From 3f13df4d019cfcbef3f9909e3b993896d3c934e6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 11:22:22 +0200 Subject: Adding upstream version 2.4.114. Signed-off-by: Daniel Baumann --- xf86drmSL.c | 319 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 319 insertions(+) create mode 100644 xf86drmSL.c (limited to 'xf86drmSL.c') diff --git a/xf86drmSL.c b/xf86drmSL.c new file mode 100644 index 0000000..3826df9 --- /dev/null +++ b/xf86drmSL.c @@ -0,0 +1,319 @@ +/* xf86drmSL.c -- Skip list support + * Created: Mon May 10 09:28:13 1999 by faith@precisioninsight.com + * + * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. + * All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) 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 + * PRECISION INSIGHT AND/OR ITS SUPPLIERS 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. + * + * Authors: Rickard E. (Rik) Faith + * + * DESCRIPTION + * + * This file contains a straightforward skip list implementation.n + * + * FUTURE ENHANCEMENTS + * + * REFERENCES + * + * [Pugh90] William Pugh. Skip Lists: A Probabilistic Alternative to + * Balanced Trees. CACM 33(6), June 1990, pp. 668-676. + * + */ + +#include +#include + +#include "libdrm_macros.h" +#include "xf86drm.h" + +#define SL_LIST_MAGIC 0xfacade00LU +#define SL_ENTRY_MAGIC 0x00fab1edLU +#define SL_FREED_MAGIC 0xdecea5edLU +#define SL_MAX_LEVEL 16 +#define SL_RANDOM_SEED 0xc01055a1LU + +#define SL_RANDOM_DECL static void *state = NULL +#define SL_RANDOM_INIT(seed) if (!state) state = drmRandomCreate(seed) +#define SL_RANDOM drmRandom(state) + +typedef struct SLEntry { + unsigned long magic; /* SL_ENTRY_MAGIC */ + unsigned long key; + void *value; + int levels; + struct SLEntry *forward[1]; /* variable sized array */ +} SLEntry, *SLEntryPtr; + +typedef struct SkipList { + unsigned long magic; /* SL_LIST_MAGIC */ + int level; + int count; + SLEntryPtr head; + SLEntryPtr p0; /* Position for iteration */ +} SkipList, *SkipListPtr; + +static SLEntryPtr SLCreateEntry(int max_level, unsigned long key, void *value) +{ + SLEntryPtr entry; + + if (max_level < 0 || max_level > SL_MAX_LEVEL) max_level = SL_MAX_LEVEL; + + entry = drmMalloc(sizeof(*entry) + + (max_level + 1) * sizeof(entry->forward[0])); + if (!entry) return NULL; + entry->magic = SL_ENTRY_MAGIC; + entry->key = key; + entry->value = value; + entry->levels = max_level + 1; + + return entry; +} + +static int SLRandomLevel(void) +{ + int level = 1; + SL_RANDOM_DECL; + + SL_RANDOM_INIT(SL_RANDOM_SEED); + + while ((SL_RANDOM & 0x01) && level < SL_MAX_LEVEL) ++level; + return level; +} + +drm_public void *drmSLCreate(void) +{ + SkipListPtr list; + int i; + + list = drmMalloc(sizeof(*list)); + if (!list) return NULL; + list->magic = SL_LIST_MAGIC; + list->level = 0; + list->head = SLCreateEntry(SL_MAX_LEVEL, 0, NULL); + list->count = 0; + + for (i = 0; i <= SL_MAX_LEVEL; i++) list->head->forward[i] = NULL; + + return list; +} + +drm_public int drmSLDestroy(void *l) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr entry; + SLEntryPtr next; + + if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */ + + for (entry = list->head; entry; entry = next) { + if (entry->magic != SL_ENTRY_MAGIC) return -1; /* Bad magic */ + next = entry->forward[0]; + entry->magic = SL_FREED_MAGIC; + drmFree(entry); + } + + list->magic = SL_FREED_MAGIC; + drmFree(list); + return 0; +} + +static SLEntryPtr SLLocate(void *l, unsigned long key, SLEntryPtr *update) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr entry; + int i; + + if (list->magic != SL_LIST_MAGIC) return NULL; + + for (i = list->level, entry = list->head; i >= 0; i--) { + while (entry->forward[i] && entry->forward[i]->key < key) + entry = entry->forward[i]; + update[i] = entry; + } + + return entry->forward[0]; +} + +drm_public int drmSLInsert(void *l, unsigned