Re: Converting an Integer into Human Readable String

[Eli Zaretskii]

> From: Thierry Volpiatto <thierry.volpiatto@gmail.com>
> Date: Fri, 08 Apr 2011 21:12:35 +0200
> 
> The result you obtain is not what is expected (i.e same than
> ls -lh)
> 
> --8<---------------cut here---------------start------------->8---
> ls -l .VirtualBox/Machines/LoseDows.vdi
> -rw------- 1 thierry thierry 7141892608 2011-04-07 08:51 
> .VirtualBox/Machines/LoseDows.vdi
> 
> ls -lh .VirtualBox/Machines/LoseDows.vdi
> -rw------- 1 thierry thierry 6,7G 2011-04-07 08:51 
> .VirtualBox/Machines/LoseDows.vdi
> 
> (file-size-human-readable 7141892608.0)
> "7G"

Well, that's what ls-lisp.el was always doing.  But since you asked
for it, here you go (will commit as soon as Savannah is fixed):

(defun file-size-human-readable (file-size &optional flavor)
  "Produce a string showing FILE-SIZE in human-readable form.

Optional second argument FLAVOR controls the units and the display format:

 If FLAVOR is nil or omitted, each kilobyte is 1024 bytes and the produced
    suffixes are \"k\", \"M\", \"G\", \"T\", etc.
 If FLAVOR is `si', each kilobyte is 1000 bytes and the produced suffixes
    are \"k\", \"M\", \"G\", \"T\", etc.
 If FLAVOR is `iec', each kilobyte is 1024 bytes and the produced suffixes
    are \"KiB\", \"MiB\", \"GiB\", \"TiB\", etc."
  (let ((power (if (or (null flavor) (eq flavor 'iec))
                   1024.0
                 1000.0))
        (post-fixes
         ;; none, kilo, mega, giga, tera, peta, exa, zetta, yotta
         (list "" "k" "M" "G" "T" "P" "E" "Z" "Y")))
    (while (and (>= file-size power) (cdr post-fixes))
      (setq file-size (/ file-size power)
            post-fixes (cdr post-fixes)))
    (format (if (> (mod file-size 1.0) 0.05)
                "%.1f%s%s"
              "%.0f%s%s")
            file-size
            (if (and (eq flavor 'iec) (string= (car post-fixes) "k"))
                "K"
              (car post-fixes))
            (if (eq flavor 'iec) "iB" ""))))