Language/OS - Multiplatform Resource Library/LANGUAGE OS.iso/a_utils/yacc/flexyacc/aflex.lha/aflex/src/dfaB.a

Text File | 1991-05-16 | 30KB | 942 lines

-- Copyright (c) 1990 Regents of the University of California.
-- All rights reserved.
--
-- This software was developed by John Self of the Arcadia project
-- at the University of California, Irvine.
--
-- Redistribution and use in source and binary forms are permitted
-- provided that the above copyright notice and this paragraph are
-- duplicated in all such forms and that any documentation,
-- advertising materials, and other materials related to such
-- distribution and use acknowledge that the software was developed
-- by the University of California, Irvine.  The name of the
-- University may not be used to endorse or promote products derived
-- from this software without specific prior written permission.
-- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
-- IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-- WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

-- TITLE DFA construction routines
-- AUTHOR: John Self (UCI)
-- DESCRIPTION converts non-deterministic finite automatons to finite ones.
-- $Header: /co/ua/self/arcadia/aflex/ada/src/RCS/dfaB.a,v 1.18 90/01/12 15:19:48 self Exp Locker: self $

with DFA, INT_IO, MISC_DEFS, TEXT_IO, MISC, TBLCMP, CCL, EXTERNAL_FILE_MANAGER;
with ECS, NFA, TSTRING, GEN, SKELETON_MANAGER; use MISC_DEFS,
  EXTERNAL_FILE_MANAGER;

package body DFA is
  use TSTRING;
  -- check_for_backtracking - check a DFA state for backtracking
  --
  -- ds is the number of the state to check and state[) is its out-transitions,
  -- indexed by equivalence class, and state_rules[) is the set of rules
  -- associated with this state

  DID_STK_INIT : BOOLEAN := FALSE;
  STK          : INT_PTR;

  procedure CHECK_FOR_BACKTRACKING(DS    : in INTEGER;
                                   STATE : in UNBOUNDED_INT_ARRAY) is
    use MISC_DEFS;
  begin
    if (DFAACC(DS).DFAACC_STATE = 0) then

      -- state is non-accepting
      NUM_BACKTRACKING := NUM_BACKTRACKING + 1;

      if (BACKTRACK_REPORT) then
        TEXT_IO.PUT(BACKTRACK_FILE, "State #");
        INT_IO.PUT(BACKTRACK_FILE, DS, 1);
        TEXT_IO.PUT(BACKTRACK_FILE, "is non-accepting -");
        TEXT_IO.NEW_LINE(BACKTRACK_FILE);

        -- identify the state
        DUMP_ASSOCIATED_RULES(BACKTRACK_FILE, DS);

        -- now identify it further using the out- and jam-transitions
        DUMP_TRANSITIONS(BACKTRACK_FILE, STATE);
        TEXT_IO.NEW_LINE(BACKTRACK_FILE);
      end if;
    end if;
  end CHECK_FOR_BACKTRACKING;


  -- check_trailing_context - check to see if NFA state set constitutes
  --                          "dangerous" trailing context
  --
  -- NOTES
  --    Trailing context is "dangerous" if both the head and the trailing
  --  part are of variable size \and/ there's a DFA state which contains
  --  both an accepting state for the head part of the rule and NFA states
  --  which occur after the beginning of the trailing context.
  --  When such a rule is matched, it's impossible to tell if having been
  --  in the DFA state indicates the beginning of the trailing context
  --  or further-along scanning of the pattern.  In these cases, a warning
  --  message is issued.
  --
  --    nfa_states[1 .. num_states) is the list of NFA states in the DFA.
  --    accset[1 .. nacc) is the list of accepting numbers for the DFA state.

  procedure CHECK_TRAILING_CONTEXT(NFA_STATES : in INT_PTR;
                                   NUM_STATES : in INTEGER;
                                   ACCSET     : in INT_PTR;
                                   NACC       : in INTEGER) is
    NS, AR              : INTEGER;
    STATE_VAR, TYPE_VAR : STATE_ENUM;

    use MISC_DEFS, MISC, TEXT_IO;
  begin
    for I in 1 .. NUM_STATES loop
      NS := NFA_STATES(I);
      TYPE_VAR := STATE_TYPE(NS);
      AR := ASSOC_RULE(NS);

      if ((TYPE_VAR = STATE_NORMAL) or (RULE_TYPE(AR) /= RULE_VARIABLE)) then
        null;

