct value *);
59
60 /* This is being used to change the type of an existing value, that
61 code should instead be creating a new value with the changed type
62 (but possibly shared content). */
63
64 extern void deprecated_set_value_type (struct value *value,
65 struct type *type);
66
67 /* Only used for bitfields; number of bits contained in them. */
68
69 extern int value_bitsize (struct value *);
70 extern void set_value_bitsize (struct value *, int bit);
71
72 /* Only used for bitfields; position of start of field. For
73 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
74 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
75
76 extern int value_bitpos (struct value *);
77 extern void set_value_bitpos (struct value *, int bit);
78
79 /* Describes offset of a value within lval of a structure in bytes.
80 If lval == lval_memory, this is an offset to the address. If lval
81 == lval_register, this is a further offset from location.address
82 within the registers structure. Note also the member
83 embedded_offset below. */
84
85 extern int value_offset (struct value *);
86 extern void set_value_offset (struct value *, int offset);
87
88 /* The comment from "struct value" reads: ``Is it modifiable? Only
89 relevant if lval != not_lval.''. Shouldn't the value instead be
90 not_lval and be done with it? */
91
92 extern int deprecated_value_modifiable (struct value *value);
93 extern void deprecated_set_value_modifiable (struct value *value,
94 int modifiable);
95
96 /* If a value represents a C++ object, then the `type' field gives the
97 object's compile-time type. If the object actually belongs to some
98 class derived from `type', perhaps with other base classes and
99 additional members, then `type' is just a subobject of the real
100 thing, and the full object is probably larger than `type' would
101 suggest.
102
103 If `type' is a dynamic class (i.e. one with a vtable), then GDB can
104 actually determine the object's run-time type by looking at the
105 run-time type information in the vtable. When this information is
106 available, we may elect to read in the entire object, for several
107 reasons:
108
109 - When printing the value, the user would probably rather see the
110 full object, not just the limited portion apparent from the
111 compile-time type.
112
113 - If `type' has virtual base classes, then even printing `type'
114 alone may require reaching outside the `type' portion of the
115 object to wherever the virtual base class has been stored.
116
117 When we store the entire object, `enclosing_type' is the run-time
118 type -- the complete object -- and `embedded_offset' is the offset
119 of `type' within that larger type, in bytes. The value_contents()
120 macro takes `embedded_offset' into account, so most GDB code
121 continues to see the `type' portion of the value, just as the
122 inferior would.
123
124 If `type' is a pointer to an object, then `enclosing_type' is a
125 pointer to the object's run-time type, and `pointed_to_offset' is
126 the offset in bytes from the full object to the pointed-to object
127 -- that is, the value `embedded_offset' would have if we followed
128 the pointer and fetched the complete object. (I don't really see
129 the point. Why not just determine the run-time type when you
130 indirect, and avoid the special case? The contents don't matter
131 until you indirect anyway.)
132
133 If we're not doing anything fancy, `enclosing_type' is equal to
134 `type', and `embedded_offset' is zero, so everything works
135 normally. */
136
137 extern struct type *value_enclosing_type (struct value *);
138 extern struct value *value_change_enclosing_type (struct value *val,
139 struct type *new_type);
140 extern int value_pointed_to_offset (struct value *value);
141 extern void set_value_pointed_to_offset (struct value *value, int val);
142 extern int value_embedded_offset (struct value *value);
143 extern void set_value_embedded_offset (struct value *value, int val);
144
145 /* For lval_computed values, this structure holds functions used to
146 retrieve and set the value (or portions of the value).
147
148 For each function, 'V' is the 'this' pointer: an lval_funcs
149 function F may always assume that the V it receives is an
150 lval_computed value, and has F in the appropriate slot of its
151 lval_funcs structure. */
152
153 struct lval_funcs
154 {
155 /* Fill in VALUE's contents. This is used to "un-lazy" values. If
156 a problem arises in obtaining VALUE's bits, this function should
157 call 'error'. */
158 void (*read) (struct value *v);
159
160 /* Handle an assignment TOVAL = FROMVAL by writing the value of
161 FROMVAL to TOVAL's location. The contents of TOVAL have not yet
162 been updated. If a problem arises in doing so, this function
163 should call 'error'. */
164 void (*write) (struct value *toval, struct value *fromval);
165
166 /* Return a duplicate of VALUE's closure, for use in a new value.
