- This is a single threaded quotient filter implementation in pure PHP.
- It uses a binary string to store the bit vector and manipulates based on byte indexes of the string.
- Apache 2.0 License.
This implementation supports 33 bit quotients (2^33 slots) and remainders up to 63 bits at the expensive of some performance.
- PHP Limitations
- Strings are limited to byte addressing of signed 32 bit integers. The maximum string is only 2GB - 1B (2^31-1 Bytes).
- The bit vector only supports powers of 2 bits in this implementation. Thus the largest vector size is 1GB.
- Workaround with multiple strings could allow for implementations greater than 1GB.
- PHP 5.4+
- PHP lacks calloc or malloc so str_repeat is used to allocate the bit array.
- PHP cannot directly use the output of str_repeat and primitive assignment will require double the memory of the vector size due to the copy.