#!/usr/bin/env texlua

kpse.set_program_name('texlua')

-- epspdf conversion utility

-- 0.6.0: first texlua version
-- 0.6.1: allow TeX installation on path with spaces

ep_version = '0.6.1'
ep_copyright = '2006, 2008, 2009, 2010, 2011, 2013, 2014'

--[[

Note.
TeX code for cropping pdfs adapted from Heiko Oberdiek's pdfcrop utility

Program structure

- early initialization
- functions for:
  - error handling
  - file- and path utilities
  - other general utilities
  - infrastructure: logging and temporary files
  - reading and writing settings
  - gui function
  - boundingboxes
  - manipulating [e]ps- and pdf files
- the PsPdf object:
  - creator functions
  - boundingbox handling
  - one-step conversion methods
  - any_to_any method
- main initialization section:
  - collecting system information
  - infrastructure: setting up logging and temp directory
  - settings:
    - defining settings-, descriptions-, options- and auxiliary tables
    - read settings
    - defining commandline options and help function
    - parsing commandline and performing non-conversion options
- calling any_to_any
- finishing up

all calls to external programs work on temporary files with a simple
generated filename. The current directory is a newly-created
temporary directory. So no need to quote names of input- and output
filenames.

POSSIBLE EXTENSIONS

- duplicating epstopdf options
- custom options for gs and pdftops

--]]

-- some general utilities and globals ---------------------------

--[[

Simple-minded error handling. At most, we call a function which
tries to write the error message to log before re-raising the error.

When run from the Tcl/Tk gui, this gui will capture error messages.

--]]

-- early initializations

eol = false
path_sep = false
if os.type=='unix' then
  eol='\n'
  path_sep = ':'
else
  eol='\r\n'
  path_sep = ';'
end

bufsize=16000 -- for reading and writing  files

-- these `declarations' are not really needed;
-- they are here mainly for my own peace of mind

from_gui = false -- whether epspdf is run from the epspsdtk gui

cwd = ''

-- Windows: miktex, TL or neither
is_miktex = false
is_tl_w32 = false

-- some global file- and directory names
gs_prog = false
pdftops = false
epsdir = false
rcfile = false
logfile = false
tempdir = false
tempfiles = {}
-- childpath = false
-- os.getenv('path') returns the parents path,
-- so we need to keep track ourselves of the child path

options = false -- actual conversion options
settings = false -- persistent settings; may be stored in config file
descriptions = false -- help strings for settings
gs_options = false
pdf_options = false
pdf_tail_options = false
ps_options = false
gray_options = false

-- logging ------------------------

-- we open and close the logfile anew for each write.
-- failure to open constitutes no error.

function print_log(s)
  local f = io.open(logfile, 'a')
  if f then
    f:write(s,eol)
    f:close()
  end
  if from_gui then
    print(s) -- intercepted by the gui
  end
end
function write_log(s)
    print_log(string.format('%s %s',
        os.date('%Y/%m/%d %H:%M:%S', os.time()), s))
end

function log_cmd(cmd)
  write_log('[' .. table.concat(cmd, '] [') .. ']')
end

-- error- and debug -------------------------

function errror(mess)
  if logfile then pcall(write_log, mess) end
  -- ignore result of pcall: we can do nothing about failure
  error(mess, 2)
end

function warn(mess)
  if logfile then write_log(mess) end
  print(mess)
end

function dbg(mess)
  if options.debug then
    warn(mess)
  end
end

--[[

function dbg_opt()
  if options.debug then
    local mess = ''
    for _, k in ipairs({'bbox', 'gray', 'page'}) do
      mess = mess.. ' ' .. k .. ': ' .. tostring(options.k)
    end
    dbg(mess)
  end
end

--]]

-- file- and path utilities ----------------

function ep_shortname(path)
  if os.type=='unix' then
    return path
  else
    -- shortname appears not to work under miktex
    -- so return original path as a fallback
    local sp = lfs.shortname(path)
    return sp or path
  end
end

