hash code 一种常用的哈希算法

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <string.h> #define BIOSBUFSIZE 2048 #define HASHSIZE 128 #define INSERTHASHFAIL -1 #define INSERTHASHSUCCESS -1 char smbiosBuf[BIOSBUFSIZE]; typedef struct smbiosTable smbiosTable_T; struct smbiosTable{ char type; char length; short handle; }; typedef struct node node_t; struct node{ void *pData; node_t *next; }; typedef struct hash hast_t; struct hash{ node_t **ppContainer; int pCapacity; int nodeCount; }; hast_t *globalHashTable; /**************************/ /************************/ int createHash(void) { globalHashTable = malloc(sizeof(hast_t)); if(NULL == globalHashTable) { return -1; } globalHashTable->ppContainer = malloc(HASHSIZE * sizeof(node_t *)); if(NULL == globalHashTable->ppContainer) { free(globalHashTable); return -1; } memset(globalHashTable->ppContainer,0,HASHSIZE * sizeof(node_t *)); globalHashTable->pCapacity = HASHSIZE; globalHashTable->nodeCount = 0; return 0; } /* 函数功能：获取哈希关键数值 */ static int getHashKey(int pdata) { return (pdata)%HASHSIZE; } /* 函数功能，将每个元素插入到哈系表中 */ int insert(void *pData) { if(NULL == pData) { return -1; } node_t *pNode = malloc(sizeof(node_t)); node_t *pTemp =NULL; int index; if(NULL == pNode) return INSERTHASHFAIL; index = getHashKey(*(char *)pData); pNode->pData = pData; pNode->next = NULL; pTemp = globalHashTable->ppContainer[index]; if(pTemp == NULL) { globalHashTable->ppContainer[index] = pNode; return INSERTHASHSUCCESS; } while( NULL != pTemp->next) { pTemp=pTemp->next; } pTemp ->next =pNode; return INSERTHASHSUCCESS; } static int cmpFunc(short data1,short data2) { if(data1 == data2 ) return 0; return -1; } /* 函数功能：查询hash表内的元素 */ void *search(int data) { if(data <0 || data > 128) { return NULL; } return globalHashTable->ppContainer[data]; } #define OPENBIOSFAIL -1 int openBios(void) { if(smbiosBuf == NULL) return OPENBIOSFAIL; char *ptmp,*ptmp2; ptmp = smbiosBuf ; int i=0; if( (0==((smbiosTable_T *)ptmp)->type) && (0 == ((smbiosTable_T *)ptmp)->handle)) { i++; insert((void *)ptmp); while(i < 45) { ptmp2=NULL; ptmp2=ptmp+((smbiosTable_T *)ptmp)->length; while((*ptmp2 != 0) || *(ptmp2+1) !=0) { ptmp2++; } ptmp2+=2; ptmp=ptmp2; i++; insert((void *)ptmp); } if(45 != i) { return OPENBIOSFAIL; } }else{ return OPENBIOSFAIL; } return 0; } int main(void) { int fd; ssize_t ret; fd = open("/dev/mem",O_RDONLY); if(-1 == fd) { perror("OPEN"); return -1; } ret = lseek(fd,0xE0010,SEEK_SET); if(-1 == ret) { perror("LSEEK"); return -1; } ret = read(fd,smbiosBuf,BIOSBUFSIZE); createHash(); smbiosTable_T *temp; temp = (smbiosTable_T *)smbiosBuf; printf("%d %d %d\n",temp->type,temp->length,temp->handle); ret =openBios(); printf("%d\n",ret); printf("------%d",((smbiosTable_T *)((globalHashTable->ppContainer[127])->pData))->type); return 0; }