2.9BSD - /usr/src/cmd/struct/3.then.c

   1: #include <stdio.h>
   2: #include "def.h"
   3: #include "3.def.h"
   4: 
   5: #define BRANCHTYPE(t)   (t == STOPVX || t == RETVX || t == BRKVX || t == NXTVX || t == GOVX)
   6: #define MAXCHUNK    20
   7:         /* if else clause smaller than MAXCHUNK and smaller than then clause,
   8: 			and there is no reason not to negate the if, negate the if */
   9: 
  10: getthen(v)      /* turn IFVX into THEN when appropriate, create else ifs where possible  */
  11: VERT v;
  12:     {
  13:     VERT tch, fch;
  14:     int tn,fn;
  15:     int recvar;
  16: 
  17:     if (NTYPE(v) == IFVX)
  18:         {
  19:         tch = LCHILD(v,THEN);
  20:         fch = LCHILD(v,ELSE);
  21:         if (!DEFINED(fch))
  22:             mkthen(v);
  23:         else if (!DEFINED(tch))
  24:             {
  25:             negate(v);
  26:             mkthen(v);
  27:             }
  28:         else if (BRANCHTYPE(NTYPE(tch)))
  29:             mkthen(v);
  30:         else if (BRANCHTYPE(NTYPE(fch)))
  31:             {
  32:             negate(v);
  33:             mkthen(v);
  34:             }
  35:         else if (NTYPE(fch) != IFVX || DEFINED(RSIB(fch)))  /* not an else if */
  36:             if ( NTYPE(tch) == IFVX && !DEFINED(RSIB(tch)))
  37:                     /* invert into else if */
  38:                 negate(v);
  39:             else
  40:                 {
  41:                 /* asoc(v,n) returns number of statements associated with v
  42: 					if <= n, -1 otherwise */
  43:                 tn = asoc(tch,MAXCHUNK);
  44:                 fn = asoc(fch,MAXCHUNK);
  45:                 if (fn >= 0 && (tn < 0 || fn < tn))
  46:                     /* else clause smaller */
  47:                     negate(v);
  48:                 }
  49:         }
  50:     RECURSE(getthen,v,recvar);
  51:     }
  52: 
  53: mkthen(v)
  54: VERT v;
  55:     {
  56:     VERT w,tc;
  57:     w = LCHILD(v,ELSE);
  58:     tc = LCHILD(v,THEN);
  59:     ASSERT(!DEFINED(w) || (DEFINED(tc) && BRANCHTYPE(NTYPE(tc)) ),mkthen);
  60:     if (DEFINED(w))
  61:         {
  62:         insib(v,w);
  63:         LCHILD(v,ELSE) = UNDEFINED;
  64:         }
  65:     ASSERT(IFTHEN(v),mkthen);
  66:     }
  67: 
  68: 
  69: negate(v)
  70: VERT v;
  71:     {
  72:     ASSERT(NTYPE(v) == IFVX,negate);
  73:     exchange(&LCHILD(v,THEN), &LCHILD(v,ELSE));
  74:     NEG(v) = !NEG(v);
  75:     }

Defined functions

Defined macros