| Version 20 (modified by os, 15 years ago) (diff) |
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Programming Languages
Hash code is based on Media Player Classic. In natural language it calculates: size + 64bit chksum of the first and last 64k (even if they overlap because the file is smaller than 128k). On opensubtitles.org is movie file size limited to 9000000000 > $moviebytesize > 131072 bytes, if is there any reason to change these sizes, let us know. Licence of hashing source codes is GPL.
Feel free to edit/add source-codes if you have faster/better implementation. Also don't forget to check, if hash is right for test. Test these 2 files please to ensure your algo is completely OK:
- AVI file (12 909 756 bytes)
- hash: 8e245d9679d31e12
- DUMMY RAR file (2 565 922 bytes, 4 295 033 890 after RAR unpacking)
- hash: 61f7751fc2a72bfb
C
#include <stdio.h> #include <stdlib.h> #define MAX(x,y) (((x) > (y)) ? (x) : (y)) #ifndef uint64_t #define uint64_t unsigned long long #endif uint64_t compute_hash(FILE * handle) { uint64_t hash, fsize; fseek(handle, 0, SEEK_END); fsize = ftell(handle); fseek(handle, 0, SEEK_SET); hash = fsize; for(uint64_t tmp = 0, i = 0; i < 65536/sizeof(tmp) && fread((char*)&tmp, sizeof(tmp), 1, handle); hash += tmp, i++); fseek(handle, (long)MAX(0, fsize - 65536), SEEK_SET); for(uint64_t tmp = 0, i = 0; i < 65536/sizeof(tmp) && fread((char*)&tmp, sizeof(tmp), 1, handle); hash += tmp, i++); return hash; } int main(int argc, char *argv) { FILE * handle; uint64_t myhash; handle = fopen("breakdance.avi", "rb"); if (!handle) { printf("Error openning file!"); return 1; } myhash = compute_hash(handle); printf("%I64x", myhash); fclose(handle); return 0; }
C - Public Domain License
#include <stdio.h> #include <stdlib.h> unsigned long long analizefileOSHahs(char *fileName){ /* * Public Domain implementation by Kamil Dziobek. turbos11(at)gmail.com * This code implements Gibest hash algorithm first use in Media Player Classics * For more implementation(various languages and authors) see: * http://trac.opensubtitles.org/projects/opensubtitles/wiki/HashSourceCodes * * -works only on little-endian procesor DEC, Intel and compatible * -sizeof(unsigned long long) must be 8 */ FILE *file; int i; unsigned long long t1=0; unsigned long long buffer1[8192*2]; file = fopen(fileName, "rb"); fread(buffer1, 8192, 8, file); fseek(file, -65536, SEEK_END); fread(&buffer1[8192], 8192, 8, file); for (i=0;i<8192*2;i++) t1+=buffer1[i]; t1+= ftell(file); //add filesize fclose(file); return t1; }; int main(int argc, char *argv){ unsigned long long myhash=analizefileOSHahs("C://tomaszkokowskizoofiliamovies.avi"); printf("hash is %16I64x",myhash); }
C++
#include <iostream> #include <fstream> typedef unsigned __int64 uint64_t; using namespace std; int MAX(int x, int y) { if((x) > (y)) return x; else return y; } uint64_t compute_hash(ifstream& f) { uint64_t hash, fsize; f.seekg(0, ios::end); fsize = f.tellg(); f.seekg(0, ios::beg); hash = fsize; for(uint64_t tmp = 0, i = 0; i < 65536/sizeof(tmp) && f.read((char*)&tmp, sizeof(tmp)); i++, hash += tmp); f.seekg(MAX(0, (uint64_t)fsize - 65536), ios::beg); for(tmp = 0, i = 0; i < 65536/sizeof(tmp) && f.read((char*)&tmp, sizeof(tmp)); i++, hash += tmp); return hash; } int main(int argc, char *argv) { ifstream f; uint64_t myhash; f.open("c:\\test.avi", ios::in|ios::binary|ios::ate); if (!f.is_open()) { cerr << "Error opening file" << endl; return 1; } myhash = compute_hash(f); cout << setw(16) << setfill('0') << hex << myhash; f.close(); return 0; }
About C and C++ implementation
This only work on little-endian processor: DEC, Intel and compatible
Java