167 This may simply return the same closure, if VALUE's is
168 reference-counted or statically allocated.
169
170 This may be NULL, in which case VALUE's closure is re-used in the
171 new value. */
172 void *(*copy_closure) (struct value *v);
173
174 /* Drop VALUE's reference to its closure. Maybe this frees the
175 closure; maybe this decrements a reference count; maybe the
176 closure is statically allocated and this does nothing.
177
178 This may be NULL, in which case no action is taken to free
179 VALUE's closure. */
180 void (*free_closure) (struct value *v);
181 };
182
183 /* Create a computed lvalue, with type TYPE, function pointers FUNCS,
184 and closure CLOSURE. */
185
186 extern struct value *allocate_computed_value (struct type *type,
187 struct lval_funcs *funcs,
188 void *closure);
189
190 /* If VALUE is lval_computed, return its lval_funcs structure. */
191
192 extern struct lval_funcs *value_computed_funcs (struct value *value);
193
194 /* If VALUE is lval_computed, return its closure. The meaning of the
195 returned value depends on the functions VALUE uses. */
196
197 extern void *value_computed_closure (struct value *value);
198
199 /* If zero, contents of this value are in the contents field. If
200 nonzero, contents are in inferior. If the lval field is lval_memory,
201 the contents are in inferior memory at location.address plus offset.
202 The lval field may also be lval_register.
203
204 WARNING: This field is used by the code which handles watchpoints
205 (see breakpoint.c) to decide whether a particular value can be
206 watched by hardware watchpoints. If the lazy flag is set for some
207 member of a value chain, it is assumed that this member of the
208 chain doesn't need to be watched as part of watching the value
209 itself. This is how GDB avoids watching the entire struct or array
210 when the user wants to watch a single struct member or array
211 element. If you ever change the way lazy flag is set and reset, be
212 sure to consider this use as well! */
213
214 extern int value_lazy (struct value *);
215 extern void set_value_lazy (struct value *value, int val);
216
217 /* value_contents() and value_contents_raw() both return the address
218 of the gdb buffer used to hold a copy of the contents of the lval.
219 value_contents() is used when the contents of the buffer are needed
220 -- it uses value_fetch_lazy() to load the buffer from the process
221 being debugged if it hasn't already been loaded
222 (value_contents_writeable() is used when a writeable but fetched
223 buffer is required).. value_contents_raw() is used when data is
224 being stored into the buffer, or when it is certain that the
225 contents of the buffer are valid.
226
227 Note: The contents pointer is adjusted by the offset required to
228 get to the real subobject, if the value happens to represent
229 something embedded in a larger run-time object. */
230
231 extern gdb_byte *value_contents_raw (struct value *);
232
233 /* Actual contents of the value. For use of this value; setting it
234 uses the stuff above. Not valid if lazy is nonzero. Target
235 byte-order. We force it to be aligned properly for any possible
236 value. Note that a value therefore extends beyond what is
237 declared here. */
238
239 extern const gdb_byte *value_contents (struct value *);
240 extern gdb_byte *value_contents_writeable (struct value *);
241
242 /* The ALL variants of the above two macros do not adjust the returned
243 pointer by the embedded_offset value. */
244
245 extern gdb_byte *value_contents_all_raw (struct value *);
246 extern const gdb_byte *value_contents_all (struct value *);
247
248 extern int value_fetch_lazy (struct value *val);
249 extern int value_contents_equal (struct value *val1, struct value *val2);
250
251 /* If nonzero, this is the value of a variable which does not actually
252 exist in the program. */
253 extern int value_optimized_out (struct value *value);
254 extern void set_value_optimized_out (struct value *value, int val);
255
256 /* Set or return field indicating whether a variable is initialized or
257 not, based on debugging information supplied by the compiler.
