blachlylab/dklib

D ports of klib algorithms

dklib's Issues

Segfault upon destruction using hashmap of hashmaps

In trying to make a hashmap of hashmaps using khash.d, I run into the issue of a segfault when using the require function.
Segfault happens here as a double free (I think):

dklib/source/dklib/khash.d

Lines 145 to 147 in 8b3fa92

	kfree(cast(void*) this.keys);
	kfree(cast(void*) this.flags);
	kfree(cast(void*) this.vals);

The initval is an empty hashmap.
Example:

auto kmers = khash!(string, khash!(string, int))();

// for loop {

    // if not present create empty hash
    // initval is empty hashmap
    kmers.require(kmer1, khash!(string, int)());

    // if not present make count zero
    kmers[kmer1].require(kmer2, 0);
  
    kmers[kmer1][kmer2]++;

//}

The fix I found was by removing the free statements in the destructor. My theory is that D's automatic destructor frees the pointers as soon as they are out of scope. Or the other theory is that the empty hashmaps are freed before ever having the pointers set to any memory and are therefore the pointers are null or invalid.

A suggestion

I ve just seen the library, and taken a quick look at the source. İf std.traits functions are omitted, it can support betterC. Sorry if I am wrong.