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bitfield: add from_bytes() function

This commit is contained in:
Silvan Büdenbender 2019-11-13 17:48:00 +01:00 committed by Alexander Medvednikov
parent ffa6bcfff5
commit f30b0f1017
2 changed files with 40 additions and 0 deletions

View File

@ -77,6 +77,32 @@ fn cleartail(instance mut BitField) {
// public functions
// from_bytes() converts a byte arry into a bitfield.
// Be aware of possible trailing zeroes being added
// due to the underlying 32bit int containers.
pub fn from_bytes(input []byte) BitField {
mut output := new(input.len * 8)
for i, b in input {
pos := i / 4
match i % 4 {
0 {
output.field[pos] = output.field[pos] | (u32(b) << 24)
}
1 {
output.field[pos] = output.field[pos] | (u32(b) << 16)
}
2 {
output.field[pos] = output.field[pos] | (u32(b) << 8)
}
3 {
output.field[pos] = output.field[pos] | u32(b)
}
}
}
return output
}
// str2bf() converts a string of characters ('0' and '1') to a bit
// array. Any character different from '0' is treated as '1'.

View File

@ -122,6 +122,20 @@ fn test_hamming() {
assert count == bitfield.hamming(input1, input2)
}
fn test_bf_from_bytes() {
input := [byte(0xF0), byte(0x0F), byte(0xF0), byte(0xFF)]
output := bitfield.from_bytes(input)
mut result := 1
for i := 0; i < input.len * 8; i++ {
expected := input[input.len - 1 - i / 8] >> i % 8 & 1
actual := output.getbit(i)
if expected != actual {
result = 0
}
}
assert result == 1
}
fn test_bf_str2bf() {
rand.seed(time.now().uni)
len := 80