--- /dev/null
+#ifndef __VDU_H
+#define __VDU_H
+
+typedef ino64_t KEY;
+typedef KEY *PKEY;
+typedef struct stat64 VAL;
+typedef VAL *PVAL;
+
+static inline
+unsigned int
+HASH(PKEY key){
+ return (int) *key;
+}
+
+static inline
+unsigned int // boolean
+EQUAL(PKEY key1, PKEY key2){
+ return *key1 == *key2;
+}
+
+#ifndef MIN
+#define MIN(x,y) (((x)<(y))?(x):(y))
+#endif // MIN
+
+#ifndef MAX
+#define MAX(x,y) (((x)>(y))?(x):(y))
+#endif // MAX
+
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+// hash table support for efficient lookup of duplicate inodes */
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+
+#define Multiplier (0x9e3779b9)
+#define MaxLogBuckets (((sizeof (unsigned long))*8) - 2)
+#define MaxBuckets (1<<MaxLogBuckets)
+#define MinLogBuckets (4)
+#define MinBuckets (1<<MinLogBuckets)
+
+// Thresholds for rehashing the table: *)
+// to avoid crazy oscillations, we must have MaxDensity > 2*MinDensity; *)
+// to avoid excessive probes, we must try to keep MaxDensity low. *)
+// Divide by 100 before using
+#define MaxDensity 75 /* max numEntries/NUMBER(buckets) */
+#define MinDensity 20 /* min numEntries/NUMBER(buckets) */
+#define IdealDensity 50
+#define BITSIZE(x) (sizeof(x)*8)
+
+#define NEW(type,num) ((type*)malloc(sizeof(type)*num))
+#define DISPOSE(ptr) (free((void*)ptr))
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+// Generic Hash Entry Type
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+
+typedef struct VoidList {
+ struct VoidList *tail;
+} VoidList, *PVoidList;
+
+typedef struct HashTable {
+ PVoidList *buckets;
+ unsigned int numBuckets; // number of buckets
+ unsigned int minLogBuckets; // minimum value for Log_2(initial size)
+ unsigned int logBuckets; // CEILING(Log2(NUMBER(buckets^)))
+ unsigned int maxEntries; // maximum number of entries
+ unsigned int minEntries; // minimum number of entries
+ unsigned int numEntries; // current num of entries in table
+ PVoidList cache; // cache of removed elements
+ int cacheSize; // current size of the cache
+ int maxCacheSize; // maximum size, -1 means unbounded, 0 no cache
+} HashTable, *PHashTable;
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+// Hash Prototypes
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+
+PHashTable
+Init(PHashTable tbl, unsigned int n, int maxCacheSize);
+
+void
+Dispose(PHashTable tbl);
+
+unsigned int
+Log_2(unsigned int x);
+
+void
+NewBuckets(PHashTable tbl, unsigned int logBuckets);
+
+//
+// Generic Hash Table support
+//
+
+PHashTable
+Init(PHashTable tbl, unsigned int n, int maxCacheSize){
+ int idealBuckets;
+ int minBuckets;
+
+ idealBuckets = MIN(((n*100)/IdealDensity),MaxBuckets);
+ minBuckets = MAX(MinBuckets, idealBuckets);
+ tbl->minLogBuckets = Log_2(minBuckets);
+
+ NewBuckets(tbl, tbl->minLogBuckets);
+ tbl->numEntries = 0;
+ tbl->maxCacheSize = maxCacheSize;
+ tbl->cacheSize = 0;
+ tbl->cache = 0;
+ return tbl;
+} // Init()
+
+
+//
+// Internal procedures
+//
+
+unsigned int
+Log_2(unsigned int x){
+ // return CEILING(LOG_2(x))
+ unsigned int log = 0;
+ unsigned int n= 1;
+
+ assert(x != 0);
+ while ((log < MaxLogBuckets) && (x > n)){
+ log++;
+ n += n;
+ }
+ return log;
+} // Log_2()
+
+void
+NewBuckets(PHashTable tbl, unsigned int logBuckets){
+ // Allocate "2^logBuckets" buckets.
+ unsigned int numBuckets = 1 << logBuckets;
+ PVoidList *b;
+ unsigned int i;
+
+ tbl->buckets = NEW(PVoidList, numBuckets);
+ tbl->numBuckets = numBuckets;
+ b = tbl->buckets;
+
+ for (i=0; i<tbl->numBuckets; i++){
+ b[i] = NULL;
+ }
+ tbl->logBuckets = logBuckets;
+ tbl->maxEntries = MaxDensity * numBuckets / 100;
+ tbl->minEntries = MinDensity * numBuckets / 100;
+} // NewBuckets()
+
+#ifndef NULL
+#define NULL (void*)0
+#endif // !NULL
+
+#ifndef TRUE
+#define TRUE 1
+#endif // !TRUE
+
+#ifndef FALSE
+#define FALSE 0
+#endif // !FALSE
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+// Type specific hash entry
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+typedef struct EntryList {
+ struct EntryList *tail;
+ KEY key;
+ VAL val;
+}EntryList, *PEntryList;
+
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+// Type specific Hash implementation functions
+////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////
+
+static
+void
+Rehash(PHashTable tbl, unsigned int logBuckets) {
+ // Reallocate "2^logBuckets" buckets, and rehash the entries into
+ // the new table.