258 1 = initialized; 0 = uninitialized. */
259 extern int value_initialized (struct value *);
260 extern void set_value_initialized (struct value *, int);
261
262 /* Set COMPONENT's location as appropriate for a component of WHOLE
263 --- regardless of what kind of lvalue WHOLE is. */
264 extern void set_value_component_location (struct value *component,
265 struct value *whole);
266
267 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
268 single value might have multiple LVALs), this hacked interface is
269 limited to just the first PIECE. Expect further change. */
270 /* Type of value; either not an lval, or one of the various different
271 possible kinds of lval. */
272 extern enum lval_type *deprecated_value_lval_hack (struct value *);
273 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
274
275 /* If lval == lval_memory, return the address in the inferior. If
276 lval == lval_register, return the byte offset into the registers
277 structure. Otherwise, return 0. The returned address
278 includes the offset, if any. */
279 extern CORE_ADDR value_address (struct value *);
280
281 /* Like value_address, except the result does not include value's
282 offset. */
283 extern CORE_ADDR value_raw_address (struct value *);
284
285 /* Set the address of a value. */
286 extern void set_value_address (struct value *, CORE_ADDR);
287
288 /* Pointer to internal variable. */
289 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
290 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
291
292 /* Frame register value is relative to. This will be described in the
293 lval enum above as "lval_register". */
294 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
295 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
296
297 /* Register number if the value is from a register. */
298 extern short *deprecated_value_regnum_hack (struct value *);
299 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
300
301 /* Convert a REF to the object referenced. */
302
303 extern struct value *coerce_ref (struct value *value);
304
305 /* If ARG is an array, convert it to a pointer.
306 If ARG is a function, convert it to a function pointer.
307
308 References are dereferenced. */
309
310 extern struct value *coerce_array (struct value *value);
311
312 \f
313
314 #include "symtab.h"
315 #include "gdbtypes.h"
316 #include "expression.h"
317
318 struct frame_info;
319 struct fn_field;
320
321 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
322
323 extern LONGEST value_as_long (struct value *val);
324 extern DOUBLEST value_as_double (struct value *val);
325 extern CORE_ADDR value_as_address (struct value *val);
326
327 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
328 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
329 int *invp);
330 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
331 extern LONGEST unpack_field_as_long (struct type *type,
332 const gdb_byte *valaddr,
333 int fieldno);
334
335 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
336
337 extern struct value *value_from_longest (struct type *type, LONGEST num);
338 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
339 extern struct value *value_from_double (struct type *type, DOUBLEST num);
340 extern struct value *value_from_decfloat (struct type *type,
341 const gdb_byte *decbytes);
342
343 extern struct value *value_at (struct type *type, CORE_ADDR addr);
344 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
345
346 extern struct value *value_from_contents_and_address (struct type *,
347 const gdb_byte *,
348 CORE_ADDR);
349
350 extern struct value *default_value_from_register (struct type *type,
351 int regnum,
352 struct frame_info *frame);
353
354 extern struct value *value_from_register (struct type *type, int regnum,
355 struct frame_info *frame);
356
357 extern CORE_ADDR address_from_register (struct type *type, int regnum,
358 struct frame_info *frame);
359
360 extern struct value *value_of_variable (struct symbol *var, struct block *b);
361
362 extern struct value *address_of_variable (struct symbol *var, struct block *b);
363
364 extern struct value *value_of_register (int regnum, struct frame_info *frame);
365
366 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
367
368 extern int symbol_read_needs_frame (struct symbol *);
369
370 extern struct value *read_var_value (struct symbol *var,
371 struct frame_info *frame);
372
373 extern struct value *allocate_value (struct type *type);
374 extern struct value *allocate_value_lazy (struct type *type);
375 extern void allocate_value_contents (struct value *value);
376
377 extern struct value *allocate_repeat_value (struct type *type, int count);
378
379 extern struct value *value_mark (void);
380
381 extern void value_free_to_mark (struct value *mark);
382
383 extern struct value *value_cstring (char *ptr, int len,
384 struct type *char_type);
385 extern struct value *value_string (char *ptr, int len,
386 struct type *char_type);
