Move libdrm/ up one level

1 files changed, 428 insertions, 0 deletions

diff --git a/xf86drmHash.c b/xf86drmHash.c
new file mode 100644
index 00000000..82cbc2a5
--- /dev/null
+++ b/xf86drmHash.c
@@ -0,0 +1,428 @@
+/* xf86drmHash.c -- Small hash table support for integer -> integer mapping
+ * Created: Sun Apr 18 09:35:45 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 <faith@valinux.com>
+ *
+ * DESCRIPTION
+ *
+ * This file contains a straightforward implementation of a fixed-sized
+ * hash table using self-organizing linked lists [Knuth73, pp. 398-399] for
+ * collision resolution.  There are two potentially interesting things
+ * about this implementation:
+ *
+ * 1) The table is power-of-two sized.  Prime sized tables are more
+ * traditional, but do not have a significant advantage over power-of-two
+ * sized table, especially when double hashing is not used for collision
+ * resolution.
+ *
+ * 2) The hash computation uses a table of random integers [Hanson97,
+ * pp. 39-41].
+ *
+ * FUTURE ENHANCEMENTS
+ *
+ * With a table size of 512, the current implementation is sufficient for a
+ * few hundred keys.  Since this is well above the expected size of the
+ * tables for which this implementation was designed, the implementation of
+ * dynamic hash tables was postponed until the need arises.  A common (and
+ * naive) approach to dynamic hash table implementation simply creates a
+ * new hash table when necessary, rehashes all the data into the new table,
+ * and destroys the old table.  The approach in [Larson88] is superior in
+ * two ways: 1) only a portion of the table is expanded when needed,
+ * distributing the expansion cost over several insertions, and 2) portions
+ * of the table can be locked, enabling a scalable thread-safe
+ * implementation.
+ *
+ * REFERENCES
+ *
+ * [Hanson97] David R. Hanson.  C Interfaces and Implementations:
+ * Techniques for Creating Reusable Software.  Reading, Massachusetts:
+ * Addison-Wesley, 1997.
+ *
+ * [Knuth73] Donald E. Knuth. The Art of Computer Programming.  Volume 3:
+ * Sorting and Searching.  Reading, Massachusetts: Addison-Wesley, 1973.
+ *
+ * [Larson88] Per-Ake Larson. "Dynamic Hash Tables".  CACM 31(4), April
+ * 1988, pp. 446-457.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define HASH_MAIN 0
+
+#if !HASH_MAIN
+# include "xf86drm.h"
+#endif
+
+#define HASH_MAGIC 0xdeadbeef
+#define HASH_DEBUG 0
+#define HASH_SIZE  512		/* Good for about 100 entries */
+				/* If you change this value, you probably
+                                   have to change the HashHash hashing
+                                   function! */
+
+#if HASH_MAIN
+#define HASH_ALLOC malloc
+#define HASH_FREE  free
+#define HASH_RANDOM_DECL
+#define HASH_RANDOM_INIT(seed)  srandom(seed)
+#define HASH_RANDOM             random()
+#define HASH_RANDOM_DESTROY
+#else
+#define HASH_ALLOC drmMalloc
+#define HASH_FREE  drmFree
+#define HASH_RANDOM_DECL        void *state
+#define HASH_RANDOM_INIT(seed)  state = drmRandomCreate(seed)
+#define HASH_RANDOM             drmRandom(state)
+#define HASH_RANDOM_DESTROY     drmRandomDestroy(state)
+
+#endif
+
+typedef struct HashBucket {
+    unsigned long     key;
+    void              *value;
+    struct HashBucket *next;
+} HashBucket, *HashBucketPtr;
+
+typedef struct HashTable {
+    unsigned long    magic;
+    unsigned long    entries;
+    unsigned long    hits;	/* At top of linked list */
+    unsigned long    partials;	/* Not at top of linked list */
+    unsigned long    misses;	/* Not in table */
+    HashBucketPtr    buckets[HASH_SIZE];
+    int              p0;
+    HashBucketPtr    p1;
+} HashTable, *HashTablePtr;
+
+#if HASH_MAIN
+extern void *drmHashCreate(void);
+extern int  drmHashDestroy(void *t);
+extern int  drmHashLookup(void *t, unsigned long key, unsigned long *value);
+extern int  drmHashInsert(void *t, unsigned long key, unsigned long value);
+extern int  drmHashDelete(void *t, unsigned long key);
