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[/] [openrisc/] [trunk/] [gnu-old/] [gcc-4.2.2/] [libiberty/] [ternary.c] - Rev 154
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/* ternary.c - Ternary Search Trees Copyright (C) 2001 Free Software Foundation, Inc. Contributed by Daniel Berlin (dan@cgsoftware.com) This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #ifdef HAVE_STDLIB_H #include <stdlib.h> #endif #include <stdio.h> #include "libiberty.h" #include "ternary.h" /* Non-recursive so we don't waste stack space/time on large insertions. */ PTR ternary_insert (ternary_tree *root, const char *s, PTR data, int replace) { int diff; ternary_tree curr, *pcurr; /* Start at the root. */ pcurr = root; /* Loop until we find the right position */ while ((curr = *pcurr)) { /* Calculate the difference */ diff = *s - curr->splitchar; /* Handle current char equal to node splitchar */ if (diff == 0) { /* Handle the case of a string we already have */ if (*s++ == 0) { if (replace) curr->eqkid = (ternary_tree) data; return (PTR) curr->eqkid; } pcurr = &(curr->eqkid); } /* Handle current char less than node splitchar */ else if (diff < 0) { pcurr = &(curr->lokid); } /* Handle current char greater than node splitchar */ else { pcurr = &(curr->hikid); } } /* It's not a duplicate string, and we should insert what's left of the string, into the tree rooted at curr */ for (;;) { /* Allocate the memory for the node, and fill it in */ *pcurr = XNEW (ternary_node); curr = *pcurr; curr->splitchar = *s; curr->lokid = curr->hikid = curr->eqkid = 0; /* Place nodes until we hit the end of the string. When we hit it, place the data in the right place, and return. */ if (*s++ == 0) { curr->eqkid = (ternary_tree) data; return data; } pcurr = &(curr->eqkid); } } /* Free the ternary search tree rooted at p. */ void ternary_cleanup (ternary_tree p) { if (p) { ternary_cleanup (p->lokid); if (p->splitchar) ternary_cleanup (p->eqkid); ternary_cleanup (p->hikid); free (p); } } /* Non-recursive find of a string in the ternary tree */ PTR ternary_search (const ternary_node *p, const char *s) { const ternary_node *curr; int diff, spchar; spchar = *s; curr = p; /* Loop while we haven't hit a NULL node or returned */ while (curr) { /* Calculate the difference */ diff = spchar - curr->splitchar; /* Handle the equal case */ if (diff == 0) { if (spchar == 0) return (PTR) curr->eqkid; spchar = *++s; curr = curr->eqkid; } /* Handle the less than case */ else if (diff < 0) curr = curr->lokid; /* All that's left is greater than */ else curr = curr->hikid; } return NULL; } /* For those who care, the recursive version of the search. Useful if you want a starting point for pmsearch or nearsearch. */ static PTR ternary_recursivesearch (const ternary_node *p, const char *s) { if (!p) return 0; if (*s < p->splitchar) return ternary_recursivesearch (p->lokid, s); else if (*s > p->splitchar) return ternary_recursivesearch (p->hikid, s); else { if (*s == 0) return (PTR) p->eqkid; return ternary_recursivesearch (p->eqkid, ++s); } }
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