mirror of https://github.com/acidanthera/audk.git
354 lines
8.3 KiB
C
354 lines
8.3 KiB
C
/* Automata conversion functions for DLG
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*
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* SOFTWARE RIGHTS
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*
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* We reserve no LEGAL rights to the Purdue Compiler Construction Tool
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* Set (PCCTS) -- PCCTS is in the public domain. An individual or
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* company may do whatever they wish with source code distributed with
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* PCCTS or the code generated by PCCTS, including the incorporation of
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* PCCTS, or its output, into commerical software.
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*
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* We encourage users to develop software with PCCTS. However, we do ask
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* that credit is given to us for developing PCCTS. By "credit",
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* we mean that if you incorporate our source code into one of your
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* programs (commercial product, research project, or otherwise) that you
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* acknowledge this fact somewhere in the documentation, research report,
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* etc... If you like PCCTS and have developed a nice tool with the
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* output, please mention that you developed it using PCCTS. In
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* addition, we ask that this header remain intact in our source code.
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* As long as these guidelines are kept, we expect to continue enhancing
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* this system and expect to make other tools available as they are
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* completed.
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*
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* DLG 1.33
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* Will Cohen
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* With mods by Terence Parr; AHPCRC, University of Minnesota
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* 1989-2001
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*/
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#include <stdio.h>
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#include "pcctscfg.h"
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#include "dlg.h"
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#ifdef MEMCHK
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#include "trax.h"
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#else
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#ifdef __STDC__
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#include <stdlib.h>
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#else
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#include <malloc.h>
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#endif /* __STDC__ */
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#endif
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#define hash_list struct _hash_list_
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hash_list{
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hash_list *next; /* next thing in list */
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dfa_node *node;
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};
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int dfa_allocated = 0; /* keeps track of number of dfa nodes */
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dfa_node **dfa_array; /* root of binary tree that stores dfa array */
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dfa_node *dfa_model_node;
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hash_list *dfa_hash[HASH_SIZE]; /* used to quickly find */
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/* desired dfa node */
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void
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#ifdef __USE_PROTOS
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make_dfa_model_node(int width)
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#else
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make_dfa_model_node(width)
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int width;
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#endif
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{
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register int i;
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dfa_model_node = (dfa_node*) malloc(sizeof(dfa_node)
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+ sizeof(int)*width);
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dfa_model_node->node_no = -1; /* impossible value for real dfa node */
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dfa_model_node->dfa_set = 0;
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dfa_model_node->alternatives = FALSE;
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dfa_model_node->done = FALSE;
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dfa_model_node->nfa_states = empty;
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for(i = 0; i<width; i++){
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dfa_model_node->trans[i] = NIL_INDEX;
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}
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}
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/* adds a new nfa to the binary tree and returns a pointer to it */
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dfa_node *
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#ifdef __USE_PROTOS
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new_dfa_node(set nfa_states)
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#else
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new_dfa_node(nfa_states)
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set nfa_states;
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#endif
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{
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register int j;
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register dfa_node *t;
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static int dfa_size=0; /* elements dfa_array[] can hold */
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++dfa_allocated;
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if (dfa_size<=dfa_allocated){
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/* need to redo array */
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if (!dfa_array){
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/* need some to do inital allocation */
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dfa_size=dfa_allocated+DFA_MIN;
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dfa_array=(dfa_node **) malloc(sizeof(dfa_node*)*
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dfa_size);
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}else{
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/* need more space */
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dfa_size=2*(dfa_allocated+1);
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dfa_array=(dfa_node **) realloc(dfa_array,
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sizeof(dfa_node*)*dfa_size);
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}
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}
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/* fill out entry in array */
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t = (dfa_node*) malloc(sizeof(nfa_node)+sizeof(int)*class_no);
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*t = *dfa_model_node;
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for (j=0; j<class_no; ++j)
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t->trans[j] = NIL_INDEX;
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t->node_no = dfa_allocated;
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t->nfa_states = set_dup(nfa_states);
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dfa_array[dfa_allocated] = t;
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return t;
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}
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/* past a pointer to the start start of the nfa graph
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* nfa_to_dfa convers this graph to dfa. The function returns
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* a pointer to the first dfa state.
