astlib.c

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/*
 * astlib.c
 *
 * SOFTWARE RIGHTS
 *
 * We reserve no LEGAL rights to SORCERER -- SORCERER is in the public
 * domain.  An individual or company may do whatever they wish with
 * source code distributed with SORCERER or the code generated by
 * SORCERER, including the incorporation of SORCERER, or its output, into
 * commerical software.
 *
 * We encourage users to develop software with SORCERER.  However, we do
 * ask that credit is given to us for developing SORCERER.  By "credit",
 * we mean that if you incorporate our source code into one of your
 * programs (commercial product, research project, or otherwise) that you
 * acknowledge this fact somewhere in the documentation, research report,
 * etc...  If you like SORCERER and have developed a nice tool with the
 * output, please mention that you developed it using SORCERER.  In
 * addition, we ask that this header remain intact in our source code.
 * As long as these guidelines are kept, we expect to continue enhancing
 * this system and expect to make other tools available as they are
 * completed.
 *
 * SORCERER 1.00B
 * Terence Parr
 * AHPCRC, University of Minnesota
 * 1992-1994
 */

#include <stdio.h>
#include "pcctscfg.h"
#include <ctype.h>

#define SORCERER_TRANSFORM

#include "CASTBase.h"
#include "astlib.h"

#ifdef PCCTS_USE_STDARG
#include <stdarg.h>
#else
#include <varargs.h>
#endif

               /* String Scanning/Parsing Stuff */

#define StringScanMaxText  50

typedef struct stringlexer {
#ifdef __USE_PROTOS
      signed int c;
#else
      int c;
#endif
      char *input;
      char *p;
      char text[StringScanMaxText];
    } StringLexer;

#define LPAREN      1
#define RPAREN      2
#define PERCENT      3
#define INT        4
#define COLON      5
#define POUND      6
#define PERIOD      7
#define StringScanEOF  -1
#define VALID_SCAN_TOKEN(t)    (t>=LPAREN && t<=PERIOD)

static char *scan_token_tbl[] = {
  "invalid",  /*  0 */
  "LPAREN",  /*  1 */
  "RPAREN",  /*  2 */
  "PERCENT",  /*  3 */
  "INT",    /*  4 */
  "COLON",  /*  5 */
  "POUND",  /*  6 */
  "PERIOD",  /*  7 */
};

char *
#ifdef __USE_PROTOS
scan_token_str(int t)
#else
scan_token_str(t)
int t;
#endif
{
  if ( VALID_SCAN_TOKEN(t) ) return scan_token_tbl[t];
  else if ( t==StringScanEOF ) return "<end-of-string>";
  else return "<invalid-token>";
}

typedef struct stringparser {
      int token;
      StringLexer *lexer;
      int num_labels;
    } StringParser;

          /* This type ONLY USED by ast_scan() */

typedef struct _scanast {
            struct _scanast *right, *down;
            int token;
      int label_num;
        } ScanAST;

#ifdef __USE_PROTOS
static void stringlexer_init(StringLexer *scanner, char *input);
static void stringparser_init(StringParser *, StringLexer *);
static ScanAST *stringparser_parse_scanast(char *templ, int *n);
static ScanAST *stringparser_parse_tree(StringParser *parser);
static ScanAST *stringparser_parse_element(StringParser *parser);
static void stringscan_advance(StringLexer *scanner);
static int stringscan_gettok(StringLexer *scanner);
#else
static void stringlexer_init();
static void stringparser_init();
static ScanAST *stringparser_parse_scanast();
static ScanAST *stringparser_parse_tree();
static ScanAST *stringparser_parse_element();
static void stringscan_advance();
static int stringscan_gettok();
#endif

/* build a tree (root child1 child2 ... NULL)
 * If root is NULL, simply make the children siblings and return ptr
 * to 1st sibling (child1).  If root is not single node, return NULL.
 *
 * Siblings that are actually sibling lists themselves are handled
 * correctly.  For example #( NULL, #( NULL, A, B, C), D) results
 * in the tree ( NULL A B C D ).
 *
 * Requires at least two parameters with the last one being NULL.  If
 * both are NULL, return NULL.
 *
 * The ast_down and ast_right down/right pointers are used to make the tree.
 */
SORAST *
#ifdef PCCTS_USE_STDARG
ast_make(SORAST *rt, ...)
#else
ast_make(va_alist)
va_dcl
#endif
{
  va_list ap;
  register SORAST *child, *sibling=NULL, *tail = NULL, *w;
  SORAST *root;

