Bug? Old KVS1: some strings are treated as float

Discussion in 'B4J Bugs & Wishlist' started by jmon, Aug 22, 2019.

  1. jmon

    jmon Well-Known Member Licensed User

    Hi,

    I think I found a bug with the old KVS. I know, I must be one of the only sticking with the first version of KVS1, but I can't upgrade it at the moment!

    The bug is that if I putSimple this:
    Code:
    KVS.PutSimple("ColorAccent""0e9395")
    The data stored in KVS is actually this:
    I tried to figure out what's happening, and it could be because any string starting with "0e" is treated as float : https://www.whitehatsec.com/blog/magic-hashes/

    I guess the problem with KVS1 was that the type of the column wasn't specified:
    Code:
    sql1.ExecNonQuery("CREATE TABLE IF NOT EXISTS main(key TEXT PRIMARY KEY, value NONE)")
    so that allows the string to be treated as float.

    I know it's a random case, but I figured I should post it, for learning purposes, and it took me quite a while to figure out the problem :)
     
  2. Erel

    Erel Administrator Staff Member Licensed User

    It is a limitation of the old KVS implementation where the type information of "simple" values are lost.
     
    jmon likes this.
  3. emexes

    emexes Well-Known Member Licensed User

    I have a vague recollection of similar confusion in C (I think it was) where integers with leading zeros were interpreted as octal.

    X = 23 'twenty-three
    X = 023 'nineteen

    I was surprised that your 0e9395 didn't crap out with an exponent-too-large error because single precision floats ("E") have a maximum exponent of 38, and double precision floats (which I thought were "D") have a maximum exponent of 308. But 0eANYTHING still equals 0, so... fair enough... :)
     
    jmon likes this.
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