/** * Hash code is based on Media Player Classic. In natural language it calculates: size + 64bit * checksum of the first and last 64k (even if they overlap because the file is smaller than * 128k). */ public class OpenSubtitlesHasher { /** * Size of the chunks that will be hashed in bytes (64 KB) */ private static final int HASH_CHUNK_SIZE = 64 * 1024; public static String computeHash(File file) throws IOException { long size = file.length(); long chunkSizeForFile = Math.min(HASH_CHUNK_SIZE, size); FileChannel fileChannel = new FileInputStream(file).getChannel(); try { long head = computeHashForChunk(fileChannel.map(MapMode.READ_ONLY, 0, chunkSizeForFile)); long tail = computeHashForChunk(fileChannel.map(MapMode.READ_ONLY, Math.max(size - HASH_CHUNK_SIZE, 0), chunkSizeForFile)); return String.format("%016x", size + head + tail); } finally { fileChannel.close(); } } public static String computeHash(InputStream stream, long length) throws IOException { int chunkSizeForFile = (int) Math.min(HASH_CHUNK_SIZE, length); // buffer that will contain the head and the tail chunk, chunks will overlap if length is smaller than two chunks byte[] chunkBytes = new byte[(int) Math.min(2 * HASH_CHUNK_SIZE, length)]; DataInputStream in = new DataInputStream(stream); // first chunk in.readFully(chunkBytes, 0, chunkSizeForFile); long position = chunkSizeForFile; long tailChunkPosition = length - chunkSizeForFile; // seek to position of the tail chunk, or not at all if length is smaller than two chunks while (position < tailChunkPosition && (position += in.skip(tailChunkPosition - position)) >= 0); // second chunk, or the rest of the data if length is smaller than two chunks in.readFully(chunkBytes, chunkSizeForFile, chunkBytes.length - chunkSizeForFile); long head = computeHashForChunk(ByteBuffer.wrap(chunkBytes, 0, chunkSizeForFile)); long tail = computeHashForChunk(ByteBuffer.wrap(chunkBytes, chunkBytes.length - chunkSizeForFile, chunkSizeForFile)); return String.format("%016x", length + head + tail); } private static long computeHashForChunk(ByteBuffer buffer) { LongBuffer longBuffer = buffer.order(ByteOrder.LITTLE_ENDIAN).asLongBuffer(); long hash = 0; while (longBuffer.hasRemaining()) { hash += longBuffer.get(); } return hash; } }
C#
You can use GetHash?.dll.
http://trac.opensubtitles.org/projects/opensubtitles/attachment/wiki/HashSourceCodes/GetHash.dll
Use Example:
private void openFileDialog1_FileOk(object sender, CancelEventArgs e)
{
byte[] hash = GetHash.Main.ComputeHash(openFileDialog1.FileName);
label1.Text = GetHash.Main.ToHexadecimal(hash);
}
or without using GetHash?.dll:
using System;
using System.Text;
using System.IO;
namespace MovieHasher
{
class Program
{
private static byte[] ComputeMovieHash(string filename)
{
byte[] result;
using (Stream input = File.OpenRead(filename))
{
result = ComputeMovieHash(input);
}
return result;
}
private static byte[] ComputeMovieHash(Stream input)
{
long lhash, streamsize;
streamsize = input.Length;
lhash = streamsize;
long i = 0;
byte[] buffer = new byte[sizeof(long)];
while (i < 65536 / sizeof(long) && (input.Read(buffer, 0, sizeof(long)) > 0))
{
i++;
lhash += BitConverter.ToInt64(buffer, 0);
}
input.Position = Math.Max(0, streamsize - 65536);
i = 0;
while (i < 65536 / sizeof(long) && (input.Read(buffer, 0, sizeof(long)) > 0))
{
i++;
lhash += BitConverter.ToInt64(buffer, 0);
}
input.Close();
byte[] result = BitConverter.GetBytes(lhash);
Array.Reverse(result);
return result;
}
private static string ToHexadecimal(byte[] bytes)
{
StringBuilder hexBuilder = new StringBuilder();
for(int i = 0; i < bytes.Length; i++)
{
hexBuilder.Append(bytes[i].ToString("x2"));
}
return hexBuilder.ToString();
}
static void Main(string[] args)
{
byte[] moviehash = ComputeMovieHash(@"C:\test.avi");
Console.WriteLine("The hash of the movie-file is: {0}", ToHexadecimal(moviehash));
}
}
}
If you get overflow error read this.
