496 lines
13 KiB
C
496 lines
13 KiB
C
/**************************************************
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* 程序名称 : HashMap.c
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* 程序作者 : icesky
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* 程序版本 : 1.0.0
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* 创建日期 : 2016.07.28
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* 程序功能 :
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* 参考java的hashmap实现机制,实现了C基本的
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* hashmap实现，支持几种功能:
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* 1.新建
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* 2.销毁
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* 3.加入/设置
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* 4.获取
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* 5.删除
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* 6.判断是否存在
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* 7.打印
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*
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* 修改记录 :
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*************************************************/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdarg.h>
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#include "hashmap.h"
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#define hmap_malloc(size) malloc(size)
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#define HMAPFREE(x) free(x);x=NULL;
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#define XIP_HASHMAP_REBUILD_ERR (void *)-1
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#define MAXIMUM_CAPACITY 1 << 30 /*1 073 741 824 */
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#define DEFAULT_CAPACITY 1 << 4 /*16*/
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#define DEFAULT_FACTOR 0.75f
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#define INTER_MAX_VALUE 1<<31 /*int的最大值*/
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/*hashmap node结构 */
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typedef struct st_xip_hashmap_node
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{
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char * key;
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union
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{
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void *ptr; /*注意ptr本身没有分配内存,只是指针*/
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int num; /*ihashmap使用*/
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}value;
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struct st_xip_hashmap_node *next;
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unsigned int hash;
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} TxipHashmapNode;
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/*hashmap 结构*/
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typedef struct
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{
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TxipHashmapNode ** table; /*T表*/
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unsigned int length; /*桶大小*/
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unsigned int size; /*实际大小*/
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unsigned int threshold; /*加载临界值*/
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float factor; /*加载因子,默认为0.75(0-1)*/
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} TxipHashmap;
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#define HMAPLOG(...) AppLog(__FILE__,__LINE__,__VA_ARGS__)
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static void AppLog(char *file, long line, char *level, char *fmtstr, ...)
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{
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va_list ap;
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char tmpstr[501];
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memset(tmpstr, 0x0, sizeof(tmpstr));
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va_start(ap, fmtstr);
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vsprintf(tmpstr, fmtstr, ap);
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va_end(ap);
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printf("[%s][%s][%03ld]", level, file, line);
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printf("[%s]\n", tmpstr);
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return ;
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}
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/*** static 声明 ***/
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/*新建T表*/
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static TxipHashmapNode ** create_T_table( int opacity);
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/*新建hashmap节点*/
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static TxipHashmapNode * create_hashmap_node( char * key, void * value, TxipHashmapNode * next);
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/*重建hashmap*/
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static int rebuild_hash( TxipHashmap * hashmap);
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/*hash算法*/
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static unsigned int XipHash(char * key);
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/*********************************************************************
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* 入口参数: hashmap的无类型指针
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* 出口参数: 无
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* 返回值 : int 永远返回0，可以不判断
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* 函数功能: 打印hashmap中所有的元素,主要用于调试和检查散列分布
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*
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*********************************************************************/
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int XipHashmapPrint( void * hashmap)
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{
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TxipHashmap * map = ( TxipHashmap *)hashmap;
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int idx = 0;
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TxipHashmapNode * e = NULL;
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TxipHashmapNode * next = NULL;
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/** 打印日志 **/
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if( map != NULL)
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{
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HMAPLOG("I", "HashMap:length(%d),size(%d),threshold(%d)", map->length, map->size, map->threshold);
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for ( idx = 0; idx < map->length; idx++)
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{
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for( e = map->table[idx]; e != NULL; )
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{
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next = e->next;
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HMAPLOG("I", "Node[%d]:hash[%d],key[%s],value[%s]", idx, e->hash, e->key, e->value.ptr);
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e = next;
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}
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}
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}
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/** 打印分布情况图 **/
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int i = 0;
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if( map != NULL)
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{
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for( idx = 0; idx < map->length; idx++)
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{
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i = 0;
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for( e= map->table[idx] ; e!= NULL; )
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{
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next = e->next;
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i++;
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e = next;
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}
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HMAPLOG("I","%08ld:%*d", idx, i, i);
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}
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}
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return 0;
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}
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/*********************************************************************
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* 入口参数: 无
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* 出口参数: 无
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* 返回值 : 创建的hashmap的指针,强制转换成了void *类型,方便调用
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* 函数功能: 以默认方式创建一个hashmap,默认的初始容量是16,加载因子是0.75f
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*
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*********************************************************************/
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void * XipHashmapNew()
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{
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return XipHashmapInit( 0, 0.00);
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}
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/*********************************************************************
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* 入口参数: int opacity 初始容量, float factor 加载因子
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* 出口参数: 无
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* 返回值 : 创建的hashmap的指针,强制转换成了void *类型,方便调用
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* 函数功能: 按照传入的信息进行初始hashmap创建,
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* 如果opacity为0,则为默认值16,如果factor为0,则默认为0.75f
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*
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*********************************************************************/
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void * XipHashmapInit( int opacity, float factor)
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{
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TxipHashmap * map = ( TxipHashmap *)hmap_malloc(sizeof( TxipHashmap));
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if ( opacity < DEFAULT_CAPACITY )
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opacity = DEFAULT_CAPACITY;
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if( opacity > MAXIMUM_CAPACITY)
