Fortran hash table {#mainpage}

The module dictionary_m implements a ““ hash table based on the djb2 hash
function.

program example_from_readme
  use dictionary_m
  implicit none
  type(dictionary_t) :: d
  call d%init(1024)
  call d%set('one', 'one')
  call d%set('pi', '3.14159')
  write(*,*) 'one', ' = ', d%get('one')
  write(*,*) 'pi', ' = ', d%get('pi')
end program example_from_readme

Author: Pierre de Buyl

License: BSD

Code repository: https://github.com/pdebuyl/fortran_hash_table/

Project goals

Demonstrate a hash table in Fortran.
Use standard Fortran 2008.
Single file implementation.
No dependency.
No preprocessing.
Not design a generic container, dictionary_m just stores strings. It is of course
possible to replace the “value” entry in the type entry_t for a single-datatype
dictionary.

The hash table is based on plain allocatable arrays and the base data is stored in (len=:), allocatable character variables. Buckets are extended arbitrarily by reallocation, thus
collisions will slow down this implementation with respect to others using better data
structures.

The goal is not to beat other implementations performance-wise but to provide the
convenience for Fortran programmers to store configuration settings, or other auxiliary data
easily.

Installation

dictionary_m consists of a single Fortran file. You can just drop src/dictionary_m.f90
in your Fortran project.

The code requires Fortran 2008 support. For gfortran, I have tested version 6.3 and 7.2. For
Intel Fortran, I have tested version 16.0.3.

Documentation and coverage

If you read this page from the “GitHub pages” doxygen-generated
documentation, you can access:

The documentation of the module dictionary_m.
The list of files and test programs
The coverage data generated from lcov and genhtml.

Fortran hash table {#mainpage}

Project goals

Installation

Documentation and coverage

See also