文章目錄

• 1.點陣圖的實現
• BitMap.h
• BitMap.c
• 2.布隆的實現
• BloomFilter.h
• BloomFilter.c

1.點陣圖的實現

BitMap.h

#ifndef __BITSET_H__
#define __BITSET_H__



#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<string.h>

typedef  struct BitSet
{
	char*  a;
	size_t  N;//開闢的位個數
}BitSet;

void BitSetInit(BitSet* p, size_t n);

void BitSetDestory(BitSet* p);

//置1
void BitSetSet1(BitSet* p, size_t x);
//把1變為0
void BitSetSet0(BitSet* p, size_t x);



//判斷數字是否在
int HaveNumber(BitSet* p, size_t x);

#endif



 

BitMap.c

#include  "BitSet.h"

void BitSetInit(BitSet* p, size_t n)
{
	assert(p);
	p->N = n;
	//確定需要的位元組數，並且+1，比如33/8應該是5個位元組
	size_t size = (n >> 3) + 1;
	//動態開闢
	p->a = (char*)malloc(size);
	//初始化
	memset(p->a, 0, size);
}

void BitSetDestory(BitSet* p)
{
	assert(p);
	free(p->a);
	p->a = NULL;
	p->N = 0;
}


void BitSetSet1(BitSet* p, size_t x)
{
	assert(p);
	//計算在第幾個char中
	int index = x >> 3;
	//第幾位
	int num = x % 8;
	p->a[index] |= (1 << num);
}

void BitSetSet0(BitSet* p, size_t x)
{
	assert(p);
	int index = x >> 3;
	int num = x % 8;
	p->a[index] &=  ~(1 << num);
}

//判斷數字是否存在
int HaveNumber(BitSet* p, size_t x)
{
	assert(p);
	int index = x >> 3;
	int num = x % 8;
	int ret = p->a[index] & (1 << num);
	if (0 == ret)
		return 0;
	else
		return 1;
}
 

2.布隆的實現

BloomFilter.h

#ifndef  __BLOOMFITER_H__
#define  __BLOOMFILTER_H__





#include"BitSet.h"



typedef struct BloomFilter
{
	BitSet b;
}BloomFilter;


void BloomFilterInit(BloomFilter* p,size_t n);
void  BloomFilterDestory(BloomFilter* p);
void  BloomFilterSet1(BloomFilter* p, char* x);
int  BloomFilterHaveNumber(BloomFilter* p, char* x);

#endif



 

BloomFilter.c

#include"BloomFilter.h"



size_t HashFunc1(char* p)
{
	assert(p);
	size_t hash = 0;
	while (*p)
	{
		hash = hash * 131 + (size_t)*p;
		p++;
	}
	return hash;
}


size_t HashFunc2(char* p)
{
	assert(p);
	size_t hash = 0;
	while (*p)
	{
		hash = hash * 31 + (size_t)*p;
		p++;
	}
	return hash;
}



size_t HashFunc3(char* p)
{
	assert(p);
	size_t hash = 0;
	while (*p)
	{
		hash = hash * 1313  + (size_t)*p;
		p++;
	}
	return hash;
}
void BloomFilterInit(BloomFilter* p ,size_t n)
{
	assert(p);
	BitSetInit(&(p->b),n );
}
void  BloomFilterDestory(BloomFilter* p)
{
	assert(p);
	BitSetDestory(&(p->b));
}
void  BloomFilterSet1(BloomFilter* p, char* x)
{
	assert(p);
	size_t index1 = HashFunc1(x);
	size_t index2 = HashFunc2(x);
	size_t index3 = HashFunc3(x);



	BitSetSet1(&(p->b), index1);
	BitSetSet1(&(p->b), index2);
	BitSetSet1(&(p->b), index3);


}
int  BloomFilterHaveNumber(BloomFilter* p, char* x)
{
	assert(p);
	size_t index1 = HashFunc1(x);
	if (HaveNumber(&(p->b), index1))
	{
		size_t index2 = HashFunc2(x);
		if (HaveNumber(&(p->b), index2))
		{
			size_t index3 = HashFunc3(x);
			if (HaveNumber(&(p->b), index3))
			{
				return 1;
			}
		}
	}
	return 0;
}