acceler.c.orig

python s60 1.4.5版本的源代码

/* Portions Copyright (c) 2005 Nokia Corporation */

/* Parser accelerator module */

/* The parser as originally conceived had disappointing performance.
   This module does some precomputation that speeds up the selection
   of a DFA based upon a token, turning a search through an array
   into a simple indexing operation.  The parser now cannot work
   without the accelerators installed.  Note that the accelerators
   are installed dynamically when the parser is initialized, they
   are not part of the static data structure written on graminit.[ch]
   by the parser generator. */

#include "pgenheaders.h"
#include "grammar.h"
#include "node.h"
#include "token.h"
#include "parser.h"

/* Forward references */
#ifndef SYMBIAN
static void fixdfa(grammar *, dfa *);
static void fixstate(grammar *, state *);
#endif

void
PyGrammar_AddAccelerators(grammar *g)
{
#ifndef SYMBIAN
	dfa *d;
	int i;
#ifdef Py_DEBUG
	fprintf(stderr, "Adding parser accelerators ...\n");
#endif
	d = g->g_dfa;
	for (i = g->g_ndfas; --i >= 0; d++)
		fixdfa(g, d);
	g->g_accel = 1;
#ifdef Py_DEBUG
	fprintf(stderr, "Done.\n");
#endif
#endif /* SYMBIAN */
}

void
PyGrammar_RemoveAccelerators(grammar *g)
{
#ifndef SYMBIAN
	dfa *d;
	int i;
	g->g_accel = 0;
	d = g->g_dfa;
	for (i = g->g_ndfas; --i >= 0; d++) {
		state *s;
		int j;
		s = d->d_state;
		for (j = 0; j < d->d_nstates; j++, s++) {
			if (s->s_accel)
				PyMem_DEL(s->s_accel);
			s->s_accel = NULL;
		}
	}
#endif /* SYMBIAN */
}

#ifndef SYMBIAN

static void
fixdfa(grammar *g, dfa *d)
{
	state *s;
	int j;
	s = d->d_state;
	for (j = 0; j < d->d_nstates; j++, s++)
		fixstate(g, s);
}

static void
fixstate(grammar *g, state *s)
{
	arc *a;
	int k;
	int *accel;
	int nl = g->g_ll.ll_nlabels;
	s->s_accept = 0;
	accel = PyMem_NEW(int, nl);
	for (k = 0; k < nl; k++)
		accel[k] = -1;
	a = s->s_arc;
	for (k = s->s_narcs; --k >= 0; a++) {
		int lbl = a->a_lbl;
		label *l = &g->g_ll.ll_label[lbl];
		int type = l->lb_type;
		if (a->a_arrow >= (1 << 7)) {
			printf("XXX too many states!\n");
			continue;
		}
		if (ISNONTERMINAL(type)) {
			dfa *d1 = PyGrammar_FindDFA(g, type);
			int ibit;
			if (type - NT_OFFSET >= (1 << 7)) {
				printf("XXX too high nonterminal number!\n");
				continue;
			}
			for (ibit = 0; ibit < g->g_ll.ll_nlabels; ibit++) {
				if (testbit(d1->d_first, ibit)) {
#ifdef applec
#define MPW_881_BUG			/* Undefine if bug below is fixed */
#endif
#ifdef MPW_881_BUG
					/* In 881 mode MPW 3.1 has a code
					   generation bug which seems to
					   set the upper bits; fix this by
					   explicitly masking them off */
					int temp;
#endif
					if (accel[ibit] != -1)
						printf("XXX ambiguity!\n");
#ifdef MPW_881_BUG
					temp = 0xFFFF &
						(a->a_arrow | (1 << 7) |
						 ((type - NT_OFFSET) << 8));
					accel[ibit] = temp;
#else
					accel[ibit] = a->a_arrow | (1 << 7) |
						((type - NT_OFFSET) << 8);
#endif
				}
			}
		}
		else if (lbl == EMPTY)
			s->s_accept = 1;
		else if (lbl >= 0 && lbl < nl)
			accel[lbl] = a->a_arrow;
	}
	while (nl > 0 && accel[nl-1] == -1)
		nl--;
	for (k = 0; k < nl && accel[k] == -1;)
		k++;
	if (k < nl) {
		int i;
		s->s_accel = PyMem_NEW(int, nl-k);
		if (s->s_accel == NULL) {
			fprintf(stderr, "no mem to add parser accelerators\n");
			exit(1);
		}
		s->s_lower = k;
		s->s_upper = nl;
		for (i = 0; k < nl; i++, k++)
			s->s_accel[i] = accel[k];
	}
	PyMem_DEL(accel);
}
#endif /* SYMBIAN */