-- prepend or append dir to path if necessary
function maybe_add_path(dir, append)
  local dircmp = path_sep .. dir .. path_sep
  local pathcmp = path_sep .. kpse.var_value('PATH') .. path_sep
  -- case folding
  if os.name=='windows' or os.name=='cygwin' or os.name=='macosx' then
    dircmp = string.lower(dir)
    pathcmp = string.lower(pathcmp)
  end
  -- slash flipping
  if os.type=='windows' then
    pathcmp = (string.gsub(pathcmp, '/', '\\'))
    dircmp = (string.gsub(dircmp, '/', '\\'))
  end
  if not string.find(pathcmp, dircmp, 1, true) then
    if not append then -- prepend
      os.setenv('PATH', dir..path_sep..kpse.var_value('PATH'))
    else -- append
      os.setenv('PATH', kpse.var_value('PATH')..path_sep..dir)
    end
  end
end

function fw(path)
  if os.type=='windows' then
    return string.gsub(path, '\\', '/')
  else
    return path
  end
end

function absolute_path(path)

  --[[ Return absolute normalized version of path, interpreted
  from the directory from where the program was called.

  We use the fact that lfs.currentdir() always returns an absolute and
  normalized path. So we go to the parent directory of path, ask for
  the current directory and then combine the current directory with
  the base filename.

  On windows, texlua has no trouble cd-ing into a UNC path.

  The function returns nil if there is no valid parent path.
  This might be an issue if path is a directory,
  but we shall apply this function only on files.
  It is ok if path itself does not exist. --]]

  path = fw(path)

  local present_dir = fw(lfs.currentdir())

  lfs.chdir(cwd)

  local parentdir
  local filename

  if string.match(path, '/') then
    parentdir, filename = string.match(path,'^(.*)/([^/]*)$')
    if parentdir=='' then
      parentdir = '/'
      -- on unix, this is an absolute path. on windows, it is not
      if os.type=='windows' then
        lfs.chdir('/')
        parentdir = fw(lfs.currentdir())
      end
    elseif os.type=='windows' and string.match(parentdir,'^[a-zA-Z]:$') then
      parentdir = string.sub(parentdir,1,2)..'/'
    else
      if not lfs.chdir(parentdir) then
        parentdir = nil
      else
        parentdir = fw(lfs.currentdir())
      end
    end
  elseif os.type=='windows' and string.match(path,'^[a-zA-Z]:') then
    -- windows: d:file
    parentdir = string.sub(path,1,2)
    if not lfs.chdir(parentdir) then
      parentdir = nil
    else
      parentdir = fw(lfs.currentdir())
      filename = string.sub(path,3)
    end
  else
    parentdir = fw(lfs.currentdir())
    filename = path
  end
  lfs.chdir(present_dir)
  if not parentdir then
    return nil
  elseif string.sub(parentdir,-1)=='/' then
    return parentdir..filename, parentdir
  else
    return parentdir..'/'..filename, parentdir
  end
end -- absolute_path

-- check whether prog is on the searchpath.
-- we need it only under unix,
-- so we save ourselves the trouble of accommodating windows.
-- we return the original string, although we only need a yes or no answer

function find_on_path (prog)
  if os.type ~= 'unix' then
    errror('find_on_path: this is a unix-only function')
  end
  for d in string.gmatch(os.getenv('PATH'),  '[^:]+') do
    if lfs.isfile(d..'/'..prog) then
      return prog
    end
  end
  return false
end -- find_on_path

-- On Windows, we do not count so much on the existing searchpath
-- so is_prog tests whether the file exists and is an exe file.

function is_prog (path)
  -- 1. test for and if necessary add extension
  -- 2. test for existence
  -- 3. returns either false or absolute path
  if os.type ~= 'windows' then
    errror('is_prog: this is a Windows-only function')
  end
  if not path then
    return false
  end
  if not string.lower(string.sub(path,-4,-1))=='.exe' then
    path = path..'.exe'
  end
  path = absolute_path(path)
  if not (path and lfs.isfile(path)) then
    return false
  else
    return path
  end
end -- is_prog

