mirror of
https://git.ari.lt/ari.lt/ari.lt.git
synced 2025-02-04 17:49:24 +01:00
update @ Thu 20 Jan 17:13:29 EET 2022
Signed-off-by: Ari Archer <truncateddinosour@gmail.com>
This commit is contained in:
Ari Archer
parent
e07bc9774b
commit
7b00b3bb81
4 changed files with 88 additions and 124 deletions
80
page/blog/blogs/Fast-atoi()-in-c-and-c++_-8139771109.html
Normal file
80
page/blog/blogs/Fast-atoi()-in-c-and-c++_-8139771109.html
Normal file
|
|
@ -0,0 +1,80 @@
|
|||
<!DOCTYPE html>
|
||||
<html lang="en">
|
||||
<head>
|
||||
<meta charset="utf-8" />
|
||||
<meta content="IE=edge" http-equiv="X-UA-Compatible" />
|
||||
<meta content="width=device-width, initial-scale=1.0" name="viewport" />
|
||||
<title>Ari::web -> Blog</title>
|
||||
<meta
|
||||
content="website webdev linux programming ari terminal dark blog javascript opensource free"
|
||||
name="keywords"
|
||||
/>
|
||||
<meta
|
||||
content="Blog on 2022-01-20 17:10:10 EET - Fast atoi() in C and C++"
|
||||
name="description"
|
||||
/>
|
||||
<meta content="follow" name="robots" />
|
||||
</head>
|
||||
<body>
|
||||
<div>
|
||||
<h1>Fast atoi() in C and C++</h1>
|
||||
<p>
|
||||
2022-01-20 17:10:10 EET |
|
||||
<a href=".."> back </a>
|
||||
|
|
||||
<a href="/"> home </a>
|
||||
|
|
||||
<a href="/git"> git </a>
|
||||
</p>
|
||||
<hr />
|
||||
|
||||
<p>
|
||||
<code>std::atoi</code> (in C++) is fast on its own but can be slow so
|
||||
for stuff you need speed you can use this:
|
||||
</p>
|
||||
<ul>
|
||||
<li>Option one</li>
|
||||
</ul>
|
||||
<pre><code><span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">fast_atoi</span>(<span class="hljs-params"><span class="hljs-keyword">const</span> <span class="hljs-keyword">char</span> *int_string</span>) </span>{
|
||||
<span class="hljs-keyword">int</span> <span class="hljs-keyword">value</span> = <span class="hljs-number">0</span>;
|
||||
|
||||
<span class="hljs-keyword">while</span> (*int_string && *int_string >= <span class="hljs-string">'0'</span> && *int_string <= <span class="hljs-string">'9'</span>)
|
||||
<span class="hljs-keyword">value</span> = <span class="hljs-keyword">value</span> * <span class="hljs-number">10</span> + (*int_string++ - <span class="hljs-string">'0'</span>);
|
||||
|
||||
<span class="hljs-keyword">return</span> <span class="hljs-keyword">value</span>;
|
||||
}
|
||||
</code></pre>
|
||||
<p>
|
||||
This requires no headers, just pure C (also valid in C++), you can put
|
||||
this into your code and it will just work!
|
||||
</p>
|
||||
<ul>
|
||||
<li>Option two</li>
|
||||
</ul>
|
||||
<pre><code><span class="hljs-meta">#include <assert.h></span>
|
||||
|
||||
<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">fast_atoi</span>(<span class="hljs-params"><span class="hljs-keyword">char</span> *int_string</span>) </span>{
|
||||
<span class="hljs-keyword">int</span> <span class="hljs-keyword">value</span> = <span class="hljs-number">0</span>;
|
||||
|
||||
<span class="hljs-keyword">while</span> (*int_string) {
|
||||
<span class="hljs-keyword">if</span> (!(*int_string >= <span class="hljs-string">'0'</span> && *int_string <= <span class="hljs-string">'9'</span>))
|
||||
assert(<span class="hljs-number">0</span> && <span class="hljs-string">"atoi(): invalid int_string"</span>);
|
||||
|
||||
<span class="hljs-keyword">value</span> = <span class="hljs-keyword">value</span> * <span class="hljs-number">10</span> + (*int_string++ - <span class="hljs-string">'0'</span>);
|
||||
}
|
||||
|
||||
<span class="hljs-keyword">return</span> <span class="hljs-keyword">value</span>;
|
||||
}
|
||||
</code></pre>
|
||||
<p>
|
||||
This option is throws an assertion error if it encounters an invalid
|
||||
string but this requires <code>assert.h</code> as a dependency.
|
||||
</p>
|
||||
<p>
|
||||
In C++ <code>assert.h</code> should be replaced with
|
||||
<code>cassert</code>.