long key, void *value) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr entry; + SLEntryPtr update[SL_MAX_LEVEL + 1]; + int level; + int i; + + if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */ + + entry = SLLocate(list, key, update); + + if (entry && entry->key == key) return 1; /* Already in list */ + + + level = SLRandomLevel(); + if (level > list->level) { + level = ++list->level; + update[level] = list->head; + } + + entry = SLCreateEntry(level, key, value); + + /* Fix up forward pointers */ + for (i = 0; i <= level; i++) { + entry->forward[i] = update[i]->forward[i]; + update[i]->forward[i] = entry; + } + + ++list->count; + return 0; /* Added to table */ +} + +drm_public int drmSLDelete(void *l, unsigned long key) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr update[SL_MAX_LEVEL + 1]; + SLEntryPtr entry; + int i; + + if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */ + + entry = SLLocate(list, key, update); + + if (!entry || entry->key != key) return 1; /* Not found */ + + /* Fix up forward pointers */ + for (i = 0; i <= list->level; i++) { + if (update[i]->forward[i] == entry) + update[i]->forward[i] = entry->forward[i]; + } + + entry->magic = SL_FREED_MAGIC; + drmFree(entry); + + while (list->level && !list->head->forward[list->level]) --list->level; + --list->count; + return 0; +} + +drm_public int drmSLLookup(void *l, unsigned long key, void **value) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr update[SL_MAX_LEVEL + 1]; + SLEntryPtr entry; + + entry = SLLocate(list, key, update); + + if (entry && entry->key == key) { + *value = entry; + return 0; + } + *value = NULL; + return -1; +} + +drm_public int drmSLLookupNeighbors(void *l, unsigned long key, + unsigned long *prev_key, void **prev_value, + unsigned long *next_key, void **next_value) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr update[SL_MAX_LEVEL + 1] = {0}; + int retcode = 0; + + SLLocate(list, key, update); + + *prev_key = *next_key = key; + *prev_value = *next_value = NULL; + + if (update[0]) { + *prev_key = update[0]->key; + *prev_value = update[0]->value; + ++retcode; + if (update[0]->forward[0]) { + *next_key = update[0]->forward[0]->key; + *next_value = update[0]->forward[0]->value; + ++retcode; + } + } + return retcode; +} + +drm_public int drmSLNext(void *l, unsigned long *key, void **value) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr entry; + + if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */ + + entry = list->p0; + + if (entry) { + list->p0 = entry->forward[0]; + *key = entry->key; + *value = entry->value; + return 1; + } + list->p0 = NULL; + return 0; +} + +drm_public int drmSLFirst(void *l, unsigned long *key, void **value) +{ + SkipListPtr list = (SkipListPtr)l; + + if (list->magic != SL_LIST_MAGIC) return -1; /* Bad magic */ + + list->p0 = list->head->forward[0]; + return drmSLNext(list, key, value); +} + +/* Dump internal data structures for debugging. */ +drm_public void drmSLDump(void *l) +{ + SkipListPtr list = (SkipListPtr)l; + SLEntryPtr entry; + int i; + + if (list->magic != SL_LIST_MAGIC) { + printf("Bad magic: 0x%08lx (expected 0x%08lx)\n", + list->magic, SL_LIST_MAGIC); + return; + } + + printf("Level = %d, count = %d\n", list->level, list->count); + for (entry = list->head; entry; entry = entry->forward[0]) { + if (entry->magic != SL_ENTRY_MAGIC) { + printf("Bad magic: 0x%08lx (expected 0x%08lx)\n", + list->magic, SL_ENTRY_MAGIC); + } + printf("\nEntry %p <0x%08lx, %p> has %2d levels\n", + entry, entry->key, entry->value, entry->levels); + for (i = 0; i < entry->levels; i++) { + if (entry->forward[i]) { + printf(" %2d: %p <0x%08lx, %p>\n", + i, + entry->forward[i], + entry->forward[i]->key, + entry->forward[i]->value); + } else { + printf(" %2d: %p\n", i, entry->forward[i]); + } + } + } +} -- cgit v1.2.3