## What is the command to decompress the files in Windows command line?

I have zip files that contain multiple xml files, I need to extract them using the command.

## information theory – decompress a flat file database on the fly

I face the following problem. I have a flat file database (eg CSV).
Since it is relatively large to store in memory, I would like to compress it.

Given a key, I have to return the uncompressed text (saving values).

So a naive idea is to symbolize the text in words and to have the mapping $$text {word} mapsto text {codeword}$$

Of course, this naive idea lacks understanding of the statistical properties of data, which other compression algorithms exploit.

So the next thing I thought of was the Huffman code. The problem I am facing is that I would like to find the optimal tokenization for the text. Let's say that a column in the CSV file only contains the text "the fox jumped over the lazy dog", it is reasonable to want the algorithm to tokenize this chain into a single token.

but then again, going over all the possibilities is not an achievable task.
Are there algorithms that deal with this problem?

So, to summarize, I have to:

1. Compress my data once and decompress on demand
2. Returns the requested value (a record) for a given key
3. Decompression should be "fairly quick"

Which algorithms correspond to my problem?

In particular, I would like to know if the Huffman code is a good option, and if so, how to tokenize the text.

Thank you!

## How to decompress a public key?

Points are decompressed by solving `y` in the equation used for the elliptical curve of secp256k1 where `x` is the last 32 bytes of your public key. The equation is `y^2 = x^3 + 7`. You will have 2 possible `y` values, a pair and an odd. The correct one is indicated by the prefix byte of your public key which indicates whether `y` is even or odd.

Note that all operations must be modulo `p` which is defined by the secp256k1 specification as `0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F`.

This python script will decompress the two public keys that you have published:

``````#! /usr/bin/env python3

import binascii

p = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F

def decompress_pubkey(pk):
x = int.from_bytes(pk(1:33), byteorder='big')
y_sq = (pow(x, 3, p) + 7) % p
y = pow(y_sq, (p + 1) // 4, p)
if y % 2 != pk(0) % 2:
y = p - y
y = y.to_bytes(32, byteorder='big')
return b'x04' + pk(1:33) + y

print(binascii.hexlify(decompress_pubkey(binascii.unhexlify('0229b3e0919adc41a316aad4f41444d9bf3a9b639550f2aa735676ffff25ba3898'))).decode())
print(binascii.hexlify(decompress_pubkey(binascii.unhexlify('02f15446771c5c585dd25d8d62df5195b77799aa8eac2f2196c54b73ca05f72f27'))).decode())

``````

The uncompressed public keys are:

``````0429b3e0919adc41a316aad4f41444d9bf3a9b639550f2aa735676ffff25ba3898d6881e81d2e0163348ff07b3a9a3968401572aa79c79e7edb522f41addc8e6ce
04f15446771c5c585dd25d8d62df5195b77799aa8eac2f2196c54b73ca05f72f274d335b71c85e064f80191e1f7e2437afa676a3e2a5a5fafcf0d27940cd33e4b4
``````

Pubkey decompression is completely different and unrelated to address generation. Addresses are generated by taking a public key as is (compressed or not) by hashing it, then coding it. Compression is important because the resulting serialized public will produce a hash (and therefore an address) when it is compressed, and a different hash (and therefore a different address) when it is not compressed.

The addresses are coded by hashing the public key serialized with SHA256 then with RIPEMD160. The resulting hash is encoded using Base58 Check encoding.

In the transaction you provided, the three public keys:

``````04ad90e5b6bc86b3ec7fac2c5fbda7423fc8ef0d58df594c773fa05e2c281b2bfe877677c668bd13603944e34f4818ee03cadd81a88542b8b4d5431264180e2c28
0229b3e0919adc41a316aad4f41444d9bf3a9b639550f2aa735676ffff25ba3898
02f15446771c5c585dd25d8d62df5195b77799aa8eac2f2196c54b73ca05f72f27
``````

have respectively the following hashes:

``````946cb2e08075bcbaf157e47bcb67eb2b2339d242
55af2ea3c45819c6c5ae710d29fcaaced5b00cc7
8b38a8d40e08362046dee55c1c94e7991d7dec75
``````

Encoding of these addresses in version 0 with Base 58 Check the encoding results in the addresses you expect:

``````1EXoDusjGwvnjZUyKkxZ4UHEf77z6A5S4P
18p4JBHP3EAKCc4jqN8XzuEJtvq8G9NAot
1Dh8oSChJWZQx5sr7ePsBNtw7uKMsNnYNC
``````