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* NOTE: The function that prints out the table will have to figure out how
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* to find the other dfa states given the first dfa_state and the number of dfa
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* nodes allocated
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*/
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dfa_node **
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#ifdef __USE_PROTOS
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nfa_to_dfa(nfa_node *start)
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#else
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nfa_to_dfa(start)
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nfa_node *start;
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#endif
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{
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register dfa_node *d_state, *trans_d_state;
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register int a;
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set t;
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int last_done;
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unsigned *nfa_list;
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unsigned *reach_list;
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reach_list = (unsigned *) malloc((2+nfa_allocated)*sizeof(unsigned));
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if (!start) return NULL;
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t = set_of(NFA_NO(start));
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_set_pdq(t,reach_list);
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closure(&t,reach_list);
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/* Make t a dfa state */
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d_state = dfastate(t);
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last_done = DFA_NO(d_state);
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do {
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/* Mark dfa state x as "done" */
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d_state->done = TRUE;
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nfa_list = set_pdq(d_state->nfa_states);
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for (a = 0; a<class_no; ++a) {
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/* Add NFA states reached by a from d_state */
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reach(nfa_list,a,reach_list);
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/* Were any states found? */
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if ((*reach_list)!=nil) {
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/* was t=empty; */
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set_free(t);
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/* yes, compute closure */
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closure(&t,reach_list);
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/* Make DFA state of it ... */
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trans_d_state = dfastate(t);
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/* And make transition x->t, labeled with a */
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d_state->trans[a] = DFA_NO(trans_d_state);
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d_state->alternatives = TRUE;
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}
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}
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free(nfa_list);
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++last_done; /* move forward in queue */
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/* And so forth until nothing isn't done */
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d_state = DFA(last_done);
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} while (last_done<=dfa_allocated);
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free(reach_list);
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set_free(t);
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/* returns pointer to the array that holds the automaton */
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return dfa_array;
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}
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void
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#ifdef __USE_PROTOS
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clear_hash(void)
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#else
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clear_hash()
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#endif
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{
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register int i;
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for(i=0; i<HASH_SIZE; ++i)
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dfa_hash[i] = 0;
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}
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#if HASH_STAT
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void
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#ifdef __USE_PROTOS
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fprint_hash_stats(FILE *f)
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#else
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fprint_hash_stats(f)
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FILE *f;
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#endif
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{
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register hash_list *p;
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register int i,j;
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register total;
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total=0;
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for(i=0; i<HASH_SIZE; ++i){
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j=0;
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p = dfa_hash[i];
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while(p){
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++j;
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p = p->next;
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}
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total+=j;
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fprintf(f,"bin[%d] has %d\n",i,j);
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}
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fprintf(f,"total = %d\n",total);
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}
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#endif
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/* Returns a pointer to a dfa node that has the same nfa nodes in it.
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* This may or maynot be a newly created node.
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*/
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dfa_node *
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#ifdef __USE_PROTOS
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dfastate(set nfa_states)
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#else
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dfastate(nfa_states)
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set nfa_states;
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#endif
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{
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register hash_list *p;
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int bin;
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/* hash using set and see if it exists */
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bin = set_hash(nfa_states,HASH_SIZE);
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p = dfa_hash[bin];
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while(p && !set_equ(nfa_states,(p->node)->nfa_states)){
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p = p->next;
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}
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if(!p){
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/* next state to add to hash table */
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p = (hash_list*)malloc(sizeof(hash_list));
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p->node = new_dfa_node(nfa_states);
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p->next = dfa_hash[bin];
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dfa_hash[bin] = p;
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}
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return (p->node);
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}
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/* this reach assumes the closure has been done already on set */
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int
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#ifdef __USE_PROTOS
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reach(unsigned *nfa_list, register int a, unsigned *reach_list)
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#else
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reach(nfa_list, a, reach_list)
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unsigned *nfa_list;
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register int a;
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unsigned *reach_list;
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#endif
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{
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register unsigned *e;
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register nfa_node *node;
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int t=0;
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e = nfa_list;
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if (e){
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while (*e != nil){
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node = NFA(*e);
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if (set_el(a,node->label)){
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t=1;
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*reach_list=NFA_NO(node->trans[0]);
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++reach_list;
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}
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++e;
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}
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}
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*reach_list=nil;
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return t;
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}
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/* finds all the nodes that can be reached by epsilon transitions
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from the set of a nodes and returns puts them back in set b */
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set
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#ifdef __USE_PROTOS
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closure(set *b, unsigned *reach_list)
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#else
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closure(b, reach_list)
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set *b;
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unsigned *reach_list;
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#endif
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{
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register nfa_node *node,*n; /* current node being examined */
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register unsigned *e;
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++operation_no;
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#if 0
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t = e = set_pdq(*b);
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#else
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e=reach_list;
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#endif
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while (*e != nil){
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node = NFA(*e);
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set_orel(NFA_NO(node),b);
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/* mark it done */
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node->nfa_set = operation_no;
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if ((n=node->trans[0]) != NIL_INDEX && set_nil(node->label) &&
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(n->nfa_set != operation_no)){
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/* put in b */
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set_orel(NFA_NO(n),b);
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close1(n,operation_no,b);
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}
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if ((n=node->trans[1]) != NIL_INDEX &&
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(n->nfa_set != operation_no)){
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/* put in b */
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set_orel(NFA_NO(node->trans[1]),b);
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close1(n,operation_no,b);
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}
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++e;
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}
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#if 0
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free(t);
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#endif
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return *b;
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}
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#ifdef __USE_PROTOS
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void close1(nfa_node *node, int o, set *b)
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#else
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void close1(node,o,b)
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nfa_node *node;
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int o; /* marker to avoid cycles */
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set *b;
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#endif
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{
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register nfa_node *n; /* current node being examined */
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/* mark it done */
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node->nfa_set = o;
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if ((n=node->trans[0]) != NIL_INDEX && set_nil(node->label) &&
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(n->nfa_set != o)){
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/* put in b */
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set_orel(NFA_NO(n),b);
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close1(n,o,b);
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}
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if ((n=node->trans[1]) != NIL_INDEX &&
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(n->nfa_set != o)){
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/* put in b */
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set_orel(NFA_NO(node->trans[1]),b);
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close1(n,o,b);
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}
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}
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