Hard coding: Difference between revisions

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{{Short description|Putting data in the source code of a program}}

{{redirect|Hardcoded|the video game|Hardcoded (video game)}}

{{More citations needed|date=May 2021}}

'''Hard coding''' (also '''hard-coding''' or '''hardcoding''') is the software development practice of embedding data directly into the [[source code]] of a [[computer program|program]] or other executable object, as opposed to obtaining the data from external sources or generating it at [[Run time (program lifecycle phase)|runtime]].

Hard-coded data typically can only be modified only by editing the source code and [[Compiling|recompiling]] the executable, although it can be changed in [[Volatile memory|memory]] or on disk using a [[debugger]] or [[hex editor]].

Data that is hard-coded is best suited for unchanging pieces of information, such as [[physical constant|physical constants]]s, [[Version number|version numbers]], and static text elements.

SoftcodedSoft-coded data, on the other hand, encodes arbitrary information through [[user input]], [[text files]], [[INI file]]s, HTTP server responses, configuration files, preprocessor macros, external constants, databases, [[command-line argument]]s, and is determined at runtime.

==Overview==

Hard coding requires the program's source code to be changed any time the input data or desired format changes, when it might be more convenient to the end user to change the detail by some means outside the program.<ref name="Dustin2002">{{cite book|author=Elfriede Dustin|title=Effective Software Testing: 50 Specific Ways to Improve Your Testing|url=https://books.google.com/books?id=K0qWBUOAf6IC&pg=PA188|year=2002|publisher=Addison-Wesley Professional|isbn=978-0-201-79429-8|pages=188–}}</ref>

Hard coding is often required, but can also be considered an [[anti-pattern]].<ref name="Janca2020">{{cite book|author=Tanya Janca|title=Alice and Bob Learn Application Security|url=https://books.google.com/books?id=UT4DEAAAQBAJ&pg=PA15|date=14 October 2020|publisher=Wiley|isbn=978-1-119-68740-5|pages=15–}}</ref> Programmers may not have a dynamic user interface solution for the end user worked out but must still deliver the feature or release the program. This is usually temporary but does resolve, in a short -term sense, the pressure to deliver the code. Later, softcodingsoft coding is done to allow a user to pass on parameters that give the end user a way to modify the results or outcome.

The term "hard-coded" was initially used as an analogy to hardwiring circuits -, and was meant to convey the inflexibility that results from its usage within software design and implementation.

In the context of run-time extensible [[collaborative development environment]]s such as [[Multi-user dungeon|MUD]]s, '''hardcoding'''hard coding also refers to developing the core engine of the system responsible for low-level tasks and executing [[Scripting language|scripts]], as opposed to '''softcodingsoft coding''' which is developing the high-level scripts that get interpreted by the system at [[Execution (computing)|runtime]], with values from external sources, such as [[text files]], [[INI file]]s, preprocessor [[Macro (computer science)|macro]]s, external constants, [[database]]s, [[command-line argument]]s, [[HTTP]] [[Server (computing)|server]] responses, [[configuration file]]s, and [[user input]]. In this case, the term is not pejorative and refers to general development, rather than specifically embedding output data.

== HardcodingHard coding and backdoors ==

HardcodingHard coding credentials is a popular way of creating a [[Backdoor (computing)|backdoor]]. HardcodedHard coded credentials are usually not visible in configuration files or the output of account-enumeration commands and cannot be easily changed or bypassed by users. If discovered, a user might be able to disable such a backdoor by modifying and rebuilding the program from its [[source code]] ([[FLOSS|if source is publicly available]]), [[decompiler|decompiling]], or [[reverse-engineering]] [[software]], [[hex editor|directly editing]] the program's [[binary code]], or instituting an integrity check (such as digital signatures, anti-tamper, and [[anti-cheat]]) to prevent the unexpected access, but such actions are often prohibited by an [[end-user license agreement]].

==HardcodingHard coding and DRM==

As a [[digital rights management]] measure, software developers may hardcodehard code a unique [[serial number]] directly into a program. Or it is common to hardcodehard code a [[public key]], creating the DRM for which it is infeasible to create a keygen.

On the opposite case, a software [[Softwaresoftware cracking|cracker]] may hard-code a valid serial number to the program or even prevent the executable from asking the user for it, allowing unauthorized copies to be redistributed without the need of entering a valid number, thus sharing the same key for every copy, if one has been hard-coded.

== Fixed installation path ==

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==Startup disk==

Some "[[copy protection|copy-protected]]" programs look for a particular file on a [[floppy disk]] or flash drive on startup to verify that they are not unauthorized copies. If the computer is replaced by a newer machine, which doesn't have a floppy drive, the program that requires it now can't be run since the floppy disk can't be inserted.

