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v0.5.1
v0.5.1
https://github.com/python/cpython
Revision ff7183920f62c47eabceab3fb9fa8f762db32cc7 authored by Fred Drake on 09 October 2000, 20:22:28 UTC, committed by Fred Drake on 09 October 2000, 20:22:28 UTC
1 parent c9a5cc1
Tip revision: ff7183920f62c47eabceab3fb9fa8f762db32cc7 authored by Fred Drake on 09 October 2000, 20:22:28 UTC
Another generated file...
Another generated file...
Tip revision: ff71839
acceler.c
/* 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 */
static void fixdfa(grammar *, dfa *);
static void fixstate(grammar *, state *);
void
PyGrammar_AddAccelerators(grammar *g)
{
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
}
void
PyGrammar_RemoveAccelerators(grammar *g)
{
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;
}
}
}
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);
}
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