dix/atom.c

   1 /***********************************************************
   2
   3 Copyright 1987, 1998  The Open Group
   4
   5 Permission to use, copy, modify, distribute, and sell this software and its
   6 documentation for any purpose is hereby granted without fee, provided that
   7 the above copyright notice appear in all copies and that both that
   8 copyright notice and this permission notice appear in supporting
   9 documentation.
  10
  11 The above copyright notice and this permission notice shall be included in
  12 all copies or substantial portions of the Software.
  13
  14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  17 OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  18 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  19 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20
  21 Except as contained in this notice, the name of The Open Group shall not be
  22 used in advertising or otherwise to promote the sale, use or other dealings
  23 in this Software without prior written authorization from The Open Group.
  24
  25 Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
  26
  27                         All Rights Reserved
  28
  29 Permission to use, copy, modify, and distribute this software and its
  30 documentation for any purpose and without fee is hereby granted,
  31 provided that the above copyright notice appear in all copies and that
  32 both that copyright notice and this permission notice appear in
  33 supporting documentation, and that the name of Digital not be
  34 used in advertising or publicity pertaining to distribution of the
  35 software without specific, written prior permission.
  36
  37 DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
  38 ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
  39 DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
  40 ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  41 WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
  42 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  43 SOFTWARE.
  44
  45 ******************************************************************/
  46
  47 #ifdef HAVE_DIX_CONFIG_H
  48 #include <dix-config.h>
  49 #endif
  50
  51 #include <X11/X.h>
  52 #include <X11/Xatom.h>
  53 #include <stdio.h>
  54 #include <string.h>
  55 #include "misc.h"
  56 #include "resource.h"
  57 #include "dix.h"
  58
  59 #define InitialTableSize 100
  60
  61 typedef struct _Node {
  62     struct _Node *left, *right;
  63     Atom a;
  64     unsigned int fingerPrint;
  65     const char *string;
  66 } NodeRec, *NodePtr;
  67
  68 static Atom lastAtom = None;
  69 static NodePtr atomRoot = NULL;
  70 static unsigned long tableLength;
  71 static NodePtr *nodeTable;
  72
  73 void FreeAtom(NodePtr patom);
  74
  75 Atom
  76 MakeAtom(const char *string, unsigned len, Bool makeit)
  77 {
  78     NodePtr *np;
  79     unsigned i;
  80     int comp;
  81     unsigned int fp = 0;
  82
  83     np = &atomRoot;
  84     for (i = 0; i < (len + 1) / 2; i++) {
  85         fp = fp * 27 + string[i];
  86         fp = fp * 27 + string[len - 1 - i];
  87     }
  88     while (*np != NULL) {
  89         if (fp < (*np)->fingerPrint)
  90             np = &((*np)->left);
  91         else if (fp > (*np)->fingerPrint)
  92             np = &((*np)->right);
  93         else {                  /* now start testing the strings */
  94             comp = strncmp(string, (*np)->string, (int) len);
  95             if ((comp < 0) || ((comp == 0) && (len < strlen((*np)->string))))
  96                 np = &((*np)->left);
  97             else if (comp > 0)
  98                 np = &((*np)->right);
  99             else
 100                 return (*np)->a;
 101         }
 102     }
 103     if (makeit) {
 104         NodePtr nd;
 105
 106         nd = malloc(sizeof(NodeRec));
 107         if (!nd)
 108             return BAD_RESOURCE;
 109         if (lastAtom < XA_LAST_PREDEFINED) {
 110             nd->string = string;
 111         }
 112         else {
 113             nd->string = strndup(string, len);
 114             if (!nd->string) {
 115                 free(nd);
 116                 return BAD_RESOURCE;
 117             }
 118         }
 119         if ((lastAtom + 1) >= tableLength) {
 120             NodePtr *table;
 121
 122             table = realloc(nodeTable, tableLength * (2 * sizeof(NodePtr)));
 123             if (!table) {
 124                 if (nd->string != string) {
 125                     /* nd->string has been strdup'ed */
 126                     free((char *) nd->string);
 127                 }
 128                 free(nd);
 129                 return BAD_RESOURCE;
 130             }
 131             tableLength <<= 1;
 132             nodeTable = table;
 133         }
 134         *np = nd;
 135         nd->left = nd->right = NULL;
 136         nd->fingerPrint = fp;
 137         nd->a = ++lastAtom;
 138         nodeTable[lastAtom] = nd;
 139         return nd->a;
 140     }
 141     else
 142         return None;
 143 }
 144
 145 Bool
 146 ValidAtom(Atom atom)
 147 {
 148     return (atom != None) && (atom <= lastAtom);
 149 }
 150
 151 const char *
 152 NameForAtom(Atom atom)
 153 {
 154     NodePtr node;
 155
 156     if (atom > lastAtom)
 157         return 0;
 158     if ((node = nodeTable[atom]) == NULL)
 159         return 0;
 160     return node->string;
 161 }
 162
 163 void
 164 AtomError(void)
 165 {
 166     FatalError("initializing atoms");
 167 }
 168
 169 void
 170 FreeAtom(NodePtr patom)
 171 {
 172     if (patom->left)
 173         FreeAtom(patom->left);
 174     if (patom->right)
 175         FreeAtom(patom->right);
 176     if (patom->a > XA_LAST_PREDEFINED) {
 177         /*
 178          * All strings above XA_LAST_PREDEFINED are strdup'ed, so it's safe to
 179          * cast here
 180          */
 181         free((char *) patom->string);
 182     }
 183     free(patom);
 184 }
 185
 186 void
 187 FreeAllAtoms(void)
 188 {
 189     if (atomRoot == NULL)
 190         return;
 191     FreeAtom(atomRoot);
 192     atomRoot = NULL;
 193     free(nodeTable);
 194     nodeTable = NULL;
 195     lastAtom = None;
 196 }
 197
 198 void
 199 InitAtoms(void)
 200 {
 201     FreeAllAtoms();
 202     tableLength = InitialTableSize;
 203     nodeTable = malloc(InitialTableSize * sizeof(NodePtr));
 204     if (!nodeTable)
 205         AtomError();
 206     nodeTable[None] = NULL;
 207     MakePredeclaredAtoms();
 208     if (lastAtom != XA_LAST_PREDEFINED)
 209         AtomError();
 210 }