387 extern struct value *value_bitstring (char *ptr, int len);
388
389 extern struct value *value_array (int lowbound, int highbound,
390 struct value **elemvec);
391
392 extern struct value *value_concat (struct value *arg1, struct value *arg2);
393
394 extern struct value *value_binop (struct value *arg1, struct value *arg2,
395 enum exp_opcode op);
396
397 extern struct value *value_ptradd (struct value *arg1, LONGEST arg2);
398
399 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2);
400
401 extern int value_must_coerce_to_target (struct value *arg1);
402
403 extern struct value *value_coerce_to_target (struct value *arg1);
404
405 extern struct value *value_coerce_array (struct value *arg1);
406
407 extern struct value *value_coerce_function (struct value *arg1);
408
409 extern struct value *value_ind (struct value *arg1);
410
411 extern struct value *value_addr (struct value *arg1);
412
413 extern struct value *value_ref (struct value *arg1);
414
415 extern struct value *value_assign (struct value *toval,
416 struct value *fromval);
417
418 extern struct value *value_pos (struct value *arg1);
419
420 extern struct value *value_neg (struct value *arg1);
421
422 extern struct value *value_complement (struct value *arg1);
423
424 extern struct value *value_struct_elt (struct value **argp,
425 struct value **args,
426 char *name, int *static_memfuncp,
427 char *err);
428
429 extern struct value *value_aggregate_elt (struct type *curtype,
430 char *name,
431 int want_address,
432 enum noside noside);
433
434 extern struct value *value_static_field (struct type *type, int fieldno);
435
436 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
437 int, int *,
438 struct type **, int *);
439
440 extern int find_overload_match (struct type **arg_types, int nargs,
441 char *name, int method, int lax,
442 struct value **objp, struct symbol *fsym,
443 struct value **valp, struct symbol **symp,
444 int *staticp);
445
446 extern struct value *value_field (struct value *arg1, int fieldno);
447
448 extern struct value *value_primitive_field (struct value *arg1, int offset,
449 int fieldno,
450 struct type *arg_type);
451
452
453 extern struct type *value_rtti_target_type (struct value *, int *, int *,
454 int *);
455
456 extern struct value *value_full_object (struct value *, struct type *, int,
457 int, int);
458
459 extern struct value *value_cast_pointers (struct type *, struct value *);
460
461 extern struct value *value_cast (struct type *type, struct value *arg2);
462
463 extern struct value *value_zero (struct type *type, enum lval_type lv);
464
465 extern struct value *value_one (struct type *type, enum lval_type lv);
466
467 extern struct value *value_repeat (struct value *arg1, int count);
468
469 extern struct value *value_subscript (struct value *array, LONGEST index);
470
471 extern struct value *value_bitstring_subscript (struct type *type,
472 struct value *bitstring,
473 LONGEST index);
474
475 extern struct value *register_value_being_returned (struct type *valtype,
476 struct regcache *retbuf);
477
478 extern int value_in (struct value *element, struct value *set);
479
480 extern int value_bit_index (struct type *type, const gdb_byte *addr,
481 int index);
482
483 extern int using_struct_return (struct gdbarch *gdbarch,
484 struct type *func_type,
485 struct type *value_type);
486
487 extern struct value *evaluate_expression (struct expression *exp);
488
489 extern struct value *evaluate_type (struct expression *exp);
490
491 extern struct value *evaluate_subexp (struct type *expect_type,
492 struct expression *exp,
493 int *pos, enum noside noside);
494
495 extern struct value *evaluate_subexpression_type (struct expression *exp,
496 int subexp);
497
498 extern char *extract_field_op (struct expression *exp, int *subexp);
499
500 extern struct value *evaluate_subexp_with_coercion (struct expression *,
501 int *, enum noside);
502
503 extern struct value *parse_and_eval (char *exp);
504
505 extern struct value *parse_to_comma_and_eval (char **expp);
506
507 extern struct type *parse_and_eval_type (char *p, int length);
508
509 extern CORE_ADDR parse_and_eval_address (char *exp);
510
511 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
512
513 extern LONGEST parse_and_eval_long (char *exp);
514
515 extern void unop_promote (const struct language_defn *language,
516 struct gdbarch *gdbarch,
517 struct value **arg1);
518
519 extern void binop_promote (const struct language_defn *language,
520 struct gdbarch *gdbarch,
521 struct value **arg1, struct value **arg2);
522
523 extern struct value *access_value_history (int num);
524
525 extern struct value *value_of_internalvar (struct internalvar *var);
526
527 extern int get_internalvar_integer (struct internalvar *var, LONGEST *l);
528
529 extern void set_internalvar (struct internalvar *var, struct value *val);
530
531 extern void set_internalvar_integer (struct internalvar *var, LONGEST l);
532