      -- do nothing
      else
        if (TYPE_VAR = STATE_TRAILING_CONTEXT) then

          -- potential trouble.  Scan set of accepting numbers for
          -- the one marking the end of the "head".  We assume that
          -- this looping will be fairly cheap since it's rare that
          -- an accepting number set is large.
          for J in 1 .. NACC loop
            if (CHECK_YY_TRAILING_HEAD_MASK(ACCSET(J)) /= 0) then
              TEXT_IO.PUT(STANDARD_ERROR,
                "aflex: Dangerous trailing context in rule at line ");
              INT_IO.PUT(STANDARD_ERROR, RULE_LINENUM(AR), 1);
              TEXT_IO.NEW_LINE(STANDARD_ERROR);
              return;
            end if;
          end loop;
        end if;
      end if;
    end loop;
  end CHECK_TRAILING_CONTEXT;


  -- dump_associated_rules - list the rules associated with a DFA state
  --
  -- goes through the set of NFA states associated with the DFA and
  -- extracts the first MAX_ASSOC_RULES unique rules, sorts them,
  -- and writes a report to the given file

  procedure DUMP_ASSOCIATED_RULES(F  : in FILE_TYPE;
                                  DS : in INTEGER) is
    J                    : INTEGER;
    NUM_ASSOCIATED_RULES : INTEGER := 0;
    RULE_SET             : INT_PTR;
    SIZE, RULE_NUM       : INTEGER;
  begin
    RULE_SET := new UNBOUNDED_INT_ARRAY(0 .. MAX_ASSOC_RULES + 1);
    SIZE := DFASIZ(DS);

    for I in 1 .. SIZE loop
      RULE_NUM := RULE_LINENUM(ASSOC_RULE(DSS(DS)(I)));

      J := 1;
      while (J <= NUM_ASSOCIATED_RULES) loop
        if (RULE_NUM = RULE_SET(J)) then
          exit;
        end if;
        J := J + 1;
      end loop;
      if (J > NUM_ASSOCIATED_RULES) then

        --new rule
        if (NUM_ASSOCIATED_RULES < MAX_ASSOC_RULES) then
          NUM_ASSOCIATED_RULES := NUM_ASSOCIATED_RULES + 1;
          RULE_SET(NUM_ASSOCIATED_RULES) := RULE_NUM;
        end if;
      end if;
    end loop;

    MISC.BUBBLE(RULE_SET, NUM_ASSOCIATED_RULES);

    TEXT_IO.PUT(F, " associated rules:");

    for I in 1 .. NUM_ASSOCIATED_RULES loop
      if (I mod 8 = 1) then
        TEXT_IO.NEW_LINE(F);
      end if;

      TEXT_IO.PUT(F, ASCII.HT);
      INT_IO.PUT(F, RULE_SET(I), 1);
    end loop;

    TEXT_IO.NEW_LINE(F);
  exception
    when STORAGE_ERROR =>
      MISC.AFLEXFATAL("dynamic memory failure in dump_associated_rules()");
  end DUMP_ASSOCIATED_RULES;


  -- dump_transitions - list the transitions associated with a DFA state
  --
  -- goes through the set of out-transitions and lists them in human-readable
  -- form (i.e., not as equivalence classes); also lists jam transitions
  -- (i.e., all those which are not out-transitions, plus EOF).  The dump
  -- is done to the given file.

  procedure DUMP_TRANSITIONS(F     : in FILE_TYPE;
                             STATE : in UNBOUNDED_INT_ARRAY) is
    EC           : INTEGER;
    OUT_CHAR_SET : C_SIZE_BOOL_ARRAY;
  begin
    for I in 1 .. CSIZE loop
      EC := ECGROUP(I);

      if (EC < 0) then
        EC :=  -EC;
      end if;

      OUT_CHAR_SET(I) := (STATE(EC) /= 0);
    end loop;

    TEXT_IO.PUT(F, " out-transitions: ");

    CCL.LIST_CHARACTER_SET(F, OUT_CHAR_SET);

    -- now invert the members of the set to get the jam transitions
    for I in 1 .. CSIZE loop
      OUT_CHAR_SET(I) := not OUT_CHAR_SET(I);
    end loop;

    TEXT_IO.NEW_LINE(F);
    TEXT_IO.PUT(F, "jam-transitions: EOF ");

    CCL.LIST_CHARACTER_SET(F, OUT_CHAR_SET);

    TEXT_IO.NEW_LINE(F);
  end DUMP_TRANSITIONS;


