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Annotation of 43BSDReno/pgrm/yacc/closure.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1989 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * This code is derived from software contributed to Berkeley by
        !             6:  * Robert Paul Corbett.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms are permitted provided
        !             9:  * that: (1) source distributions retain this entire copyright notice and
        !            10:  * comment, and (2) distributions including binaries display the following
        !            11:  * acknowledgement:  ``This product includes software developed by the
        !            12:  * University of California, Berkeley and its contributors'' in the
        !            13:  * documentation or other materials provided with the distribution and in
        !            14:  * all advertising materials mentioning features or use of this software.
        !            15:  * Neither the name of the University nor the names of its contributors may
        !            16:  * be used to endorse or promote products derived from this software without
        !            17:  * specific prior written permission.
        !            18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            19:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            20:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            21:  */
        !            22: 
        !            23: #ifndef lint
        !            24: static char sccsid[] = "@(#)closure.c  5.2 (Berkeley) 6/1/90";
        !            25: #endif /* not lint */
        !            26: 
        !            27: #include "defs.h"
        !            28: 
        !            29: short *itemset;
        !            30: short *itemsetend;
        !            31: unsigned *ruleset;
        !            32: 
        !            33: static unsigned *first_derives;
        !            34: static unsigned *EFF;
        !            35: 
        !            36: 
        !            37: set_EFF()
        !            38: {
        !            39:     register unsigned *row;
        !            40:     register int symbol;
        !            41:     register short *sp;
        !            42:     register int rowsize;
        !            43:     register int i;
        !            44:     register int rule;
        !            45: 
        !            46:     rowsize = WORDSIZE(nvars);
        !            47:     EFF = NEW2(nvars * rowsize, unsigned);
        !            48: 
        !            49:     row = EFF;
        !            50:     for (i = start_symbol; i < nsyms; i++)
        !            51:     {
        !            52:        sp = derives[i];
        !            53:        for (rule = *sp; rule > 0; rule = *++sp)
        !            54:        {
        !            55:            symbol = ritem[rrhs[rule]];
        !            56:            if (ISVAR(symbol))
        !            57:            {
        !            58:                symbol -= start_symbol;
        !            59:                SETBIT(row, symbol);
        !            60:            }
        !            61:        }
        !            62:        row += rowsize;
        !            63:     }
        !            64: 
        !            65:     reflexive_transitive_closure(EFF, nvars);
        !            66: 
        !            67: #ifdef DEBUG
        !            68:     print_EFF();
        !            69: #endif
        !            70: }
        !            71: 
        !            72: 
        !            73: set_first_derives()
        !            74: {
        !            75:   register unsigned *rrow;
        !            76:   register unsigned *vrow;
        !            77:   register int j;
        !            78:   register unsigned mask;
        !            79:   register unsigned cword;
        !            80:   register short *rp;
        !            81: 
        !            82:   int rule;
        !            83:   int i;
        !            84:   int rulesetsize;
        !            85:   int varsetsize;
        !            86: 
        !            87:   rulesetsize = WORDSIZE(nrules);
        !            88:   varsetsize = WORDSIZE(nvars);
        !            89:   first_derives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
        !            90: 
        !            91:   set_EFF();
        !            92: 
        !            93:   rrow = first_derives + ntokens * rulesetsize;
        !            94:   for (i = start_symbol; i < nsyms; i++)
        !            95:     {
        !            96:       vrow = EFF + ((i - ntokens) * varsetsize);
        !            97:       cword = *vrow++;
        !            98:       mask = 1;
        !            99:       for (j = start_symbol; j < nsyms; j++)
        !           100:        {
        !           101:          if (cword & mask)
        !           102:            {
        !           103:              rp = derives[j];
        !           104:              while ((rule = *rp++) >= 0)
        !           105:                {
        !           106:                  SETBIT(rrow, rule);
        !           107:                }
        !           108:            }
        !           109: 
        !           110:          mask <<= 1;
        !           111:          if (mask == 0)
        !           112:            {
        !           113:              cword = *vrow++;
        !           114:              mask = 1;
        !           115:            }
        !           116:        }
        !           117: 
        !           118:       vrow += varsetsize;
        !           119:       rrow += rulesetsize;
        !           120:     }
        !           121: 
        !           122: #ifdef DEBUG
        !           123:   print_first_derives();
        !           124: #endif
        !           125: 
        !           126:   FREE(EFF);
        !           127: }
        !           128: 
        !           129: 
        !           130: closure(nucleus, n)
        !           131: short *nucleus;
        !           132: int n;
        !           133: {
        !           134:     register int ruleno;
        !           135:     register unsigned word;
        !           136:     register unsigned mask;
        !           137:     register short *csp;
        !           138:     register unsigned *dsp;
        !           139:     register unsigned *rsp;
        !           140:     register int rulesetsize;
        !           141: 
