传说的Bloom Filter源代码

bloom.h

#ifndef __BLOOM_H__#define __BLOOM_H__#include <stdlib.h>typedef unsigned int (*hashfunc_t)(const char *);typedef struct {    size_t asize;    unsigned char *a;    size_t nfuncs;    hashfunc_t *funcs;} BLOOM;BLOOM *bloom_create(size_t size, size_t nfuncs, ...);int bloom_destroy(BLOOM *bloom);int bloom_add(BLOOM *bloom, const char *s);int bloom_check(BLOOM *bloom, const char *s);#endif 

bloom.c

#include<limits.h>#include<stdarg.h>#include"bloom.h"#define SETBIT(a, n) (a[n/CHAR_BIT] |= (1<<(n%CHAR_BIT)))#define GETBIT(a, n) (a[n/CHAR_BIT] & (1<<(n%CHAR_BIT)))BLOOM *bloom_create(size_t size, size_t nfuncs, ...){    BLOOM *bloom;    va_list l;    int n;        if(!(bloom=malloc(sizeof(BLOOM)))) return NULL;    if(!(bloom->a=calloc((size+CHAR_BIT-1)/CHAR_BIT, sizeof(char)))) {        free(bloom);        return NULL;    }    if(!(bloom->funcs=(hashfunc_t*)malloc(nfuncs*sizeof(hashfunc_t)))) {        free(bloom->a);        free(bloom);        return NULL;    }    va_start(l, nfuncs);    for(n=0; n<nfuncs; ++n) {        bloom->funcs[n]=va_arg(l, hashfunc_t);    }    va_end(l);    bloom->nfuncs=nfuncs;    bloom->asize=size;    return bloom;}int bloom_destroy(BLOOM *bloom){    free(bloom->a);    free(bloom->funcs);    free(bloom);    return 0;}int bloom_add(BLOOM *bloom, const char *s){    size_t n;    for(n=0; n<bloom->nfuncs; ++n) {        SETBIT(bloom->a, bloom->funcs[n](s)%bloom->asize);    }    return 0;}int bloom_check(BLOOM *bloom, const char *s){    size_t n;    for(n=0; n<bloom->nfuncs; ++n) {        if(!(GETBIT(bloom->a, bloom->funcs[n](s)%bloom->asize))) return 0;    }    return 1;}

测试程序mybloom.c

编译指令 gcc mybloom.c bloom.c -o mybloom

功能：查询整个linux文件系统中是否有从用户端输入的文件

#include<stdio.h>#include<string.h>#include <dirent.h>#include <time.h>#include "bloom.h"long n=0;unsigned int sax_hash(const char *key){    unsigned int h=0;    while(*key) h^=(h<<5)+(h>>2)+(unsigned char)*key++;    return h;}unsigned int sdbm_hash(const char *key){    unsigned int h=0;    while(*key) h=(unsigned char)*key++ + (h<<6) + (h<<16) - h;    return h;}// JS Hashunsigned int JS_hash(char *str){    unsigned int hash = 1315423911;     while (*str)    {        hash ^= ((hash << 5) + (*str++) + (hash >> 2));    }     return (hash & 0x7FFFFFFF);}int traverse(char *s,BLOOM *bloom1){    DIR *directory_pointer;    char current_path[10000];    char filepath[10000];    char now[10000];    struct dirent *entry;    strcpy(current_path,s);      if ((directory_pointer=opendir(s))==NULL)            printf("Error opening!/n");      else      {          while ((entry=readdir(directory_pointer))!=NULL)            {               if(strcmp(entry->d_name,".")!=0&&strcmp(entry->d_name,"..")!=0)                {                if(entry->d_type==4)                {                    strcpy(filepath,current_path);                    strcat(filepath,"/");                       strcat(filepath,entry->d_name);                    traverse(filepath,bloom1);                }                else if(entry->d_type==8)                {                    strcpy(now,current_path);                    strcat(now,"/");                    strcat(now,entry->d_name);                    n++;                    printf("%ld/n",n);                    bloom_add(bloom1,now);                }            }            }                closedir(directory_pointer);      }}void bloom_set(BLOOM *bloom1){        DIR *directory_pointer;        char temp[100]="";        struct dirent *entry;        if ((directory_pointer=opendir("/"))==NULL)        printf("Error opening!/n");        else          {          while ((entry=readdir(directory_pointer))!=NULL)            {               if(strcmp(entry->d_name,".")!=0&&strcmp(entry->d_name,"..")!=0)                {                if(entry->d_type==4)                {                       strcpy(temp,"/");                    strcat(temp,entry->d_name);                    traverse(temp,bloom1);                }                else                {                    strcpy(temp,"/");                    strcat(temp,entry->d_name);                    bloom_add(bloom1,temp);                    n++;                    printf("%ld/n",n);                }            }            }            closedir(directory_pointer);          }}int main(){    BLOOM *bloom;    char s[200];    int result;    if(!(bloom=bloom_create(250000, 3, sax_hash, sdbm_hash,JS_hash)))    {            fprintf(stderr, "ERROR: Could not create bloom filter/n");            return EXIT_FAILURE;        }    bloom_set(bloom);    printf("bloom set successfully!/ninput the file u want to search:/n");    while(1)    {        scanf("%s",s);        if(strcmp(s,"quit")==0)break;        result=bloom_check(bloom,s);        if(result==1)printf("file found!/n");        else printf("no such file!/n");    }   }