Bitmask is a technique used to isolate specific bits in a byte in order to work only on the desired ones. They are used in IP addresses to separate the network prefix and the host number for example.
Questions tagged [bitmask]
738 questions
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0 answers
Parsing String to a Short Mask
Good day.
I'm working with the Tinkerforge Java API to do some programming.
I ran into a Problem, where i've to create a short Mask looking something like:
"0b11011011"
I'm using the following code to parse my config into the Mask Required:
I'm…
Fabian Meier
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0
votes
1 answer
Apply boolean mask to Scala array
I'm trying to use an array of booleans to choose particular elements in another array. For example:
val arr = Seq("A", "B", "C")
val mask = Seq(true,false,true)
and I'd like the output to be a new array:
val arr_new = Seq("A","C")
Is there a way…
Feynman27
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Hamming Weight of Int64
I'd like to ask how the BitMask looks like when I need to apply the hamming weight
algoritm on an Int64 to count the set bits.
For an Int32 it looks like this:
public int HammingWeight(int value)
{
value = value - ((value >> 1) &…
yq8
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2 answers
Mapping a bitfield to another bitfield in C#
I have two bitfields, one of 8 bits and one of 4 bits.
[Flags]
public enum Bits1 {
A = 1,
B = 2,
C = 4,
D = 8,
E = 16,
F = 32,
G = 64,
H = 128
}
[Flags]
public enum Bits2 {
I = 1,
J = 2,
K = 4,
L = 8
}
I need to map the…
GameKyuubi
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What work Bitmask at C#
I am trying to deal with a bit mask:
Mask |= 1 << MapID;
anybody can explain how it works?
Thanks for help guys
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1 answer
Check if a bitmask value is contained in the sum of many bitmask values
I have the following specification of bitmask values:
// Structure of Database:
// SC_NAME, flag
//
// flag 1 - SC cannot be removed by death.
// 2 - SC cannot be saved.
// 4 - SC cannot be reset by dispell.
// 8 - SC…
Latheesan
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Bit masking with decimal offset: Faster algorithm?
I've a sum build of 0 up to 3 specific decimal numbers that can build 8 different sums:
100 --- 100 --- 100 --- 100 ---
200 200 --- --- 200 200 --- ---
+ 400 + 400 + 400…
Sebastian Barth
- 4,079
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1 answer
Is It Possible to Use Hashcodes as a Bitmask to Efficiently Store/Track Collection Membership?
Currently I have a solution where I keep track of objects I am interested in by getting their hashcode via Object.GetHashCode and then storing them in a HashSet.
However, I have also been learning about bitmasks and bitwise operations and I am…
Mike-E
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2 answers
Why does a shifted integer mask with a tilde casted to a long return zero? (Java, bit shift)
I am trying to create a mask to view specific bits on a long in Java. I tried the following:
long mask = ~ (0xffffffff << 32);
If I print this on the console it will return 0 but I am expecting 4294967295 since my result should look like…
thiloilg
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1 answer
Placing a new value into a section of a big Python bitarray
Using Python 2.7 and bitarray 0.8.1 to hold several sequenced register values (registers can be from 16 to 512 Byte long).
I want to set a value to a specific part of this bitarray?
For example:
from bitarray import bitarray
BYTE = [False,…
Gilbert
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2 answers
SpriteKit Category Bitmask Not Working Correctly
In my xcode project I am trying to create a function that gets called when a SKShapeNode hits the world border(edge of screen) that I have created. The SKShapeNode hits the edge of the screen and rolls to the right due to the gravity but when the…
Charles
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1 answer
Calculating subsets of an array within a given range?
Given an array of n numbers, how can we calculate the subsets of that array (0 based indexed) in a given range i.e starting from ith index to jth index. I tried using bitmasking but couldn't figure out how to solve this because of the range.
For…
ashwani
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1 answer
Bitmask operations on slices of Python bytearrays
Say I have a bytearray like the following :
mask = bytearray([0b0001, 0b0100, 0b0111]),
where each bit represents a certain flag. I would like to add a flag to slices of the mask array like so :
mask[0:2] = mask[0:2] | 0b1000
but I get a TypeError…
user5283407
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2 answers
combining two different information in binary code
I have Dictionary where string represents the key of record, and I have two other pieces of information about the record that I need to maintain for each record in the dictionary, which are the category of the record and its redundancy…
hassan alrehamy
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1 answer
Don't understand why result is one
I had to create a function that can be given an int with up to 32 bits. It is supposed to return 1 if an odd bit is 1 and 0 otherwise. I understand that if it does not match the mask it returns zero, but I don't understand why it returns one if it…
Stan
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