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Diffstat (limited to 'generic/tclHash.c')
| -rw-r--r-- | generic/tclHash.c | 921 |
1 files changed, 921 insertions, 0 deletions
diff --git a/generic/tclHash.c b/generic/tclHash.c new file mode 100644 index 0000000..e20275a --- /dev/null +++ b/generic/tclHash.c @@ -0,0 +1,921 @@ +/* + * tclHash.c -- + * + * Implementation of in-memory hash tables for Tcl and Tcl-based + * applications. + * + * Copyright (c) 1991-1993 The Regents of the University of California. + * Copyright (c) 1994 Sun Microsystems, Inc. + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * + * SCCS: @(#) tclHash.c 1.16 96/04/29 10:30:49 + */ + +#include "tclInt.h" + +/* + * When there are this many entries per bucket, on average, rebuild + * the hash table to make it larger. + */ + +#define REBUILD_MULTIPLIER 3 + + +/* + * The following macro takes a preliminary integer hash value and + * produces an index into a hash tables bucket list. The idea is + * to make it so that preliminary values that are arbitrarily similar + * will end up in different buckets. The hash function was taken + * from a random-number generator. + */ + +#define RANDOM_INDEX(tablePtr, i) \ + (((((long) (i))*1103515245) >> (tablePtr)->downShift) & (tablePtr)->mask) + +/* + * Procedure prototypes for static procedures in this file: + */ + +static Tcl_HashEntry * ArrayFind _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key)); +static Tcl_HashEntry * ArrayCreate _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key, int *newPtr)); +static Tcl_HashEntry * BogusFind _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key)); +static Tcl_HashEntry * BogusCreate _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key, int *newPtr)); +static unsigned int HashString _ANSI_ARGS_((CONST char *string)); +static void RebuildTable _ANSI_ARGS_((Tcl_HashTable *tablePtr)); +static Tcl_HashEntry * StringFind _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key)); +static Tcl_HashEntry * StringCreate _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key, int *newPtr)); +static Tcl_HashEntry * OneWordFind _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key)); +static Tcl_HashEntry * OneWordCreate _ANSI_ARGS_((Tcl_HashTable *tablePtr, + CONST char *key, int *newPtr)); + +/* + *---------------------------------------------------------------------- + * + * Tcl_InitHashTable -- + * + * Given storage for a hash table, set up the fields to prepare + * the hash table for use. + * + * Results: + * None. + * + * Side effects: + * TablePtr is now ready to be passed to Tcl_FindHashEntry and + * Tcl_CreateHashEntry. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_InitHashTable(tablePtr, keyType) + register Tcl_HashTable *tablePtr; /* Pointer to table record, which + * is supplied by the caller. */ + int keyType; /* Type of keys to use in table: + * TCL_STRING_KEYS, TCL_ONE_WORD_KEYS, + * or an integer >= 2. */ +{ + tablePtr->buckets = tablePtr->staticBuckets; + tablePtr->staticBuckets[0] = tablePtr->staticBuckets[1] = 0; + tablePtr->staticBuckets[2] = tablePtr->staticBuckets[3] = 0; + tablePtr->numBuckets = TCL_SMALL_HASH_TABLE; + tablePtr->numEntries = 0; + tablePtr->rebuildSize = TCL_SMALL_HASH_TABLE*REBUILD_MULTIPLIER; + tablePtr->downShift = 28; + tablePtr->mask = 3; + tablePtr->keyType = keyType; + if (keyType == TCL_STRING_KEYS) { + tablePtr->findProc = StringFind; + tablePtr->createProc = StringCreate; + } else if (keyType == TCL_ONE_WORD_KEYS) { + tablePtr->findProc = OneWordFind; + tablePtr->createProc = OneWordCreate; + } else { + tablePtr->findProc = ArrayFind; + tablePtr->createProc = ArrayCreate; + }; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_DeleteHashEntry -- + * + * Remove a single entry from a hash table. + * + * Results: + * None. + * + * Side effects: + * The entry given by entryPtr is deleted from its table and + * should never again be used by the caller. It is up to the + * caller to free the clientData field of the entry, if that + * is relevant. