How to implement hexadecimal conversion and bit filling in php

PHP is a server-side scripting language widely used in the field of Web development. Processing number operations is also an important part of PHP. In digital operations, base conversion and complement are two key concepts. This article will introduce in detail the base conversion and padding operations in PHP to help readers better understand and use these two operations.

1. Base conversion

1.1 Convert decimal to other bases

PHP provides functions for converting decimal numbers to other bases, the most commonly used of which is decbin (), decoct() and dechex() functions. These functions convert decimal numbers into binary, octal, and hexadecimal strings respectively, and return the results.

The sample code is as follows:

$decimal_num = 35;
$bin_num = decbin($decimal_num);  // 二进制
$oct_num = decoct($decimal_num);  // 八进制
$hex_num = dechex($decimal_num);  // 十六进制
echo "{$decimal_num}的二进制是：{$bin_num}\n";  // 输出35的二进制
echo "{$decimal_num}的八进制是：{$oct_num}\n";  // 输出35的八进制
echo "{$decimal_num}的十六进制是：{$hex_num}\n";  // 输出35的十六进制

The output result is as follows:

35的二进制是：100011
35的八进制是：43
35的十六进制是：23

1.2 Converting other bases to decimal

is similar to converting decimal numbers to other bases Corresponding to the operation of converting other base numbers to decimal, PHP also provides corresponding functions, namely bindec(), octdec() and hexdec() functions. These functions convert binary, octal, and hexadecimal strings to decimal integers and return the results.

The sample code is as follows:

$bin_num = '100011';
$oct_num = '43';
$hex_num = '23';
$decimal_num_from_bin = bindec($bin_num);  // 二进制转十进制
$decimal_num_from_oct = octdec($oct_num);  // 八进制转十进制
$decimal_num_from_hex = hexdec($hex_num);  // 十六进制转十进制
echo "{$bin_num}的十进制是：{$decimal_num_from_bin}\n";  // 输出二进制的十进制转换结果
echo "{$oct_num}的十进制是：{$decimal_num_from_oct}\n";  // 输出八进制的十进制转换结果
echo "{$hex_num}的十进制是：{$decimal_num_from_hex}\n";  // 输出十六进制的十进制转换结果

The output result is as follows:

100011的十进制是：35
43的十进制是：35
23的十进制是：35

2. Fill-in operation

In computers, digital storage and operations are often performed in binary proceed in form. Sometimes we need to "fill" binary numbers, that is, fill in the highest bit with 0 or 1 to meet the calculation requirements of certain types of arithmetic operations. The bitset library provided in PHP can complete such "bit filling" operations.

2.1 Install the bitset library

To use the bitset library, you need to install the library first. The installation steps are as follows:

Step 1: Execute the following command in the terminal to install the bitset library:

composer require lucasassis/bitset

Step 2: Reference the autoloader automatically generated by composer in the code:

require 'vendor/autoload.php';

2.2 Create a bit set

Before using the bitset library to perform bit filling operations, you need to create a bit set (i.e. bitset) first. A bit set is a collection of sequential bits, where each bit is a binary symbol 0 or 1.

The function to create a bit set is BitSet::create(), and its parameter is the total number of bits, which can be an integer or a string.

The sample code is as follows:

use Lucasassis\BitSet;

$num_of_bits = 8;  // 位数
$bitset = BitSet::create($num_of_bits);  // 创建8位的bitset
echo "创建的{$num_of_bits}位bitset为：{$bitset}\n";

The output result is as follows:

创建的8位bitset为：00000000

2.3 Fill-in operation

With the bit set, the fill-in operation can be performed . For example, in the calculation of binary addition 1, the operand (that is, the number to be added 1) needs to be "returned and added 1" to produce the correct result of adding 1.

The sample code is as follows:

use Lucasassis\BitSet;

$num_of_bits = 8;  // 位数
$number = 35;  // 要进行加1操作的数字
$bitset = BitSet::create($num_of_bits);  // 创建8位的bitset
$bitset->setValue($number);  // 将$number值存入bitset中
echo "原数字：{$number}，补位结果：";
echo $bitset->not()->add(1)->asBinaryString();  // 取反加1，输出结果

The output result is as follows:

原数字：35，补位结果：00100010

In the above code, the BitSet::setValue() function is used to store the number in the carry set, using The BitSet::not() function performs the inversion operation, the BitSet::add() function is used to perform the increment operation, and the BitSet::asBinaryString() function is used to output the binary string result.

3. Summary

This article introduces the base conversion and bit filling operations in PHP. Base conversion is an important concept in computer operations and plays an important role in the representation and processing of digital data. The fill-in operation is an operation often used in specific algorithms to improve the results of digital data operations. I hope this article can help readers better understand and apply these two operations.

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