Looking for a good hash table implementation in C [closed]

I had the same need and did some research and ended up using libcfu

It's simple and readable so if I have a need to modify, I can do it without spending too much time to understand. It's also of BSD license. No need to change my structs (to embed say a next pointer)

I had to reject the other options for following reasons (my personal reasons, YMMV):

• sglib --> it's a macro maze and I wasn't comfortable debugging/makingchanges on such a code base using just macros
• cbfalconer --> lot of licensing redflags, and the site was down and too many unfavorable discussions on web about support/author; didn't want to take the risk
• google sparce-hash --> as stated already, it's for C++, not C
• glib (gnome hash) --> looked very promising; but I couldn't find any easy way to install the developer kit; I just needed the C routines/files -- not the full blown developement environment
• Judy --> seems too complex for a simple use.. also was not ready to debug myself if I had to run into any issues
• npsml (mentioned here) --> can't find the source
• strmap found very simple and useful -- it's just too simplistic that both key and value must be strings; value being string seems too restrictive (should accept void *)
• uthash --> seems good (has been mentioned on wikipedia on hashtable); found that it requires struct to be modified -- didn't want to do that as performace is not really a concern for my use --it's more of development velocity.

In summary for very simple use strmap is good; uthash if you are concerned with additional memory use. If just speed of development or ease of use is primary objective, libcfu wins [note libcfu internally does memory allocation to maintain the nodes/hashtables]. It's surprising that there aren't many simple C hash implementations available.

GLib is a great library to use as a foundation in your C projects. They have some decent data structure offerings including Hash Tables: http://developer.gnome.org/glib/2.28/glib-Hash-Tables.html (link updated 4/6/2011)

For strings, the Judy Array might be good.

A Judy array is a complex but very fast associative array data structure for storing and looking up values using integer or string keys. Unlike normal arrays, Judy arrays may be sparse; that is, they may have large ranges of unassigned indices.

Here is a Judy library in C.

A C library that provides a state-of-the-art core technology that implements a sparse dynamic array. Judy arrays are declared simply with a null pointer. A Judy array consumes memory only when it is populated, yet can grow to take advantage of all available memory if desired.

Other references,
This Wikipedia hash implementation reference has some C open source links.
Also, cmph -- A Minimal Perfect Hashing Library in C, supports several algorithms.