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_DeleteHashEntry(entryPtr) + Tcl_HashEntry *entryPtr; +{ + register Tcl_HashEntry *prevPtr; + + if (*entryPtr->bucketPtr == entryPtr) { + *entryPtr->bucketPtr = entryPtr->nextPtr; + } else { + for (prevPtr = *entryPtr->bucketPtr; ; prevPtr = prevPtr->nextPtr) { + if (prevPtr == NULL) { + panic("malformed bucket chain in Tcl_DeleteHashEntry"); + } + if (prevPtr->nextPtr == entryPtr) { + prevPtr->nextPtr = entryPtr->nextPtr; + break; + } + } + } + entryPtr->tablePtr->numEntries--; + ckfree((char *) entryPtr); +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_DeleteHashTable -- + * + * Free up everything associated with a hash table except for + * the record for the table itself. + * + * Results: + * None. + * + * Side effects: + * The hash table is no longer useable. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_DeleteHashTable(tablePtr) + register Tcl_HashTable *tablePtr; /* Table to delete. */ +{ + register Tcl_HashEntry *hPtr, *nextPtr; + int i; + + /* + * Free up all the entries in the table. + */ + + for (i = 0; i < tablePtr->numBuckets; i++) { + hPtr = tablePtr->buckets[i]; + while (hPtr != NULL) { + nextPtr = hPtr->nextPtr; + ckfree((char *) hPtr); + hPtr = nextPtr; + } + } + + /* + * Free up the bucket array, if it was dynamically allocated. + */ + + if (tablePtr->buckets != tablePtr->staticBuckets) { + ckfree((char *) tablePtr->buckets); + } + + /* + * Arrange for panics if the table is used again without + * re-initialization. + */ + + tablePtr->findProc = BogusFind; + tablePtr->createProc = BogusCreate; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_FirstHashEntry -- + * + * Locate the first entry in a hash table and set up a record + * that can be used to step through all the remaining entries + * of the table. + * + * Results: + * The return value is a pointer to the first entry in tablePtr, + * or NULL if tablePtr has no entries in it. The memory at + * *searchPtr is initialized so that subsequent calls to + * Tcl_NextHashEntry will return all of the entries in the table, + * one at a time. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +Tcl_HashEntry * +Tcl_FirstHashEntry(tablePtr, searchPtr) + Tcl_HashTable *tablePtr; /* Table to search. */ + Tcl_HashSearch *searchPtr; /* Place to store information about + * progress through the table. */ +{ + searchPtr->tablePtr = tablePtr; + searchPtr->nextIndex = 0; + searchPtr->nextEntryPtr = NULL; + return Tcl_NextHashEntry(searchPtr); +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_NextHashEntry -- + * + * Once a hash table enumeration has been initiated by calling + * Tcl_FirstHashEntry, this procedure may be called to return + * successive elements of the table. + * + * Results: + * The return value is the next entry in the hash table being + * enumerated, or NULL if the end of the table is reached. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +Tcl_HashEntry * +Tcl_NextHashEntry(searchPtr) + register Tcl_HashSearch *searchPtr; /* Place to store information about + * progress through the table. Must + * have been initialized by calling + * Tcl_FirstHashEntry. */ +{ + Tcl_HashEntry *hPtr; + + while (searchPtr->nextEntryPtr == NULL) { + if (searchPtr->nextIndex >= searchPtr->tablePtr->numBuckets) { + return NULL; + } + searchPtr->nextEntryPtr = + searchPtr->tablePtr->buckets[searchPtr->nextIndex]; + searchPtr->nextIndex++; + } + hPtr = searchPtr->nextEntryPtr; + searchPtr->nextEntryPtr = hPtr->nextPtr; + return hPtr; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_HashStats -- + * + * Return statistics describing the layout of the hash table + * in its hash buckets. + * + * Results: + * The return value is a malloc-ed string containing information + * about tablePtr. It is the caller's responsibility to free + * this string. