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* src/closure.h: New file.
* src/closure.c: Formatting changes, topological sort over the functions, use of closure.h. (initialize_closure, finalize_closure): Rename as... (new_closure, free_closure): these. Adjust dependencies. * src/LR0.c: Formatting changes, topological sort, use of cloture.h. (initialize_states): Rename as... (new_states): this. * src/Makefile.am (noinst_HEADERS): Adjust.
This commit is contained in:
Akim Demaille
333
src/closure.c
333
src/closure.c
@@ -19,52 +19,15 @@
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02111-1307, USA. */
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/* Subroutines of file LR0.c.
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Entry points:
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closure (items, n)
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Given a vector of item numbers items, of length n, set up ruleset and
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itemset to indicate what rules could be run and which items could be
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accepted when those items are the active ones.
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ruleset contains a bit for each rule. closure sets the bits for all
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rules which could potentially describe the next input to be read.
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itemset is a vector of item numbers; itemsetend points to just beyond
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the end of the part of it that is significant. closure places there
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the indices of all items which represent units of input that could
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arrive next.
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initialize_closure (n)
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Allocates the itemset and ruleset vectors, and precomputes useful data
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so that closure can be called. n is the number of elements to
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allocate for itemset.
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finalize_closure ()
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Frees itemset, ruleset and internal data.
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*/
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#include "system.h"
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#include "alloc.h"
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#include "gram.h"
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#include "closure.h"
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extern short **derives;
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extern char **tags;
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extern void initialize_closure PARAMS((int));
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extern void closure PARAMS((short *, int));
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extern void finalize_closure PARAMS((void));
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static void set_fderives PARAMS((void));
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static void set_firsts PARAMS((void));
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extern void RTC PARAMS((unsigned *, int));
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extern void RTC PARAMS ((unsigned *, int));
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short *itemset;
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short *itemsetend;
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@@ -79,47 +42,143 @@ static int rulesetsize;
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/* number of words required to hold a bit for each variable */
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static int varsetsize;
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#if DEBUG
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#ifdef DEBUG
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static void print_closure PARAMS((int));
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static void print_fderives PARAMS((void));
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static void print_firsts PARAMS((void));
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#endif
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/*-----------------.
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| Debugging code. |
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`-----------------*/
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void
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initialize_closure (int n)
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static void
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print_closure (int n)
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{
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itemset = NEW2(n, short);
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short *isp;
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rulesetsize = WORDSIZE(nrules + 1);
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ruleset = NEW2(rulesetsize, unsigned);
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set_fderives();
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printf ("\n\nn = %d\n\n", n);
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for (isp = itemset; isp < itemsetend; isp++)
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printf (" %d\n", *isp);
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}
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static void
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print_firsts (void)
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{
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int i;
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int j;
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unsigned *rowp;
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printf ("\n\n\nFIRSTS\n\n");
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for (i = ntokens; i < nsyms; i++)
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{
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printf ("\n\n%s firsts\n\n", tags[i]);
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rowp = firsts + ((i - ntokens) * varsetsize);
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for (j = 0; j < nvars; j++)
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if (BITISSET (rowp, j))
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printf (" %s\n", tags[j + ntokens]);
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}
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}
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static void
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print_fderives (void)
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{
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int i;
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int j;
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unsigned *rp;
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printf ("\n\n\nFDERIVES\n");
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for (i = ntokens; i < nsyms; i++)
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{
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printf ("\n\n%s derives\n\n", tags[i]);
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rp = fderives + i * rulesetsize;
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for (j = 0; j <= nrules; j++)
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if (BITISSET (rp, j))
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printf (" %d\n", j);
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}
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fflush (stdout);
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}
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#endif
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/*-------------------------------------------------------------------.
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| Set FIRSTS to be an NVARS by NVARS bit matrix indicating which |
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| items can represent the beginning of the input corresponding to |
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| which other items. |
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| |
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| For example, if some rule expands symbol 5 into the sequence of |
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| symbols 8 3 20, the symbol 8 can be the beginning of the data for |
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| symbol 5, so the bit [8 - ntokens, 5 - ntokens] in firsts is set. |
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`-------------------------------------------------------------------*/
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static void
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set_firsts (void)
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{
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unsigned *row;
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int symbol;
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short *sp;
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int rowsize;
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int i;
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varsetsize = rowsize = WORDSIZE (nvars);
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firsts = NEW2 (nvars * rowsize, unsigned);
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row = firsts;
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for (i = ntokens; i < nsyms; i++)
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{
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sp = derives[i];
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while (*sp >= 0)
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{
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symbol = ritem[rrhs[*sp++]];
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if (ISVAR (symbol))
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{
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symbol -= ntokens;
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SETBIT (row, symbol);
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}
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}
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row += rowsize;
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}
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RTC (firsts, nvars);
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#ifdef DEBUG
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print_firsts ();
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#endif
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}
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/*-------------------------------------------------------------------.
