In some cases, one might want to disable what is currently
SipHash for speed / better security mechansims. For example, using
red black trees for caches rather than hash tables.
The hash key still needs to randomly initialized
for the security advantage, but this patch is a
step closer to avoiding hash based DOS.
Further work may including exposing the raw hash
function for use by abstract types who also choose to
implement hash.
On very long binding names > 256 characters, a buffer overrun would be
trigger in janet_cfuns. Not a huge issue, since this is not really code
that would ever be user facing, but we can fix this.
If JANET_ENTRY_NAME is defined, we are compiling into a single binary.
In this case, we don't want to define the config symbol multiple times
with same name, as this causes the linker error.
While C functions are not re-entrant, signaling from a C function
can be used to implement async returns. When resuming a fiber that
signalled from within a C function, the fiber is started after the
instruction that emitted the signal. The resume argument is used
as the return result from the c function.
Also make integer to size_t casts explicit rather than relying on
int32_t * sizeof(x) = size_t. This is kind of a personal preference for
this problem.
Because we use an amalgated build, feature
test macros should be set in a single file that
is included before any other headers, and is placed
at the top of the amalgamated build.
This unifies equality and comparison checking. Before, we had
separate functions and vm opcodes for comparing general values vs.
for comparing numbers, where the numberic functions were polymorphic and
had special cases for handling NaNs. By unfiying them, abstract types
can now better integrate with other number types and behave as keys.
For now, the old functions are aliased but will eventually be removed.