|
||||
</p>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
<!-- this is automatically generated by scripts/add_blog -->
|
||||
|
|
@ -1,116 +0,0 @@
|
|||
<!DOCTYPE html>
|
||||
<html lang="en">
|
||||
<head>
|
||||
<meta charset="utf-8"/>
|
||||
<meta content="IE=edge" http-equiv="X-UA-Compatible"/>
|
||||
<meta content="width=device-width, initial-scale=1.0" name="viewport"/>
|
||||
<title>
|
||||
Ari::web -> Blog
|
||||
</title>
|
||||
<meta content="website webdev linux programming ari terminal dark blog javascript opensource free" name="keywords"/>
|
||||
<meta content="Blog on 2022-01-20 16:58:31 EET - Fast atoi in C(++)" name="description"/>
|
||||
<meta content="follow" name="robots"/>
|
||||
</head>
|
||||
<body>
|
||||
<div>
|
||||
<h1>
|
||||
Fast atoi in C(++)
|
||||
</h1>
|
||||
<p>
|
||||
2022-01-20 16:58:31 EET |
|
||||
<a href="..">
|
||||
back
|
||||
</a>
|
||||
|
|
||||
<a href="/">
|
||||
home
|
||||
</a>
|
||||
|
|
||||
<a href="/git">
|
||||
git
|
||||
</a>
|
||||
</p>
|
||||
<hr/>
|
||||
<p>
|
||||
<code>
|
||||
std::atoi
|
||||
</code>
|
||||
(in C++) is fast on its own but can be slow
|
||||
so for stuff you need speed you can use this:
|
||||
</p>
|
||||
<ul>
|
||||
<li>
|
||||
Option one
|
||||
</li>
|
||||
</ul>
|
||||
<p>
|
||||
```
|
||||
int fast_atoi(const char *int_string) {
|
||||
int value = 0;
|
||||
</p>
|
||||
<pre><code>while (*int_string && *int_string >= '0' && *int_string <= '9')
|
||||
value = value * 10 + (*int_string++ - '0');
|
||||
|
||||
return value;
|
||||
</code></pre>
|
||||
<p>
|
||||
}
|
||||
```
|
||||
</p>
|
||||
<p>
|
||||
This requires no headers, just pure C (also valid in C++),
|
||||
you can put this into your code and it will just work!
|
||||
</p>
|
||||
<ul>
|
||||
<li>
|
||||
Option two
|
||||
</li>
|
||||
</ul>
|
||||
<p>
|
||||
```
|
||||
</p>
|
||||
<h1>
|
||||
include
|
||||
<assert.h>
|
||||
</assert.h>
|
||||
</h1>
|
||||
<p>
|
||||
int fast_atoi(char *int_string) {
|
||||
int value = 0;
|
||||
</p>
|
||||
<pre><code>while (*int_string) {
|
||||
if (!(*int_string >= '0' && *int_string <= '9'))
|
||||
assert(0 && "atoi(): invalid int_string");
|
||||
|
||||
value = value * 10 + (*int_string++ - '0');
|
||||
}
|
||||
|
||||
return value;
|
||||
</code></pre>
|
||||
<p>
|
||||
}
|
||||
```
|
||||
</p>
|
||||
<p>
|
||||
This option is throws an assertion error if it encounters an
|
||||
invalid string but this requires
|
||||
<code>
|
||||
assert.h
|
||||
</code>
|
||||
as a dependency.
|
||||
</p>
|
||||
<p>
|
||||
In C++
|
||||
<code>
|
||||
assert.h
|
||||
</code>
|
||||
should be replaced with
|
||||
<code>
|
||||
cassert
|
||||
</code>
|
||||
.
|
||||
</p>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
<!-- this is automatically generated by scripts/add_blog -->
|
||||
|
|
@ -16,7 +16,7 @@
|
|||
My blogs
|
||||
</h1>
|
||||
<code>
|
||||
Last updated on: 2022-01-20 16:58:31 EET
|
||||
Last updated on: 2022-01-20 17:10:10 EET
|
||||
</code>
|
||||
<div>
|
||||
<ul>
|
||||
|
|
@ -136,8 +136,8 @@
|
|||
</a>
|
||||
</li>
|
||||
<li>
|
||||
<a href="/page/blog/blogs/Fast-atoi-in-c(++)_8279372928.html">
|
||||
Fast atoi in C(++)
|
||||
<a href="/page/blog/blogs/Fast-atoi()-in-c-and-c++_-8139771109.html">
|
||||
Fast atoi() in C and C++
|
||||
</a>
|
||||
</li>
|
||||
</ul>
|
||||
|
|
|
|||
|
|
@ -21,4 +21,4 @@
|
|||
* [New domain! -- ari-web.xyz](/page/blog/blogs/New-domain!----ari-web.xyz_7375640347.html)
|
||||
* [Funny thing about my site](/page/blog/blogs/Funny-thing-about-my-site_6342443591.html)
|
||||
* [Fixing kernel freezing on realtek WiFi](/page/blog/blogs/Fixing-kernel-freezing-on-realtek-wifi_5342268108.html)
|
||||
* [Fast atoi in C(++)](/page/blog/blogs/Fast-atoi-in-c(++)_8279372928.html)
|
||||
* [Fast atoi() in C and C++](/page/blog/blogs/Fast-atoi()-in-c-and-c++_-8139771109.html)
|
||||
Loading…
Add table
Reference in a new issue