Parser/node.c

   1 /* Parse tree node implementation */
   2
   3 #include "Python.h"
   4 #include "node.h"
   5 #include "errcode.h"
   6
   7 node *
   8 PyNode_New(int type)
   9 {
  10         node *n = PyMem_NEW(node, 1);
  11         if (n == NULL)
  12                 return NULL;
  13         n->n_type = type;
  14         n->n_str = NULL;
  15         n->n_lineno = 0;
  16         n->n_nchildren = 0;
  17         n->n_child = NULL;
  18         return n;
  19 }
  20
  21 #define XXX 3 /* Node alignment factor to speed up realloc */
  22 #define XXXROUNDUP(n) ((n) == 1 ? 1 : ((n) + XXX - 1) / XXX * XXX)
  23
  24 int
  25 PyNode_AddChild(register node *n1, int type, char *str, int lineno)
  26 {
  27         register int nch = n1->n_nchildren;
  28         register int nch1 = nch+1;
  29         register node *n;
  30         if (nch == INT_MAX || nch < 0)
  31                 return E_OVERFLOW;
  32         if (XXXROUNDUP(nch) < nch1) {
  33                 n = n1->n_child;
  34                 nch1 = XXXROUNDUP(nch1);
  35                 PyMem_RESIZE(n, node, nch1);
  36                 if (n == NULL)
  37                         return E_NOMEM;
  38                 n1->n_child = n;
  39         }
  40         n = &n1->n_child[n1->n_nchildren++];
  41         n->n_type = type;
  42         n->n_str = str;
  43         n->n_lineno = lineno;
  44         n->n_nchildren = 0;
  45         n->n_child = NULL;
  46         return 0;
  47 }
  48
  49 /* Forward */
  50 static void freechildren(node *);
  51
  52
  53 void
  54 PyNode_Free(node *n)
  55 {
  56         if (n != NULL) {
  57                 freechildren(n);
  58                 PyMem_DEL(n);
  59         }
  60 }
  61
  62 static void
  63 freechildren(node *n)
  64 {
  65         int i;
  66         for (i = NCH(n); --i >= 0; )
  67                 freechildren(CHILD(n, i));
  68         if (n->n_child != NULL)
  69                 PyMem_DEL(n->n_child);
  70         if (STR(n) != NULL)
  71                 PyMem_DEL(STR(n));
  72 }