Class: Pocolog::Upgrade::Ops::NumericCast

Inherits:
Base
  • Object
show all
Defined in:
lib/pocolog/upgrade/ops/numeric_cast.rb

Instance Attribute Summary collapse

Attributes inherited from Base

#to_type

Instance Method Summary collapse

Methods inherited from Base

#call, #identity?

Constructor Details

#initialize(from_t, to_t) ⇒ NumericCast

Returns a new instance of NumericCast



17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
 
# File 'lib/pocolog/upgrade/ops/numeric_cast.rb', line 17

def initialize(from_t, to_t)
    super(to_t)
    if from_t.integer?
        from_range = compute_integer_range(from_t)
    end
    if to_t.integer?
        to_range   = compute_integer_range(to_t)
    end
    if !from_range
        if to_range
            @range_min, @range_max = *to_range
        end
    elsif to_range && (from_range.first < to_range.first || from_range.last > to_range.last)
        @range_min, @range_max = *to_range
    end
end

Instance Attribute Details

#range_max ⇒ Numeric? (readonly)

Maximum value allowed in Base#to_type if a range check is needed

Returns:

  • (Numeric, nil) —

    the maximum value, or nil if the source type cannot cause a range error



15
16
17
 
# File 'lib/pocolog/upgrade/ops/numeric_cast.rb', line 15

def range_max
  @range_max
end

#range_min ⇒ Numeric? (readonly)

Minimum value allowed in Base#to_type if a range check is needed

Returns:

  • (Numeric, nil) —

    the minimum value, or nil if the source type cannot cause a range error



9
10
11
 
# File 'lib/pocolog/upgrade/ops/numeric_cast.rb', line 9

def range_min
  @range_min
end

Instance Method Details

#compute_integer_range(type) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Compute the range for the given type



37
38
39
40
41
42
43
44
 
# File 'lib/pocolog/upgrade/ops/numeric_cast.rb', line 37

def compute_integer_range(type)
    if type.unsigned?
        [0, 2**type.size]
    else
        limit = 2**(type.size - 1)
        [-(limit-1), limit]
    end
end

#convert(value) ⇒ Object 



46
47
48
49
50
51
52
53
54
55
56
 
# File 'lib/pocolog/upgrade/ops/numeric_cast.rb', line 46

def convert(value)
    ruby_value = Typelib.to_ruby(value)
    if range_min
        if ruby_value < range_min
            raise RangeError, "value below minimum value for #{to_type}"
        elsif ruby_value > range_max
            raise RangeError, "value above maximum value for #{to_type}"
        end
    end
    Typelib.from_ruby(ruby_value, to_type)
end