nim-stew/tests/test_bitseqs.nim

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import
unittest, strformat,
../stew/[bitseqs]
suite "Bit fields":
test "roundtrips":
var
a = BitSeq.init(100)
b = BitSeq.init(100)
check:
not a[0]
a.setBit 1
check:
not a[0]
a[1]
b.setBit 2
a.combine(b)
check:
not a[0]
a[1]
a[2]
test "iterating words":
for bitCount in [8, 3, 7, 8, 14, 15, 16, 19, 260]:
checkpoint &"trying bit count {bitCount}"
var
a = BitSeq.init(bitCount)
b = BitSeq.init(bitCount)
bitsInWord = sizeof(uint) * 8
expectedWordCount = (bitCount div bitsInWord) + 1
for i in 0 ..< expectedWordCount:
let every3rdBit = i * sizeof(uint) * 8 + 2
a[every3rdBit] = true
b[every3rdBit] = true
for word in words(a):
check word == 4
word = 2
for wa, wb in words(a, b):
check wa == 2 and wb == 4
wa = 1
wb = 2
for i in 0 ..< expectedWordCount:
for j in 0 ..< bitsInWord:
let bitPos = i * bitsInWord + j
if bitPos < bitCount:
check a[j] == (j == 0)
check b[j] == (j == 1)
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test "overlaps":
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for bitCount in [1, 62, 63, 64, 91, 127, 128, 129]:
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checkpoint &"trying bit count {bitCount}"
var
a = BitSeq.init(bitCount)
b = BitSeq.init(bitCount)
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for pos in [4, 8, 9, 12, 29, 32, 63, 64, 67]:
if pos + 2 < bitCount:
a.setBit(pos)
b.setBit(pos + 2)
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check:
not a.overlaps(b)
not b.overlaps(a)
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