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +char * +Tcl_HashStats(tablePtr) + Tcl_HashTable *tablePtr; /* Table for which to produce stats. */ +{ +#define NUM_COUNTERS 10 + int count[NUM_COUNTERS], overflow, i, j; + double average, tmp; + register Tcl_HashEntry *hPtr; + char *result, *p; + + /* + * Compute a histogram of bucket usage. + */ + + for (i = 0; i < NUM_COUNTERS; i++) { + count[i] = 0; + } + overflow = 0; + average = 0.0; + for (i = 0; i < tablePtr->numBuckets; i++) { + j = 0; + for (hPtr = tablePtr->buckets[i]; hPtr != NULL; hPtr = hPtr->nextPtr) { + j++; + } + if (j < NUM_COUNTERS) { + count[j]++; + } else { + overflow++; + } + tmp = j; + average += (tmp+1.0)*(tmp/tablePtr->numEntries)/2.0; + } + + /* + * Print out the histogram and a few other pieces of information. + */ + + result = (char *) ckalloc((unsigned) ((NUM_COUNTERS*60) + 300)); + sprintf(result, "%d entries in table, %d buckets\n", + tablePtr->numEntries, tablePtr->numBuckets); + p = result + strlen(result); + for (i = 0; i < NUM_COUNTERS; i++) { + sprintf(p, "number of buckets with %d entries: %d\n", + i, count[i]); + p += strlen(p); + } + sprintf(p, "number of buckets with %d or more entries: %d\n", + NUM_COUNTERS, overflow); + p += strlen(p); + sprintf(p, "average search distance for entry: %.1f", average); + return result; +} + +/* + *---------------------------------------------------------------------- + * + * HashString -- + * + * Compute a one-word summary of a text string, which can be + * used to generate a hash index. + * + * Results: + * The return value is a one-word summary of the information in + * string. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static unsigned int +HashString(string) + register CONST char *string;/* String from which to compute hash value. */ +{ + register unsigned int result; + register int c; + + /* + * I tried a zillion different hash functions and asked many other + * people for advice. Many people had their own favorite functions, + * all different, but no-one had much idea why they were good ones. + * I chose the one below (multiply by 9 and add new character) + * because of the following reasons: + * + * 1. Multiplying by 10 is perfect for keys that are decimal strings, + * and multiplying by 9 is just about as good. + * 2. Times-9 is (shift-left-3) plus (old). This means that each + * character's bits hang around in the low-order bits of the + * hash value for ever, plus they spread fairly rapidly up to + * the high-order bits to fill out the hash value. This seems + * works well both for decimal and non-decimal strings. + */ + + result = 0; + while (1) { + c = *string; + string++; + if (c == 0) { + break; + } + result += (result<<3) + c; + } + return result; +} + +/* + *---------------------------------------------------------------------- + * + * StringFind -- + * + * Given a hash table with string keys, and a string key, find + * the entry with a matching key. + * + * Results: + * The return value is a token for the matching entry in the + * hash table, or NULL if there was no matching entry. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static Tcl_HashEntry * +StringFind(tablePtr, key) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + CONST char *key; /* Key to use to find matching entry. */ +{ + register Tcl_HashEntry *hPtr; + register CONST char *p1, *p2; + int index; + + index = HashString(key) & tablePtr->mask; + + /* + * Search all of the entries in the appropriate bucket. + */ + + for (hPtr = tablePtr->buckets[index]; hPtr != NULL; + hPtr = hPtr->nextPtr) { + for (p1 = key, p2 = hPtr->key.string; ; p1++, p2++) { + if (*p1 != *p2) { + break; + } + if (*p1 == '\0') { + return hPtr; + } + } + } + return NULL; +} + +/* + *---------------------------------------------------------------------- + * + * StringCreate -- + * + * Given a hash table with string keys, and a string key, find + * the entry with a matching key. If there is no matching entry, + * then create a new entry