Gumby.String.psm1
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function Assert($Condition, $Message = "assertion failed") { if (!$Condition) { throw $Message } } <# .SYNOPSIS If necessary, abbreviates a string by replacing part of it with the ellipsis. .PARAMETER Text String to abbreviate. .PARAMETER MaxLength Maximum length of abbreviated string. .PARAMETER Ellipsis Ellipsis string (optional, defaults to "..."). .OUTPUTS Abbreviated string. #> function Abbreviate([string] $Text, [uint32] $MaxLength, [string] $Ellipsis = "...") { if ($Text.Length -le $MaxLength) { return $Text } else { # Assert ($MaxLength -gt $Ellipsis.length) # PS converts floats to ints by rounding, not by truncation of the fractional part # 01234567890123456789 # abcdefghij # # p q # | | # l v v p q # 9 abc... hij 3 7 x = (9-3)/2 = 3 p = round(x, 0, 1) q = l - trunc(x) # 8 abc... ij 3 8 x = (8-3)/2 = 2.5 p = round(x, 0, 1) q = l - trunc(x) # 7 ab... ij 2 8 x = (7-3)/2 = 2 p = round(x, 0, 1) q = l - trunc(x) # 6 ab... j 2 9 x = (6-3)/2 = 1.5 p = round(x, 0, 1) q = l - trunc(x) # 5 a... j 1 9 x = (5-3)/2 = 1 p = round(x, 0, 1) q = l - trunc(x) # 4 a... 1 10 x = (4-3)/2 = 0.5 $x = ($MaxLength - $Ellipsis.Length ) / 2 return $Text.Substring(0, [Math]::Round($x, 0, 1)) + $Ellipsis + $Text.Substring($Text.Length - [Math]::Truncate($x)) } } <# .SYNOPSIS Ensures a string has the specified length. .PARAMETER Text Text to ensure length of. .PARAMETER Length Desired length of the text. .PARAMETER FillChar Character to pad the text with if it is shorter than the specified length (optional, defaults to ' '). .OUTPUTS Text with the specified length. #> function EnsureStringLength([string] $Text, [int] $Length, [string] $FillChar = ' ') { if ($Text.Length -lt $Length) { return $Text.PadRight($Length, $FillChar) } else { return $Text.Substring(0, $Length) } } <# .SYNOPSIS Normalizes a string by removing whitespace characters from its beginning and end, and by reducing whitespace character sequences in the middle of the string to a single whitespace character. .PARAMETER Text String to normalize. .OUTPUTS Normalized string. #> function NormalizeWhitespace([string] $Text) { $([regex] '\s+').Replace($Text.Trim().Replace('`r`n', ' ').Replace('`r', ' ').Replace('`n', ' '), ' ') } function SpaceWords([string[]] $Words, [int] $Width, [string] $SpacingChar = ' ') { # The code below is a sketch that only works correctly for 2 words. A proper version needs # to provide heterogenous spacing lengths according to the integer divisibility of the # total spacing length. Assert ($Words.Count -ge 2) Assert ($SpacingChar.Length -eq 1) $totalSpacingLength = $Width foreach ($word in $Words) { $totalSpacingLength -= $word.Length } Assert ($totalSpacingLength -ge 0) $spacingLength = $totalSpacingLength / ($Words.Count - 1) $sb = [Text.StringBuilder]::new($Width) for ($i = 0; $i -lt $Words.Count; ++$i) { $sb.Append($Words[$i]) | Out-Null if ($i -lt $Words.Count - 1) { $sb.Append($SpacingChar * $spacingLength) | Out-Null } } return $sb.ToString() } <# .SYNOPSIS Splits a string of comma-separated, quoted sub-strings (e.g. a line from a CSV file). .PARAMETER Line String to split. .OUTPUTS List of substrings. #> function SplitCSVLine([string] $Line) { [bool] $inString = $false; $fields = @() $accu = "" for ($i = 0; $i -lt $Line.Length; $i++) { switch ($Line[$i]) { #{$_ -eq '"' -and -not $inString} {$inString = $true; break} #{$_ -eq '"' -and $inString} {$inString = $false; break} {$_ -eq '"'} {$inString = !$inString; break} {($_ -in ',', ';') -and -not $inString} {$fields += $accu; $accu = ""; break} default {$accu += $_} } } $fields += $accu return $fields } |