Go: Php Park, Unpark, Ord function using method (binary stream Interface application example)

At work, I also learned that Park,unpark,ord is powerful for binary byte processing.  Let me introduce them to you. Park,unpark,ord These 3 functions, in our work, they are estimated to be few. I am in a recent job, because the communication needs to use the binary stream, and then the interface is received in PHP. At that time, a lot of information was consulted. Because they are really less used, they are seldom used by friends in their work. At work, I also learned that Park,unpark,ord is powerful for binary byte processing. Let me introduce them to you.

Introduction to the use of Park,unpark,ord functions

Park Function Description : This function is used to compress data into a string in place.

Syntax : Pack (format,args+)

Parameters	Describe
Format	Necessary. Specifies the format to use when wrapping the data.
args+	Optional. Specifies one or more parameters that are packaged.

Character	Description
A	Fills the string blank with a NULL character
A	Fills the string blank with space characters (spaces)
H	16 string, low in front
H	16 string, high in front
C	Character with number
C	No number character
S	Number of short integers (16 bits, depending on the computer's bit order)
S	No number short integer (16 bits, depending on the computer's bit order)
N	unsigned short integers (16-bit, high-order in the back)
V	No number short integers (16 bits, low in the back order)
I	Number of integers (depending on the order and scope of the computer)
I	unsigned integers (depending on the computer's order and range)
L	Number of long integers (32 bits, depending on the computer's bit order)
L	unsigned long integers (32 bits, depending on the computer's bit order)
N	unsigned short integers (32-bit, high-order in the back)
V	No number short integers (32 bits, low in the back order)
F	Single-precision floating-point number (depending on the computer's range)
D	Times the exact floating point number (depending on the computer's range)
X	Vacancy
X	Rewind One
@	Fill in the NULL character to the absolute position

unpark Function Description: This function is used to extract the data of the bit string

Syntax : Unpack (format,args+)

Parameters	Describe
Format	Necessary. Specifies the format to use when wrapping the data.
args+	Optional. Specifies one or more parameters that are packaged.

The parameters are the same as park.

Ord function Description: Returns the Acill code value of the corresponding character

Syntax : Ord ($character);

Example Description:

Copy CodeThe code is as follows:
<?php
A character
$str = (Pack ("A *", "China"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);
H character
$str = (Pack ("h*", "Fffe"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);
C character
$str = (Pack ("c*", "55", "56", "57"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);

I-character short-shaped 32-bit 4-byte 64-bit 8-byte
$str = (Pack ("I", "100"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);

s character short shaping 2 bytes
$str = (Pack ("s", "100"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);

L character-length shaping 4 bytes
$str = (Pack ("L", "100"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);

F-character single-precision floating-point 4 bytes
$str = (Pack ("F", "100"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);

D-character double-precision floating-point 8 bytes
$str = (Pack ("D", "100"));
echo $str, "=", strlen ($STR), "Byte \ n";
Getascill ($STR);

function Getascill ($STR)
{
$arr =str_split ($STR);
foreach ($arr as $v)
{
echo $v, "=", Ord ($v), "\ n";
}
echo "=============\r\n\r\n";
}

With the above example, we can see that the same string, stored in a different format, consumes a different number of bytes. It can also be seen here that saving characters in different formats can save space for storage. and start the unreadable encryption effect. Suddenly think of a bit, Design database field type problems, if a field is just: 10-bit length integer type. We set it to reshape: 256*256*256*256 is 4 bytes, if set to 10 length string. That accounts for 10 bytes. The whole digestive space is twice times the size. Setting the correct character type is a great help in improving database performance. Oh, a little off-topic ...

A case analysis of PHP processing byte code communication
Just said pack function: space-saving, encrypted format

Here are 2 examples to illustrate, interface development requirements:

Parameters	Describe
User name	20 bytes, character type
Password	10 bytes, Character type
Age	1 bytes, no character char type
Date of birth	4 bytes, integer (19800101)
Mailbox	50 bytes, string
Between fields: "\" split

A, pack Packaging
Copy CodeThe code is as follows:
<?php
$code =array (
"Username" =>array ("A20", "Zhang San Adfb12"),
"Pass" =>array ("A10", "asdf* #1"),
"Age" =>array ("C", "23"),
"Birthday" =>array ("I", "19900101"),
"Email" =>array ("A50", "[email protected]"));

$stream =join ("n", Parkbyarr ($code));
Echo $stream, strlen ($stream);

Copy CodeThe code is as follows:
File_put_contents ("C:/1.txt", $stream);//Save the stream for easy reading below

function Parkbyarr ($arr)
{
$ATARR =array ();
foreach ($arr as $k = $v)
{
$ATARR []=pack ($v [0], $v [1]);
}
return $ATARR;
}
function Getascill ($STR)
{
$arr =str_split ($STR);
foreach ($arr as $v)
{
echo $v, "=", Ord ($v), "\ n";
}
}
The entire length is 89 bytes, because it is split with "\". With the above output, some string output can be read, the others have become garbled. This is what I said can be kept secret effect reason.
B, unpack unpacking
The unpacking needs to be read in a packaged manner, the length of the read, what type to read, and the same as the packing rules.
Copy CodeThe code is as follows:
<?php
$code =array (
"Username" =>array ("A20"),
"Pass" =>array ("A10"),
"Age" =>array ("C"),
"Birthday" =>array ("I"),
"Email" =>array ("A50"));
$stream =file_get_contents ("C:/1.txt");
Var_dump (Parkbyarr ($stream, $code));
function Parkbyarr ($STR, $code)
{
$ARR =explode ("n", $str);
$ATARR =array ();
$i = 0;
foreach ($code as $k = $v)
{
$ATARR [$k]=unpack ($v [0], $ARR [$i]);
$i + +;
}
return $ATARR;
}

Go: Php Park, Unpark, Ord function using method (binary stream Interface application example)