McUsr’s gists

McUsr / find.c

Last active June 1, 2024 07:30

C-version of Software Tools in Pascal "find" command, with done exercises

	// Software tools p.p 146
	/* Converted to C by me. All faults are mine. No warranties what so ever.
	* Most of the code is written by Kernighan or Plaugher, so the code is really
	* copyrighted by them. I only translated it to C.
	*/

	#include <stdbool.h>
	#include <ctype.h>
	#include <stdio.h>
	#include <stdlib.h>

McUsr / real_arena.c

Last active February 26, 2024 16:25

An arena backed memory allocator

	/* License:
	* Copyright (C) 2023 - McUsr This program is free software; you can
	* redistribute it and/or modify it under the terms of the GNU General
	* Public License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version. This
	* program is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details. You should have received a copy of the GNU General Public
	* License along with this program; if not, write to the Free Software

McUsr / noncanon.c

Last active October 15, 2023 23:38

Press any key to continue function that reprints message when brought back to foreground.

	#define _XOPEN_SOURCE 500

	/*
	* Termios handling stolen from https://www.gnu.org/software/libc/manual/html_node/Noncanon-Example.html_node
	* Reworked to make a press any key to continue function, which handles SIGCONT in a shell with
	* job control, so that the message reappears, if we hit SUSP (^Z), while we are waiting for a keypress.
	*
	* To compile:
	* cc -std=c99 -g3 -D_POSIX_SOURCE -o noncanon noncanon.c
	*

McUsr / sem_mmap_fork.c

Last active September 21, 2023 11:16

Semaphores controlling access to mmap between parent and child

	/*

	This is a demo of sharing memory between parent and child, and
	to use semaphores to controll access between the processes
	for the shared memory.

	Based on:

	The example with semaphores in `man shm_open`, and
	the mmap demo shared between parent and child in:

McUsr / nrcp.c

Last active July 12, 2023 11:16

A utility to create a numbered copy of a file into the current directory

	/**
	* @brief nrcp : makes a numbered copy of a file.
	*
	* It finds the ascending number that isn't used
	* as a suffix for the file, and creates a copy
	* of the file with that number appended as a
	* suffix -- in the same directory as the original
	* file!
	*
	* @author McUsr

McUsr / hashtable.c

Last active June 5, 2023 20:30

	/* Basic hash example an example found on the internet
	*
	*
	* I u/McUsr made it work flawlessly with the good help of
	* r/C_programming:
	* u/Bitwise_Gamgee, u/No-Adhesiveness-8125 and u/curiously-b2.
	* I got insights and suggestions from u/t40, u/ThatsMyFavoriteThing.
	* u/flyingiron, u/Daiktana, and last but not least u/skeeto!
	* Thanks a bunch guys!
	*

McUsr / ckwd.c

Last active May 23, 2023 01:30

	/* K&R p.p 136
	* Exercise 6-1
	* 2023 (c) McUsr -- Vim licence.
	*
	* "Our version of getword does not properly handle underscores, string
	* constants, comments or preprocesor control lines. Write a better version."
	*
	* My solution is a tad different from what I have seen online, probably
	* because my motivation is that I'd like to have my options open for
	* including the entities at a later point in time into hash tables, for

McUsr / field.c

Last active May 14, 2023 18:57

	/* 1987 (c) Stephen R. Bourne (from the Unix system V Environment).
	* I have been true to the style, except for adding typedeclarations in order
	* for it to compile without warnings on gcc (-std90?) without warnings.
	* McUsr 14.05.2023
	*/

	#include <stdio.h>

	#define MAXF 256

McUsr / field.1

Created May 14, 2023 18:50

	.TH FIELD 1 1987-1-1
	.SH NAME
	\fBfield\fR \(en select fields or columns from a file.
	.SH SYNOPSIS
	\fBfield\fR [\fB n \fR] \fI...\fR
	.SH DESCRIPTION
	The \fBfield\fR command copies specified, tab-separated fields from the
	standard input to the standard output. Fields are numbered from 1
	and a field may be requested more than once.
	.SH BUGS

McUsr / chunk.c

Last active May 12, 2023 10:28

Chunk.c prints chunks from a text file.

	/* chunk.c A combination of head and tail for ease of use.
	* A derivation of an exercise of writing a tail command in K&R.
	*
	* Thank you u/xkcd__386 for pointing out flaws in the comments.
	*
	* The largest chunk can be MAXLINES long, and files can be arbitrarily long
	* (in lines). (see show_help())
	*
	* Arguments:
	*

Tommy Bollman McUsr