that does match. + * + * Results: + * The return value is a pointer to the matching entry. If this + * is a newly-created entry, then *newPtr will be set to a non-zero + * value; otherwise *newPtr will be set to 0. If this is a new + * entry the value stored in the entry will initially be 0. + * + * Side effects: + * A new entry may be added to the hash table. + * + *---------------------------------------------------------------------- + */ + +static Tcl_HashEntry * +StringCreate(tablePtr, key, newPtr) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + CONST char *key; /* Key to use to find or create matching + * entry. */ + int *newPtr; /* Store info here telling whether a new + * entry was created. */ +{ + register Tcl_HashEntry *hPtr; + register CONST char *p1, *p2; + int index; + + index = HashString(key) & tablePtr->mask; + + /* + * Search all of the entries in this bucket. + */ + + for (hPtr = tablePtr->buckets[index]; hPtr != NULL; + hPtr = hPtr->nextPtr) { + for (p1 = key, p2 = hPtr->key.string; ; p1++, p2++) { + if (*p1 != *p2) { + break; + } + if (*p1 == '\0') { + *newPtr = 0; + return hPtr; + } + } + } + + /* + * Entry not found. Add a new one to the bucket. + */ + + *newPtr = 1; + hPtr = (Tcl_HashEntry *) ckalloc((unsigned) + (sizeof(Tcl_HashEntry) + strlen(key) - (sizeof(hPtr->key) -1))); + hPtr->tablePtr = tablePtr; + hPtr->bucketPtr = &(tablePtr->buckets[index]); + hPtr->nextPtr = *hPtr->bucketPtr; + hPtr->clientData = 0; + strcpy(hPtr->key.string, key); + *hPtr->bucketPtr = hPtr; + tablePtr->numEntries++; + + /* + * If the table has exceeded a decent size, rebuild it with many + * more buckets. + */ + + if (tablePtr->numEntries >= tablePtr->rebuildSize) { + RebuildTable(tablePtr); + } + return hPtr; +} + +/* + *---------------------------------------------------------------------- + * + * OneWordFind -- + * + * Given a hash table with one-word keys, and a one-word key, find + * the entry with a matching key. + * + * Results: + * The return value is a token for the matching entry in the + * hash table, or NULL if there was no matching entry. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static Tcl_HashEntry * +OneWordFind(tablePtr, key) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + register CONST char *key; /* Key to use to find matching entry. */ +{ + register Tcl_HashEntry *hPtr; + int index; + + index = RANDOM_INDEX(tablePtr, key); + + /* + * Search all of the entries in the appropriate bucket. + */ + + for (hPtr = tablePtr->buckets[index]; hPtr != NULL; + hPtr = hPtr->nextPtr) { + if (hPtr->key.oneWordValue == key) { + return hPtr; + } + } + return NULL; +} + +/* + *---------------------------------------------------------------------- + * + * OneWordCreate -- + * + * Given a hash table with one-word keys, and a one-word key, find + * the entry with a matching key. If there is no matching entry, + * then create a new entry that does match. + * + * Results: + * The return value is a pointer to the matching entry. If this + * is a newly-created entry, then *newPtr will be set to a non-zero + * value; otherwise *newPtr will be set to 0. If this is a new + * entry the value stored in the entry will initially be 0. + * + * Side effects: + * A new entry may be added to the hash table. + * + *---------------------------------------------------------------------- + */ + +static Tcl_HashEntry * +OneWordCreate(tablePtr, key, newPtr) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + register CONST char *key; /* Key to use to find or create matching + * entry. */ + int *newPtr; /* Store info here telling whether a new + * entry was created. */ +{ + register Tcl_HashEntry *hPtr; + int index; + + index = RANDOM_INDEX(tablePtr, key); + + /* + * Search all of the entries in this bucket. + */ + + for (hPtr = tablePtr->buckets[index]; hPtr != NULL; + hPtr = hPtr->nextPtr) { + if (hPtr->key.oneWordValue == key) { + *newPtr = 0; + return hPtr; + } + } + + /* + * Entry