VB.Net
Imports System
Imports System.Text
Imports System.IO
'Note: you must remove integer overflow checking.
Namespace MovieHasher
Class Program
Private Shared Function ComputeMovieHash(ByVal filename As String) As Byte()
Dim result As Byte()
Using input As Stream = File.OpenRead(filename)
result = ComputeMovieHash(input)
End Using
Return result
End Function
Private Function ComputeMovieHash(ByVal input As Stream) As Byte()
Dim lhash As System.Int64, streamsize As Long
streamsize = input.Length
lhash = streamsize
Dim i As Long = 0
Dim buffer As Byte() = New Byte(Marshal.SizeOf(GetType(Long)) - 1) {}
While i < 65536 / Marshal.SizeOf(GetType(Long)) AndAlso (input.Read(buffer, 0, Marshal.SizeOf(GetType(Long))) > 0)
i += 1
lhash += BitConverter.ToInt64(buffer, 0)
End While
input.Position = Math.Max(0, streamsize - 65536)
i = 0
While i < 65536 / Marshal.SizeOf(GetType(Long)) AndAlso (input.Read(buffer, 0, Marshal.SizeOf(GetType(Long))) > 0)
i += 1
lhash += BitConverter.ToInt64(buffer, 0)
End While
input.Close()
Dim result As Byte() = BitConverter.GetBytes(lhash)
Array.Reverse(result)
Return result
End Function
Private Shared Function ToHexadecimal(ByVal bytes As Byte()) As String
Dim hexBuilder As New StringBuilder()
For i As Integer = 0 To bytes.Length - 1
hexBuilder.Append(bytes(i).ToString("x2"))
Next
Return hexBuilder.ToString()
End Function
Private Shared Sub Main(ByVal args As String())
Dim moviehash As Byte() = ComputeMovieHash("C:\test.avi")
Console.WriteLine("The hash of the movie-file is: {0}", ToHexadecimal(moviehash))
End Sub
End Class
End Namespace
Python
import struct, os def hashFile(name): try: longlongformat = 'q' # long long bytesize = struct.calcsize(longlongformat) f = open(name, "rb") filesize = os.path.getsize(name) hash = filesize if filesize < 65536 * 2: return "SizeError" for x in range(65536/bytesize): buffer = f.read(bytesize) (l_value,)= struct.unpack(longlongformat, buffer) hash += l_value hash = hash & 0xFFFFFFFFFFFFFFFF #to remain as 64bit number f.seek(max(0,filesize-65536),0) for x in range(65536/bytesize): buffer = f.read(bytesize) (l_value,)= struct.unpack(longlongformat, buffer) hash += l_value hash = hash & 0xFFFFFFFFFFFFFFFF f.close() returnedhash = "%016x" % hash return returnedhash except(IOError): return "IOError"
Delphi
This is just a quick conversion of Gabest's original C code. Anyone who can come up with a cleaner code, please feel free to do so and post here.