+#endif
+
+static unsigned long HashHash(unsigned long key)
+{
+    unsigned long        hash = 0;
+    unsigned long        tmp  = key;
+    static int           init = 0;
+    static unsigned long scatter[256];
+    int                  i;
+
+    if (!init) {
+	HASH_RANDOM_DECL;
+	HASH_RANDOM_INIT(37);
+	for (i = 0; i < 256; i++) scatter[i] = HASH_RANDOM;
+	HASH_RANDOM_DESTROY;
+	++init;
+    }
+
+    while (tmp) {
+	hash = (hash << 1) + scatter[tmp & 0xff];
+	tmp >>= 8;
+    }
+
+    hash %= HASH_SIZE;
+#if HASH_DEBUG
+    printf( "Hash(%d) = %d\n", key, hash);
+#endif
+    return hash;
+}
+
+void *drmHashCreate(void)
+{
+    HashTablePtr table;
+    int          i;
+
+    table           = HASH_ALLOC(sizeof(*table));
+    if (!table) return NULL;
+    table->magic    = HASH_MAGIC;
+    table->entries  = 0;
+    table->hits     = 0;
+    table->partials = 0;
+    table->misses   = 0;
+
+    for (i = 0; i < HASH_SIZE; i++) table->buckets[i] = NULL;
+    return table;
+}
+
+int drmHashDestroy(void *t)
+{
+    HashTablePtr  table = (HashTablePtr)t;
+    HashBucketPtr bucket;
+    HashBucketPtr next;
+    int           i;
+
+    if (table->magic != HASH_MAGIC) return -1; /* Bad magic */
+
+    for (i = 0; i < HASH_SIZE; i++) {
+	for (bucket = table->buckets[i]; bucket;) {
+	    next = bucket->next;
+	    HASH_FREE(bucket);
+	    bucket = next;
+	}
+    }
+    HASH_FREE(table);
+    return 0;
+}
+
+/* Find the bucket and organize the list so that this bucket is at the
+   top. */
+
+static HashBucketPtr HashFind(HashTablePtr table,
+			      unsigned long key, unsigned long *h)
+{
+    unsigned long hash = HashHash(key);
+    HashBucketPtr prev = NULL;
+    HashBucketPtr bucket;
+
+    if (h) *h = hash;
+
+    for (bucket = table->buckets[hash]; bucket; bucket = bucket->next) {
+	if (bucket->key == key) {
+	    if (prev) {
+				/* Organize */
+		prev->next           = bucket->next;
+		bucket->next         = table->buckets[hash];
+		table->buckets[hash] = bucket;
+		++table->partials;
+	    } else {
+		++table->hits;
+	    }
+	    return bucket;
+	}
+	prev = bucket;
+    }
+    ++table->misses;
+    return NULL;
+}
+
+int drmHashLookup(void *t, unsigned long key, void **value)
+{
+    HashTablePtr  table = (HashTablePtr)t;
+    HashBucketPtr bucket;
+
+    if (!table || table->magic != HASH_MAGIC) return -1; /* Bad magic */
+
+    bucket = HashFind(table, key, NULL);
+    if (!bucket) return 1;	/* Not found */
+    *value = bucket->value;
+    return 0;			/* Found */
+}
+
+int drmHashInsert(void *t, unsigned long key, void *value)
+{
+    HashTablePtr  table = (HashTablePtr)t;
+    HashBucketPtr bucket;
+    unsigned long hash;
+
+    if (table->magic != HASH_MAGIC) return -1; /* Bad magic */
+
+    if (HashFind(table, key, &hash)) return 1; /* Already in table */
+
+    bucket               = HASH_ALLOC(sizeof(*bucket));
+    if (!bucket) return -1;	/* Error */
+    bucket->key          = key;
+    bucket->value        = value;
+    bucket->next         = table->buckets[hash];
+    table->buckets[hash] = bucket;
+#if HASH_DEBUG
+    printf("Inserted %d at %d/%p\n", key, hash, bucket);
+#endif
+    return 0;			/* Added to table */
+}
+
+int drmHashDelete(void *t, unsigned long key)
+{
+    HashTablePtr  table = (HashTablePtr)t;
+    unsigned long hash;
+    HashBucketPtr bucket;
+
+    if (table->magic != HASH_MAGIC) return -1; /* Bad magic */
+
+    bucket = HashFind(table, key, &hash);
+
+    if (!bucket) return 1;	/* Not found */
+
+    table->buckets[hash] = bucket->next;
+    HASH_FREE(bucket);
+    return 0;
+}
+
+int drmHashNext(void *t, unsigned long *key, void **value)
+{
+    HashTablePtr  table = (HashTablePtr)t;
+
+    while (table->p0 < HASH_SIZE) {
+	if (table->p1) {
+	    *key       = table->p1->key;
+	    *value     = table->p1->value;
+	    table->p1  = table->p1->next;
+	    return 1;
+	}
+	table->p1 = table->buckets[table->p0];
+	++table->p0;
+    }
+    return 0;
+}
+
