ahtable uses msb or lsb for two-byte length indicator?

[canadaduane]

I was puzzling over the code this morning and came across this comment:

        /* The most significant bit is set to indicate that two bytes are
         * being used to store the key length. */
        *((uint16_t*) s) = ((uint16_t) len << 1) | 0x1;
        s += 2;

It seems like that is the least significant bit being set, not the most significant, right? If I understand the Intel convention, the LSB (least significant byte) is then packed into the smaller memory address, so the 0x1 will be in the first byte of the 2-byte word. (Just doing a verbal sanity check :)

[canadaduane]

BTW, how is this for a summary of ahtable?

/*
 * ahtable : an array hash table
 *
 * ahtable keeps a dynamically sized array of variable-length keys and
 * fixed-length values. A key/value pair is stored in a "slot". The first
 * byte of each slot indicates the length of the key, UNLESS the least
 * significant bit of the first byte is set, in which case the first TWO
 * bytes of the slot indicate the length of the key (allowing for keys longer
 * than 127 bytes).
 *
 */

[canadaduane]

I see I'm missing the whole hash aspect of this. Need to mention pre-allocated fixed number of slots and the use of hashing to get to the correct slot number. Also, I must have misunderstood the one key/value pair per slot bit.

[canadaduane]

Ahh, finally found a free version of the paper. http://naskitis.com/naskitis-spire05.pdf

[dcjones]

Judging from your pull request, you figured this out already?

[canadaduane]

Yes, but I don't work on C code very often, so it was more a confidence
check than anything.
On Sep 20, 2014 3:08 PM, "Daniel Jones" [email protected] wrote:

Judging from your pull request, you figured this out already?

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