Bitwise refers to a bitwise operation which operates on one or more bit patterns or binary numerals at the level of their individual bits.

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Bit string builder for Java

I have this Java class for building bit strings. The set of methods it provides resembles that of java.lang.StringBuilder. See what I have: BitStringBuilder.java: ...
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1answer
38 views

LEB128 in Haskell

I have implemented the LEB128 encoding for unsigned integers. I'm fairly new to Haskell so I have some doubt about the coding style I'm using, particularly the definition of ...
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27 views

Convert tri-gram of type wchar_t to an integer type

I am trying to convert a tri-gram containing 3 characters of type wchar_t to an integer type (an uint64_t at the present time). ...
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3answers
212 views

Calculating the 'binary gap' of a number

Inspired by this question and therefore this one I decided that clearly the best most readable way to solve this is with Regular Expressions. A binary gap within a positive integer N is any ...
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0answers
20 views

Implement “at” lens for Data.Map

I've been working on adding an operation like Data.Lens.At.at to Data.Map. This uses an extremely fast, extremely small, and ...
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3answers
40 views

Byte array to floating point such as FPE2 in Java

Apple's System Management Controller uses FPE2 and SP78 as floating-point formats. While writing a Java library that that interfaces with the SMC, I ported someone's C function to convert read a ...
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223 views

Finding the fastest common prefix of 2 strings in Python

I'm comparing my algorithms, slice_prefix and bit_prefix, with existing ones to find the common prefix length of 2 strings as ...
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40 views

A bitwise common prefix algorithm in Python

Is my algorithm slow because it has problems? Or, is any bitwise common prefix solution not going to give me the performance I'm looking for? After profiling my algorithm, I found that over 60% of ...
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1answer
194 views

Console app to teach bitwise operators

I'm creating a console app that has the purpose to teach you how to use C# bitwise operators. I have several classes which contain info about the different operators and I instantiate/add them in the ...
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1answer
58 views

Parsing an IP address (Bit manipulation)

Given a string representing of an IP address, such as "127.43.23.59", return a 32 bit integer representation of this string. The 32 bit integer is separated into four bytes, where each byte is one of ...
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1answer
270 views

Calculating the results of bit operations

I have a simple program that calculates and outputs the results of all the bit operators. I'm planning to send it to my friend and to explain some stuff about them to him. Before I do that, I want to ...
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1answer
220 views

Printing longest sequence of zeroes

I am doing a coding exercise in codility and I came across this question: A binary gap within a positive integer N is any maximal sequence of consecutive zeros that is surrounded by ones at both ...
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2answers
76 views

Concatenate three 16-bit integers in one 64-bit integer with C++

I am looking for an elegant alternative of the following code where wordXX contains always 16 bits: ...
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2answers
60 views

Portable byte order conversion

I'm trying to improve the portability of a file format converter, specifically to POSIX platforms other than Linux. I'd appreciate a review of the following functions used for converting between ...
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43 views

Parallel popcount of packed bytes

I want to do a popcount of bytes in an array. Not a total popcount of everything, but lots of little popcounts for every individual byte to determine the neighborhood count in GoL. The following ...
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2answers
42 views

BMP writer in C

I recently wrote a BMP writer in C: bmpWriter.h ...
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3answers
84 views

Bit manipulation tool set

I made a tool set to facilitate bit manipulation as follows. Any comments are welcome, be it about the interface design, the implementation, or even the naming. Also, I want to make sure that the tool ...
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1answer
93 views

Speeding up the generation all bit strings with Hamming distance one

I'm playing around with hypercubes. For this, I need to create its edge set. Specifically, the edge set is the set of all bit strings with Hamming distance 1. An important property is that I want to ...
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1answer
73 views

Saturated signed addition

So this a exercise from the book COMPUTERS SYSTEMS A PROGRAMMERS PERSPECTIVE I need to add two signed numbers and in case it overflows or underflows return ...
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2answers
102 views

Simulation of image transfer over noisy channel

Following this question, I've tried to rewrite some core methods to avoid using String for bit operations, and I ended up using ...
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1answer
172 views

Solution to part 1 of Day 7 Advent of Code in Scala

Does someone want to review my solution to part 1 of Day 7 Advent of Code in Scala? The assignment is here: http://adventofcode.com/day/7 Without repeating the whole text, in short: Given a text file ...
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92 views

FUTABA SBUS serial communication in C++

I would like to reimplement the current Futaba SBUS protocol in ArduPilot for Navio+. It seems to be a relatively expensive protocol, so I changed the code from an existing git project and to make it ...
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1answer
42 views

Routine for convert decimal digits to Densely Packed Decimal

I've written an amd64 assembly routine (in gas syntax using the System V calling convention) to convert three decimal digits to densely packed decimal because I wasn't satisfied by the performance of ...
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5answers
82 views

Toggle four relays on/off based on bitmap stored in uint8_t

I am using a one-byte bitmap to control four relays. I am writing a function which will take the bitmap stored as uint8_t, look to see which bits are set/cleared, ...
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2answers
409 views

