Exception thrown on NULL pointer in ahtable_iter_key() #41

RajNaiduWTG · 2025-04-13T07:05:54Z

Hi Daniel, thank you so much for sharing your code with the community.
While experimenting with the hat-trie, I hit an exception in ahtable_iter_key() - when the "i" iterator is NULL:
const char* ahtable_iter_key(ahtable_iter_t* i, size_t* len).
I do not understand the code enough to suggest a proper fix, I just "patched" it as follows:

Add a null check upon the entry into ahtable_iter_key():

const char* ahtable_iter_key(ahtable_iter_t* i, size_t* len)
{
    if (i == NULL) return NULL; //add this null check

Add a null check in hattrie_iter_prefix_satisfied():

    if (i->level + size < i->prefixsize) {
        // early exit, child key is too short to match prefix
        return false;
    }
    else if (key == NULL) { //add this null check
        return false;
    } else {
        return (memcmp(key, i->prefix + i->level, i->prefixsize - i->level) == 0);
    }

This problem only occurs under specific conditions - if necessary, I can provide the input data to replicate the exception.
Kind regards, --Raj

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Exception thrown on NULL pointer in ahtable_iter_key() #41

Exception thrown on NULL pointer in ahtable_iter_key() #41

Exception thrown on NULL pointer in ahtable_iter_key() #41

Exception thrown on NULL pointer in ahtable_iter_key() #41

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