xserver

atom.c (5885B)

---

 /***********************************************************
 
 Copyright 1987, 1998  The Open Group
 
 Permission to use, copy, modify, distribute, and sell this software and its
 documentation for any purpose is hereby granted without fee, provided that
 the above copyright notice appear in all copies and that both that
 copyright notice and this permission notice appear in supporting
 documentation.
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 Except as contained in this notice, the name of The Open Group shall not be
 used in advertising or otherwise to promote the sale, use or other dealings
 in this Software without prior written authorization from The Open Group.
 
 Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
 
                         All Rights Reserved
 
 Permission to use, copy, modify, and distribute this software and its
 documentation for any purpose and without fee is hereby granted,
 provided that the above copyright notice appear in all copies and that
 both that copyright notice and this permission notice appear in
 supporting documentation, and that the name of Digital not be
 used in advertising or publicity pertaining to distribution of the
 software without specific, written prior permission.
 
 DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
 ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
 DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
 ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 SOFTWARE.
 
 ******************************************************************/
 
 #ifdef HAVE_DIX_CONFIG_H
 #include <dix-config.h>
 #endif
 
 #include <X11/X.h>
 #include <X11/Xatom.h>
 #include <stdio.h>
 #include <string.h>
 #include "misc.h"
 #include "resource.h"
 #include "dix.h"
 
 #define InitialTableSize 256
 
 typedef struct _Node {
     struct _Node *left, *right;
     Atom a;
     unsigned int fingerPrint;
     const char *string;
 } NodeRec, *NodePtr;
 
 static Atom lastAtom = None;
 static NodePtr atomRoot = NULL;
 static unsigned long tableLength;
 static NodePtr *nodeTable;
 
 Atom
 MakeAtom(const char *string, unsigned len, Bool makeit)
 {
     NodePtr *np;
     unsigned i;
     int comp;
     unsigned int fp = 0;
 
     np = &atomRoot;
     for (i = 0; i < (len + 1) / 2; i++) {
         fp = fp * 27 + string[i];
         fp = fp * 27 + string[len - 1 - i];
     }
     while (*np != NULL) {
         if (fp < (*np)->fingerPrint)
             np = &((*np)->left);
         else if (fp > (*np)->fingerPrint)
             np = &((*np)->right);
         else {                  /* now start testing the strings */
             comp = strncmp(string, (*np)->string, (int) len);
             if ((comp < 0) || ((comp == 0) && (len < strlen((*np)->string))))
                 np = &((*np)->left);
             else if (comp > 0)
                 np = &((*np)->right);
             else
                 return (*np)->a;
         }
     }
     if (makeit) {
         NodePtr nd;
 
         nd = malloc(sizeof(NodeRec));
         if (!nd)
             return BAD_RESOURCE;
         if (lastAtom < XA_LAST_PREDEFINED) {
             nd->string = string;
         }
         else {
             nd->string = strndup(string, len);
             if (!nd->string) {
                 free(nd);
                 return BAD_RESOURCE;
             }
         }
         if ((lastAtom + 1) >= tableLength) {
             NodePtr *table;
 
             table = reallocarray(nodeTable, tableLength, 2 * sizeof(NodePtr));
             if (!table) {
                 if (nd->string != string) {
                     /* nd->string has been strdup'ed */
                     free((char *) nd->string);
                 }
                 free(nd);
                 return BAD_RESOURCE;
             }
             tableLength <<= 1;
             nodeTable = table;
         }
         *np = nd;
         nd->left = nd->right = NULL;
         nd->fingerPrint = fp;
         nd->a = ++lastAtom;
         nodeTable[lastAtom] = nd;
         return nd->a;
     }
     else
         return None;
 }
 
 Bool
 ValidAtom(Atom atom)
 {
     return (atom != None) && (atom <= lastAtom);
 }
 
 const char *
 NameForAtom(Atom atom)
 {
     NodePtr node;
 
     if (atom > lastAtom)
         return 0;
     if ((node = nodeTable[atom]) == NULL)
         return 0;
     return node->string;
 }
 
 void
 AtomError(void)
 {
     FatalError("initializing atoms");
 }
 
 static void
 FreeAtom(NodePtr patom)
 {
     if (patom->left)
         FreeAtom(patom->left);
     if (patom->right)
         FreeAtom(patom->right);
     if (patom->a > XA_LAST_PREDEFINED) {
         /*
          * All strings above XA_LAST_PREDEFINED are strdup'ed, so it's safe to
          * cast here
          */
         free((char *) patom->string);
     }
     free(patom);
 }
 
 void
 FreeAllAtoms(void)
 {
     if (atomRoot == NULL)
         return;
     FreeAtom(atomRoot);
     atomRoot = NULL;
     free(nodeTable);
     nodeTable = NULL;
     lastAtom = None;
 }
 
 void
 InitAtoms(void)
 {
     FreeAllAtoms();
     tableLength = InitialTableSize;
     nodeTable = xallocarray(InitialTableSize, sizeof(NodePtr));
     if (!nodeTable)
         AtomError();
     nodeTable[None] = NULL;
     MakePredeclaredAtoms();
     if (lastAtom != XA_LAST_PREDEFINED)
         AtomError();
 }