#ifdef PCCTS_USE_STDARG
  va_start(ap, rt);
  root = rt;
#else
  va_start(ap);
  root = va_arg(ap, SORAST *);
#endif

  if ( root != NULL )
    if ( root->ast_down != NULL ) return NULL;
  child = va_arg(ap, SORAST *);
  while ( child != NULL )
  {
    /* find end of child */
    for (w=child; w->ast_right!=NULL; w=w->ast_right) {;}
    if ( sibling == NULL ) {sibling = child; tail = w;}
    else {tail->ast_right = child; tail = w;}
    child = va_arg(ap, SORAST *);
  }
  if ( root==NULL ) root = sibling;
  else root->ast_down = sibling;
  va_end(ap);
  return root;
}

/* The following push and pop routines are only used by ast_find_all() */

static void
#ifdef __USE_PROTOS
_push(SORAST **st, int *sp, SORAST *e)
#else
_push(st, sp, e)
SORAST **st;
int *sp;
SORAST *e;
#endif
{
  (*sp)--;
  require((*sp)>=0, "stack overflow");
  st[(*sp)] = e;
}

static SORAST *
#ifdef __USE_PROTOS
_pop(SORAST **st, int *sp)
#else
_pop(st, sp)
SORAST **st;
int *sp;
#endif
{
  SORAST *e = st[*sp];
  (*sp)++;
  require((*sp)<=MaxTreeStackDepth, "stack underflow");
  return e;
}

/* Is 'u' a subtree of 't' beginning at the root? */
int
#ifdef __USE_PROTOS
ast_match_partial(SORAST *t, SORAST *u)
#else
ast_match_partial(t, u)
SORAST *t, *u;
#endif
{
  SORAST *sib;

  if ( u==NULL ) return 1;
  if ( t==NULL ) if ( u!=NULL ) return 0; else return 1;

  for (sib=t; sib!=NULL&&u!=NULL; sib=sib->ast_right, u=u->ast_right)
  {
    if ( sib->token != u->token ) return 0;
    if ( sib->ast_down!=NULL )
      if ( !ast_match_partial(sib->ast_down, u->ast_down) ) return 0;
  }
  return 1;
}

/* Find all occurrences of u in t.
 * 'cursor' must be initialized to 't'.  It eventually
 * returns NULL when no more occurrences of 'u' are found.
 */
SORAST *
#ifdef __USE_PROTOS
ast_find_all(SORAST *t, SORAST *u, SORAST **cursor)
#else
ast_find_all(t, u, cursor)
SORAST *t, *u, **cursor;
#endif
{
  SORAST *sib;
  static SORAST *template_stack[MaxTreeStackDepth];
  static int tsp = MaxTreeStackDepth;

  if ( *cursor == NULL ) return NULL;
  if ( *cursor!=t ) sib = *cursor;
  else {
    /* else, first time--start at top of template 't' */
    tsp = MaxTreeStackDepth;
    sib = t;
    /* bottom of stack is always a NULL--"cookie" indicates "done" */
    _push(template_stack, &tsp, NULL);
  }

keep_looking:
  if ( sib==NULL )  /* hit end of sibling list */
  {
    sib = _pop(template_stack, &tsp);
    if ( sib == NULL ) { *cursor = NULL; return NULL; }
  }

  if ( sib->token != u->token )
  {
    /* look for another match */
    if ( sib->ast_down!=NULL )
    {
      if ( sib->ast_right!=NULL ) _push(template_stack, &tsp, sib->ast_right);
      sib=sib->ast_down;
      goto keep_looking;
    }
    /* nothing below to try, try next sibling */
    sib=sib->ast_right;
    goto keep_looking;
  }