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opacity = MAXIMUM_CAPACITY;
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if ( factor >= -0.005 && factor <=0.005 )
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factor = DEFAULT_FACTOR;
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if( opacity <= 1)
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{
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HMAPLOG("E","初始容量必须大于1!!!");
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HMAPFREE(map);
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map = NULL;
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return NULL;
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}
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if( factor < 0.00 || factor > 1.00)
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{
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HMAPLOG("E","加载因子取值区间为[0.00-1.00],但本次加载因子为[%.2f]", factor);
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HMAPFREE(map);
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map = NULL;
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return NULL;
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}
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map->table = create_T_table( opacity);
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if( map->table == NULL)
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{
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HMAPLOG("E","创建hash值的T表失败!!!");
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HMAPFREE(map);
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map = NULL;
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return NULL;
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}
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map->length = opacity;
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map->size = 0;
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map->factor = factor;
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map->threshold = (unsigned int)( factor * opacity);
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return (void *)map;
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}
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/*********************************************************************
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* 入口参数: hashmap指针
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* 出口参数: 无
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* 返回值 : int , 永远返回0可以不判断
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* 函数功能: 按照传入的信息进行初始hashmap创建,
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* 如果opacity为0,则为默认值16,如果factor为0,则默认为0.75f
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*
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*********************************************************************/
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int XipHashmapDestory( void * hashmap)
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{
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TxipHashmap * map = (TxipHashmap *) hashmap;
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TxipHashmapNode * e = NULL;
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TxipHashmapNode * next = NULL;
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register unsigned int idx;
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/** 释放hashmap node 内存 **/
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if( map != NULL)
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{
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for ( idx = 0; idx < map->length; idx++)
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{
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for( e = map->table[idx]; e != NULL; )
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{
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next = e->next;
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HMAPFREE(e);
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e = next;
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}
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}
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/** 释放hashmap的T表 **/
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HMAPFREE( map->table);
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map->table = NULL;
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}
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return 0;
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}
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/*********************************************************************
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* 入口参数: hashmap指针, char * key, void * value
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* 出口参数: 无
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* 返回值 : 返回 void * oldvalue 的指针,如果为新增则返回NULL
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* 如果put失败则返回XIP_HASHMAP_PUT_ERR
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* 函数功能: 根据key和value放入到hashmap中,如果map中已经存在该key的值
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* 则替换成最新的value,同时返回旧value指针
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* 如果put之后，达到了临界值,则重新创建hashmap
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*********************************************************************/
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void * XipHashmapPut( void * hashmap, char * key, void * value)
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{
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TxipHashmap * map = (TxipHashmap *)hashmap;
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void * oldvalue = NULL;
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TxipHashmapNode *e = NULL;
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unsigned int hcode = XipHash(key);
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unsigned int idx = hcode % map->length;
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/*如果找到了key,则相当于set*/
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for ( e = map->table[idx]; e != NULL ; e = e->next)
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{
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/*参考java的hashmap实现,先比较hash,再比较strcmp*/
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if ( hcode == e->hash && (key == e->key || strcmp( key, e->key) == 0))
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{
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oldvalue = e->value.ptr;
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e->value.ptr = value;
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return oldvalue; /*将原value返回给调用者*/
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}
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}
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/*新建node*/
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map->table[idx] = create_hashmap_node( key, value, map->table[idx]);
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if( map->table[idx] == NULL)
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{
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HMAPLOG("E","新建hashnode节点异常!!!");
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return XIP_HASHMAP_PUT_ERR; /*返回固定值*/
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}
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/*修改hashmap*/
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e = map->table[idx];
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e->hash = hcode;
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map->size++;
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/*如果触发临界值，则重建hash表*/
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if( map->size > map->threshold)
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{
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if( rebuild_hash(map) != 0)
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{
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HMAPLOG("E","重建hash表错误!!!");
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return XIP_HASHMAP_PUT_ERR; /*返回固定值*/
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}
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}
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return NULL;
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}
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/*********************************************************************
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* 入口参数: hashmap指针, char * key
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* 出口参数: 无
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* 返回值 : 返回 void * value 的指针
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* 函数功能: 根据key值从hashmap中取得value的指针返回
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*********************************************************************/
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void * XipHashmapGet( void * hashmap, char *key)
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{
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TxipHashmap * map = (TxipHashmap *) hashmap;
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unsigned int hcode = XipHash(key);
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unsigned int idx = hcode % map->length;
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TxipHashmapNode * e = NULL;
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for ( e = map->table[idx]; e != NULL ; e = e->next)
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{
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/*参考java的hashmap实现,先比较hash,再比较strcmp, key == e->key是用来给ihashmap用的,待扩展*/
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if ( hcode == e->hash && (key == e->key || strcmp( key, e->key) == 0))
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{
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return e->value.ptr;
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}
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}
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return NULL;
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}
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/*********************************************************************
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* 入口参数: hashmap指针, char * key
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* 出口参数: 无
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* 返回值 : int 返回值XIP_HASHMAP_EXIST_TURE(1), XIP_HASHMAP_EXIST_FALSE(0)
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* 函数功能: 根据key值从hashmap中查找是否存在,存在返回真,不存在返回假
