php短网址算法实例代码分享

php实现的短网址算法,理论上支持1,073,741,824个短网址。

每个网址用6个字符代替，(6^32) 最多可以拥有1,073,741,824个短网址。
当然，你还可以记录更详细的信息，如访问记录，创建时间等。
如果真不够用了，还可以删掉很久不用的。

<span>function</span> shorturl(<span>$input</span><span>) {
</span><span>$base32</span> = <span>array</span><span> (
</span>'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', '0', '1', '2', '3', '4', '5'<span>
);

</span><span>$hex</span> = <span>md5</span>(<span>$input</span><span>);
</span><span>$hexLen</span> = <span>strlen</span>(<span>$hex</span><span>);
</span><span>$subHexLen</span> = <span>$hexLen</span> / 8<span>;
</span><span>$output</span> = <span>array</span><span>();

</span><span>for</span> (<span>$i</span> = 0; <span>$i</span> < <span>$subHexLen</span>; <span>$i</span>++<span>) {
</span><span>$subHex</span> = <span>substr</span> (<span>$hex</span>, <span>$i</span> * 8, 8<span>);
</span><span>$int</span> = 0x3FFFFFFF & (1 * ('0x'.<span>$subHex</span><span>));
</span><span>$out</span> = ''<span>;

</span><span>for</span> (<span>$j</span> = 0; <span>$j</span> < 6; <span>$j</span>++<span>) {
</span><span>$val</span> = 0x0000001F & <span>$int</span><span>;
</span><span>$out</span> .= <span>$base32</span>[<span>$val</span><span>];
</span><span>$int</span> = <span>$int</span> >> 5<span>;
}

</span><span>$output</span>[] = <span>$out</span><span>;
}

</span><span>return</span> <span>$output</span><span>;
}</span>

测试代码：

<span>$input</span> = 'http://www.jbxue.com/1'<span>;
</span><span>$output</span> = shorturl(<span>$input</span><span>);

</span><span>echo</span> "Input : <span>$input</span>\n"<span>;
</span><span>echo</span> "Output : {<span>$output</span>[0]}\n"<span>;
</span><span>echo</span> " {<span>$output</span>[1]}\n"<span>;
</span><span>echo</span> " {<span>$output</span>[2]}\n"<span>;
</span><span>echo</span> " {<span>$output</span>[3]}\n"<span>;
</span><span>echo</span> "\n"<span>;

</span><span>$input</span> = 'http://www.jbxue.com/2'<span>;
</span><span>$output</span> = shorturl(<span>$input</span><span>);

</span><span>echo</span> "Input : <span>$input</span>\n"<span>;
</span><span>echo</span> "Output : {<span>$output</span>[0]}\n"<span>;
</span><span>echo</span> " {<span>$output</span>[1]}\n"<span>;
</span><span>echo</span> " {<span>$output</span>[2]}\n"<span>;
</span><span>echo</span> " {<span>$output</span>[3]}\n"<span>;
</span><span>echo</span> "\n";

输出：

Input : http://www.jbxue.com/1
Output : h0xg4r
bdr3tw
osk2d3
4azfqa

Input : http://www.jbxue.com/2
Output : tm5kxb
ceoj2s
yw3dvl
nrmrxl

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