function dir_writable(d)
  -- because directory attributes do not tell the whole story,
  -- we actually try to create a file in the directory.
  if not lfs.isdir(d) then
    return false
  end
  -- try to create a new file, write to it and delete it afterwards
  for i=1,1000 do
    local s = d .. '/' .. tostring(i)
    if not lfs.isfile(s) then
      local fh = io.open(s, "w")
      if fh then
        fh:write('test')
        fh:close()
        if lfs.isfile(s) then
          if lfs.attributes(s, 'size') > 0 then
            os.remove(s)
            return true
          else
            os.remove(s)
            return false -- open and write resulted in empty file
          end -- lfs.attributes
        else
          return false -- open and write did not result in a file
        end -- lfs.isfile
      end -- fh
      return false -- filename available; could not open for write
    end -- not lfs.isfile
  end -- for
  return false
end

function system_tempdir ()
  local d
  if os.type=='windows' then
    d = os.getenv('TEMP')
    if not d then
      d = os.getenv('TMP')
    end
  else
    d = os.getenv('TMPDIR')
    if not d then
      d = '/tmp'
    end
  end
  -- if d then dbg('system tempdir: '..d) end
  -- cygwin: $TEMP=/tmp, root '/' being root of cygwin installation
  if d and not dir_writable(d) then
    dbg('unfortunately, '..d..' not writable')
    d = false
  end
  return d
end

-- other general utilities ---------------------------

-- check whether el occurs in array lst
function in_list (el, lst)
  if not lst then return false end
  for _,p in ipairs(lst) do
    if el == p then
      return true
    end
  end
  return false
end -- in_list

-- remove leading and trailing, but not embedded spaces
function strip_outer_spaces(s)
  s = string.gsub(s, '%s*$', '')
  s = string.gsub(s, '^%s*', '')
  return s
end -- strip_outer_spaces

function join(t, sep, lastsep)
  -- there is a table function concat which does this,
  -- but without optional different lastsep
  if t==nil or #t<1 then return '' end -- or should we return nil?
  local s = t[1]
  for i=2,#t do -- ok if #t<2
    if i==#t and lastsep then
      s = s .. lastsep .. t[i]
    else
      s = s .. sep .. t[i]
    end
  end
  return s
end -- join

-- combine several tables into one.
-- the parameter is a table of tables.
function tab_combine (t)
  local res = {}
  for _,tt in ipairs(t) do
    for __, ttt in ipairs(tt) do
      table.insert(res, ttt)
    end
  end
  return res
end -- tab_combine

-- Copy a file in chunks, with optional length and offset.
-- Since files may be very large, we copy them piecemeal.
-- An initial chunk of size bufsize should be plenty to include
-- any interesting header information.

function slice_file(source, dest, len, offset, mode)
  -- The final three parameters can be independently left out by
  -- specifying false as value
  -- Assume caller ensured parameters of correct type.
  -- We do not allow negative offsets.
  local sz = lfs.attributes(source, 'size')
  if not offset then
    offset = 0
  elseif offset>sz then
    offset = sz
  end
  if not len or len>sz-offset then
    len = sz - offset
  end
  if not mode then mode = 'wb' end
  -- dbg('copying '..len..' bytes of '..source..' to '..dest..' from '..offset
  --       ..' in '..mode..' mode')
  local buffer=''
  local s=io.open(source, 'rb')
  s:seek('set', offset)
  local copied = 0
  local d=io.open(dest, mode)
  if not d then errror('slice_file: failed to copy to '..dest) end
  local slen = len
  while slen>0 do
    if slen>=bufsize then
      buffer = s:read(bufsize)
      slen = slen - bufsize
    else
      buffer = s:read(slen)
      slen = 0
    end
    if not d:write(buffer) then
      errror('slice_file: failed to copy to '..dest)
    end
  end
  s:close()
  d:close()
end -- slice_file

function move_or_copy(source, dest)
  if lfs.isfile(dest) and lfs.attributes(dest, 'size')>0 then
    warn('Removing old '..dest)
    os.remove(dest) -- in case of failure, go ahead anyway
  end
  if not os.rename(source, dest) then
    slice_file(source, dest) -- bails out on failure
    local ok, err_mess = os.remove(source)
    if not ok then
      warn('Failed to remove old ' .. source .. ': ' .. err_mess)
    end
  end
end

-- temporary files ----------------------------------------

-- tempdir = false -- will be created later and chdir-ed into
-- tempfiles initialized early to empty table