  -- epsclosure - construct the epsilon closure of a set of ndfa states
  --
  -- NOTES
  --    the epsilon closure is the set of all states reachable by an arbitrary
  --  number of epsilon transitions which themselves do not have epsilon
  --  transitions going out, unioned with the set of states which have non-null
  --  accepting numbers.  t is an array of size numstates of nfa state numbers.
--  Upon return, t holds the epsilon closure and numstates is updated.  accset
  --  holds a list of the accepting numbers, and the size of accset is given
  --  by nacc.  t may be subjected to reallocation if it is not large enough
  --  to hold the epsilon closure.
  --
  --    hashval is the hash value for the dfa corresponding to the state set

  procedure EPSCLOSURE(T                  : in out INT_PTR;
                       NS_ADDR            : in out INTEGER;
                       ACCSET             : in out INT_PTR;
                       NACC_ADDR, HV_ADDR : out INTEGER;
                       RESULT             : out INT_PTR) is
    NS, TSP                                      : INTEGER;
    NUMSTATES, NACC, HASHVAL, TRANSSYM, NFACCNUM : INTEGER;
    STKEND                                       : INTEGER;
    STKPOS                                       : INTEGER;
    procedure MARK_STATE(STATE : in INTEGER) is
    begin
      TRANS1(STATE) := TRANS1(STATE) - MARKER_DIFFERENCE;
    end MARK_STATE;
    pragma INLINE(MARK_STATE);

    function IS_MARKED(STATE : in INTEGER) return BOOLEAN is
    begin
      return TRANS1(STATE) < 0;
    end IS_MARKED;
    pragma INLINE(IS_MARKED);

    procedure UNMARK_STATE(STATE : in INTEGER) is
    begin
      TRANS1(STATE) := TRANS1(STATE) + MARKER_DIFFERENCE;
    end UNMARK_STATE;
    pragma INLINE(UNMARK_STATE);


    procedure CHECK_ACCEPT(STATE : in INTEGER) is
    begin
      NFACCNUM := ACCPTNUM(STATE);
      if (NFACCNUM /= NIL) then
        NACC := NACC + 1;
        ACCSET(NACC) := NFACCNUM;
      end if;
    end CHECK_ACCEPT;
    pragma INLINE(CHECK_ACCEPT);

    procedure DO_REALLOCATION is
    begin
      CURRENT_MAX_DFA_SIZE := CURRENT_MAX_DFA_SIZE + MAX_DFA_SIZE_INCREMENT;
      NUM_REALLOCS := NUM_REALLOCS + 1;
      REALLOCATE_INTEGER_ARRAY(T, CURRENT_MAX_DFA_SIZE);
      REALLOCATE_INTEGER_ARRAY(STK, CURRENT_MAX_DFA_SIZE);
    end DO_REALLOCATION;
    pragma INLINE(DO_REALLOCATION);


    procedure PUT_ON_STACK(STATE : in INTEGER) is
    begin
      STKEND := STKEND + 1;
      if (STKEND >= CURRENT_MAX_DFA_SIZE) then
        DO_REALLOCATION;
      end if;
      STK(STKEND) := STATE;
      MARK_STATE(STATE);
    end PUT_ON_STACK;
    pragma INLINE(PUT_ON_STACK);

    procedure ADD_STATE(STATE : in INTEGER) is
    begin
      NUMSTATES := NUMSTATES + 1;
      if (NUMSTATES >= CURRENT_MAX_DFA_SIZE) then
        DO_REALLOCATION;
      end if;
      T(NUMSTATES) := STATE;
      HASHVAL := HASHVAL + STATE;
    end ADD_STATE;
    pragma INLINE(ADD_STATE);

    procedure STACK_STATE(STATE : in INTEGER) is
    begin
      PUT_ON_STACK(STATE);
      CHECK_ACCEPT(STATE);
      if ((NFACCNUM /= NIL) or (TRANSCHAR(STATE) /= SYM_EPSILON)) then
        ADD_STATE(STATE);
      end if;
    end STACK_STATE;
    pragma INLINE(STACK_STATE);

  begin
    NUMSTATES := NS_ADDR;
    if (not DID_STK_INIT) then
      STK := ALLOCATE_INTEGER_ARRAY(CURRENT_MAX_DFA_SIZE);
      DID_STK_INIT := TRUE;
    end if;

    NACC := 0;
    STKEND := 0;
    HASHVAL := 0;

    for NSTATE in 1 .. NUMSTATES loop
      NS := T(NSTATE);

      -- the state could be marked if we've already pushed it onto
      -- the stack
      if (not IS_MARKED(NS)) then
        PUT_ON_STACK(NS);
        null;
      end if;

