| Index: bison/src/bison/2.4.1/bison-2.4.1-src/src/state.h
|
| ===================================================================
|
| --- bison/src/bison/2.4.1/bison-2.4.1-src/src/state.h (revision 0)
|
| +++ bison/src/bison/2.4.1/bison-2.4.1-src/src/state.h (revision 0)
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| @@ -0,0 +1,266 @@
|
| +/* Type definitions for nondeterministic finite state machine for Bison.
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| +
|
| + Copyright (C) 1984, 1989, 2000, 2001, 2002, 2003, 2004, 2007 Free
|
| + Software Foundation, Inc.
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| +
|
| + This file is part of Bison, the GNU Compiler Compiler.
|
| +
|
| + This program is free software: you can redistribute it and/or modify
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| + it under the terms of the GNU General Public License as published by
|
| + the Free Software Foundation, either version 3 of the License, or
|
| + (at your option) any later version.
|
| +
|
| + This program is distributed in the hope that it will be useful,
|
| + but WITHOUT ANY WARRANTY; without even the implied warranty of
|
| + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
| + GNU General Public License for more details.
|
| +
|
| + You should have received a copy of the GNU General Public License
|
| + along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
| +
|
| +
|
| +/* These type definitions are used to represent a nondeterministic
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| + finite state machine that parses the specified grammar. This
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| + information is generated by the function generate_states in the
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| + file LR0.
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| +
|
| + Each state of the machine is described by a set of items --
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| + particular positions in particular rules -- that are the possible
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| + places where parsing could continue when the machine is in this
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| + state. These symbols at these items are the allowable inputs that
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| + can follow now.
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| +
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| + A core represents one state. States are numbered in the NUMBER
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| + field. When generate_states is finished, the starting state is
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| + state 0 and NSTATES is the number of states. (FIXME: This sentence
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| + is no longer true: A transition to a state whose state number is
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| + NSTATES indicates termination.) All the cores are chained together
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| + and FIRST_STATE points to the first one (state 0).
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| +
|
| + For each state there is a particular symbol which must have been
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| + the last thing accepted to reach that state. It is the
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| + ACCESSING_SYMBOL of the core.
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| +
|
| + Each core contains a vector of NITEMS items which are the indices
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| + in the RITEM vector of the items that are selected in this state.
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| +
|
| + The two types of actions are shifts/gotos (push the lookahead token
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| + and read another/goto to the state designated by a nterm) and
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| + reductions (combine the last n things on the stack via a rule,
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| + replace them with the symbol that the rule derives, and leave the
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| + lookahead token alone). When the states are generated, these
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| + actions are represented in two other lists.
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| +
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| + Each transition structure describes the possible transitions out
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| + of one state, the state whose number is in the number field. Each
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| + contains a vector of numbers of the states that transitions can go
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| + to. The accessing_symbol fields of those states' cores say what
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| + kind of input leads to them.
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| +
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| + A transition to state zero should be ignored: conflict resolution
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| + deletes transitions by having them point to zero.
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| +
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| + Each reductions structure describes the possible reductions at the
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| + state whose number is in the number field. rules is an array of
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| + num rules. lookahead_tokens is an array of bitsets, one per rule.
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| +
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| + Conflict resolution can decide that certain tokens in certain
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| + states should explicitly be errors (for implementing %nonassoc).
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| + For each state, the tokens that are errors for this reason are
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| + recorded in an errs structure, which holds the token numbers.
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| +
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| + There is at least one goto transition present in state zero. It
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| + leads to a next-to-final state whose accessing_symbol is the
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| + grammar's start symbol. The next-to-final state has one shift to
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| + the final state, whose accessing_symbol is zero (end of input).
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| + The final state has one shift, which goes to the termination state.
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| + The reason for the extra state at the end is to placate the
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| + parser's strategy of making all decisions one token ahead of its
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| + actions. */
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| +
|
| +#ifndef STATE_H_
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| +# define STATE_H_
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| +
|
| +# include <bitset.h>
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| +
|
| +# include "gram.h"
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| +# include "symtab.h"
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| +
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| +
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| +/*-------------------.
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| +| Numbering states. |
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| +`-------------------*/
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| +
|
| +typedef int state_number;
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| +# define STATE_NUMBER_MAXIMUM INT_MAX
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| +
|
| +/* Be ready to map a state_number to an int. */
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| +static inline int
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| +state_number_as_int (state_number s)
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| +{
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| + return s;
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| +}
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| +
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| +
|
| +typedef struct state state;
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| +
|
| +/*--------------.