not found. Add a new one to the bucket. + */ + + *newPtr = 1; + hPtr = (Tcl_HashEntry *) ckalloc(sizeof(Tcl_HashEntry)); + hPtr->tablePtr = tablePtr; + hPtr->bucketPtr = &(tablePtr->buckets[index]); + hPtr->nextPtr = *hPtr->bucketPtr; + hPtr->clientData = 0; + hPtr->key.oneWordValue = (char *) key; /* CONST XXXX */ + *hPtr->bucketPtr = hPtr; + tablePtr->numEntries++; + + /* + * If the table has exceeded a decent size, rebuild it with many + * more buckets. + */ + + if (tablePtr->numEntries >= tablePtr->rebuildSize) { + RebuildTable(tablePtr); + } + return hPtr; +} + +/* + *---------------------------------------------------------------------- + * + * ArrayFind -- + * + * Given a hash table with array-of-int keys, and a key, find + * the entry with a matching key. + * + * Results: + * The return value is a token for the matching entry in the + * hash table, or NULL if there was no matching entry. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +static Tcl_HashEntry * +ArrayFind(tablePtr, key) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + CONST char *key; /* Key to use to find matching entry. */ +{ + register Tcl_HashEntry *hPtr; + int *arrayPtr = (int *) key; + register int *iPtr1, *iPtr2; + int index, count; + + for (index = 0, count = tablePtr->keyType, iPtr1 = arrayPtr; + count > 0; count--, iPtr1++) { + index += *iPtr1; + } + index = RANDOM_INDEX(tablePtr, index); + + /* + * Search all of the entries in the appropriate bucket. + */ + + for (hPtr = tablePtr->buckets[index]; hPtr != NULL; + hPtr = hPtr->nextPtr) { + for (iPtr1 = arrayPtr, iPtr2 = hPtr->key.words, + count = tablePtr->keyType; ; count--, iPtr1++, iPtr2++) { + if (count == 0) { + return hPtr; + } + if (*iPtr1 != *iPtr2) { + break; + } + } + } + return NULL; +} + +/* + *---------------------------------------------------------------------- + * + * ArrayCreate -- + * + * Given a hash table with one-word keys, and a one-word key, find + * the entry with a matching key. If there is no matching entry, + * then create a new entry that does match. + * + * Results: + * The return value is a pointer to the matching entry. If this + * is a newly-created entry, then *newPtr will be set to a non-zero + * value; otherwise *newPtr will be set to 0. If this is a new + * entry the value stored in the entry will initially be 0. + * + * Side effects: + * A new entry may be added to the hash table. + * + *---------------------------------------------------------------------- + */ + +static Tcl_HashEntry * +ArrayCreate(tablePtr, key, newPtr) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + register CONST char *key; /* Key to use to find or create matching + * entry. */ + int *newPtr; /* Store info here telling whether a new + * entry was created. */ +{ + register Tcl_HashEntry *hPtr; + int *arrayPtr = (int *) key; + register int *iPtr1, *iPtr2; + int index, count; + + for (index = 0, count = tablePtr->keyType, iPtr1 = arrayPtr; + count > 0; count--, iPtr1++) { + index += *iPtr1; + } + index = RANDOM_INDEX(tablePtr, index); + + /* + * Search all of the entries in the appropriate bucket. + */ + + for (hPtr = tablePtr->buckets[index]; hPtr != NULL; + hPtr = hPtr->nextPtr) { + for (iPtr1 = arrayPtr, iPtr2 = hPtr->key.words, + count = tablePtr->keyType; ; count--, iPtr1++, iPtr2++) { + if (count == 0) { + *newPtr = 0; + return hPtr; + } + if (*iPtr1 != *iPtr2) { + break; + } + } + } + + /* + * Entry not found. Add a new one to the bucket. + */ + + *newPtr = 1; + hPtr = (Tcl_HashEntry *) ckalloc((unsigned) (sizeof(Tcl_HashEntry) + + (tablePtr->keyType*sizeof(int)) - 4)); + hPtr->tablePtr = tablePtr; + hPtr->bucketPtr = &(tablePtr->buckets[index]); + hPtr->nextPtr = *hPtr->bucketPtr; + hPtr->clientData = 0; + for (iPtr1 = arrayPtr, iPtr2 = hPtr->key.words, count = tablePtr->keyType; + count > 0; count--, iPtr1++, iPtr2++) { + *iPtr2 = *iPtr1; + } + *hPtr->bucketPtr = hPtr; + tablePtr->numEntries++; + + /* + * If the table has exceeded