-- We just name our temporary files nn.<ext> with successive nn.
-- We cannot exclude that another process uses our tempdir
-- so we have to first check for each new file whether it already exists.
-- Epspdf does all the real work from the temp directory.

function mktemp(ext)
  local froot, fname, f, g
  for i=0,99 do
    froot = string.format('%02d.', i)
    fname = froot..ext
    -- dbg('New temp file '..fname..'?')
    if ext~='tex' then
      if not lfs.isfile(fname) then
        -- dbg(fname..' available')
        f = io.open(fname, 'wb')
        if not f then
          errror('Cannot create temporary file '..fname)
        end
        f:close()
        table.insert(tempfiles, fname)
        return froot..ext -- no need to record pdf name
      end
    else
      -- tex; we also need a pdf
      if not lfs.isfile(fname) and not lfs.isfile(froot..'pdf') then
        local f = io.open(fname, 'wb')
        if not f then
          errror('Cannot create temporary file '..fname)
        end
        f:close()
        table.insert(tempfiles, fname)
        fname = froot..'pdf'
        g = io.open(fname, 'wb')
        if not g then
          errror('Cannot create temporary file '..fname)
        end
        g:close()
        table.insert(tempfiles, fname)
        table.insert(tempfiles, froot..'log')
        return froot..ext -- no need to record pdf name
      end
    end -- if
  end -- for
  errror('Cannot create temporary file in '..tempdir)
end

function waitasec()
  -- stupid windows file locking
  if os.type=='windows' and (tonumber(os.uname().version) or 0)>=6 then
    os.execute('timeout /t 1 /nobreak >nul')
  elseif os.type=='windows' then
    os.execute('ping -n 1 localhost >NUL')
  -- else do nothing
  end
  -- error checking pointless
end

function cleantemp()
  lfs.chdir(tempdir)
  if os.type=='windows' then waitasec() end
  for _,f in ipairs(tempfiles) do
    if lfs.isfile(f) then
      local success, mess = os.remove(f)
      if not success then write_log(mess) end
    end
  end
  local empty = true
  for f in lfs.dir('.') do
    if f ~= '.' and f ~= '..' then
      empty = false
      write_log('Temp dir '..tempdir..' contains '..f..' therefore not removed')
      break
    end
  end
  if os.type=='windows' then waitasec() end
  lfs.chdir('..')
  if empty then
    local res, mess
    res, mess = lfs.rmdir(tempdir)
    if not res then
      write_log('Failed to remove empty '..tempdir..'\n'..mess)
    end
  end
end

-- epsdevice -----------------------

function epsdevice()
  local gh = io.popen(gs_prog..' -help')
  local s = gh:read("*a")
  gh:close()
  if string.find(s,'eps2write') then
    return 'eps2write'
  elseif string.find(s,'epswrite') then
    return 'epswrite'
  else
    return false
  end
end

-- settings -----------------------

function write_settings (file)
  local f
  if file then
    f = io.open(file, 'wb')
    if not f then
      return
    end
  else -- stdout to be captured by epspdftk
    f = io.output()
    if os.type=='windows' and not is_tl_w32 then
      f:write('tl_w = no', eol)
    end
  end
  for k, v in pairs(settings) do
    if k ~= 'pdftops_prog' or os.type=='windows' then
      if descriptions[k] and file then
        f:write(eol, '# ', descriptions[k], eol)
      end
      f:write(k, ' = ', tostring(v), eol)
    end
  end
  if file then
    f:close()
  end
end

