dvpl

README

dvpl-go | A package for Go to work with DVPL compression format.

Overview

World of Tanks Blitz and Tanks Blitz use a custom compression format named DVPL that is actually a LZ4 compression, usually of a level 2 with the exception of level 0 for .tex files, with the addition of a special footer. This package is made to work with this format, namely to convert files in and out of DVPL format.

What's inside?

There are one struct and three functions available:

type DVPLFooterData struct {
	OriginalSize   uint32 // The original size of the content.
	CompressedSize uint32 // The compressed size of the content without footer.
	CRC32          uint32 // The CRC32 hash sum of the content without footer.
	CompressType   uint32 // The compression type used. Usually is 2, with the exception of 0 for .tex files.
}

// Read a DVPL footer from the given byte array and return the DVPLFooterData struct type,
// or return an error if no valid DVPL footer is present in the given byte array.
func ReadDVPLFooterData(buf []byte) (DVPLFooterData, error)

// Compress the given byte array using HC_2 compression, or no compression if noCompression is specified,
// add a DVPL footer and return the resulting byte array, or return an error if the compression algorithm fails.
func CompressDVPL(buf []byte, noCompression bool) ([]byte, error)

// Decompress the given byte array and return the decompressed byte array,
// or return an error if the given byte array is not a valid DVPL.
func DecompressDVPL(buf []byte) ([]byte, error)

Install

Assuming you have the go toolchain installed

go get github.com/Endg4meZer0/dvpl-go

Usage

file, err := os.ReadFile(path)
if err != nil {
  fmt.Fprintf(os.Stderr, "An unknown error occured when trying to read %s. An issue with permissions?", path)
  return
}

var convertedFile []byte
var newPath string

if decompressMode {
  convertedFile, err = dvpl.DecompressDVPL(file)
  var hasSuffix bool
  newPath, hasSuffix = strings.CutSuffix(path, ".dvpl")
  if !hasSuffix {
    newPath = path + ".nodvpl"
  }
} else {
  convertedFile, err = dvpl.CompressDVPL(file, strings.HasSuffix(path, ".tex"))
  newPath = path + ".dvpl"
}

if err != nil {
  fmt.Fprintf(os.Stderr, "An error occured during the conversion of the file %s:\n%s", path, err.Error())
  return
}
os.WriteFile(newPath, convertedFile, 0777)

Documentation

Index

• func CompressDVPL(buf []byte, noCompression bool) ([]byte, error)
• func DecompressDVPL(buf []byte) ([]byte, error)
• type DVPLFooterData
  • func ReadDVPLFooterData(buf []byte) (DVPLFooterData, error)

Functions

func CompressDVPL

func CompressDVPL(buf []byte, noCompression bool) ([]byte, error)

Compress the given byte array using HC_2 compression, or no compression if noCompression is specified, add a DVPL footer and return the resulting byte array, or return an error if the compression algorithm fails.

func DecompressDVPL

func DecompressDVPL(buf []byte) ([]byte, error)

Decompress the given byte array and return the decompressed byte array, or return an error if the given byte array is not a valid DVPL.

Types

type DVPLFooterData

type DVPLFooterData struct {
	OriginalSize   uint32 // The original size of the content.
	CompressedSize uint32 // The compressed size of the content without footer.
	CRC32          uint32 // The CRC32 hash sum of the content without footer.
	CompressType   uint32 // The compression type used. Usually is 2, with the exception of 0 for .tex files.
}

func ReadDVPLFooterData

func ReadDVPLFooterData(buf []byte) (DVPLFooterData, error)

Read a DVPL footer from the given byte array. If no valid DVPL footer is present, return error.