  /* found a matching root node, try to match what's below */
  if ( ast_match_partial(sib, u) )
  {
    /* record sibling cursor so we can pick up next from there */
    if ( sib->ast_down!=NULL )
    {
      if ( sib->ast_right!=NULL ) _push(template_stack, &tsp, sib->ast_right);
      *cursor = sib->ast_down;
    }
    else if ( sib->ast_right!=NULL ) *cursor = sib->ast_right;
    else *cursor = _pop(template_stack, &tsp);
    return sib;
  }

  /* no match, keep searching */
  if ( sib->ast_down!=NULL )
  {
    if ( sib->ast_right!=NULL ) _push(template_stack, &tsp, sib->ast_right);
    sib=sib->ast_down;
  }
  else sib = sib->ast_right;  /* else, try to right if zip below */
  goto keep_looking;
}

/* are two trees exactly alike? */
int
#ifdef __USE_PROTOS
ast_match(SORAST *t, SORAST *u)
#else
ast_match(t, u)
SORAST *t, *u;
#endif
{
  SORAST *sib;

  if ( t==NULL ) if ( u!=NULL ) return 0; else return 1;
  if ( u==NULL ) return 0;

  for (sib=t; sib!=NULL&&u!=NULL; sib=sib->ast_right, u=u->ast_right)
  {
    if ( sib->token != u->token ) return 0;
    if ( sib->ast_down!=NULL )
      if ( !ast_match(sib->ast_down, u->ast_down) ) return 0;
  }
  return 1;
}

static int
#ifdef __USE_PROTOS
ast_scanmatch(ScanAST *t, SORAST *u, SORAST **labels[], int *n)
#else
ast_scanmatch(t, u, labels, n)
ScanAST *t;
SORAST *u;
SORAST **labels[];
int *n;
#endif
{
  ScanAST *sib;

  if ( t==NULL ) if ( u!=NULL ) return 0; else return 1;
  if ( u==NULL ) return 0;

  for (sib=t; sib!=NULL&&u!=NULL; sib=sib->right, u=u->ast_right)
  {
    /* make sure tokens match; token of '0' means wildcard match */
    if ( sib->token != u->token && sib->token!=0 ) return 0;
    /* we have a matched token here; set label pointers if exists */
    if ( sib->label_num>0 )
    {
      require(labels!=NULL, "label found in template, but no array of labels");
      (*n)++;
      *(labels[sib->label_num-1]) = u;
    }
    /* match what's below if something there and current node is not wildcard */
    if ( sib->down!=NULL && sib->token!=0 )
      if ( !ast_scanmatch(sib->down, u->ast_down, labels, n) ) return 0;
  }
  return 1;
}

void
#ifdef __USE_PROTOS
ast_insert_after(SORAST *a, SORAST *b)
#else
ast_insert_after(a, b)
SORAST *a,*b;
#endif
{
  SORAST *end;
  require(a!=NULL, "ast_insert_after: NULL input tree");
  if ( b==NULL ) return;
  /* find end of b's child list */
  for (end=b; end->ast_right!=NULL; end=end->ast_right) {;}
  end->ast_right = a->ast_right;
  a->ast_right = b;
}

void
#ifdef __USE_PROTOS
ast_append(SORAST *a, SORAST *b)
#else
ast_append(a, b)
SORAST *a,*b;
#endif
{
  SORAST *end;
  require(a!=NULL&&b!=NULL, "ast_append: NULL input tree");
  /* find end of child list */
  for (end=a; end->ast_right!=NULL; end=end->ast_right) {;}
  end->ast_right = b;
}

SORAST *
#ifdef __USE_PROTOS
ast_tail(SORAST *a)
#else
ast_tail(a)
SORAST *a;
#endif
{
  SORAST *end;
  require(a!=NULL, "ast_tail: NULL input tree");
  /* find end of child list */
  for (end=a; end->ast_right!=NULL; end=end->ast_right) {;}
  return end;
}

SORAST *
#ifdef __USE_PROTOS
ast_bottom(SORAST *a)
#else
ast_bottom(a)
SORAST *a;
#endif
{
  SORAST *end;
  require(a!=NULL, "ast_bottom: NULL input tree");
  /* find end of child list */
  for (end=a; end->ast_down!=NULL; end=end->ast_down) {;}
  return end;