function read_settings(file)
  -- read and interpret rcfile
  -- we shall ignore illegal entries.
  local contents
  local f
  if file then
    f = io.open(rcfile, 'rb')
    if not f then
      return
    end
  else
    f = io.input()
  end
  contents = f:read(10000)
  if file then
    f:close()
  end
  if not contents or contents=='' then
    dbg('No settings read')
    return
  -- else
  --   dbg(contents)
  end
  -- remove initial \r and \n characters
  contents = string.gsub(contents, '^[\r\n]*', '');
  -- gmatch chops contents into series of non-line-ending characters
  -- possibly followed by line-ending characters.
  local k, v, vl, vnum
  for l in string.gmatch(contents, '[^\r\n]+[\r\n]*') do
    l =  string.match(l,'[^\r\n]*')
    if not string.match(l, '^#') then
      k, v = string.match(l, '^%s*([^%s]+)%s*=%s*(.*)$')
      if v then v = string.gsub(v,'%s*$', '') end
      -- now handle k and v
      if k == 'pdf_target' then
        -- ignore unless valid option
        if in_list(v, pdf_targets) then
          settings[k] = v
        end
      elseif k == 'pdf_version' then
        -- ignore unless valid option
        if in_list(v, pdf_versions) then
          settings[k] = v
        end
      --[[
      elseif k == 'ignore_hires_bb' then
        vl = string.lower(string.sub(v,1,1))
        if v == 0 or vl == 'n' or vl == 'f' then
          settings.use_hires_bb = true
        elseif v == 1 or vl == 'y' or vl == 't' then
          settings.use_hires_bb = false
        end
      elseif k == 'use_hires_bb' then
        vl = string.lower(string.sub(v,1,1))
        if v == 0 or vl == 'n' or vl == 'f' then
          settings.use_hires_bb = false
        elseif v == 1 or vl == 'y' or vl == 't' then
          settings.use_hires_bb = true
        end
      elseif k == 'bb_spread' then
        vnum = tonumber(v)
        if vnum and vnum >= 0 then
          settings[k] = math.modf(v) -- truncate to integer
        end
        --]]
      elseif k == 'pdftops_prog' then
        if is_miktex then
          settings.pdftops_prog = is_prog(v)
        end -- else ignore
      elseif k == 'ignore_pdftops' then
        vl = string.lower(string.sub(v,1,1))
        if v == 0 or vl == 'n' or vl == 'f' then
          settings.use_pdftops = true
        elseif v == 1 or vl == 'y' or vl == 't' then
          settings.use_pdftops = false
        end
      elseif k == 'use_pdftops' then
        vl = string.lower(string.sub(v,1,1))
        if v == '0' or vl == 'n' or vl == 'f' then
          settings.use_pdftops = false
        elseif v == '1' or vl == 'y' or vl == 't' then
          settings.use_pdftops = true
        end
      -- final three settings not used by epspdf itself but
      -- passed along to epspdftk
      elseif k == 'ps_viewer' then
        settings.ps_viewer = v
      elseif k == 'pdf_viewer' then
        settings.pdf_viewer = v
      elseif k == 'default_dir' then
        settings.default_dir = v
      elseif k == 'default_dir' then
        settings.default_dir = v
      end -- test for k
    end -- not matching ^#
  end -- for
end -- read settings

-- gui: reading and writing settings -----------

function gui(action)
  -- use stdin for reading settings from gui, and stdout for writing
  if action=='config_w' then
    -- called at start of epspdftk
    write_settings() -- to pipe epspdf => epspdftk
    os.exit()
  elseif action=='config_r' then
    read_settings() -- from 'pipe' epspdftk => epspdf
    write_settings(rcfile)
    os.exit()
  else
    from_gui = true
  end
end

-- boundingboxes ---------------------------------------------------

-- Bb.coords names now same as those of epdf PDFRectangle

Bb = {}
Bb.coords = {'x1', 'y1', 'x2', 'y2'}

function Bb:from_rect(r)
  for _,k in ipairs(self.coords) do
    if not r[k] or type(r[k])~='number' then
      errror('from_rect called with illegal parameters')
    end
    -- sanity check on size
    -- FIXME: this limit is far too high
    if r[k]+.5==r[k] or r[k]-.5==r[k] then
      errror('Bb:from_rect: ' .. r[k] ..' greater than maxint')
    end
    local b = {}
    local eps = 0.000001
    b.x1, b.x2 = math.floor(math.min(r.x1, r.x2) + eps),
        math.ceil(math.max(r.x1, r.x2) - eps)
    b.y1, b.y2 = math.floor(math.min(r.y1, r.y2) + eps),
        math.ceil(math.max(r.y1, r.y2) - eps)
    if b.x1==b.x2 or b.y1==b.y2 then
      errror('from_rect: width or height is zero')
    end
    setmetatable(b, {__index=self})
    return b
  end
end

