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#include <stdio.h>
#include <stdlib.h>
#include <setjmp.h>
// TODO: handle conflicts (itemset_insert returns 2 on table problem)
#ifndef XCALLOC_IMPLEMENTED
#define XCALLOC_IMPLEMENTED
void *xcalloc(size_t n, size_t size) { void *addr = calloc(n, size); return addr ? addr : (exit(1), NULL); }
#else
extern void *xcalloc(size_t n, size_t size);
#endif
// Requirements
#include "parts/symbol.h"
#include "parts/grammar.h"
#include "parts/util-tables.h"
// Implements
#include "parts/table.h"
#define TABLE_CAP 64
static struct action *__table[TABLE_CAP];
struct action **table = __table;
size_t table_states = 0;
static jmp_buf fail_jmpbuf;
static void table_allocate() { for(size_t i = 0; i < TABLE_CAP; i++) table[i] = xcalloc(total_symbols, sizeof(*table[i])); }
static void table_deallocate() { for(size_t i = 0; i < TABLE_CAP; i++) free(table[i]); }
static int table_insert(size_t state, symbol sym, struct action a);
struct item {
size_t prod_idx;
size_t dot;
};
static int item_eq(struct item *i1, struct item *i2) { return (i1->dot == i2->dot && i1->prod_idx == i2->prod_idx) ? 1 : 0; }
#define SEEN_SETS_CAP 64
static struct {
struct item *items;
size_t nitems;
size_t state;
} seen_sets[SEEN_SETS_CAP];
static size_t nseen_sets;
static void seen_sets_free() { for(size_t i = 0; i < nseen_sets; i++) free(seen_sets[i].items);}
static size_t itemset_handle(struct item *set, size_t nset);
static int itemset_insert(size_t state, struct item *initial_set, size_t ninitial);
static size_t itemset_closure(struct item *in_set, size_t nin, struct item *out_set, size_t nout);
static void itemset_print(struct item *set, size_t nset)
{
printf("{");
for(size_t i = 0; i < nset; i++)
printf("{%zu, %zu}, ", set[i].prod_idx, set[i].dot);
printf("}\n");
}
static size_t itemset_handle(struct item *set, size_t nset)
{
// 1. is set in seen_sets
for(size_t i = 0; i < nseen_sets; i++) {
if(seen_sets[i].nitems != nset) continue;
int _seen = 0;
for(size_t j = 0; j < nset; j++) {
_seen = 0;
for(size_t k = 0; k < nset; k++)
if(item_eq(&seen_sets[i].items[k], &set[j])) _seen = 1;
if(!_seen) break;
}
if(_seen) return seen_sets[i].state;
}
// 2. add set to seen_sets
if(nseen_sets >= SEEN_SETS_CAP) {
fprintf(stderr, "ERROR: SEEN_SET_CAP exceeded\n");
longjmp(fail_jmpbuf, 1);
}
seen_sets[nseen_sets].items = xcalloc(nset, sizeof(*set));
seen_sets[nseen_sets].nitems = nset;
for(size_t i = 0; i < nset; i++)
seen_sets[nseen_sets].items[i] = set[i];
// 3. insert new state
size_t new_state = seen_sets[nseen_sets++].state = table_states++;
if(new_state >= TABLE_CAP) {
fprintf(stderr, "ERROR: TABLE_CAP exceeded\n");
longjmp(fail_jmpbuf, 1);
}
if(itemset_insert(new_state, set, nset)) {
fprintf(stderr, "ERROR: itemset_insert failed\n");
longjmp(fail_jmpbuf, 1);
}
return new_state;
}
#define CLOSURE_SET_CAP 64
#define GOTO_SET_CAP 32
static int itemset_insert(size_t state, struct item *initial_set, size_t ninitial)
{
struct item closure_set[CLOSURE_SET_CAP];
size_t nclosure = itemset_closure(initial_set, ninitial, closure_set, CLOSURE_SET_CAP);
if(nclosure > CLOSURE_SET_CAP) {
fprintf(stderr, "ERROR: CLOSURE_SET_CAP exceeded\n");
return 1;
}