a decent size, rebuild it with many + * more buckets. + */ + + if (tablePtr->numEntries >= tablePtr->rebuildSize) { + RebuildTable(tablePtr); + } + return hPtr; +} + +/* + *---------------------------------------------------------------------- + * + * BogusFind -- + * + * This procedure is invoked when an Tcl_FindHashEntry is called + * on a table that has been deleted. + * + * Results: + * If panic returns (which it shouldn't) this procedure returns + * NULL. + * + * Side effects: + * Generates a panic. + * + *---------------------------------------------------------------------- + */ + + /* ARGSUSED */ +static Tcl_HashEntry * +BogusFind(tablePtr, key) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + CONST char *key; /* Key to use to find matching entry. */ +{ + panic("called Tcl_FindHashEntry on deleted table"); + return NULL; +} + +/* + *---------------------------------------------------------------------- + * + * BogusCreate -- + * + * This procedure is invoked when an Tcl_CreateHashEntry is called + * on a table that has been deleted. + * + * Results: + * If panic returns (which it shouldn't) this procedure returns + * NULL. + * + * Side effects: + * Generates a panic. + * + *---------------------------------------------------------------------- + */ + + /* ARGSUSED */ +static Tcl_HashEntry * +BogusCreate(tablePtr, key, newPtr) + Tcl_HashTable *tablePtr; /* Table in which to lookup entry. */ + CONST char *key; /* Key to use to find or create matching + * entry. */ + int *newPtr; /* Store info here telling whether a new + * entry was created. */ +{ + panic("called Tcl_CreateHashEntry on deleted table"); + return NULL; +} + +/* + *---------------------------------------------------------------------- + * + * RebuildTable -- + * + * This procedure is invoked when the ratio of entries to hash + * buckets becomes too large. It creates a new table with a + * larger bucket array and moves all of the entries into the + * new table. + * + * Results: + * None. + * + * Side effects: + * Memory gets reallocated and entries get re-hashed to new + * buckets. + * + *---------------------------------------------------------------------- + */ + +static void +RebuildTable(tablePtr) + register Tcl_HashTable *tablePtr; /* Table to enlarge. */ +{ + int oldSize, count, index; + Tcl_HashEntry **oldBuckets; + register Tcl_HashEntry **oldChainPtr, **newChainPtr; + register Tcl_HashEntry *hPtr; + + oldSize = tablePtr->numBuckets; + oldBuckets = tablePtr->buckets; + + /* + * Allocate and initialize the new bucket array, and set up + * hashing constants for new array size. + */ + + tablePtr->numBuckets *= 4; + tablePtr->buckets = (Tcl_HashEntry **) ckalloc((unsigned) + (tablePtr->numBuckets * sizeof(Tcl_HashEntry *))); + for (count = tablePtr->numBuckets, newChainPtr = tablePtr->buckets; + count > 0; count--, newChainPtr++) { + *newChainPtr = NULL; + } + tablePtr->rebuildSize *= 4; + tablePtr->downShift -= 2; + tablePtr->mask = (tablePtr->mask << 2) + 3; + + /* + * Rehash all of the existing entries into the new bucket array. + */ + + for (oldChainPtr = oldBuckets; oldSize > 0; oldSize--, oldChainPtr++) { + for (hPtr = *oldChainPtr; hPtr != NULL; hPtr = *oldChainPtr) { + *oldChainPtr = hPtr->nextPtr; + if (tablePtr->keyType == TCL_STRING_KEYS) { + index = HashString(hPtr->key.string) & tablePtr->mask; + } else if (tablePtr->keyType == TCL_ONE_WORD_KEYS) { + index = RANDOM_INDEX(tablePtr, hPtr->key.oneWordValue); + } else { + register int *iPtr; + int count; + + for (index = 0, count = tablePtr->keyType, + iPtr = hPtr->key.words; count > 0; count--, iPtr++) { + index += *iPtr; + } + index = RANDOM_INDEX(tablePtr, index); + } + hPtr->bucketPtr = &(tablePtr->buckets[index]); + hPtr->nextPtr = *hPtr->bucketPtr; + *hPtr->bucketPtr = hPtr; + } + } + + /* + * Free up the old bucket array, if it was dynamically allocated. + */ + + if (oldBuckets != tablePtr->staticBuckets) { + ckfree((char *) oldBuckets); + } +} |