The code I used for this is:

``````#! /usr/bin/env python3

import binascii
import hashlib

b58_digits = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'

def sha256(s):
return hashlib.new('sha256', s).digest()

def ripemd160(s):
return hashlib.new('ripemd160', s).digest()

def hash256(s):
return sha256(sha256(s))

def hash160(s):
return ripemd160(sha256(s))

def encode(b):
# Convert big-endian bytes to integer
n = int('0x0' + binascii.hexlify(b).decode('utf8'), 16)

# Divide that integer into bas58
res = ()
while n > 0:
n, r = divmod (n, 58)
res.append(b58_digits(r))
res = ''.join(res(::-1))

# Encode leading zeros as base58 zeros
import sys
czero = b'x00'
if sys.version > '3':
# In Python3 indexing a bytes returns numbers, not characters.
czero = 0
pad = 0
for c in b:
if c == czero: pad += 1
else: break
return b58_digits(0) * pad + res

def to_address(b, version):
data = version + b
checksum = hash256(data)(0:4)
data += checksum
return encode(data)

pk1 = binascii.unhexlify("0229b3e0919adc41a316aad4f41444d9bf3a9b639550f2aa735676ffff25ba3898")
pk2 = binascii.unhexlify("02f15446771c5c585dd25d8d62df5195b77799aa8eac2f2196c54b73ca05f72f27")
pk3 = binascii.unhexlify("04ad90e5b6bc86b3ec7fac2c5fbda7423fc8ef0d58df594c773fa05e2c281b2bfe877677c668bd13603944e34f4818ee03cadd81a88542b8b4d5431264180e2c28")

h1 = hash160(pk1)
h2 = hash160(pk2)
h3 = hash160(pk3)

print(to_address(h3, b'x00'))
print(to_address(h1, b'x00'))
print(to_address(h2, b'x00'))
``````

(Base58 encoding function from https://github.com/bitcoin-core/HWI/blob/master/hwilib/base58.py)

As you can see, this does not compress or decompress points. Rather, it takes the public key as it is and encodes it.

## rom – Unable to properly decompress android 10 boot.img

Devices: sanders and rolex

Unpacking / repackaging boot.img was fine until android 9 on most roms.

But, impossible to decompress "boot.img" from android 10 roms,
tried boot.img of Android 10 based on Havoc, Lineage etc.

want to modify "init.rc"
but only by getting the "init" file and some empty folders like

"

Using Android.Image.Kitchen.v3.6-Win32.

## c # – The message box appears at a specific time that the user enters with a digital decompress

``````private void RemindButton_Click(object sender, EventArgs e)
{
string FinalMessage = "";

//add text from the radio buttons

if (MathRadioButton.Checked == true)
{
FinalMessage += MathRadioButton.Text;
}

if (HistoryRadioButton.Checked == true)
{
FinalMessage += HistoryRadioButton.Text;
}

if (EnglishRadioButton.Checked == true)
{
FinalMessage += EnglishRadioButton.Text;
}

if (ScienceRadioButton.Checked == true)
{
FinalMessage += ScienceRadioButton.Text;
}

if (ElectiveRadioButton.Checked == true)
{
FinalMessage += ElectiveRadioButton.Text;
}

FinalMessage += " work from ";
string Teacher_Name = TeacherNameTextBox.Text;
FinalMessage += Teacher_Name + " is due on ";

string Month = MonthNumericUpDown.Value.ToString();
string Day = DayNumericUpDown.Value.ToString();
string Str_Time = TimeNumericUpDown.Value.ToString();
// int Int_Time = (int)TimeNumericUpDown.Value;

FinalMessage += Month + "https://stackoverflow.com/" + Day + " at " + Str_Time;
FinalMessage += " and is about " + DescriptionTextBox.Text;

MessageBox.Show(FinalMessage);

}
``````

So, I stored it in by the button, which simply concatenates all the user entries. You still do not know how to display a message box at a specific time, set by the user with a numeric countdown and the use of DateTime.

## unit – How can I decompress texture data in a 16 * 8 bit model?

Is it possible to decompress the texture data by following a specific bit packaging scheme?

I read that texture data in HLSL can be read as 4 32-bit floats totaling 128 bits. The packaging scheme I am trying to use is 16 packing groups of 8 bits each. I can not understand how to decompress this data without loss because they are interpreted as floating files.

## command line – how to decompress a zip file by creating a new folder on the path specified under linux

I have to decompress a file, I do not want a CD, then run mkdir newfolder then go back to the folder where the zip file is located, then run unzip file.zip / home / user / newfolder

I just want to run the command from the directory whatever directory I am, it will create the folder for me or ask me on the location / home / user, there is no newfolder directory, do you want to create one (Y / n)? and chose it for there
(it does not matter if this operation requires root access)

I've checked unzip swtiches and google, but in all the examples they make a directory then unzip the file in it

I'm using Debian Buster

## import – how to quickly decompress a zip file

What is the fastest way to uncompress zip files with the following content?

It contains numbered ".png" files, corresponding ".header" files (these are text files) and a file called "png_content.txt" (also a text file).

In reality, a zip file has a size of about 3 GB, each png file has a size of 1 MB, the header files are about 600 bytes and the "png_content.txt" has a size of about 200 KB.

What I have tried that fails:

``````dir = NotebookDirectory[];

setDirectory[dir];

data = Import["file.zip"];

len = Length[data];

Make[
element = Import["data.zip", data[[i]]];
Export[data[[i]], element];
Impression[data[[i]]];
, {i, 1, len}
]
``````

I see that I have to extract the file type one way or another, and then provide the information that the ".header" files are text files.

As mentioned, my zip files are relatively large. When I use winzip, it takes about 1 minute for my computer to decompress a 3.3 GB zip file (about 3,300 png files plus other text files).

I have a lot of these zip files that I would decompress one by one, would do something with the data contained and would continue with the following zip file.

Therefore, I need a quick solution to unzip a single zip file.

Here is a small example of a zip file: https://drive.google.com/open?id=1PvzxC2HKcSCLFL01i2jtOcjrV2ziqyAD