This last example shows why hard coding may turn out to be impractical even when it seems at the time that it would work completely. In the 1980s and 1990s, the great majority of PCs were fitted with at least one floppy drive, but floppy drives later fell out of use. A program hard-coded in that manner 15 years ago could face problems if not updated.

==Special folders==

Some Windows operating systems have so-called ''[[Special Folders]]'' which organize files logically on the hard disk. There are problems that can arise involving hard coding:

Some Windows programs hardcode the path to <code>[[My Documents]]</code> as <code>''ProfilePath''\My Documents</code>. These programs would work on machines running the English version, but on [[internationalization and localization|localized]] versions of Windows this folder normally has a different name. For example, in Italian versions the <code>My Documents</code> folder is named ''Documenti''. <code>My Documents</code> may also have been relocated using Folder Redirection in Group Policy in Windows 2000 or above. The proper way to get it is to call the <code>SHGetFolderPath</code> function.

===Profile path===

Some Windows programs hard code the profile path to developer-defined locations such as <code>C:\Documents and Settings\''Username''</code>. This is the path for the vast majority of [[Windows 2000]] or above, but this would cause an error if the profile is stored on a network or otherwise relocated. The proper way to get it is to call the <code>GetUserProfileDirectory</code> function or to resolve the <code>%userprofile%</code> [[environment variable]]. Another assumption that developers often make is assuming that the profile is located on a local hard disk.

===My Documents folder path===

Some Windows programs hardcodehard code the path to <code>[[My Documents]]</code> as <code>''ProfilePath''\My Documents</code>. These programs would work on machines running the English version, but on [[internationalization and localization|localized]] versions of Windows this folder normally has a different name. For example, in Italian versions the <code>My Documents</code> folder is named ''Documenti''. <code>My Documents</code> may also have been relocated using Folder Redirection in [[Group Policy]] in Windows 2000 or above. The proper way to get it is to call the <code>SHGetFolderPath</code> function.

==Solution==

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In rare cases where the possible number of inputs is small enough, a contestant might consider using an approach that maps all possible inputs to their correct outputs. This program would be considered a hard-coded solution as opposed to an [[algorithm]]ic one (even though the hard-coded program might be the output of an algorithmic program).

==SoftcodingSoft coding==

'''SoftcodingSoft coding''' is a [[computer programming|computer coding]] term that refers to obtaining a value or function from some external resource, such as [[text files]], [[INI file]]s, [[preprocessor]] [[Macro (computer science)|macros]], external constants, [[configuration file]]s, [[command-line argument]]s, databases, user input, HTTP server responses. It is the opposite of [[hardcoding]]hard coding, which refers to coding values and functions in the source code.

===Programming practice===

Avoiding hard coding of commonly altered values is good programming practice. Users of the software should be able to customize it to their needs, within reason, without having to edit the program's source code. Similarly, careful programmers avoid [[Magic number (programming)#Unnamed numerical constants|magic numbers]] in their code, to improve its readability, and assist maintenance. These practices are generally not referred to as ''softcodingsoft coding''.

The term is generally used where softcodingsoft coding becomes an [[anti-pattern]]. Abstracting too many values and features can introduce more complexity and maintenance issues than would be experienced with changing the code when required. SoftcodingSoft coding, in this sense, was featured in an article on [[The Daily WTF]].<ref>[http://thedailywtf.com/Articles/Soft_Coding.aspx Softcoding] from [[The Daily WTF]]</ref>

===Potential problems===

At the extreme end, soft-coded programs develop their own poorly designed and implemented scripting languages, and configuration files that require advanced programming skills to edit. This can lead to the production of utilities to assist in configuring the original program, and these utilities often end up being 'softcoded'soft coded themselves.

The boundary between proper configurability and problematic soft-coding changes with the style and nature of a program. Closed-source programs must be very configurable<!-- but generally aren't! -->, as the end user does not have access to the source to make any changes. In-house software and software with limited distribution can be less configurable, as distributing altered copies is simpler. Custom-built web applications are often best with limited configurability, as altering the scripts is seldom any harder than altering a configuration file. <!-- Witness the scores of CMS systems that are so much harder to work with than a bunch of html files in www/data! -->

To avoid softcodingsoft coding, consider the value to the end user of any additional flexibility you provide, and compare it with the increased complexity and related ongoing maintenance costs the added configurability involves.

===Achieving flexibility===

Several legitimate design patterns exist for achieving the flexibility that softcodingsoft coding attempts to provide. An application requiring more flexibility than is appropriate for a configuration file may benefit from the incorporation of a [[scripting language]]. In many cases, the appropriate design is a [[___domain-specific language]] integrated into an established scripting language. Another approach is to move most of an application's functionality into a library, providing an API for writing-related applications quickly.

==See also==