mrb_read_float's underflow short-circuit used `final_p < -342 - nd`,
which for nd > 1 can be below POW10_MIN (-343). That let
parse_decimal call prescale() with a final_p below POW10_MIN, causing
an out-of-bounds read of pow10_tab. Tighten the guard to
`final_p < POW10_MIN`; values below that threshold cannot be
represented as a non-zero double for any mantissa within the parser's
19-digit cap.
Reported by OSS-Fuzz (testcase 6097379597287424).
Co-authored-by: Claude <noreply@anthropic.com>
mruby used to use float numbers for overflown integers before we
implemented big integers. Now we don't need bit operations for float
numbers anymore. Also removed tests for shift operations for float
numbers.
#### Before this patch:
```console
$ bin/mruby -e 'p(Float::NAN/0)'
Infinity
```
#### After this patch (same as Ruby):
```console
$ bin/mruby -e 'p(Float::NAN/0)'
NaN
```
Trailing `.0` is removed from `Float#to_s` and `Float#inspect` at
9d08025b. However, I think the more human-readable format is better
for `Float#inspect`.
For example, in the `Float#to_s` format, the failure message is not
well understood when testing values including types by `eql?` (e.g.
`Numeric#step` test).
```ruby
assert "example" do
exp = 1.0
act = 1
assert_operator(exp, :eql?, act) #=> Expected 1 to be eql? 1.
end
```
- `MRB_WITHOUT_FLOAT` => `MRB_NO_FLOAT`
- `MRB_USE_FLOAT` => `MRB_USE_FLOAT32`
The former is to use `USE_XXX` naming convention. The latter is to make
sure `float` is 32bit float and not floating point number in general.
Yukihiro "Matz" Matsumoto