      CHECK_ACCEPT(NS);
      HASHVAL := HASHVAL + NS;
    end loop;


    STKPOS := 1;
    while (STKPOS <= STKEND) loop
      NS := STK(STKPOS);
      TRANSSYM := TRANSCHAR(NS);

      if (TRANSSYM = SYM_EPSILON) then
        TSP := TRANS1(NS) + MARKER_DIFFERENCE;

        if (TSP /= NO_TRANSITION) then
          if (not IS_MARKED(TSP)) then
            STACK_STATE(TSP);
          end if;

          TSP := TRANS2(NS);

          if (TSP /= NO_TRANSITION) then
            if (not IS_MARKED(TSP)) then
              STACK_STATE(TSP);
            end if;
          end if;
        end if;
      end if;
      STKPOS := STKPOS + 1;
    end loop;

    -- clear out "visit" markers
    for CHK_STKPOS in 1 .. STKEND loop
      if (IS_MARKED(STK(CHK_STKPOS))) then
        UNMARK_STATE(STK(CHK_STKPOS));
      else
        MISC.AFLEXFATAL("consistency check failed in epsclosure()");
      end if;
    end loop;

    NS_ADDR := NUMSTATES;
    HV_ADDR := HASHVAL;
    NACC_ADDR := NACC;

    RESULT := T;
  end EPSCLOSURE;


  -- increase_max_dfas - increase the maximum number of DFAs

  procedure INCREASE_MAX_DFAS is
  begin
    CURRENT_MAX_DFAS := CURRENT_MAX_DFAS + MAX_DFAS_INCREMENT;

    NUM_REALLOCS := NUM_REALLOCS + 1;

    REALLOCATE_INTEGER_ARRAY(BASE, CURRENT_MAX_DFAS);
    REALLOCATE_INTEGER_ARRAY(DEF, CURRENT_MAX_DFAS);
    REALLOCATE_INTEGER_ARRAY(DFASIZ, CURRENT_MAX_DFAS);
    REALLOCATE_INTEGER_ARRAY(ACCSIZ, CURRENT_MAX_DFAS);
    REALLOCATE_INTEGER_ARRAY(DHASH, CURRENT_MAX_DFAS);
    REALLOCATE_INT_PTR_ARRAY(DSS, CURRENT_MAX_DFAS);
    REALLOCATE_DFAACC_UNION(DFAACC, CURRENT_MAX_DFAS);
  end INCREASE_MAX_DFAS;


  -- ntod - convert an ndfa to a dfa
  --
  --  creates the dfa corresponding to the ndfa we've constructed.  the
  --  dfa starts out in state #1.

  procedure NTOD is

    ACCSET                                             : INT_PTR;
    DS, NACC, NEWDS                                    : INTEGER;
    DUPLIST, TARGFREQ, TARGSTATE, STATE                : C_SIZE_ARRAY;
    SYMLIST                                            : C_SIZE_BOOL_ARRAY;
    HASHVAL, NUMSTATES, DSIZE                          : INTEGER;
    NSET, DSET                                         : INT_PTR;
    TARGPTR, TOTALTRANS, I, J, COMSTATE, COMFREQ, TARG : INTEGER;
    NUM_START_STATES, TODO_HEAD, TODO_NEXT             : INTEGER;
    SNSRESULT                                          : BOOLEAN;
    FULL_TABLE_TEMP_FILE                               : FILE_TYPE;
    BUF                                                : VSTRING;
    NUM_NXT_STATES                                     : INTEGER;
    use TEXT_IO;

    -- this is so find_table_space(...) will know where to start looking in
    -- chk/nxt for unused records for space to put in the state
  begin
    ACCSET := ALLOCATE_INTEGER_ARRAY(NUM_RULES + 1);
    NSET := ALLOCATE_INTEGER_ARRAY(CURRENT_MAX_DFA_SIZE);

    -- the "todo" queue is represented by the head, which is the DFA
    -- state currently being processed, and the "next", which is the
    -- next DFA state number available (not in use).  We depend on the
    -- fact that snstods() returns DFA's \in increasing order/, and thus
    -- need only know the bounds of the dfas to be processed.
    TODO_HEAD := 0;
    TODO_NEXT := 0;

    for CNT in 0 .. CSIZE loop
      DUPLIST(CNT) := NIL;
      SYMLIST(CNT) := FALSE;
    end loop;

    for CNT in 0 .. NUM_RULES loop
      ACCSET(CNT) := NIL;
    end loop;

    if (TRACE) then
      NFA.DUMPNFA(SCSET(1));
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      TEXT_IO.PUT(STANDARD_ERROR, "DFA Dump:");
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
      TEXT_IO.NEW_LINE(STANDARD_ERROR);
    end if;

