garymacindoe’s gists

garymacindoe / check-keywords

Created April 15, 2015 12:13

Checks for invalid/obsolete keywords in Gentoo Portage's packages.accept_keywords files

	#!/bin/bash
	#
	# Author: Gary Macindoe
	# Date: May 2013

	files="/etc/portage/package.accept_keywords /etc/portage/package.keywords"
	fs=""
	for f in ${files}
	do
	if [ -d "${f}" ]

garymacindoe / check-use

Created April 15, 2015 12:14

Checks for invalid/obsolete entries in Gentoo Portage's package.use files

	#!/bin/bash
	#
	# Author: Gary Macindoe
	# Date: May 2013

	files="/etc/portage/package.use"
	if [ -d "${files}" ]
	then
	files="${files}/*"
	fi

garymacindoe / upgrade-kernel

Last active November 25, 2018 19:08

Compiles and installs two versions of a new kernel source - one with an EFI stub loader and one without - using the running kernel's config as a template (requires /proc/config.gz)

	#!/bin/bash
	#
	# Author: Gary Macindoe
	# Date: November 2014

	set -eu

	EFI_KEYS="/root/efi"

	LINUX_SOURCE="/usr/src/linux"

garymacindoe / check-world

Created May 6, 2015 12:48

Checks for invalid/obsolete entries in Gentoo Portage's world file

	#!/bin/bash
	#
	# Author: Gary Macindoe
	# Date: May 2015

	WORLD_FILE=/var/lib/portage/world

	while read package;
	do
	DEPS=$(grep -l ${package} /var/db/pkg///{,R}DEPEND \| cut -d'/' -f5,6 \| sort -u);

garymacindoe / nextpow2.hpp

Created June 18, 2015 14:44

Round up to the next highest power of 2 using C++11 compile-time templates

	#include <type_traits>
	#include <limits>

	template <typename UIntType, UIntType v, unsigned int n>
	struct set_lower_bits : public std::integral_constant<UIntType, v \| (v >> n) \| set_lower_bits<UIntType, v \| (v >> n), (n >> 1)>::value> {};

	template <typename UIntType, UIntType v>
	struct set_lower_bits<UIntType, v, 1> : public std::integral_constant<UIntType, v \| (v >> 1)> {};

	template <typename UIntType, UIntType v>

garymacindoe / vtable.cpp

Created July 29, 2015 13:55

Calling a private method through the vtable

	#include <iostream>

	class A {
	virtual void function() const {
	std::cout << "You bastard!" << std::endl;
	}
	};

	int main() {
	A a;

garymacindoe / woo.cpp

Created August 12, 2015 15:16

Implementation of voxel traversal algorithm from "A Fast Voxel Traversal Algorithm for Ray Tracing" (Amanatides and Woo)

	/*
	* Implementation of voxel traversal algorithm from "A Fast Voxel Traversal
	* Algorithm for Ray Tracing" (Amanatides and Woo).
	*/

	#include <iostream>
	#include <iterator>
	#include <tuple>
	#include <limits>
	#include <algorithm>

garymacindoe / hg2git.sh

Last active August 29, 2015 14:28

	#!/bin/bash
	#
	# Converts mercurial repostories to git repositories.
	# Requires git-remote-hg from https://github.com/felipec/git-remote-hg.
	#

	if [ $# -lt 2 ] \|\| [ $# -gt 3 ]
	then
	echo "Usage: ${0} <url> <local_directory> [user_map]"
	echo "Where"

garymacindoe / fibonacci.c

Created September 12, 2015 18:32

Calculation of the nth term of the Fibonacci sequence in constant time

	#include <stdio.h>
	#include <inttypes.h>
	#include <math.h>

	uint64_t fibonacci(uint64_t n) {
	static const double golden = 1.61803398874989484820;
	return (uint64_t)floor((pow(golden, (double)n) / sqrt(5.0)) + 0.5);
	}

garymacindoe / kadane.cpp

Created September 14, 2015 20:38

O(n) solution to the maximum subarray sum problem using Kadane's algorithm

	#include <tuple>
	#include <iterator>
	#include <algorithm>

	template <class InputIterator>
	std::tuple<typename std::iterator_traits<InputIterator>::value_type,
	InputIterator, InputIterator>
	maximum_subarray(InputIterator first, InputIterator last) {
	typedef typename std::iterator_traits<InputIterator>::value_type value_type;
	using std::max;

Gary Macindoe garymacindoe