https://github.com/mdietrichstein/objc-murmur3-bloomfilter
Bloom filter implementation using murmur3 hashing written in Objective-C
https://github.com/mdietrichstein/objc-murmur3-bloomfilter
algorithm bloom-filter bloom-filters hash ios murmur3-hashing objective-c probability
Last synced: 3 months ago
JSON representation
Bloom filter implementation using murmur3 hashing written in Objective-C
- Host: GitHub
- URL: https://github.com/mdietrichstein/objc-murmur3-bloomfilter
- Owner: mdietrichstein
- Created: 2016-08-24T16:00:19.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2017-05-18T12:45:10.000Z (over 8 years ago)
- Last Synced: 2025-07-04T07:05:29.497Z (4 months ago)
- Topics: algorithm, bloom-filter, bloom-filters, hash, ios, murmur3-hashing, objective-c, probability
- Language: Objective-C
- Size: 8.79 KB
- Stars: 3
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# Objective-C Bloom Filter implementation
An Objective-C Bloom Filter implementation using 128 Bit (x64) Murmur3 Hashing. Hashes are generated using the Double Hashing Methond described in [Less Hashing, Same Performance: Building a Better Bloom Filter](https://www.eecs.harvard.edu/~michaelm/postscripts/tr-02-05.pdf).
## Usage
```objc
NSUInteger expectedNumberOfItems = 10000;
double falsePositiveRate = 0.01;
uint32_t seed = 1234;
BloomFilter *bloomFilter = [[BloomFilter alloc] initWithExceptedNumberOfItems:expectedNumberOfItems falsePositiveRate:falsePositiveRate seed:seed];
// Containment
NSString *containedId = [[NSUUID UUID] UUIDString];
NSData *containedData = [containedId dataUsingEncoding:NSUTF8StringEncoding];
[bloomFilter add:containedData];
NSAssert([bloomFilter contains:containedData] == YES);
NSString *invalidId = [[NSUUID UUID] UUIDString];
NSData *invalidData = [containedId dataUsingEncoding:NSUTF8StringEncoding];
NSAssert([bloomFilter contains:invalidData] == NO);
// Serialization
BloomFilter *deserializedBloomFilter = [[BloomFilter alloc] initWithData:bloomFilter.data exceptedNumberOfItems:expectedNumberOfItems falsePositivePercentage:falsePositiveRate seed:seed];
NSAssert([deserializedBloomFilter contains:containedData] == YES);
NSAssert([deserializedBloomFilter contains:invalidData] == NO);
```
## Resources
* [Bloom Filter (Wikipedia)](https://en.wikipedia.org/wiki/Bloom_filter)
* [Murmur3 hash implementation (C++)](https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp)
* [Less Hashing, Same Performance: Building a Better Bloom Filter (pdf)](https://www.eecs.harvard.edu/~michaelm/postscripts/tr-02-05.pdf)