    TBLCMP.INITTBL;

    if (FULLTBL) then
      GEN.DO_SECT3_OUT;

      -- output user code up to ##
      SKELETON_MANAGER.SKELOUT;

      -- declare it "short" because it's a real long-shot that that
      -- won't be large enough
      begin -- make a temporary file to write yy_nxt array into
        CREATE(FULL_TABLE_TEMP_FILE, OUT_FILE);
      exception
        when USE_ERROR | NAME_ERROR =>
          MISC.AFLEXFATAL("can't create temporary file");
      end;

      NUM_NXT_STATES := 1;
      TEXT_IO.PUT(FULL_TABLE_TEMP_FILE, "( ");
      -- generate 0 entries for state #0
      for CNT in 0 .. NUMECS loop
        MISC.MK2DATA(FULL_TABLE_TEMP_FILE, 0);
      end loop;

      TEXT_IO.PUT(FULL_TABLE_TEMP_FILE, " )");
      -- force extra blank line next dataflush()
      DATALINE := NUMDATALINES;
    end if;

    -- create the first states

    NUM_START_STATES := LASTSC*2;

    for CNT in 1 .. NUM_START_STATES loop
      NUMSTATES := 1;

      -- for each start condition, make one state for the case when
      -- we're at the beginning of the line (the '%' operator) and
      -- one for the case when we're not

      if (CNT mod 2 = 1) then
        NSET(NUMSTATES) := SCSET((CNT/2) + 1);
      else
        NSET(NUMSTATES) := NFA.MKBRANCH(SCBOL(CNT/2), SCSET(CNT/2));
      end if;

      DFA.EPSCLOSURE(NSET, NUMSTATES, ACCSET, NACC, HASHVAL, NSET);

      SNSTODS(NSET, NUMSTATES, ACCSET, NACC, HASHVAL, DS, SNSRESULT);
      if (SNSRESULT) then
        NUMAS := NUMAS + NACC;
        TOTNST := TOTNST + NUMSTATES;
        TODO_NEXT := TODO_NEXT + 1;

        if (VARIABLE_TRAILING_CONTEXT_RULES and (NACC > 0)) then
          CHECK_TRAILING_CONTEXT(NSET, NUMSTATES, ACCSET, NACC);
        end if;
      end if;
    end loop;

    SNSTODS(NSET, 0, ACCSET, 0, 0, END_OF_BUFFER_STATE, SNSRESULT);
    if (not SNSRESULT) then
      MISC.AFLEXFATAL("could not create unique end-of-buffer state");
    end if;
    NUMAS := NUMAS + 1;
    NUM_START_STATES := NUM_START_STATES + 1;
    TODO_NEXT := TODO_NEXT + 1;

    while (TODO_HEAD < TODO_NEXT) loop
      NUM_NXT_STATES := NUM_NXT_STATES + 1;
      TARGPTR := 0;
      TOTALTRANS := 0;

      for STATE_CNT in 1 .. NUMECS loop
        STATE(STATE_CNT) := 0;
      end loop;

      TODO_HEAD := TODO_HEAD + 1;
      DS := TODO_HEAD;

      DSET := DSS(DS);
      DSIZE := DFASIZ(DS);

      if (TRACE) then
        TEXT_IO.PUT(STANDARD_ERROR, "state # ");
        INT_IO.PUT(STANDARD_ERROR, DS, 1);
        TEXT_IO.PUT_LINE(STANDARD_ERROR, ":");
      end if;

      SYMPARTITION(DSET, DSIZE, SYMLIST, DUPLIST);

      for SYM in 1 .. NUMECS loop
        if (SYMLIST(SYM)) then
          SYMLIST(SYM) := FALSE;

          if (DUPLIST(SYM) = NIL) then
          -- symbol has unique out-transitions
            NUMSTATES := SYMFOLLOWSET(DSET, DSIZE, SYM, NSET);
            DFA.EPSCLOSURE(NSET, NUMSTATES, ACCSET, NACC, HASHVAL, NSET);

            SNSTODS(NSET, NUMSTATES, ACCSET, NACC, HASHVAL, NEWDS, SNSRESULT);
            if (SNSRESULT) then
              TOTNST := TOTNST + NUMSTATES;
              TODO_NEXT := TODO_NEXT + 1;
              NUMAS := NUMAS + NACC;

              if (VARIABLE_TRAILING_CONTEXT_RULES and (NACC > 0)) then
                CHECK_TRAILING_CONTEXT(NSET, NUMSTATES, ACCSET, NACC);
              end if;
            end if;

