| /*********************************************************** |
| * 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 |
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| * 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. |
| * |
| ******************************************************************/ |
| |
| /************************************************************ |
| * Copyright 1994 by Silicon Graphics Computer Systems, Inc. |
| * |
| * 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 Silicon Graphics not be |
| * used in advertising or publicity pertaining to distribution |
| * of the software without specific prior written permission. |
| * Silicon Graphics makes no representation about the suitability |
| * of this software for any purpose. It is provided "as is" |
| * without any express or implied warranty. |
| * |
| * SILICON GRAPHICS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS |
| * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY |
| * AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON |
| * GRAPHICS 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. |
| * |
| ********************************************************/ |
| |
| #include "config.h" |
| |
| #include "utils.h" |
| #include "atom.h" |
| |
| /* FNV-1a (http://www.isthe.com/chongo/tech/comp/fnv/). */ |
| static inline uint32_t |
| hash_buf(const char *string, size_t len) |
| { |
| uint32_t hash = 2166136261u; |
| for (size_t i = 0; i < (len + 1) / 2; i++) { |
| hash ^= (uint8_t) string[i]; |
| hash *= 0x01000193; |
| hash ^= (uint8_t) string[len - 1 - i]; |
| hash *= 0x01000193; |
| } |
| return hash; |
| } |
| |
| /* |
| * The atom table is a insert-only unbalanced binary search tree |
| * mapping strings to atoms. |
| * |
| * The tree nodes are kept contiguously in the `table` array. |
| * |
| * The atom value is the index of the tree node in the array. |
| * |
| * As an optimization, strings are not compared by value directly, |
| * s1 < s2 |
| * instead, they are compared by fingerprint (hash) and the value |
| * is only used to resolve collisions: |
| * (fingerprint(s1), s1) < (fingerprint(s2), s2) |
| * Fingerprint are pre-calculated and saved in the tree nodes. |
| * |
| * Why is this not just a hash table? Who knows! |
| */ |
| struct atom_node { |
| xkb_atom_t left, right; |
| uint32_t fingerprint; |
| char *string; |
| }; |
| |
| struct atom_table { |
| xkb_atom_t root; |
| darray(struct atom_node) table; |
| }; |
| |
| struct atom_table * |
| atom_table_new(void) |
| { |
| struct atom_table *table = calloc(1, sizeof(*table)); |
| if (!table) |
| return NULL; |
| |
| darray_init(table->table); |
| /* The original throw-away root is here, at the illegal atom 0. */ |
| darray_resize0(table->table, 1); |
| |
| return table; |
| } |
| |
| void |
| atom_table_free(struct atom_table *table) |
| { |
| if (!table) |
| return; |
| |
| struct atom_node *node; |
| darray_foreach(node, table->table) |
| free(node->string); |
| darray_free(table->table); |
| free(table); |
| } |
| |
| const char * |
| atom_text(struct atom_table *table, xkb_atom_t atom) |
| { |
| assert(atom < darray_size(table->table)); |
| return darray_item(table->table, atom).string; |
| } |
| |
| xkb_atom_t |
| atom_intern(struct atom_table *table, const char *string, size_t len, bool add) |
| { |
| uint32_t fingerprint = hash_buf(string, len); |
| |
| xkb_atom_t *atomp = &table->root; |
| while (*atomp != XKB_ATOM_NONE) { |
| struct atom_node *node = &darray_item(table->table, *atomp); |
| |
| if (fingerprint > node->fingerprint) { |
| atomp = &node->right; |
| } |
| else if (fingerprint < node->fingerprint) { |
| atomp = &node->left; |
| } |
| else { |
| /* Now start testing the strings. */ |
| const int cmp = strncmp(string, node->string, len); |
| if (likely(cmp == 0 && node->string[len] == '\0')) { |
| return *atomp; |
| } |
| else if (cmp > 0) { |
| atomp = &node->right; |
| } |
| else { |
| atomp = &node->left; |
| } |
| } |
| } |
| |
| if (!add) |
| return XKB_ATOM_NONE; |
| |
| struct atom_node node; |
| node.string = strndup(string, len); |
| assert(node.string != NULL); |
| node.left = node.right = XKB_ATOM_NONE; |
| node.fingerprint = fingerprint; |
| xkb_atom_t atom = darray_size(table->table); |
| /* Do this before the append, as it may realloc and change the offsets. */ |
| *atomp = atom; |
| darray_append(table->table, node); |
| return atom; |
| } |