Copy-FileWithContigCheck.ps1

param (
    [string]$SourceFile = "C:\source\largefile.iso",
    [string]$TargetFile = "D:\target\largefile.iso"
)

$contigUrl = "https://download.sysinternals.com/files/Contig.zip"
$contigFolder = "$env:TEMP\ContigTool"
$contigExe = Join-Path $contigFolder "contig.exe"
$contigZip = Join-Path $contigFolder "contig.zip"

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

function Ensure-Contig {
    if (-Not (Test-Path $contigExe)) {
        Write-Host "Contig.exe not found. Downloading from Sysinternals..."

        New-Item -ItemType Directory -Path $contigFolder -Force | Out-Null
        Invoke-WebRequest -Uri $contigUrl -OutFile $contigZip

        Write-Host "Extracting..."
        Add-Type -AssemblyName System.IO.Compression.FileSystem
        [System.IO.Compression.ZipFile]::ExtractToDirectory($contigZip, $contigFolder)

        if (-Not (Test-Path $contigExe)) {
            throw "Failed to extract contig.exe"
        }
        Write-Host "Contig.exe ready at $contigExe"
    } else {
        Write-Host "Contig.exe already available."
    }
}

function Get-FileFragmentation {
    param (
        [string]$filePath
    )

    Ensure-Contig
    Write-Host "`nChecking fragmentation for $filePath..."
    & $contigExe "$filePath"
}

# Step 1: Preallocate
$sourceSize = (Get-Item $SourceFile).Length
Write-Host "Preallocating $TargetFile..."
fsutil file createnew $TargetFile $sourceSize

# Step 2: Sequential copy
Write-Host "Copying file data sequentially..."
$bufferSize = 1MB
$sourceStream = [System.IO.File]::OpenRead($SourceFile)
$targetStream = [System.IO.File]::OpenWrite($TargetFile)

$buffer = New-Object byte[] $bufferSize
do {
    $read = $sourceStream.Read($buffer, 0, $bufferSize)
    if ($read -gt 0) {
        $targetStream.Write($buffer, 0, $read)
    }
} while ($read -gt 0)

$sourceStream.Close()
$targetStream.Close()

Write-Host "Copy complete."

# Step 3: Fragmentation check
Get-FileFragmentation -filePath $TargetFile