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#!/usr/bin/env ruby
require File.expand_path(File.join(File.dirname(__FILE__), "test_helper"))
module AllBitfields
def test_has_a_sensible_value_of_zero
all_objects do |obj, nbits|
_(obj).must_equal 0
end
end
def test_avoids_underflow
all_objects do |obj, nbits|
obj.assign(min_value - 1)
_(obj).must_equal min_value
end
end
def test_avoids_overflow
all_objects do |obj, nbits|
obj.assign(max_value + 1)
_(obj).must_equal max_value
end
end
def test_assign_values
all_objects do |obj, nbits|
some_values_within_range.each do |val|
obj.assign(val)
_(obj).must_equal val
end
end
end
def test_assign_values_from_other_bit_objects
all_objects do |obj, nbits|
some_values_within_range.each do |val|
obj.assign(obj.new(val))
_(obj).must_equal val
end
end
end
def test_symmetrically_read_and_write
all_objects do |obj, nbits|
some_values_within_range.each do |val|
obj.assign(val)
other = obj.new
other.read(obj.to_binary_s)
_(other).must_equal obj
end
end
end
def all_objects(&block)
@bits.each do |obj, nbits|
@nbits = nbits
yield obj, nbits
end
end
def min_value
if @signed
-max_value - 1
else
0
end
end
def max_value
if @signed
(1 << (@nbits - 1)) - 1
else
(1 << @nbits) - 1
end
end
def some_values_within_range
lo = min_value + 1
mid = (min_value + max_value) / 2
hi = max_value - 1
[lo, mid, hi].select { |val| value_within_range?(val) }
end
def value_within_range?(val)
(min_value .. max_value).include?(val)
end
end
def generate_bit_classes_to_test(endian, signed)
bits = []
if signed
base = "Sbit"
start = 2
else
base = "Bit"
start = 1
end
(start .. 64).each do |nbits|
name = "#{base}#{nbits}"
name += "le" if endian == :little
obj = BinData.const_get(name).new
bits << [obj, nbits]
end
(start .. 64).each do |nbits|
name = "#{base}"
name += "Le" if endian == :little
obj = BinData.const_get(name).new(nbits: nbits)
bits << [obj, nbits]
end
bits
end
describe "Unsigned big endian bitfields" do
include AllBitfields
before do
@signed = false
@bits = generate_bit_classes_to_test(:big, @signed)
end
it "read big endian values" do
all_objects do |obj, nbits|
nbytes = (nbits + 7) / 8
str = [0b1000_0000].pack("C") + "\000" * (nbytes - 1)
obj.read(str)
_(obj).must_equal 1 << (nbits - 1)
end
end
end
describe "Signed big endian bitfields" do
include AllBitfields
before do
@signed = true
@bits = generate_bit_classes_to_test(:big, @signed)
end
it "read big endian values" do
all_objects do |obj, nbits|
nbytes = (nbits + 7) / 8
str = [0b0100_0000].pack("C") + "\000" * (nbytes - 1)
obj.read(str)
_(obj).must_equal 1 << (nbits - 2)
end
end
end
describe "Unsigned little endian bitfields" do
include AllBitfields
before do
@signed = false
@bits = generate_bit_classes_to_test(:little, @signed)
end
it "read little endian values" do
all_objects do |obj, nbits|
nbytes = (nbits + 7) / 8
str = [0b0000_0001].pack("C") + "\000" * (nbytes - 1)
obj.read(str)
_(obj).must_equal 1
end
end
end
describe "Signed little endian bitfields" do
include AllBitfields
before do
@signed = true
@bits = generate_bit_classes_to_test(:little, @signed)
end
it "read little endian values" do
all_objects do |obj, nbits|
nbytes = (nbits + 7) / 8
str = [0b0000_0001].pack("C") + "\000" * (nbytes - 1)
obj.read(str)
_(obj).must_equal 1
end
end
end
describe "Bits of size 1" do
let(:bit_classes) { [BinData::Bit1, BinData::Bit1le] }
it "accept true as value" do
bit_classes.each do |bit_class|
obj = bit_class.new
obj.assign(true)
_(obj).must_equal 1
end
end
it "accept false as value" do
bit_classes.each do |bit_class|
obj = bit_class.new
obj.assign(false)
_(obj).must_equal 0
end
end
it "accept nil as value" do
bit_classes.each do |bit_class|
obj = bit_class.new
obj.assign(nil)
_(obj).must_equal 0
end
end
it "must not be signed" do
_ {
BinData::Sbit1
}.must_raise RuntimeError
_ {
BinData::Sbit1le
}.must_raise RuntimeError
end
end
|
