C implementation of Io's Number proto. A Number is an IoObject whose
inline data union stores a double — no separate heap payload, no
dataPointer. The CNUMBER / DATA macros just reinterpret the inline
slot, and IoNumber_free is a no-op because there is nothing to release.
Most arithmetic methods are thin shims that read the double out of
self (and any operand), compute, and return a freshly minted Number
via IONUMBER. Number is registered as a primitive proto on the state
so IONUMBER can clone without going through the message machinery.
Bitwise and character-class methods cast the double to long / int on
the fly; the limits methods expose the host's
Formats a double into a fixed buffer. Integer values in long long range print as integers (no trailing ".0"); very large or very small magnitudes use %e; everything else is printed with 16-digit precision and then has its trailing zeros — and trailing decimal point — trimmed in place. Used by IoNumber_print and IoNumber_asAllocedCString.
Returns a heap-allocated zero-padded string representation of the receiver (caller owns it and must io_free). Sized at 1024 bytes to cover the worst case of a small whole field width combined with a fully expanded %.16f. Used by printNumber and justAsString.
Returns a stack-allocated UArray that aliases the receiver's inline double — no copy, no heap. Used by code paths that want to treat a Number as a 1-element numeric vector (comparisons, coercion into Sequence ops). Caller must not mutate the view's data field.
Registered as the tag's compareFunc. Compares on numeric value when v is another Number, otherwise delegates to IoObject_defaultCompare (pointer-order fallback) so heterogeneous comparisons stay total for sorting. NaN comparisons inherit IEEE semantics via ==/>.
Registered as the tag's freeFunc. Body is empty: the double lives in the inline data slot, so there is nothing to release. The function exists only to override IoObject's default freer, which would try to io_free a dataPointer that was never allocated.
Builds the Number tag with clone/free/compare hooks. No stream read/write hooks are installed — the commented block below shows the legacy BStream-based serialization that was removed. The assert enforces that a double fits into the two-pointer inline data slot that all IoObjects reserve, which is what lets Number skip an allocated payload entirely.
Primary factory for Numbers. Normalizes every NaN to the canonical NAN bit pattern (x86 emits positive and negative NaNs from different paths; collapsing them keeps equality and hashing well-defined). The comment hints at a potential optimization: because Numbers hold no references, the full IOCLONE dance could in principle be shortened.
Returns one of the two supplied Numbers if its value already equals n, otherwise allocates a fresh Number. Arithmetic helpers call this to avoid minting a new IoObject for the common case where the result coincides with an operand (e.g. x + 0).
Creates the Number proto: allocates a bare IoObject, sets its tag, seeds the inline double to zero, registers the proto on the state, and installs the (large) method table of arithmetic, bitwise, character-class, and limit methods. Every Number returned by IONUMBER is a clone of this proto.
Registered as the tag's cloneFunc. Uses the primitive clone path (no slot hashtable copy) and memcopies the inline double from the proto. Numbers have no heap payload, so this is cheap.
Returns the minimum number of bytes needed to hold ld when shifted right 8 bits at a time. Used by asCharacter to pick a UCS encoding (1, 2, or 4 bytes) for the resulting single-character Sequence.