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| +| Transitions. |
|
| +`--------------*/
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| +
|
| +typedef struct
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| +{
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| + int num;
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| + state *states[1];
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| +} transitions;
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| +
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| +
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| +/* What is the symbol labelling the transition to
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| + TRANSITIONS->states[Num]? Can be a token (amongst which the error
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| + token), or non terminals in case of gotos. */
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| +
|
| +#define TRANSITION_SYMBOL(Transitions, Num) \
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| + (Transitions->states[Num]->accessing_symbol)
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| +
|
| +/* Is the TRANSITIONS->states[Num] a shift? (as opposed to gotos). */
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| +
|
| +#define TRANSITION_IS_SHIFT(Transitions, Num) \
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| + (ISTOKEN (TRANSITION_SYMBOL (Transitions, Num)))
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| +
|
| +/* Is the TRANSITIONS->states[Num] a goto?. */
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| +
|
| +#define TRANSITION_IS_GOTO(Transitions, Num) \
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| + (!TRANSITION_IS_SHIFT (Transitions, Num))
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| +
|
| +/* Is the TRANSITIONS->states[Num] labelled by the error token? */
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| +
|
| +#define TRANSITION_IS_ERROR(Transitions, Num) \
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| + (TRANSITION_SYMBOL (Transitions, Num) == errtoken->number)
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| +
|
| +/* When resolving a SR conflicts, if the reduction wins, the shift is
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| + disabled. */
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| +
|
| +#define TRANSITION_DISABLE(Transitions, Num) \
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| + (Transitions->states[Num] = NULL)
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| +
|
| +#define TRANSITION_IS_DISABLED(Transitions, Num) \
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| + (Transitions->states[Num] == NULL)
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| +
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| +
|
| +/* Iterate over each transition over a token (shifts). */
|
| +#define FOR_EACH_SHIFT(Transitions, Iter) \
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| + for (Iter = 0; \
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| + Iter < Transitions->num \
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| + && (TRANSITION_IS_DISABLED (Transitions, Iter) \
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| + || TRANSITION_IS_SHIFT (Transitions, Iter)); \
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| + ++Iter) \
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| + if (!TRANSITION_IS_DISABLED (Transitions, Iter))
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| +
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| +
|
| +/* Return the state such SHIFTS contain a shift/goto to it on SYM.
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| + Abort if none found. */
|
| +struct state *transitions_to (transitions *shifts, symbol_number sym);
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| +
|
| +
|
| +/*-------.
|
| +| Errs. |
|
| +`-------*/
|
| +
|
| +typedef struct
|
| +{
|
| + int num;
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| + symbol *symbols[1];
|
| +} errs;
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| +
|
| +errs *errs_new (int num, symbol **tokens);
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| +
|
| +
|
| +/*-------------.
|
| +| Reductions. |
|
| +`-------------*/
|
| +
|
| +typedef struct
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| +{
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| + int num;
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| + bitset *lookahead_tokens;
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| + /* Sorted ascendingly on rule number. */
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| + rule *rules[1];
|
| +} reductions;
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| +
|
| +
|
| +
|
| +/*---------.
|
| +| states. |
|
| +`---------*/
|
| +
|
| +struct state
|
| +{
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| + state_number number;
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| + symbol_number accessing_symbol;
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| + transitions *transitions;
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| + reductions *reductions;
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| + errs *errs;
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| +
|
| + /* If non-zero, then no lookahead sets on reduce actions are needed to
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| + decide what to do in state S. */
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| + char consistent;
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| +
|
| + /* If some conflicts were solved thanks to precedence/associativity,
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| + a human readable description of the resolution. */
|
| + const char *solved_conflicts;
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| + const char *solved_conflicts_xml;
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| +
|
| + /* Its items. Must be last, since ITEMS can be arbitrarily large. Sorted
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| + ascendingly on item index in RITEM, which is sorted on rule number. */
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| + size_t nitems;
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| + item_number items[1];
|
| +};
|
| +
|
| +extern state_number nstates;
|
| +extern state *final_state;
|
| +
|
| +/* Create a new state with ACCESSING_SYMBOL for those items. */
|
| +state *state_new (symbol_number accessing_symbol,
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| + size_t core_size, item_number *core);
|
| +
|
| +/* Set the transitions of STATE. */
|
| +void state_transitions_set (state *s, int num, state **trans);
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| +
|
| +/* Set the reductions of STATE. */
|
| +void state_reductions_set (state *s, int num, rule **reds);
|
| +
|
| +int state_reduction_find (state *s, rule *r);
|
| +
|
| +/* Set the errs of STATE. */
|
| +void state_errs_set (state *s, int num, symbol **errors);
|
| +
|
| +/* Print on OUT all the lookahead tokens such that this STATE wants to
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| + reduce R. */
|
| +void state_rule_lookahead_tokens_print (state *s, rule *r, FILE *out);
|
| +void state_rule_lookahead_tokens_print_xml (state *s, rule *r,
|
| + FILE *out, int level);
|
| +
|
| +/* Create/destroy the states hash table. */
|
| +void state_hash_new (void);
|
| +void state_hash_free (void);
|
| +
|
| +/* Find the state associated to the CORE, and return it. If it does
|
| + not exist yet, return NULL. */
|
| +state *state_hash_lookup (size_t core_size, item_number *core);
|
| +
|
| +/* Insert STATE in the state hash table. */
|
| +void state_hash_insert (state *s);
|
| +
|
| +/* Remove unreachable states, renumber remaining states, update NSTATES, and
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| + write to OLD_TO_NEW a mapping of old state numbers to new state numbers such
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| + that the old value of NSTATES is written as the new state number for removed
|
| + states. The size of OLD_TO_NEW must be the old value of NSTATES. */
|
| +void state_remove_unreachable_states (state_number old_to_new[]);
|
| +
|
| +/* All the states, indexed by the state number. */
|
| +extern state **states;
|
| +
|
| +/* Free all the states. */
|
| +void states_free (void);
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| +
|
| +#endif /* !STATE_H_ */
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|
|
| Property changes on: bison\src\bison\2.4.1\bison-2.4.1-src\src\state.h
|
| ___________________________________________________________________
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| Added: svn:eol-style
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| + LF
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|