mirror of https://github.com/sqlite/sqlite
Optimizations in the hash table module. (CVS 1896)
FossilOrigin-Name: d5b0269e0dd7c310460a7ffc4120ed45db823ce9
This commit is contained in:
drh
parent
7ac25c7510
commit
e8cf2cacb1
14
manifest
14
manifest
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@ -1,5 +1,5 @@
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C Enhance\slemon\sso\sthat\sa\s@X\sinstead\sof\sjust\sX\sin\sthe\scode\sexpands\sto\sthe\nmajor\stoken\svalue\srather\sthan\sthe\sminor\stoken\svalue.\s\sUse\sthis\sto\smake\nthe\sparser\sa\sfew\shundred\sbytes\ssmaller.\s(CVS\s1895)
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D 2004-08-19T15:12:26
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C Optimizations\sin\sthe\shash\stable\smodule.\s(CVS\s1896)
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D 2004-08-20T14:08:51
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F Makefile.in 4a5e570a9e2d35b09c31b3cf01b78cea764ade4b
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F Makefile.linux-gcc a9e5a0d309fa7c38e7c14d3ecf7690879d3a5457
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F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
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@ -35,8 +35,8 @@ F src/delete.c e81545e546f6bc87d7508a93a09ca70695265af3
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F src/encode.c a876af473d1d636faa3dca51c7571f2e007eea37
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F src/expr.c f11a1e5c489bc8f5cc83b10aa80f21e85f48141e
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F src/func.c 7e2eeebe219aa612ce7a04c74ae6d57379c6656b
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F src/hash.c f0a2f22c2a7052d67053b5f4690ea3010bb3fb9f
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F src/hash.h 762d95f1e567664d1eafc1687de755626be962fb
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F src/hash.c a97721a55440b7bea31ffe471bb2f6b4123cddd5
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F src/hash.h 1b0c445e1c89ff2aaad9b4605ba61375af001e84
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F src/insert.c bedcba371401395033a1a1c578d8fdc3fec87bec
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F src/legacy.c 2f3617c61bcdcd1d776154a9cfebf99facda8ad8
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F src/main.c a779422c5402df92c390e233ac32ab718fc4436b
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@ -243,7 +243,7 @@ F www/tclsqlite.tcl 06a86cba4d7fc88e2bcd633b57702d3d16abebb5
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F www/vdbe.tcl 59288db1ac5c0616296b26dce071c36cb611dfe9
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F www/version3.tcl 092a01f5ef430d2c4acc0ae558d74c4bb89638a0
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F www/whentouse.tcl a8335bce47cc2fddb07f19052cb0cb4d9129a8e4
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P 25fe7a42ec2e06e659d7a0a6664789114c007e17
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R 0379dd9278368974892dd5434039fab5
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P 28215096e0748b5b02776ddb4c964e0161bc0f16
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R 5607576f6316ac80134bcd33d2f77b9e
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U drh
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Z ddb5c020240eaf2ea91499a31fc16aa6
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Z d2ae7348c29545bbd90048ea25e77c25
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@ -1 +1 @@
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28215096e0748b5b02776ddb4c964e0161bc0f16
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d5b0269e0dd7c310460a7ffc4120ed45db823ce9
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126
src/hash.c
126
src/hash.c
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@ -12,7 +12,7 @@
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** This is the implementation of generic hash-tables
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** used in SQLite.