            STATE(SYM) := NEWDS;

            if (TRACE) then
              TEXT_IO.PUT(STANDARD_ERROR, ASCII.HT);
              INT_IO.PUT(STANDARD_ERROR, SYM, 1);
              TEXT_IO.PUT(STANDARD_ERROR, ASCII.HT);
              INT_IO.PUT(STANDARD_ERROR, NEWDS, 1);
              TEXT_IO.NEW_LINE(STANDARD_ERROR);
            end if;

            TARGPTR := TARGPTR + 1;
            TARGFREQ(TARGPTR) := 1;
            TARGSTATE(TARGPTR) := NEWDS;
            NUMUNIQ := NUMUNIQ + 1;
          else
          -- sym's equivalence class has the same transitions
          -- as duplist(sym)'s equivalence class

            TARG := STATE(DUPLIST(SYM));
            STATE(SYM) := TARG;
            if (TRACE) then
              TEXT_IO.PUT(STANDARD_ERROR, ASCII.HT);
              INT_IO.PUT(STANDARD_ERROR, SYM, 1);
              TEXT_IO.PUT(STANDARD_ERROR, ASCII.HT);
              INT_IO.PUT(STANDARD_ERROR, TARG, 1);
              TEXT_IO.NEW_LINE(STANDARD_ERROR);
            end if;

            -- update frequency count for destination state

            I := 1;

            while (TARGSTATE(I) /= TARG) loop
              I := I + 1;
            end loop;

            TARGFREQ(I) := TARGFREQ(I) + 1;
            NUMDUP := NUMDUP + 1;
          end if;

          TOTALTRANS := TOTALTRANS + 1;
          DUPLIST(SYM) := NIL;
        end if;
      end loop;

      NUMSNPAIRS := NUMSNPAIRS + TOTALTRANS;

      if (CASEINS and not USEECS) then
        I := CHARACTER'POS('A');
        J := CHARACTER'POS('a');
        while (I < CHARACTER'POS('Z')) loop
          STATE(I) := STATE(J);
          I := I + 1;
          J := J + 1;
        end loop;
      end if;

      if (DS > NUM_START_STATES) then
        CHECK_FOR_BACKTRACKING(DS, STATE);
      end if;

      if (FULLTBL) then
      -- supply array's 0-element
        TEXT_IO.PUT(FULL_TABLE_TEMP_FILE, ",");
        MISC.DATAFLUSH(FULL_TABLE_TEMP_FILE);
        TEXT_IO.PUT(FULL_TABLE_TEMP_FILE, "( ");
        if (DS = END_OF_BUFFER_STATE) then
          MISC.MK2DATA(FULL_TABLE_TEMP_FILE,  -END_OF_BUFFER_STATE);
        else
          MISC.MK2DATA(FULL_TABLE_TEMP_FILE, END_OF_BUFFER_STATE);
        end if;

        for CNT in 1 .. NUMECS loop
        -- jams are marked by negative of state number
          if ((STATE(CNT) /= 0)) then
            MISC.MK2DATA(FULL_TABLE_TEMP_FILE, STATE(CNT));
          else
            MISC.MK2DATA(FULL_TABLE_TEMP_FILE,  -DS);
          end if;
        end loop;

        TEXT_IO.PUT(FULL_TABLE_TEMP_FILE, " )");
        -- force extra blank line next dataflush()
        DATALINE := NUMDATALINES;
      else
        if (DS = END_OF_BUFFER_STATE) then
        -- special case this state to make sure it does what it's
        -- supposed to, i.e., jam on end-of-buffer
          TBLCMP.STACK1(DS, 0, 0, JAMSTATE_CONST);
        else  -- normal, compressed state
        -- determine which destination state is the most common, and
        -- how many transitions to it there are
          COMFREQ := 0;
          COMSTATE := 0;

          for CNT in 1 .. TARGPTR loop
            if (TARGFREQ(CNT) > COMFREQ) then
              COMFREQ := TARGFREQ(CNT);
              COMSTATE := TARGSTATE(CNT);
            end if;
          end loop;

          TBLCMP.BLDTBL(STATE, DS, TOTALTRANS, COMSTATE, COMFREQ);
        end if;
      end if;
    end loop;

    if (FULLTBL) then
      TEXT_IO.PUT("yy_nxt : constant array(0..");
      INT_IO.PUT(NUM_NXT_STATES - 1, 1);
      TEXT_IO.PUT_LINE(" , character'first..character'last) of short :=");
      TEXT_IO.PUT_LINE("   (");

