SFV tool: Adaptation of SFVCON to PowerShell #crc #sfv

sfv.ps1

# TODO:
# sfv.exe takes in a file that can include a path.
#
# sfv.exe supports -rep, -noperc
#
# sfv seems to have a filename truncation routine where it puts ellipses. Not sure what the logic is.
# should be:
#  │  [  4/ 23] Info/05 - Roxy Music - While My Hear...ng.dsf_report.png  MISS
#  │  [  5/ 23] Info/07 - Roxy Music - Take A Chance W...dsf_report.png   MISS
# not:
#  │  [  4/ 23] Info/05 - Roxy Music - While My Heart Is Still Beating.ds  OK
#  │  [  5/ 23] Info/07 - Roxy Music - Take A Chance With Me.dsf_report.p  OK


param([string]$File = '*.sfv')

# Bit order of polynomial representation is reversed.
# 0xEDB88320 means reversed bit order representation of the following polynomial
# x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^11 + x^10 + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1

Add-Type -TypeDefinition @"
// Copyright (c) Damien Guard.  All rights reserved.
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
/// <summary>
/// Implements a 32-bit CRC hash algorithm compatible with Zip etc.
/// </summary>
/// <remarks>
/// Crc32 should only be used for backward compatibility with older file formats
/// and algorithms. It is not secure enough for new applications.
/// If you need to call multiple times for the same data either use the HashAlgorithm
/// interface or remember that the result of one Compute call needs to be ~ (XOR) before
/// being passed in as the seed for the next Compute call.
/// </remarks>
public sealed class Crc32 : HashAlgorithm
{
    public const UInt32 DefaultPolynomial = 0xedb88320u;
    public const UInt32 DefaultSeed = 0xffffffffu;
    static UInt32[] defaultTable;
    readonly UInt32 seed;
    readonly UInt32[] table;
    UInt32 hash;
    public Crc32()
        : this(DefaultPolynomial, DefaultSeed)
    {
    }
    public Crc32(UInt32 polynomial, UInt32 seed)
    {
        table = InitializeTable(polynomial);
        this.seed = hash = seed;
    }
    public override void Initialize()
    {
        hash = seed;
    }
    protected override void HashCore(byte[] array, int ibStart, int cbSize)
    {
        hash = CalculateHash(table, hash, array, ibStart, cbSize);
    }
    protected override byte[] HashFinal()
    {
        var hashBuffer = UInt32ToBigEndianBytes(~hash);
        HashValue = hashBuffer;
        return hashBuffer;
    }
    public override int HashSize { get { return 32; } }
    public static UInt32 Compute(byte[] buffer)
    {
        return Compute(DefaultSeed, buffer);
    }
    public static UInt32 Compute(UInt32 seed, byte[] buffer)
    {
        return Compute(DefaultPolynomial, seed, buffer);
    }
    public static UInt32 Compute(UInt32 polynomial, UInt32 seed, byte[] buffer)
    {
        return ~CalculateHash(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
    }
    static UInt32[] InitializeTable(UInt32 polynomial)
    {
        if (polynomial == DefaultPolynomial && defaultTable != null)
            return defaultTable;
        var createTable = new UInt32[256];
        for (var i = 0; i < 256; i++)
        {
            var entry = (UInt32)i;
            for (var j = 0; j < 8; j++)
                if ((entry & 1) == 1)
                    entry = (entry >> 1) ^ polynomial;
                else
                    entry = entry >> 1;
            createTable[i] = entry;
        }
        if (polynomial == DefaultPolynomial)
            defaultTable = createTable;
        return createTable;
    }
    static UInt32 CalculateHash(UInt32[] table, UInt32 seed, IList<byte> buffer, int start, int size)
    {
        var hash = seed;
        for (var i = start; i < start + size; i++)
            hash = (hash >> 8) ^ table[buffer[i] ^ hash & 0xff];
        return hash;
    }
    static byte[] UInt32ToBigEndianBytes(UInt32 uint32)
    {
        var result = BitConverter.GetBytes(uint32);
        if (BitConverter.IsLittleEndian)
            Array.Reverse(result);
        return result;
    }
}
"@ -PassThru | Out-Null

Function Get-FileHashCRC32 {
    Param (
        [Parameter(Mandatory = $true)][String]$Path
    )

    $ErrorActionPreference = "Stop"
    $crc32 = New-Object Crc32
    $stream = New-Object IO.FileStream($Path, [System.IO.FileMode]::Open)
    $hash = [String]::Empty

    foreach ($byte in $crc32.ComputeHash($stream)) {
        $hash += $byte.toString('x2').toUpper()
    }

    $stream.Close()

    $hash
}

@'
SFV/CON v1.6 (Win9x/NT/2000)
(C) 2001 seaw0lf (www.amok.am)

 [+] Looking for SFV files...
'@

$sfvs = Get-ChildItem  -Filter $File -File -ErrorAction SilentlyContinue
if ($sfvs.Count -eq 0) {
    @'
  │
  └─ No files to check
'@
    return
}

@'
  │  {0} file(s) found.
  │
'@ -f $sfvs.Count

$missing = 0
$errors = 0

$sfvs | ForEach-Object {
    @'
 [=] {0}
  │
'@ -f $_.Name

    $folder = Split-Path -Parent  $_.FullName

    # Need to replace [ with `[
    $files = Get-Content -Path ($_.FullName -replace '\[', '``[') ` | Select-String -Pattern '^([^;].*) ([A-F0-9]{8})$' `

    $i = 1

    $files | ForEach-Object {
        $sfv_file = $_.Matches.Groups[1].value
        $crc = $_.Matches.Groups[2].value

        if (-not (Test-Path -Path $sfv_file -PathType Leaf)) {
            $missing++
            $result = 'MISS'
        }
        else {
            if ((Get-FileHashCRC32 (Join-Path $folder $sfv_file)) -eq $crc) {
                $result = ' OK '
            }
            else {
                $errors++
                $result = 'ERROR'
            }
        }


        $file_format = ('{0}  {1}' -f $file, ('.' * 57)).Substring(0, 57)

        '  │  [{0,3}/{1,3}] {2}{3}' -f $i, $files.Count, $file_format, $result

        $i++
    }
    '  │'

}

'  └─ Completed.'

if (!$missing -and !$errors) {
    '     All OK.'
}
else {
    if ($missing) {
        '    {0} file{1} missing.' -f $missing, @('', 's')[$missing -ne 1]
    }

    if ($errors) {
        '    {0} file{1} error.' -f $errors, @('', 's')[$errors -ne 1]
    }
}