Bb.bb_pat = '^%s*%%%%BoundingBox:'
Bb.bb_end = '^%s*%%%%BoundingBox:%s*%(%s*atend%s*%)'

function Bb:from_comment(s)
  local p = self.bb_pat..'%s*([-+%d]+)'..string.rep('%s+([-+%d]+)',3)
  local b = {}
  b.x1, b.y1, b.x2, b.y2 = string.match(s, p)
  if not b.y2 then
    errror('Bb.from_comment: illegal boundingbox string ' .. s)
  end
  for _,k in ipairs(self.coords) do
    b[k] = tonumber(b[k])
  end
  return Bb:from_rect(b)
end

--[[

function Bb:copy ()
  local b = {}
  for _,k in ipairs(self.coords) do b[k] = self[k] end
  setmetatable(b, {__index=self})
end

function Bb:width()
  return self.x2 - self.x1
end

function Bb:height()
  return self.y2 - self.y1
end

function Bb:expand ()
  -- in-place expansion; does not return an object.
  -- any point in preserving non-negativity?
  local i = settings.bb_spread
  if i and i>0 then
    -- if x1~=0 then x1 = x1-1 end
    -- if y1~=0 then y1 = y1-1 end
    self.x1 = self.x1 - 1
    self.y1 = self.y1 - 1
    self.x2 = self.x2 + 1
    self.y2 = self.y2 + 1
  end
end

-- no longer used: gs handles this
-- call this via pcall
function Bb:wrapper()
  local fn = mktemp('ps')
  local f = io.open(fn, 'wb')
  f:write(string.format('%%%%BoundingBox: 0 0 %d %d\n',
      self:width(), self:height())
      .. string.format('<< /PageSize [%d %d] >> setpagedevice\n',
         self:width(), self:height())
      .. 'gsave\n'
      .. string.format('%d %d translate\n', -self.x1, -self.y1))
  f:close()
  return fn
end

--]]

function Bb:nonnegative ()
  return self.x1>=0 and self.y1>=0
end

function Bb:comment()
  -- if options.debug then print(debug.traceback()) end
  return string.format('%%%%BoundingBox: %d %d %d %d',
      self.x1, self.y1, self.x2, self.y2)
end

-- hires boundingboxes ---------------------------------------------

HRBb = {}

setmetatable(HRBb, {__index=Bb})

function HRBb:from_rect(r)
  for _,k in ipairs(self.coords) do
    if not r[k] or type(r[k])~='number' then
      errror('from_rect called with illegal parameters')
    end
    -- sanity check on size
    if r[k]+.5==r[k] or r[k]-.5==r[k] then
      errror('HRBb:from_rect: ' .. b[k] ..' greater than maxint')
    end
    local b = {}
    b.x1, b.x2 = math.min(r.x1, r.x2), math.max(r.x1, r.x2)
    b.y1, b.y2 = math.min(r.y1, r.y2), math.max(r.y1, r.y2)
    if b.x1==b.x2 or b.y1==b.y2 then
      errror('from_rect: width or height is zero')
    end
    setmetatable(b, {__index=self})
    return b
  end
end

HRBb.bb_pat = '^%s*%%%%HiResBoundingBox:'
HRBb.bb_end = '^%s*%%%%HiResBoundingBox:%s*%(%s*atend%s*%)%s*$'

function HRBb:from_comment(s)
  -- dbg('hrbb from '..s)
  local p = self.bb_pat..'%s*([-+.%deE]+)'..string.rep('%s+([-+.%deE]+)',3)
  local b = {}
  b.x1, b.y1, b.x2, b.y2 = string.match(s, p)
  if not b.y2 then
    errror('HRBb.from_comment: illegal boundingbox string ' .. s)
  end
  for _,k in ipairs(self.coords) do
    b[k] = tonumber(b[k])
  end
  return HRBb:from_rect(b)
end

function HRBb:comment()
  return string.format('%%%%HiResBoundingBox: %f %f %f %f',
      self.x1, self.y1, self.x2, self.y2)
end

--[[

function HRBb:expand ()
  errror('HRBb:expand not available')
end

-- no longer used: gs handles this
-- call this one also via pcall
function HRBb:wrapper()