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| Set FDERIVES to an NVARS by NRULES matrix of bits indicating which |
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| rules can help derive the beginning of the data for each |
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| nonterminal. |
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| |
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| For example, if symbol 5 can be derived as the sequence of symbols |
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| 8 3 20, and one of the rules for deriving symbol 8 is rule 4, then |
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| the [5 - NTOKENS, 4] bit in FDERIVES is set. |
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`-------------------------------------------------------------------*/
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/* set fderives to an nvars by nrules matrix of bits
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indicating which rules can help derive the beginning of the data
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for each nonterminal. For example, if symbol 5 can be derived as
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the sequence of symbols 8 3 20, and one of the rules for deriving
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symbol 8 is rule 4, then the [5 - ntokens, 4] bit in fderives is set. */
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static void
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set_fderives (void)
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{
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register unsigned *rrow;
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register unsigned *vrow;
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register int j;
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register unsigned cword;
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register short *rp;
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register int b;
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unsigned *rrow;
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unsigned *vrow;
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int j;
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unsigned cword;
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short *rp;
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int b;
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int ruleno;
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int i;
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fderives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
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fderives = NEW2 (nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
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set_firsts();
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set_firsts ();
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rrow = fderives + ntokens * rulesetsize;
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@@ -135,7 +194,7 @@ set_fderives (void)
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rp = derives[j];
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while ((ruleno = *rp++) > 0)
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{
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SETBIT(rrow, ruleno);
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SETBIT (rrow, ruleno);
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}
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}
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@@ -151,71 +210,34 @@ set_fderives (void)
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}
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#ifdef DEBUG
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print_fderives();
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print_fderives ();
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#endif
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FREE(firsts);
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FREE (firsts);
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}
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/* set firsts to be an nvars by nvars bit matrix indicating which
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items can represent the beginning of the input corresponding to
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which other items.
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For example, if some rule expands symbol 5 into the sequence of
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symbols 8 3 20, the symbol 8 can be the beginning of the data for
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symbol 5, so the bit [8 - ntokens, 5 - ntokens] in firsts is
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set. */
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static void
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set_firsts (void)
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void
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new_closure (int n)
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{
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register unsigned *row;
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/* register int done; JF unused */
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register int symbol;
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register short *sp;
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register int rowsize;
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itemset = NEW2 (n, short);
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int i;
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rulesetsize = WORDSIZE (nrules + 1);
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ruleset = NEW2 (rulesetsize, unsigned);
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varsetsize = rowsize = WORDSIZE(nvars);
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firsts = NEW2(nvars * rowsize, unsigned);
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row = firsts;
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for (i = ntokens; i < nsyms; i++)
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{
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sp = derives[i];
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while (*sp >= 0)
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{
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symbol = ritem[rrhs[*sp++]];
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if (ISVAR(symbol))
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{
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symbol -= ntokens;
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SETBIT(row, symbol);
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}
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}
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row += rowsize;
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}
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RTC(firsts, nvars);
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#ifdef DEBUG
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print_firsts ();
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#endif
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set_fderives ();
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}
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void
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closure (short *core, int n)
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{
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register int ruleno;
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register unsigned word;
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register short *csp;
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register unsigned *dsp;
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register unsigned *rsp;
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int ruleno;
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unsigned word;
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short *csp;
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unsigned *dsp;
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unsigned *rsp;
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short *csend;
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unsigned *rsend;
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@@ -241,7 +263,7 @@ closure (short *core, int n)
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while (csp < csend)
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{
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symbol = ritem[*csp++];
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if (ISVAR(symbol))
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if (ISVAR (symbol))
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{
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dsp = fderives + symbol * rulesetsize;
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rsp = ruleset;
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@@ -264,7 +286,7 @@ closure (short *core, int n)
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}
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else
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{
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register int b;
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int b;
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for (b = 0; b < BITS_PER_WORD; b++)
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{
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@@ -284,77 +306,16 @@ closure (short *core, int n)
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while (csp < csend)
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*itemsetend++ = *csp++;
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#ifdef DEBUG
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print_closure(n);
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#if DEBUG
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print_closure (n);
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#endif
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}
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void
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finalize_closure (void)
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free_closure (void)
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{
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FREE(itemset);
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FREE(ruleset);
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FREE(fderives + ntokens * rulesetsize);
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FREE (itemset);
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FREE (ruleset);
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FREE (fderives + ntokens * rulesetsize);
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}
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#ifdef DEBUG
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static void
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print_closure(int n)
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{
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register short *isp;
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printf ("\n\nn = %d\n\n", n);
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for (isp = itemset; isp < itemsetend; isp++)
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printf (" %d\n", *isp);
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}
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static void
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print_firsts (void)
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{
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register int i;
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register int j;
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register unsigned *rowp;
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printf ("\n\n\nFIRSTS\n\n");
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for (i = ntokens; i < nsyms; i++)
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{
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printf ("\n\n%s firsts\n\n", tags[i]);
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rowp = firsts + ((i - ntokens) * varsetsize);
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for (j = 0; j < nvars; j++)
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if (BITISSET (rowp, j))
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printf (" %s\n", tags[j + ntokens]);
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}
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}
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static void
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print_fderives (void)
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{
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register int i;
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register int j;
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register unsigned *rp;
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printf ("\n\n\nFDERIVES\n");
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for (i = ntokens; i < nsyms; i++)
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{
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printf ("\n\n%s derives\n\n", tags[i]);
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rp = fderives + i * rulesetsize;
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for (j = 0; j <= nrules; j++)
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if (BITISSET (rp, j))
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printf (" %d\n", j);
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}
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fflush(stdout);
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}
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#endif
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