As long as you can fully round-trip the integer, it doesn't matter how many bytes you use.
nano-count dup 4 >be be> = . f nano-count dup 8 >be be> = . t nano-count dup 128 >be be> = . t ``log2 1 +`` will give you the required number of bits to store an integer. You will want to round up to a power of 8 bits or a power of two bytes. USE: math.bitwise nano-count dup dup log2 1 + bits = On Fri, Jun 5, 2020 at 4:44 PM Alexander Ilin <ajs...@yandex.ru> wrote: > Hello again! > > My specific example is the following. I want to put the output of > `nano-count` into a `byte-array`, which is fed into a hash. The current > value of `nano-count` is one of the sources of randomness gathered from the > system and poured into the hash. To convert the integer value into a > `byte-array` there are `>le` and `>be`, but they require the number of > bytes as a parameter. The question is, what should I supply for the value > received from `nano-count`? > > And the bigger question is, given an integer value, is there a way to > interrogate it about its byte size, i.e. the minimum number of bytes it > takes to hold the value without truncation and without leading zeroes: > > Value -- MinSize > 0 -- 1 > 255 -- 1 > 256 -- 2 > 65535 -- 2 > 65536 -- 3 > etc. > > I would expect such information to be available somewhere without doing > the power of two calculations in a loop. > > 23.03.2020, 05:41, "Doug Coleman" <doug.cole...@gmail.com>: > > For Factor, integers are either fixnum or bignum size. For C, you tell it > how many bytes it occupies according to the C header. Generally the sizes > are the same across platforms. If they aren't, you might need two different > STRUCT: declarations like in basis/unix/stat/linux/32/32.factor > and basis/unix/stat/linux/64/64.factor. > > The main point -- function signatures and struct declarations usually > handle the integer sizes and you shouldn't have to think much about it. Do > you have a specific example? > > > > > Earlier I wrote: > > One more question. I want to convert an integer into a byte-array > containing its bytes. In my use case it was the return value of the > nano-count, but the question is general: how can I get the bytes of an > integer. > > For floats there are primitives like float>bits and double>bits, and for > integers there is >le and >be, but for the latter two I need to specify the > size in bytes. Is there a way to ask an integer how many bytes it occupies? > Because from the documentation it's not clear at all how many bytes > nano-count would return, and it may vary depending on the current platform. > What am I missing? > > _______________________________________________ > Factor-talk mailing list > Factor-talk@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/factor-talk >
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