Java conversion of base 16 to base 64

I wrote a solution in Java to solve the problem here. I use BigInteger to convert first from base 16 to base 10, then base 10 to base 64. This seems quite ...
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1answer
151 views

Remove elements existing in a list built from an enum

The objective of this code is to make the difference inbetween two lists of items, that is knowing which items are missing in the second list in regards to the first one. The first list is built from ...
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3answers
79 views

Testing if the binary representation of an integer has an odd number of ones

The fn odd_ones(x: u32) -> bool function should return true when x contains a odd number ...
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2answers
127 views

All arithmetic operator functions (+, -, *, /, %) coded only using bitwise operators in C

Here's all the functions in C that does all the arithmetic operators without using arithmetic operators themselves, mostly using bitwise operators. Recursive functions and comparison operators are ...
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1answer
51 views

Three ways to read a number for a BitInputStream

I'm trying to learn how to write more readable code without introducing easily avoidable performance killers. This is part of a BitInputStream Java class I'm ...
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1answer
37 views

PWM wave generation

This code takes a integer x of range [0,127] as input, returns an array of four 32-bit integers, with x bits set. I'm trying to ...
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1answer
62 views

Testing for divisibility of numbers - follow-up

(Here is the follow up question) I had another go at trying to speed up my program described in my previous question. JS1's answer was particulary helpful and now my code is only about 20% slower ...
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Program to test for divisibility of numbers

(EDIT: here is the follow up qusetion) Using this program to test for the smallest number where its permutations or itself is divisible by 10 or less numbers is twice as slow as the fastest program I ...
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3answers
334 views

Finding nearest power of 2

I have the following simple program which calculates and returns the nearest power of 2 of a given number. Because I use increments and decrements to find the closest power, this takes a very long ...
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141 views

Read bits, write bits data to arbitrary position in char array

I created functions to read bit data from arbitrary bit position of a char array to long long int, and I also created a function ...
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1answer
132 views

Bitmask type to perform binary operations

Without any specific implementation details, how would you create a bitmask type that wraps binary arithmetic into something easy to read? Ideally, this would be used with an ...
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1answer
123 views

“Flipping bits” Python implementation

Problem Statement You will be given a list of 32 bits unsigned integers. You are required to output the list of the unsigned integers you get by flipping bits in its binary representation (i.e. ...
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1answer
100 views

Return Y integer with same bit sets as X & having | X - Y | minimum value

I happened to come across one question: Given an integer 'x' (Only positive), write an algorithm that returns integer 'y' such that it has the same number of bits set as 'x' and is not equal ...
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1answer
72 views

Code Chef problem COOKMACH

Firstly, I got the solution for this question in CodeChef, but I noticed one thing which still confuses me. This was the code which was accepted as correct. ...
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1answer
125 views

Reading bits from a stream from least to most significant

For a recent project I was in need of excessive bit manipulation. Specifically, I had to write to or read from a variable number of bits up from the least significant bit towards the most significant ...
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115 views

Performing add/delete/count operations on a list

Problem Statement (HackerRank) You have a list of integers, initially the list is empty. You have to process Q operations of three kinds: add s: Add integer s to your list, note ...
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2answers
606 views

Division without multiplication, addition or division

In context of preparing for a coding interview, I gave the division problem a go using Java. This is what I came up with. It's a little bit different to other solutions I've come across the interweb. ...
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8answers
2k views

String reversal, capitalize vowels, lowercase consonants

This was a portion of a skills test given to me by a company. The task was to write a method that takes a string, reverses it, and sets the vowels as capitals and consonants to lowercase. I was also ...
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3answers
634 views

Number of right cyclic shifts to give the biggest number

I am preparing to coding interview and I met this task today: You are given 30-bit unsigned integer N. A right cyclic shift of N by K bits is the result of performing a right cyclic shift of N by one ...
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3answers
325 views

Mockup in C of hardware implementation for multiplication of signed integers

I challenged myself to implement multiplication of signed integers using only +, -, ...
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1answer
84 views

Encoding variable-length quanties for MIDI

I was reading about the MIDI spec and I challenged myself to implement a function to convert an int32 to a variable length quantity uint32. I didn't look it up or ...
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1answer
290 views

Pixel bit-wise LSB extraction to byte array

I wrote the following code below to extract the least significant bit (LSB) of each pixel and store it into a byte[] array. I was wondering if Java has a more ...
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234 views

Verifying validity of Intel.hex file records

I have a class called FirmwareFile which represents and Intel HEX format file. The file is constructed with the name, build time and build date, at a later point ...
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1answer
139 views

Printing lines in a file, filtering by the first column

I am setting up a project which involves a lot of data analysis, each data point represented by a line in a large text file. In order to test for certain types of data, I added a tag to each line (It ...
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3answers
135 views

Bitstream reader

I have a program which reads and analyses MPEG-TS files. I've been using gperftools to identify hotspots and optimize them, and 45% of all samples at this point are in my main bitstream reader ...
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155 views

Fastest sum of absolute values of 32 differences

A long should be treated as a list of 32 unsigned numbers, each of them just two bit long. So 0x1234F... represents ...