+
+ PVoidList *oldBucketPointer;
+ PEntryList *ob, obi;
+ PEntryList *nb, *nbh;
+ PEntryList that, tail;
+ unsigned int index;
+ unsigned int i;
+ unsigned int oldNumBuckets;
+
+ return;
+ assert(logBuckets <= MaxLogBuckets);
+ assert(logBuckets >= tbl->minLogBuckets);
+ oldBucketPointer = tbl->buckets;
+ ob = (PEntryList*)tbl->buckets;
+ oldNumBuckets = tbl->numBuckets;
+
+ NewBuckets(tbl, logBuckets);
+ nb = (PEntryList*)tbl->buckets;
+
+ for(i=0;i<oldNumBuckets;i++){
+ obi = ob[i];
+ that = obi;
+ while (that != NULL) {
+ index = (HASH(&(that->key))*Multiplier)>>(BITSIZE(unsigned long)-tbl->logBuckets);
+ nbh = &(nb[index]);
+ tail = that->tail;
+ that->tail = *nbh;
+ *nbh = that;
+ that = tail;
+ }
+ }
+ DISPOSE (oldBucketPointer);
+}
+
+static inline
+unsigned int // boolean
+Get(PHashTable tbl, PKEY key, PVAL *val){
+ PEntryList that;
+ unsigned int index;
+
+ index = (HASH(key)*Multiplier)>>(BITSIZE(unsigned long)-tbl->logBuckets);
+ that = (PEntryList)tbl->buckets[index];
+ while ((that != NULL) && !EQUAL(key,&(that->key))) {
+ that = that->tail;
+ }
+ if (that != NULL){
+ *val = &that->val;
+ return TRUE;
+ }
+ else {
+ return FALSE;
+ }
+} // Get()
+
+static inline
+unsigned int // boolean
+Put(PHashTable tbl, PKEY key, PVAL *val){
+ PEntryList that;
+ PEntryList *first;
+ unsigned int index;
+ unsigned int res;
+
+ index = (HASH(key)*Multiplier)>>(BITSIZE(unsigned long)-tbl->logBuckets);
+ first = (PEntryList*)&(tbl->buckets[index]);
+ that = *first;
+ while ((that != NULL) && !EQUAL(key, &(that->key))){
+ that = that->tail;
+ }
+
+ // found an entry in the hash table given above key
+ if (that != NULL){
+ res = TRUE;
+ }
+ else {
+ // check if we can reuse something from the cache
+ if (tbl->cache != NULL) {
+ that = (PEntryList)tbl->cache;
+ tbl->cache = (PVoidList)tbl->cache->tail;
+ that->key = *key;
+ that->tail = *first;
+ *first = that;
+ }
+ else {
+ that = NEW(EntryList,1);
+ that->key = *key;
+ that->tail = *first;
+ *first = that;
+ }
+ that->val = **val;
+
+ tbl->numEntries++;
+ if ((tbl->logBuckets < MaxLogBuckets)
+ && (tbl->numEntries > tbl->maxEntries)){
+ Rehash(tbl, tbl->logBuckets + 1); // too crowded
+ }
+ res = FALSE;
+ }
+ *val = &that->val;
+ return res;
+
+} // Put()
+
+static inline
+int
+Delete(PHashTable tbl,PKEY key){
+ PEntryList that, prev;
+ PEntryList *first;
+ unsigned int index;
+
+ index = (HASH(key)*Multiplier)>>(BITSIZE(unsigned long)-tbl->logBuckets);
+ first = (PEntryList*)&(tbl->buckets[index]);
+ that = *first;
+ prev = NULL;
+
+ while ((that != NULL) && !EQUAL(key, &(that->key))){
+ prev = that;
+ that = that->tail;
+ }
+ if (that != NULL) {
+ if (prev == NULL) {
+ *first = that->tail;
+ }
+ else {
+ prev->tail = that->tail;
+ }
+ if ((tbl->maxCacheSize == -1)||(tbl->cacheSize < tbl->maxCacheSize)) {
+ that->tail = (PEntryList)tbl->cache;
+ tbl->cache = (PVoidList)that;
+ tbl->cacheSize++;
+ }
+ else {
+ DISPOSE (that);
+ }
+ tbl->numEntries--;
+ if (tbl->maxCacheSize == 0) {
+ if ((tbl->logBuckets > tbl->minLogBuckets)
+ && (tbl->numEntries < tbl->minEntries)) {
+ Rehash(tbl, tbl->logBuckets - 1); // too sparse
+ }
+ }
+ return TRUE;
+ }
+ else {
+ return FALSE;
+ }
+} // Delete()
+
+typedef void (*callback)(PKEY key, PVAL val);
+
+void
+Iterate(PHashTable tbl, callback fn)
+{
+ PVoidList that;
+ unsigned int i;
+
+ for(i=0;i<tbl->numBuckets;i++) {
+ that = tbl->buckets[i];
+ while ( that != (PVoidList)0 ) {
+ PEntryList entry = (PEntryList)that;
+ fn(&entry->key,&entry->val);
+ that = that->tail;
+ }
+ }
+}
+
+void
+Dispose(PHashTable tbl)
+{
+ PVoidList that, next;
+ unsigned int i;
+
+ for(i=0;i<tbl->numBuckets;i++) {
+ that = tbl->buckets[i];
+ while( that != NULL) {
+ next = that->tail;
+ DISPOSE (that);
+ tbl->numEntries--;
+ that = next;
+ }
+ }
+ DISPOSE(tbl->buckets);
+ assert(tbl->numEntries = 0);
+} // Dispose;
+
+
+
+#endif // __VDU_H
git://git.onelab.eu / util-vserver.git / blobdiff