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*********************************************************************/
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int XipHashmapExists( void * hashmap, char *key)
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{
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TxipHashmap * map = (TxipHashmap *) hashmap;
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unsigned int hcode = XipHash(key);
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unsigned int idx = hcode % map->length;
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TxipHashmapNode * e = NULL;
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for ( e = map->table[idx]; e != NULL ; e = e->next)
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{
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/*参考java的hashmap实现,先比较hash,再比较strcmp*/
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if ( hcode == e->hash && (key == e->key || strcmp( key, e->key) == 0))
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{
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return 1;
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}
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}
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return 0;
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}
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/*********************************************************************
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* 入口参数: hashmap指针, char * key
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* 出口参数: 无
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* 返回值 : void * value
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* 函数功能: 根据key值从hashmap中删除key对应的node节点,如果删除成功，
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* 则返回删除节点的value的地址,未找到节点则返回NULL
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*********************************************************************/
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void * XipHashmapRemove( void * hashmap, char *key)
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{
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TxipHashmap * map = (TxipHashmap *) hashmap;
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unsigned int hcode = XipHash(key);
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unsigned int idx = hcode % map->length;
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void * oldvalue = NULL;
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TxipHashmapNode * e = NULL;
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TxipHashmapNode * prev = NULL;
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for ( e = map->table[idx]; e != NULL ; prev = e, e = e->next)
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{
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/*参考java的hashmap实现,先比较hash,再比较strcmp*/
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if ( hcode == e->hash && (key == e->key || strcmp( key, e->key) == 0))
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{
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if( prev == NULL)
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map->table[idx] = e->next;
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else
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prev->next = e->next;
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oldvalue = e->value.ptr;
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HMAPFREE(e);
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map->size--;
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return oldvalue;
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}
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}
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return NULL;
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}
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static TxipHashmapNode ** create_T_table( int opacity)
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{
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register unsigned int i=0;
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TxipHashmapNode ** table = (TxipHashmapNode **)hmap_malloc( sizeof(TxipHashmapNode*) *opacity);
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if( table == NULL)
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{
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return NULL;
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}
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/*初始化*/
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for ( i = 0; i < opacity; i++)
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table[i] = NULL;
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return table;
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}
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static TxipHashmapNode * create_hashmap_node( char * key, void * value, TxipHashmapNode * next)
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{
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TxipHashmapNode * node = ( TxipHashmapNode *) hmap_malloc( sizeof(TxipHashmapNode));
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if ( node == NULL)
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{
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return NULL;
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}
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node->key = key;
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node->value.ptr = value;
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node->next = next;
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return node;
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}
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static int rebuild_hash( TxipHashmap * map)
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{
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register unsigned int i = 0;
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unsigned int idx = 0;
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/*如果达到最大了,则不在rebuild*/
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if( map->length == MAXIMUM_CAPACITY)
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{
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map->threshold = INTER_MAX_VALUE;
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return 0;
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}
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unsigned int length = map->length*2;
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if( length > MAXIMUM_CAPACITY)
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length = MAXIMUM_CAPACITY;
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TxipHashmapNode *e=NULL;
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TxipHashmapNode *next=NULL;
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TxipHashmapNode ** newtable = create_T_table( length);
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if ( newtable == NULL)
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{
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return -5;
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}
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for( i = 0; i < map->length; i++)
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{
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/*遍历*/
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e = *(map->table + i);
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if( e != NULL)
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{
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do
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{
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next = e->next;
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idx = e->hash % length;
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e->next = newtable[idx]; /*如果newtable[idx]的值已经存在了,该行则会将该值变为newtable[idx]->idx*/
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newtable[idx] = e;
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e = next;
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}while( e != NULL);
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}
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}
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/*释放oldtable*/
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HMAPFREE(map->table);
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map->table = newtable;
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map->length = length;
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map->threshold = (unsigned int)(map->factor * length);
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return 0;
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}
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/********************************************************
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* hash算法,此处使用的是 simple BKDR hash algorithm
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* 为JAVA的JDK中使用的算法
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* 也可以使用PHP等使用的time33算法(DJP hash algorithm）
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* 还可以使用暴雪公司的的One-Way-Hash,号称最快的hash算法
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*
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* 之所以没有使用我推荐的算法,是因为我把机会留给了你.如果
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* 你看到了这个地方,并且试图优化算法的话,可以使用我建议的
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* 算法进行尝试.
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* 不过我想等到系统瓶颈追溯到本代码的时候,或许早就有了更
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* 完美的算法来保证趋近一致散列了.o(∩_∩)o
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* icesky.2016.07.08
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*********************************************************/
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static unsigned int XipHash(char * key)
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{
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register uint32_t h = 0;
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uint32_t seed = 131; //31 131 1313 13131
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while ( *key != '\0' )
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{
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h = h * seed + ( *key++ );
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}
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return (h & 0x7FFFFFFF);
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}
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