533 extern void clear_internalvar (struct internalvar *var);
534
535 extern void set_internalvar_component (struct internalvar *var,
536 int offset,
537 int bitpos, int bitsize,
538 struct value *newvalue);
539
540 extern struct internalvar *lookup_only_internalvar (const char *name);
541
542 extern struct internalvar *create_internalvar (const char *name);
543
544 typedef struct value * (*internalvar_make_value) (struct internalvar *);
545
546 extern struct internalvar *
547 create_internalvar_type_lazy (char *name, internalvar_make_value fun);
548
549 extern struct internalvar *lookup_internalvar (const char *name);
550
551 extern int value_equal (struct value *arg1, struct value *arg2);
552
553 extern int value_less (struct value *arg1, struct value *arg2);
554
555 extern int value_logical_not (struct value *arg1);
556
557 /* C++ */
558
559 extern struct value *value_of_this (int complain);
560
561 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
562 enum exp_opcode op,
563 enum exp_opcode otherop,
564 enum noside noside);
565
566 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
567 enum noside noside);
568
569 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
570 int j, struct type *type, int offset);
571
572 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
573 struct value *arg2);
574
575 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
576
577 extern int destructor_name_p (const char *name, const struct type *type);
578
579 extern void value_free (struct value *val);
580
581 extern void free_all_values (void);
582
583 extern void release_value (struct value *val);
584
585 extern int record_latest_value (struct value *val);
586
587 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
588 int bitsize);
589
590 extern void type_print (struct type *type, char *varstring,
591 struct ui_file *stream, int show);
592
593 extern char *type_to_string (struct type *type);
594
595 extern gdb_byte *baseclass_addr (struct type *type, int index,
596 gdb_byte *valaddr,
597 struct value **valuep, int *errp);
598
599 extern void print_longest (struct ui_file *stream, int format,
600 int use_local, LONGEST val);
601
602 extern void print_floating (const gdb_byte *valaddr, struct type *type,
603 struct ui_file *stream);
604
605 extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
606 struct ui_file *stream);
607
608 extern int value_print (struct value *val, struct ui_file *stream,
609 const struct value_print_options *options);
610
611 extern void value_print_array_elements (struct value *val,
612 struct ui_file *stream, int format,
613 enum val_prettyprint pretty);
614
615 extern struct value *value_release_to_mark (struct value *mark);
616
617 extern int val_print (struct type *type, const gdb_byte *valaddr,
618 int embedded_offset, CORE_ADDR address,
619 struct ui_file *stream, int recurse,
620 const struct value_print_options *options,
621 const struct language_defn *language);
622
623 extern int common_val_print (struct value *val,
624 struct ui_file *stream, int recurse,
625 const struct value_print_options *options,
626 const struct language_defn *language);
627
628 extern int val_print_string (struct type *elttype, CORE_ADDR addr, int len,
629 struct ui_file *stream,
630 const struct value_print_options *options);
631
632 extern void print_variable_and_value (const char *name,
633 struct symbol *var,
634 struct frame_info *frame,
635 struct ui_file *stream,
636 int indent);
637
638 extern int check_field (struct type *, const char *);
639
640 extern void typedef_print (struct type *type, struct symbol *news,
641 struct ui_file *stream);
642
643 extern char *internalvar_name (struct internalvar *var);
644
645 extern void preserve_values (struct objfile *);
646
647 /* From values.c */
648
649 extern struct value *value_copy (struct value *);
650
651 /* From valops.c */
652
653 extern struct value *varying_to_slice (struct value *);
654
655 extern struct value *value_slice (struct value *, int, int);
656
657 extern struct value *value_literal_complex (struct value *, struct value *,
658 struct type *);
659
660 extern struct value *find_function_in_inferior (const char *,
661 struct objfile **);
662
663 extern struct value *value_allocate_space_in_inferior (int);
664
665 extern struct value *value_of_local (const char *name, int complain);
666
667 extern struct value *value_subscripted_rvalue (struct value *array,
668 LONGEST index, int lowerbound);
669
670 /* User function handler. */
671
672 typedef struct value *(*internal_function_fn) (void *cookie,
673 int argc,
674 struct value **argv);
675
676 void add_internal_function (const char *name, const char *doc,
677 internal_function_fn handler,
678 void *cookie);
679
680 struct value *call_internal_function (struct value *function,
681 int argc, struct value **argv);
682
683 char *value_internal_function_name (struct value *);
684
685 #endif /* !defined (VALUE_H) */
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