function CalcGabestHash(const fname: string): string;
var
i : integer;
s : array[1..8] of char;
tmp : Int64 absolute s;
hash : Int64;
readed : integer;
aStream: TFileStream;
begin
result := '';
if not FileExists(fname) then Exit;
aStream := TFileStream.Create(fName, fmShareDenyNone);
hash := aStream.Size;
i := 0; readed := 1;
while ((i < 8192) and (readed > 0)) do begin
readed := aStream.Read(s, sizeof(s));
if readed > 0 then
begin
hash := hash + tmp;
end;
i := i + 1;
end;
aStream.Seek(-65536, soFromEnd); // 65536
i := 0; readed:= 1;
while ((i < 8192) and (readed > 0)) do begin
readed := aStream.Read(s, sizeof(s));
if readed > 0 then
hash := hash + tmp;
i := i + 1;
end;
aStream.Free;
result := Format('%.16x',[hash]);
end;
RealBasic
Combined routine that will calculate a fast hash for videofiles over 65K and a normal md5 for subtitles
dim b as BinaryStream
dim mb as MemoryBlock
dim hash,bytesize as UINT64
dim i, x, chunksize, filelen, difference as integer
hash = 0 //Reset Hash
difference = 0
if f <> nil and f.Exists then
b= f.OpenAsBinaryFile
hash = b.Length
bytesize = b.Length
bytesizestr = str(bytesize)
if bytesize >= 65536 and routine = "video" then
chunksize = 65536
mb = b.Read(65536)
mb.LittleEndian = True
for i= 0 to chunksize -1 step 8
hash = hash+ mb.UINT64Value(i)
next
b.Position = max(b.Length-chunksize, 0)
mb= b.Read(chunksize)
mb.LittleEndian = True
for i= 0 to chunksize -1 step 8
hash = hash+ mb.UINT64Value(i)
next
myhash = Lowercase(str(hex(hash)))
elseif routine = "subtitle" then
dim c,result as string
mb = md5(b.Read(b.Length))
mb.LittleEndian = True
for i = 0 to mb.size-1
x = mb.byte( i )
c = right( "00"+hex( x ), 2 )
result = result + c
next
result = lowercase( result )
myhash = result
end
PHP 4/5
function OpenSubtitlesHash($file)
{
$handle = fopen($file, "rb");
$fsize = filesize($file);
$hash = array(3 => 0,
2 => 0,
1 => ($fsize >> 16) & 0xFFFF,
0 => $fsize & 0xFFFF);
for ($i = 0; $i < 8192; $i++)
{
$tmp = ReadUINT64($handle);
$hash = AddUINT64($hash, $tmp);
}
$offset = $fsize - 65536;
fseek($handle, $offset > 0 ? $offset : 0, SEEK_SET);
for ($i = 0; $i < 8192; $i++)
{
$tmp = ReadUINT64($handle);
$hash = AddUINT64($hash, $tmp);
}
fclose($handle);
return UINT64FormatHex($hash);
}
function ReadUINT64($handle)
{
$u = unpack("va/vb/vc/vd", fread($handle, 8));
return array(0 => $u["a"], 1 => $u["b"], 2 => $u["c"], 3 => $u["d"]);
}
function AddUINT64($a, $b)
{
$o = array(0 => 0, 1 => 0, 2 => 0, 3 => 0);
$carry = 0;
for ($i = 0; $i < 4; $i++)
{
if (($a[$i] + $b[$i] + $carry) > 0xffff )
{
$o[$i] += ($a[$i] + $b[$i] + $carry) & 0xffff;
$carry = 1;
}
else
{
$o[$i] += ($a[$i] + $b[$i] + $carry);
$carry = 0;
}
}
return $o;
}
function UINT64FormatHex($n)
{
return sprintf("%04x%04x%04x%04x", $n[3], $n[2], $n[1], $n[0]);
}
Perl
#!/usr/bin/perl use strict; use warnings; print OpenSubtitlesHash('breakdance.avi'); sub OpenSubtitlesHash { my $filename = shift or die("Need video filename"); open my $handle, "<", $filename or die $!; my $fsize = -s $filename; my $hash = [$fsize & 0xFFFF, ($fsize >> 16) & 0xFFFF, 0, 0]; $hash = AddUINT64($hash, ReadUINT64($handle)) for (1..8192); my $offset = $fsize - 65536; seek($handle, $offset > 0 ? $offset : 0, 0) or die $!; $hash = AddUINT64($hash, ReadUINT64($handle)) for (1..8192); close $handle or die $!; return UINT64FormatHex($hash); } sub ReadUINT64 { read($_[0], my $u, 8); return [unpack("vvvv", $u)]; } sub AddUINT64 { my $o = [0,0,0,0]; my $carry = 0; for my $i (0..3) { if (($_[0]->[$i] + $_[1]->[$i] + $carry) > 0xffff ) { $o->[$i] += ($_[0]->[$i] + $_[1]->[$i] + $carry) & 0xffff; $carry = 1; } else { $o->[$i] += ($_[0]->[$i] + $_[1]->[$i] + $carry); $carry = 0; } } return $o; } sub UINT64FormatHex { return sprintf("%04x%04x%04x%04x", $_[0]->[3], $_[0]->[2], $_[0]->[1], $_[0]->[0]); }
Ruby
This is a quick translation/transliteration of the Perl script.
