Data Compression

Only when the market data is returned after subscription, the remote service will compress the data and return it to the client. The remote service returns data in two formats, Binary format and Text format. When the binary format is returned, the data has been compressed by the remote service and the client needs to decompress it.

Compression Introduction

zlib is a library for data compression, developed by Jean-loup Gailly and Mark Adler. The first version (v0.9) was published on May 1, 1995. zlib uses the abstract DEFLATE algorithm, originally written for the libpng library, and later generally used by many software. This library is free. Official link http://zlib.net/

Decompression Example

Sample Code

import zlib

message = b'abcd1234'
compressed = zlib.compress(message)
decompressed = zlib.decompress(compressed).decode('UTF-8')
print(decompressed) # abcd1234
import java.util.zip.*;
try {
     // Encode a String into bytes
     String inputString = "blahblahblah";
     byte[] input = inputString.getBytes("UTF-8");

     // Compress the bytes
     byte[] output = new byte[100];
     Deflater compresser = new Deflater(true);
     compresser.setInput(input);
     compresser.finish();
     int compressedDataLength = compresser.deflate(output);
     compresser.end();

     // Decompress the bytes
     Inflater decompresser = new Inflater(true);
     decompresser.setInput(output, 0, compressedDataLength);
     byte[] result = new byte[100];
     int resultLength = decompresser.inflate(result);
     decompresser.end();

     // Decode the bytes into a String
     String outputString = new String(result, 0, resultLength, "UTF-8");
 } catch(java.io.UnsupportedEncodingException ex) {
     // handle
 } catch (java.util.zip.DataFormatException ex) {
     // handle
 }

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