+int drmHashFirst(void *t, unsigned long *key, void **value)
+{
+    HashTablePtr  table = (HashTablePtr)t;
+
+    if (table->magic != HASH_MAGIC) return -1; /* Bad magic */
+
+    table->p0 = 0;
+    table->p1 = table->buckets[0];
+    return drmHashNext(table, key, value);
+}
+
+#if HASH_MAIN
+#define DIST_LIMIT 10
+static int dist[DIST_LIMIT];
+
+static void clear_dist(void) {
+    int i;
+
+    for (i = 0; i < DIST_LIMIT; i++) dist[i] = 0;
+}
+
+static int count_entries(HashBucketPtr bucket)
+{
+    int count = 0;
+
+    for (; bucket; bucket = bucket->next) ++count;
+    return count;
+}
+
+static void update_dist(int count)
+{
+    if (count >= DIST_LIMIT) ++dist[DIST_LIMIT-1];
+    else                     ++dist[count];
+}
+
+static void compute_dist(HashTablePtr table)
+{
+    int           i;
+    HashBucketPtr bucket;
+
+    printf("Entries = %ld, hits = %ld, partials = %ld, misses = %ld\n",
+	   table->entries, table->hits, table->partials, table->misses);
+    clear_dist();
+    for (i = 0; i < HASH_SIZE; i++) {
+	bucket = table->buckets[i];
+	update_dist(count_entries(bucket));
+    }
+    for (i = 0; i < DIST_LIMIT; i++) {
+	if (i != DIST_LIMIT-1) printf("%5d %10d\n", i, dist[i]);
+	else                   printf("other %10d\n", dist[i]);
+    }
+}
+
+static void check_table(HashTablePtr table,
+			unsigned long key, unsigned long value)
+{
+    unsigned long retval  = 0;
+    int           retcode = drmHashLookup(table, key, &retval);
+
+    switch (retcode) {
+    case -1:
+	printf("Bad magic = 0x%08lx:"
+	       " key = %lu, expected = %lu, returned = %lu\n",
+	       table->magic, key, value, retval);
+	break;
+    case 1:
+	printf("Not found: key = %lu, expected = %lu returned = %lu\n",
+	       key, value, retval);
+	break;
+    case 0:
+	if (value != retval)
+	    printf("Bad value: key = %lu, expected = %lu, returned = %lu\n",
+		   key, value, retval);
+	break;
+    default:
+	printf("Bad retcode = %d: key = %lu, expected = %lu, returned = %lu\n",
+	       retcode, key, value, retval);
+	break;
+    }
+}
+
+int main(void)
+{
+    HashTablePtr table;
+    int          i;
+
+    printf("\n***** 256 consecutive integers ****\n");
+    table = drmHashCreate();
+    for (i = 0; i < 256; i++) drmHashInsert(table, i, i);
+    for (i = 0; i < 256; i++) check_table(table, i, i);
+    for (i = 256; i >= 0; i--) check_table(table, i, i);
+    compute_dist(table);
+    drmHashDestroy(table);
+
+    printf("\n***** 1024 consecutive integers ****\n");
+    table = drmHashCreate();
+    for (i = 0; i < 1024; i++) drmHashInsert(table, i, i);
+    for (i = 0; i < 1024; i++) check_table(table, i, i);
+    for (i = 1024; i >= 0; i--) check_table(table, i, i);
+    compute_dist(table);
+    drmHashDestroy(table);
+
+    printf("\n***** 1024 consecutive page addresses (4k pages) ****\n");
+    table = drmHashCreate();
+    for (i = 0; i < 1024; i++) drmHashInsert(table, i*4096, i);
+    for (i = 0; i < 1024; i++) check_table(table, i*4096, i);
+    for (i = 1024; i >= 0; i--) check_table(table, i*4096, i);
+    compute_dist(table);
+    drmHashDestroy(table);
+
+    printf("\n***** 1024 random integers ****\n");
+    table = drmHashCreate();
+    srandom(0xbeefbeef);
+    for (i = 0; i < 1024; i++) drmHashInsert(table, random(), i);
+    srandom(0xbeefbeef);
+    for (i = 0; i < 1024; i++) check_table(table, random(), i);
+    srandom(0xbeefbeef);
+    for (i = 0; i < 1024; i++) check_table(table, random(), i);
+    compute_dist(table);
+    drmHashDestroy(table);
+
+    printf("\n***** 5000 random integers ****\n");
+    table = drmHashCreate();
+    srandom(0xbeefbeef);
+    for (i = 0; i < 5000; i++) drmHashInsert(table, random(), i);
+    srandom(0xbeefbeef);
+    for (i = 0; i < 5000; i++) check_table(table, random(), i);
+    srandom(0xbeefbeef);
+    for (i = 0; i < 5000; i++) check_table(table, random(), i);
+    compute_dist(table);
+    drmHashDestroy(table);
+
+    return 0;
+}
+#endif