      RESET(FULL_TABLE_TEMP_FILE, IN_FILE);
      while (not END_OF_FILE(FULL_TABLE_TEMP_FILE)) loop
        TSTRING.GET_LINE(FULL_TABLE_TEMP_FILE, BUF);
        TSTRING.PUT_LINE(BUF);
      end loop;
      DELETE(FULL_TABLE_TEMP_FILE);

      MISC.DATAEND;
    else
      TBLCMP.CMPTMPS;  -- create compressed template entries

      -- create tables for all the states with only one out-transition
      while (ONESP > 0) loop
        TBLCMP.MK1TBL(ONESTATE(ONESP), ONESYM(ONESP), ONENEXT(ONESP), ONEDEF(
          ONESP));
        ONESP := ONESP - 1;
      end loop;

      TBLCMP.MKDEFTBL;
    end if;
  end NTOD;

  -- snstods - converts a set of ndfa states into a dfa state
  --
  -- on return, the dfa state number is in newds.
  procedure SNSTODS(SNS           : in INT_PTR;
                    NUMSTATES     : in INTEGER;
                    ACCSET        : in INT_PTR;
                    NACC, HASHVAL : in INTEGER;
                    NEWDS_ADDR    : out INTEGER;
                    RESULT        : out BOOLEAN) is
    DIDSORT : BOOLEAN := FALSE;
    J       : INTEGER;
    NEWDS   : INTEGER;
    OLDSNS  : INT_PTR;
  begin
    for I in 1 .. LASTDFA loop
      if (HASHVAL = DHASH(I)) then
        if (NUMSTATES = DFASIZ(I)) then
          OLDSNS := DSS(I);

          if (not DIDSORT) then
          -- we sort the states in sns so we can compare it to
          -- oldsns quickly.  we use bubble because there probably
          -- aren't very many states

            MISC.BUBBLE(SNS, NUMSTATES);
            DIDSORT := TRUE;
          end if;

          J := 1;
          while (J <= NUMSTATES) loop
            if (SNS(J) /= OLDSNS(J)) then
              exit;
            end if;
            J := J + 1;
          end loop;

          if (J > NUMSTATES) then
            DFAEQL := DFAEQL + 1;
            NEWDS_ADDR := I;
            RESULT := FALSE;
            return;
          end if;

          HSHCOL := HSHCOL + 1;
        else
          HSHSAVE := HSHSAVE + 1;
        end if;
      end if;
    end loop;
    -- make a new dfa

    LASTDFA := LASTDFA + 1;
    if (LASTDFA >= CURRENT_MAX_DFAS) then
      INCREASE_MAX_DFAS;
    end if;

    NEWDS := LASTDFA;

    DSS(NEWDS) := new UNBOUNDED_INT_ARRAY(0 .. NUMSTATES + 1);

    -- if we haven't already sorted the states in sns, we do so now, so that
    -- future comparisons with it can be made quickly

    if (not DIDSORT) then
      MISC.BUBBLE(SNS, NUMSTATES);
    end if;

    for I in 1 .. NUMSTATES loop
      DSS(NEWDS)(I) := SNS(I);
    end loop;

    DFASIZ(NEWDS) := NUMSTATES;
    DHASH(NEWDS) := HASHVAL;

    if (NACC = 0) then
      DFAACC(NEWDS).DFAACC_STATE := 0;
      ACCSIZ(NEWDS) := 0;
    else
    -- find lowest numbered rule so the disambiguating rule will work
      J := NUM_RULES + 1;

      for I in 1 .. NACC loop
        if (ACCSET(I) < J) then
          J := ACCSET(I);
        end if;
      end loop;

      DFAACC(NEWDS).DFAACC_STATE := J;
    end if;

    NEWDS_ADDR := NEWDS;
    RESULT := TRUE;
    return;

  exception
    when STORAGE_ERROR =>
      MISC.AFLEXFATAL("dynamic memory failure in snstods()");
  end SNSTODS;