  -- local fn = mktemp('ps')
  -- local f = io.open(fn, 'wb')
  -- f.write(string.format('<< /PageSize [%f %f] >> setpagedevice\n',
  --        self.x2 - self.x1, self.y2 - self.y1))
  -- f.write(string.format('gsave\n%f %f translate\n', -self.x1, -self.y1))
  -- f:close()
  -- return fn

  return string.format(
      '<< /PageSize [%f %f] >> setpagedevice gsave %f %f translate',
       self.x2 - self.x1, self.y2 - self.y1, -self.x1, -self.y1)
end

--]]

-- manipulating eps/ps/pdf files -----------------------------------

function identify(path)
  local f = io.open(path, 'rb')
  if not f then
    errror('Failure to open '..path..' for identification')
  end
  local filestart= f:read(23)
  f:close()
  if not filestart or filestart=='' then
    return false
  elseif string.match(filestart,'^\197\208\211\198') then -- c5 d0 d3 c6
    return 'epsPreview'
  elseif string.match(filestart,'^%%!PS%-Adobe%-%d%.%d EPSF%-%d%.%d') then
    return 'eps'
  elseif string.match(filestart,'^%%!PS%-Adobe%-%d%.%d') then
    for _, p in ipairs({'.eps', '.epi', '.epsi', '.epsf'}) do
      if string.sub(string.lower(path), -1-string.len(p),-1) == p then
        return 'eps'
      else
        return 'ps'
      end
    end
    return 'ps'
  elseif string.match(filestart, '^%%PDF') then
    return 'pdf'
  else
    return false
  end
end -- identify

function pdf_props(path)
  local pdfdoc = epdf.open(path)
  if not pdfdoc then
    errror('epdf.open failed on '..path)
  end
  -- if os.type=='windows' then waitasec() end
  local cat = pdfdoc:getCatalog()
  if not cat then
    errror('Cannot open pdf catalog of '..path)
  end
  local pg = cat:getNumPages()
  if not pg then
    errror('Cannot read n. of pages of '..path)
  end
  local maver = pdfdoc:getPDFMajorVersion()
  if not maver then
    errror('Cannot read pdf major version of '..path)
  end
  local miver = pdfdoc:getPDFMinorVersion()
  if not miver then
    errror('Cannot read pdf minor version of '..path)
  end
  if maver > 1 then
    print(path..' has pdf major version \n'..tostring(maver)..
          ' which is unsupported;\n'..
          'Continuing with fingers crossed...')
  end
  return pg, miver, maver
end

function info (infile)
  local intype = identify(infile)
  if not intype then
    print(infile..' has an unsupported filetype.')
  elseif intype~='pdf' then
    print(infile..' has type '..intype..'.')
  else
    local pg, miver, maver = pdf_props(infile)
    print(infile..' has type pdf, version '..tostring(maver)..
        '.'..tostring(miver)..' and has '..tostring(pg)..' pages.')
  end
  os.exit()
end

-- PsPdf object -------------------------------------------------

PsPdf = {}

-- creators

function PsPdf:new(ext)
  -- dbg('PsPdf:new')
  local psp = {}
  setmetatable(psp, {__index = self})
  -- assign temp file
  psp.path = mktemp(string.lower(ext))
  if string.lower(ext)=='pdf' then
    psp.type = 'pdf'
  elseif string.lower(ext)=='eps' then
    psp.type = 'eps'
  elseif string.lower(ext)=='ps' then
    psp.type = 'ps'
  else
    psp.type = false
  end
  if psp.type=='eps' then
    psp.pages = 1
  end
  psp.bb = false
  psp.hrbb = false
  return psp
end -- PsPdf:new

function PsPdf:from_path(path)
  -- dbg('PsPdf:from_path')
  local psp = {}
  setmetatable(psp, {__index = self})
  psp.path = path
  if lfs.isfile(path) then
    -- turn existing file into PsPdf object.
    psp.type = identify(psp.path)
    if psp.type=='pdf' then
      psp.pages, psp.miver, psp.maver = pdf_props(psp.path)
    end
  else
    errror('PsPdf:from_path called with non-existant file '..path)
  end
  if psp.type=='eps' then
    psp.pages = 1
  end
  psp.bb = false
  psp.hrbb = false
  -- calculate when needed
  return psp
end -- PsPdf:from_path

--[===[ getting boundingbox property from file itself --------------

find_bb_simple: use only for eps PsPdf objects we generated
ourselves, so we can assume that the bbox comments are in the header
and the hires bb lies within the lores bb.
Of course the file itself is not rewritten.