for(size_t sym = 0; sym < total_symbols; sym++) {
struct item goto_set[GOTO_SET_CAP];
size_t ngoto = 0;
for(size_t j = 0; j < nclosure; j++) {
struct production *p = &grammar[closure_set[j].prod_idx];
size_t dot = closure_set[j].dot;
if(dot == p->nRHS) {
if(!follow[p->LHS][sym]) continue;
if(table_insert(state, sym, (struct action){
ACTION_REDUCE, closure_set[j].prod_idx}))
return 2;
continue;
}
if(p->RHS[dot] == sym) {
if(ngoto >= GOTO_SET_CAP) {
fprintf(stderr, "ERROR: GOTO_SET_CAP exceeded\n");
return 1;
}
goto_set[ngoto] = closure_set[j];
goto_set[ngoto++].dot++;
}
}
if(ngoto == 0) continue;
if(symbol_is_input_end(sym)) {
if(table_insert(state, sym, (struct action){ACTION_ACCEPT, 0}))
return 2;
continue;
}
size_t new_state = itemset_handle(goto_set, ngoto);
if(table_insert(state, sym, (struct action){
symbol_is_terminal(sym) ? ACTION_SHIFT : ACTION_GOTO,
new_state})) return 2;
}
return 0;
}
static size_t itemset_closure(struct item *in_set, size_t nin, struct item *out_set, size_t nout_max)
{
size_t nout = nin;
if(nout > nout_max) return nout;
for(size_t i = 0; i < nin; i++) out_set[i] = in_set[i];
int *is_in_closure = xcalloc(total_productions, sizeof(int));
for(size_t i = 0; i < nout; i++)
{
struct production *p = &grammar[out_set[i].prod_idx];
if(out_set[i].dot == p->nRHS) continue;
symbol sym = p->RHS[out_set[i].dot];
for(size_t j = 0; j < total_productions; j++)
if(grammar[j].LHS == sym) {
if(is_in_closure[j]) continue;
is_in_closure[j] = 1;
if(nout++ >= nout_max) goto cleanup;
out_set[nout-1] = (struct item){j, 0};
}
}
cleanup:
free(is_in_closure);
return nout;
}
static int table_insert(size_t state, symbol sym, struct action a)
{
if(table[state][sym].type != ACTION_NOT_SET) {
fprintf(stderr, "TABLE COLLISION on state '%zu' sym '%d'\n", state, sym);
fprintf(stderr, "\t{%d %zu} vs {%d %zu}\n",
table[state][sym].type, table[state][sym].arg,
a.type, a.arg);
return 1;
}
table[state][sym] = a;
return 0;
}
IMPLEMENT_FUNCPTR(int, table_fill, ())
{
table_allocate();
int r = setjmp(fail_jmpbuf);
if(r == 0) itemset_handle((struct item[]){{0, 0}}, 1);
return r;
}
IMPLEMENT_FUNCPTR(void, table_free, ())
{
seen_sets_free();
table_deallocate();
}
#ifdef _SLR_TABLE_STANDALONE
// implement symbol.h
enum symbol {
PLUS = 0,
MINUS,
LPAREN,
RPAREN,
N0, N1,
END_INPUT,
EP, E, T, N,
SYMBOLS_END,
};
size_t total_symbols = SYMBOLS_END;
IMPLEMENT_FUNCPTR(int, symbol_is_terminal, (symbol s)) { return s < EP; }
IMPLEMENT_FUNCPTR(int, symbol_is_input_end, (symbol s)) { return s == END_INPUT; }
// implement grammar.h
#define PROD(LHS, _, ...) {LHS, (symbol[]){__VA_ARGS__}, sizeof((symbol[]){__VA_ARGS__})/sizeof(symbol)}
static struct production _grammar[] = {
PROD(EP, ->, E, END_INPUT),
PROD(E, -->, E, PLUS, T),
PROD(E, -->, E, MINUS, T),
PROD(E, -->, T),
PROD(T, -->, LPAREN, E, RPAREN),
PROD(T, -->, N),
PROD(N, -->, N0),
PROD(N, -->, N1),
};
struct production *grammar = _grammar;
size_t total_productions = sizeof(_grammar)/sizeof(*_grammar);
// implement util-tables.h
#include "util-tables.c"
int main(void)
{
int r = 0;
util_tables_fill();
if((r = table_fill())) goto cleanup;
table_print();
cleanup:
table_free();
util_tables_free();
return r;
}
#endif
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