  -- symfollowset - follow the symbol transitions one step
  function SYMFOLLOWSET(DS              : in INT_PTR;
                        DSIZE, TRANSSYM : in INTEGER;
                        NSET            : in INT_PTR) return INTEGER is
    NS, TSP, SYM, LENCCL, CH, NUMSTATES, CCLLIST : INTEGER;
  begin
    NUMSTATES := 0;

    for I in 1 .. DSIZE loop
    -- for each nfa state ns in the state set of ds
      NS := DS(I);
      SYM := TRANSCHAR(NS);
      TSP := TRANS1(NS);

      if (SYM < 0) then
      -- it's a character class
        SYM :=  -SYM;
        CCLLIST := CCLMAP(SYM);
        LENCCL := CCLLEN(SYM);

        if (CCLNG(SYM) /= 0) then
          for J in 0 .. LENCCL - 1 loop
          -- loop through negated character class
            CH := CHARACTER'POS(CCLTBL(CCLLIST + J));

            if (CH > TRANSSYM) then
              exit;  -- transsym isn't in negated ccl
            else
              if (CH = TRANSSYM) then
                goto BOTTOM;  -- next 2
              end if;
            end if;
          end loop;

          -- didn't find transsym in ccl
          NUMSTATES := NUMSTATES + 1;
          NSET(NUMSTATES) := TSP;
        else
          for J in 0 .. LENCCL - 1 loop
            CH := CHARACTER'POS(CCLTBL(CCLLIST + J));

            if (CH > TRANSSYM) then
              exit;
            else
              if (CH = TRANSSYM) then
                NUMSTATES := NUMSTATES + 1;
                NSET(NUMSTATES) := TSP;
                exit;
              end if;
            end if;
          end loop;
        end if;
      else
        if ((SYM >= CHARACTER'POS('A')) and (SYM <= CHARACTER'POS('Z')) and
          CASEINS) then
          MISC.AFLEXFATAL("consistency check failed in symfollowset");
        else
          if (SYM = SYM_EPSILON) then
            null;  -- do nothing
          else
            if (ECGROUP(SYM) = TRANSSYM) then
              NUMSTATES := NUMSTATES + 1;
              NSET(NUMSTATES) := TSP;
            end if;
          end if;
        end if;
      end if;

      <<BOTTOM>> null;
    end loop;
    return NUMSTATES;
  end SYMFOLLOWSET;

  -- sympartition - partition characters with same out-transitions
  procedure SYMPARTITION(DS        : in INT_PTR;
                         NUMSTATES : in INTEGER;
                         SYMLIST   : in out C_SIZE_BOOL_ARRAY;
                         DUPLIST   : in out C_SIZE_ARRAY) is
    TCH, J, NS, LENCCL, CCLP, ICH : INTEGER;
    DUPFWD                        : C_SIZE_ARRAY;

  -- partitioning is done by creating equivalence classes for those
  -- characters which have out-transitions from the given state.  Thus
  -- we are really creating equivalence classes of equivalence classes.
  begin
    for I in 1 .. NUMECS loop
    -- initialize equivalence class list
      DUPLIST(I) := I - 1;
      DUPFWD(I) := I + 1;
    end loop;

    DUPLIST(1) := NIL;
    DUPFWD(NUMECS) := NIL;
    DUPFWD(0) := 0;

    for I in 1 .. NUMSTATES loop
      NS := DS(I);
      TCH := TRANSCHAR(NS);

      if (TCH /= SYM_EPSILON) then
        if ((TCH <  -LASTCCL) or (TCH > CSIZE)) then
          MISC.AFLEXFATAL("bad transition character detected in sympartition()")
            ;
        end if;

        if (TCH > 0) then
        -- character transition
          ECS.MKECHAR(ECGROUP(TCH), DUPFWD, DUPLIST);
          SYMLIST(ECGROUP(TCH)) := TRUE;
        else
        -- character class
          TCH :=  -TCH;

          LENCCL := CCLLEN(TCH);
          CCLP := CCLMAP(TCH);
          ECS.MKECCL(CCLTBL(CCLP .. CCLP + LENCCL), LENCCL, DUPFWD, DUPLIST,
            NUMECS);

          if (CCLNG(TCH) /= 0) then
            J := 0;

            for K in 0 .. LENCCL - 1 loop
              ICH := CHARACTER'POS(CCLTBL(CCLP + K));

              J := J + 1;
              while (J < ICH) loop
                SYMLIST(J) := TRUE;
                J := J + 1;
              end loop;
            end loop;

            J := J + 1;
            while (J <= NUMECS) loop
              SYMLIST(J) := TRUE;
              J := J + 1;
            end loop;
          else
            for K in 0 .. LENCCL - 1 loop
              ICH := CHARACTER'POS(CCLTBL(CCLP + K));
              SYMLIST(ICH) := TRUE;
            end loop;
          end if;
        end if;
      end if;
    end loop;
  end SYMPARTITION;
end DFA;