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**
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** $Id: hash.c,v 1.14 2004/06/30 22:43:22 drh Exp $
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** $Id: hash.c,v 1.15 2004/08/20 14:08:51 drh Exp $
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*/
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#include "sqliteInt.h"
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#include <assert.h>
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@ -31,10 +31,12 @@
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*/
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void sqlite3HashInit(Hash *pNew, int keyClass, int copyKey){
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assert( pNew!=0 );
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assert( keyClass>=SQLITE_HASH_INT && keyClass<=SQLITE_HASH_BINARY );
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assert( keyClass>=SQLITE_HASH_STRING && keyClass<=SQLITE_HASH_BINARY );
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pNew->keyClass = keyClass;
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pNew->copyKey = copyKey &&
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(keyClass==SQLITE_HASH_STRING || keyClass==SQLITE_HASH_BINARY);
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#if 0
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if( keyClass==SQLITE_HASH_POINTER || keyClass==SQLITE_HASH_INT ) copyKey = 0;
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#endif
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pNew->copyKey = copyKey;
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pNew->first = 0;
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pNew->count = 0;
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pNew->htsize = 0;
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@ -99,7 +101,7 @@ static int strHash(const void *pKey, int nKey){
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return sqlite3HashNoCase((const char*)pKey, nKey);
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}
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static int strCompare(const void *pKey1, int n1, const void *pKey2, int n2){
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if( n1!=n2 ) return n2-n1;
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if( n1!=n2 ) return 1;
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return sqlite3StrNICmp((const char*)pKey1,(const char*)pKey2,n1);
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}
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@ -115,7 +117,7 @@ static int binHash(const void *pKey, int nKey){
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return h & 0x7fffffff;
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}
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static int binCompare(const void *pKey1, int n1, const void *pKey2, int n2){
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if( n1!=n2 ) return n2-n1;
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if( n1!=n2 ) return 1;
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return memcmp(pKey1,pKey2,n1);
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}
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@ -132,14 +134,23 @@ static int binCompare(const void *pKey1, int n1, const void *pKey2, int n2){
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** with types "const void*" and "int" and returns an "int".
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*/
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static int (*hashFunction(int keyClass))(const void*,int){
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#if 0 /* HASH_INT and HASH_POINTER are never used */
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switch( keyClass ){
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/* case SQLITE_HASH_INT: return &intHash; // NOT USED */
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/* case SQLITE_HASH_POINTER: return &ptrHash; // NOT USED */
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case SQLITE_HASH_INT: return &intHash;
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case SQLITE_HASH_POINTER: return &ptrHash;
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case SQLITE_HASH_STRING: return &strHash;
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case SQLITE_HASH_BINARY: return &binHash;;
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default: break;
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}
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return 0;
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#else
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if( keyClass==SQLITE_HASH_STRING ){
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return &strHash;
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}else{
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assert( keyClass==SQLITE_HASH_BINARY );
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return &binHash;
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}
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#endif
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}
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/*
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@ -149,14 +160,48 @@ static int (*hashFunction(int keyClass))(const void*,int){
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** see the header comment on the previous function.
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*/
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static int (*compareFunction(int keyClass))(const void*,int,const void*,int){
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#if 0 /* HASH_INT and HASH_POINTER are never used */
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switch( keyClass ){
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/* case SQLITE_HASH_INT: return &intCompare; // NOT USED */
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/* case SQLITE_HASH_POINTER: return &ptrCompare; // NOT USED */
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case SQLITE_HASH_INT: return &intCompare;
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case SQLITE_HASH_POINTER: return &ptrCompare;
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case SQLITE_HASH_STRING: return &strCompare;
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case SQLITE_HASH_BINARY: return &binCompare;
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default: break;
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}
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return 0;
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#else
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if( keyClass==SQLITE_HASH_STRING ){
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return &strCompare;
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}else{
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assert( keyClass==SQLITE_HASH_BINARY );
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return &binCompare;
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}
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#endif
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}
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/* Link an element into the hash table
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*/
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static void insertElement(
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Hash *pH, /* The complete hash table */
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struct _ht *pEntry, /* The entry into which pNew is inserted */
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HashElem *pNew /* The element to be inserted */
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){
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HashElem *pHead; /* First element already in pEntry */
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pHead = pEntry->chain;
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if( pHead ){
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pNew->next = pHead;
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pNew->prev = pHead->prev;
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if( pHead->prev ){ pHead->prev->next = pNew; }
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else { pH->first = pNew; }
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pHead->prev = pNew;
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}else{
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pNew->next = pH->first;
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if( pH->first ){ pH->first->prev = pNew; }
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pNew->prev = 0;
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pH->first = pNew;
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}
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pEntry->count++;
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pEntry->chain = pNew;
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}
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@ -167,7 +212,6 @@ static int (*compareFunction(int keyClass))(const void*,int,const void*,int){
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static void rehash(Hash *pH, int new_size){
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struct _ht *new_ht; /* The new hash table */
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HashElem *elem, *next_elem; /* For looping over existing elements */
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HashElem *x; /* Element being copied to new hash table */