        !           142:     short *csend;
        !           143:     unsigned *rsend;
        !           144:     int symbol;
        !           145:     int itemno;
        !           146: 
        !           147:     rulesetsize = WORDSIZE(nrules);
        !           148:     rsp = ruleset;
        !           149:     rsend = ruleset + rulesetsize;
        !           150:     for (rsp = ruleset; rsp < rsend; rsp++)
        !           151:        *rsp = 0;
        !           152: 
        !           153:     csend = nucleus + n;
        !           154:     for (csp = nucleus; csp < csend; ++csp)
        !           155:     {
        !           156:        symbol = ritem[*csp];
        !           157:        if (ISVAR(symbol))
        !           158:        {
        !           159:            dsp = first_derives + symbol * rulesetsize;
        !           160:            rsp = ruleset;
        !           161:            while (rsp < rsend)
        !           162:                *rsp++ |= *dsp++;
        !           163:        }
        !           164:     }
        !           165: 
        !           166:     ruleno = 0;
        !           167:     itemsetend = itemset;
        !           168:     csp = nucleus;
        !           169:     for (rsp = ruleset; rsp < rsend; ++rsp)
        !           170:     {
        !           171:        word = *rsp;
        !           172:        if (word == 0)
        !           173:            ruleno += BITS_PER_WORD;
        !           174:        else
        !           175:        {
        !           176:            mask = 1;
        !           177:            while (mask)
        !           178:            {
        !           179:                if (word & mask)
        !           180:                {
        !           181:                    itemno = rrhs[ruleno];
        !           182:                    while (csp < csend && *csp < itemno)
        !           183:                        *itemsetend++ = *csp++;
        !           184:                    *itemsetend++ = itemno;
        !           185:                    while (csp < csend && *csp == itemno)
        !           186:                        ++csp;
        !           187:                }
        !           188: 
        !           189:                    mask <<= 1;
        !           190:                    ++ruleno;
        !           191:            }
        !           192:        }
        !           193:     }
        !           194: 
        !           195:     while (csp < csend)
        !           196:        *itemsetend++ = *csp++;
        !           197: 
        !           198: #ifdef DEBUG
        !           199:   print_closure(n);
        !           200: #endif
        !           201: }
        !           202: 
        !           203: 
        !           204: 
        !           205: finalize_closure()
        !           206: {
        !           207:   FREE(itemset);
        !           208:   FREE(ruleset);
        !           209:   FREE(first_derives + ntokens * WORDSIZE(nrules));
        !           210: }
        !           211: 
        !           212: 
        !           213: #ifdef DEBUG
        !           214: 
        !           215: print_closure(n)
        !           216: int n;
        !           217: {
        !           218:   register short *isp;
        !           219: 
        !           220:   printf("\n\nn = %d\n\n", n);
        !           221:   for (isp = itemset; isp < itemsetend; isp++)
        !           222:     printf("   %d\n", *isp);
        !           223: }
        !           224: 
        !           225: 
        !           226: print_EFF()
        !           227: {
        !           228:     register int i, j, k;
        !           229:     register unsigned *rowp;
        !           230:     register unsigned word;
        !           231:     register unsigned mask;
        !           232: 
        !           233:     printf("\n\nEpsilon Free Firsts\n");
        !           234: 
        !           235:     for (i = start_symbol; i < nsyms; i++)
        !           236:     {
        !           237:        printf("\n%s", symbol_name[i]);
        !           238:        rowp = EFF + ((i - start_symbol) * WORDSIZE(nvars));
        !           239:        word = *rowp++;
        !           240: 
        !           241:        mask = 1;
        !           242:        for (j = 0; j < nvars; j++)
        !           243:        {
        !           244:            if (word & mask)
        !           245:                printf("  %s", symbol_name[start_symbol + j]);
        !           246: 
        !           247:            mask <<= 1;
        !           248:            if (mask == 0)
        !           249:            {
        !           250:                word = *rowp++;
        !           251:                mask = 1;
        !           252:            }
        !           253:        }
        !           254:     }
        !           255: }
        !           256: 
        !           257: 
        !           258: print_first_derives()
        !           259: {
        !           260:   register int i;
        !           261:   register int j;
        !           262:   register unsigned *rp;
        !           263:   register unsigned cword;
        !           264:   register unsigned mask;
        !           265: 
        !           266:   printf("\n\n\nFirst Derives\n");
        !           267: 
        !           268:   for (i = start_symbol; i < nsyms; i++)
        !           269:     {
        !           270:       printf("\n%s derives\n", symbol_name[i]);
        !           271:       rp = first_derives + i * WORDSIZE(nrules);
        !           272:       cword = *rp++;
        !           273:       mask = 1;
        !           274:       for (j = 0; j <= nrules; j++)
        !           275:         {
        !           276:          if (cword & mask)
        !           277:            printf("   %d\n", j);
        !           278: 
        !           279:          mask <<= 1;
        !           280:          if (mask == 0)
        !           281:            {
        !           282:              cword = *rp++;
        !           283:              mask = 1;
        !           284:            }
        !           285:        }
        !           286:     }
        !           287: 
        !           288:   fflush(stdout);
        !           289: }
        !           290: 
        !           291: #endif

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