class Hasher def open_subtitles_hash(filename) raise "Need video filename" unless filename fh = File.open(filename) fsize = File.size(filename) hash = [fsize & 0xffff, (fsize >> 16) & 0xffff, 0, 0] 8192.times { hash = add_unit_64(hash, read_uint_64(fh)) } offset = fsize - 65536 fh.seek([0,offset].max, 0) 8192.times { hash = add_unit_64(hash, read_uint_64(fh)) } fh.close return uint_64_format_hex(hash) end def read_uint_64(stream) stream.read(8).unpack("vvvv") end def add_unit_64(hash, input) res = [0,0,0,0] carry = 0 hash.zip(input).each_with_index do |(h,i),n| sum = h + i + carry if sum > 0xffff res[n] += sum & 0xffff carry = 1 else res[n] += sum carry = 0 end end return res end def uint_64_format_hex(hash) sprintf("%04x%04x%04x%04x", *hash.reverse) end end if __FILE__ == $0 require 'test/unit' class HashTester < Test::Unit::TestCase def setup @h = Hasher.new end def test_test_file_hash assert_equal("8e245d9679d31e12", @h.open_subtitles_hash('breakdance.avi')) end end end
Another more "rubyesque" implementation.
module MovieHasher CHUNK_SIZE = 64 * 1024 # in bytes def self.compute_hash(filename) filesize = File.size(filename) hash = filesize # Read 64 kbytes, divide up into 64 bits and add each # to hash. Do for beginning and end of file. File.open(filename, 'rb') do |f| # Q = unsigned long long = 64 bit f.read(CHUNK_SIZE).unpack("Q*").each do |n| hash = hash + n & 0xffffffffffffffff # to remain as 64 bit number end f.seek([0, filesize - CHUNK_SIZE].max, IO::SEEK_SET) # And again for the end of the file f.read(CHUNK_SIZE).unpack("Q*").each do |n| hash = hash + n & 0xffffffffffffffff end end sprintf("%016x", hash) end end if __FILE__ == $0 require 'test/unit' class MovieHasherTest < Test::Unit::TestCase def test_compute_hash assert_equal("8e245d9679d31e12", MovieHasher::compute_hash('breakdance.avi')) end def test_compute_hash_large_file assert_equal("61f7751fc2a72bfb", MovieHasher::compute_hash('dummy.bin')) end end end
Haskell
import IO(bracket)
import System.Environment(getArgs)
import System.IO(openBinaryFile,hClose,hFileSize,hSeek,IOMode(ReadMode),SeekMode(AbsoluteSeek,SeekFromEnd))
import qualified Data.ByteString.Lazy as L(hGet,unpack)
import Data.Binary.Get(runGet,getWord64le)
import Data.Binary.Put(runPut,putWord64le)
import Data.Word(Word64)
import Control.Monad(foldM)
import Data.Bits.Utils(w82s)
import Data.Hex(hex)
shortsum :: FilePath -> IO Word64
shortsum filename = bracket (openBinaryFile filename ReadMode) hClose $ \h -> do
fs <- hFileSize h
hSeek h AbsoluteSeek 0 ; begin <- L.hGet h chunksize
hSeek h SeekFromEnd (-(toInteger chunksize)) ; end <- L.hGet h chunksize
return $ (flip runGet $ begin) $ chunksum $ (flip runGet $ end) (chunksum . fromInteger $ fs)
where
chunksize = 0x10000
chunksum n = foldM (\a _ -> getWord64le >>= return . (+a)) n [1..(chunksize`div`8)]
main :: IO ()
main = do
args <- getArgs
let fn = head $ args
p <- shortsum fn
putStrLn $ "The hash of file " ++ fn ++ ": " ++ (hex $ w82s $ reverse (L.unpack $ runPut $ putWord64le p))
Attachments (1)
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GetHash.dll
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added by guest 15 years ago.
GetHash?.dll
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