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int (*xHash)(const void*,int); /* The hash function */
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assert( (new_size & (new_size-1))==0 );
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@ -180,21 +224,7 @@ static void rehash(Hash *pH, int new_size){
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for(elem=pH->first, pH->first=0; elem; elem = next_elem){
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int h = (*xHash)(elem->pKey, elem->nKey) & (new_size-1);
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next_elem = elem->next;
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x = new_ht[h].chain;
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if( x ){
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elem->next = x;
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elem->prev = x->prev;
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if( x->prev ) x->prev->next = elem;
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else pH->first = elem;
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x->prev = elem;
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}else{
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elem->next = pH->first;
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if( pH->first ) pH->first->prev = elem;
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elem->prev = 0;
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pH->first = elem;
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}
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new_ht[h].chain = elem;
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new_ht[h].count++;
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insertElement(pH, &new_ht[h], elem);
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}
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}
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@ -213,8 +243,9 @@ static HashElem *findElementGivenHash(
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int (*xCompare)(const void*,int,const void*,int); /* comparison function */
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if( pH->ht ){
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elem = pH->ht[h].chain;
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count = pH->ht[h].count;
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struct _ht *pEntry = &pH->ht[h];
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elem = pEntry->chain;
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count = pEntry->count;
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xCompare = compareFunction(pH->keyClass);
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while( count-- && elem ){
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if( (*xCompare)(elem->pKey,elem->nKey,pKey,nKey)==0 ){
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@ -234,6 +265,7 @@ static void removeElementGivenHash(
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HashElem* elem, /* The element to be removed from the pH */
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int h /* Hash value for the element */
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){
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struct _ht *pEntry;
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if( elem->prev ){
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elem->prev->next = elem->next;
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}else{
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@ -242,12 +274,13 @@ static void removeElementGivenHash(
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if( elem->next ){
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elem->next->prev = elem->prev;
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}
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if( pH->ht[h].chain==elem ){
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pH->ht[h].chain = elem->next;
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pEntry = &pH->ht[h];
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if( pEntry->chain==elem ){
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pEntry->chain = elem->next;
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}
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pH->ht[h].count--;
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if( pH->ht[h].count<=0 ){
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pH->ht[h].chain = 0;
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pEntry->count--;
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if( pEntry->count<=0 ){
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pEntry->chain = 0;
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}
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if( pH->copyKey && elem->pKey ){
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sqliteFree(elem->pKey);
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}
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new_elem->nKey = nKey;
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pH->count++;
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if( pH->htsize==0 ) rehash(pH,8);
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if( pH->htsize==0 ){
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pH->count = 0;
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sqliteFree(new_elem);
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return data;
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rehash(pH,8);
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if( pH->htsize==0 ){
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pH->count = 0;
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sqliteFree(new_elem);
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return data;
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}
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}
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if( pH->count > pH->htsize ){
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rehash(pH,pH->htsize*2);
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}
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assert( pH->htsize>0 );
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assert( (pH->htsize & (pH->htsize-1))==0 );
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h = hraw & (pH->htsize-1);
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elem = pH->ht[h].chain;
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if( elem ){
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new_elem->next = elem;
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new_elem->prev = elem->prev;
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if( elem->prev ){ elem->prev->next = new_elem; }
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else { pH->first = new_elem; }
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elem->prev = new_elem;
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}else{
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new_elem->next = pH->first;
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new_elem->prev = 0;
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if( pH->first ){ pH->first->prev = new_elem; }
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pH->first = new_elem;
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}
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pH->ht[h].count++;
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pH->ht[h].chain = new_elem;
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insertElement(pH, &pH->ht[h], new_elem);
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new_elem->data = data;
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return 0;
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}
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@ -12,7 +12,7 @@
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** This is the header file for the generic hash-table implemenation
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** used in SQLite.
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**
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** $Id: hash.h,v 1.7 2004/05/08 08:23:25 danielk1977 Exp $
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** $Id: hash.h,v 1.8 2004/08/20 14:08:51 drh Exp $
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*/
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#ifndef _SQLITE_HASH_H_
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#define _SQLITE_HASH_H_
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@ -70,7 +70,7 @@ struct HashElem {
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** A copy of the key is made for SQLITE_HASH_STRING and SQLITE_HASH_BINARY
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** if the copyKey parameter to HashInit is 1.
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*/
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#define SQLITE_HASH_INT 1
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/* #define SQLITE_HASH_INT 1 // NOT USED */
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/* #define SQLITE_HASH_POINTER 2 // NOT USED */
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#define SQLITE_HASH_STRING 3
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#define SQLITE_HASH_BINARY 4
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#define sqliteHashCount(H) ((H)->count)
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#endif /* _SQLITE_HASH_H_ */
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