--]===]

function PsPdf:find_bb_simple()
  -- dbg('PsPdf:find_bb_simple')
  if self.type~='eps' then
    errror('find_bb_simple called with non-eps file '..self.path)
  end
  self.bb = false
  self.hrbb = false
  local slurp = false
  local f = io.open(self.path, 'rb')
  if f then
    slurp = f:read(bufsize)
    f:close()
  end
  lines = {}
  for l in string.gmatch(slurp, '[^\n\r]+') do
    if string.match(l, Bb.bb_pat) then
      self.bb = Bb:from_comment(l)
    elseif string.match(l, HRBb.bb_pat) then
      self.hrbb = HRBb:from_comment(l)
    elseif self.bb then
      break -- stop looking; we expect hrbb next to bb
    end
    if self.bb and self.hrbb then break end
  end
  if not self.bb then
    errror('No valid boundingbox for generated file' .. self.path)
  end
  return self -- no real need for a return value
end

function PsPdf:bb_from_gs(pg)

  -- dbg('bb_from_gs '..pg)

  if self.type=='ps' then
    errror('bb_from_gs called with ps file '..self.path)
    -- not needed for generic PostScript,
    -- page selection only works with pdf files, so we save ourselves
    -- the trouble of picking the right bbox from a list
  end
  if self.type=='eps' and not self.bb:nonnegative() then
    errror('bb_from_gs called on ' .. self.path ..
        ' which has some negative boundingbox coordinates')
  end
  -- A pdf can also have negative ...Box coordinates, but apparently
  -- for pdf the bbox returned by gs is relative to the lower-left corner.
  -- Anyhow, with pdf it all works out even with negative coordinates.

  -- Since Ghostscript writes the boundingbox comments to stderr,
  -- we need a shell to intercept this output:

  local bb_file = mktemp('dsc')
  local cmdline = gs_prog .. ' ' .. table.concat(gs_options,' ')
  if self.type=='pdf' then
    if not pg then pg=1 end
    cmdline = cmdline .. ' -dFirstPage#' .. tostring(pg) ..
      ' -dLastPage#' .. tostring(pg)
  end
  cmdline = cmdline .. ' -sDEVICE#bbox ' .. self.path .. ' 2>'..bb_file

  -- execute shell command

  local r, cmd
  write_log('os.execute: '..cmdline)
  r = os.execute(cmdline)
  if not r then
    errror('Cannot get fixed boundingbox for '..self.path)
  end

  -- read new bbox from ghostscript output
  -- can we really count on the plain bb coming first?
  -- OTOH, I would rather not introduce unnecessary complexity
  -- still, it may be better to match each line with [HR]Bb_pat

  local bb = false
  local hrbb = false
  local fin = io.open(bb_file, 'r')
  if fin then
    for i=1,10 do -- actually, 2 should suffice
      local l = fin:read("*line")
      if not l then break end
      if string.match(l, Bb.bb_pat) then
        bb = Bb:from_comment(l)
      end
      if string.match(l, HRBb.bb_pat) then
        hrbb = HRBb:from_comment(l)
      end
    end
    fin:close()
  end
  if not bb or not hrbb then
    errror('Cannot get fixed boundingbox for '..self.path)
  end
  return bb, hrbb
end

-- eps_clean: remove some problem features from eps (new file & object)

function PsPdf:eps_clean()

  -- return a PsPdf object referring to a new file
  -- without a preview header and with boundingbox(es) in the header

  local function bytes2num (s, i)
    -- convert substring s[i..i+3] to a number.
    -- by working byte for byte we avoid endian issues
    local n = string.byte(s, i+3)
    for j=2,0,-1 do n = 256*n + string.byte(s, i+j) end
    return n
    -- somehow the explicit expression below didn't work
    -- return ((256 * (256 * (256 * string.byte(s,i+3)) + string.byte(s,i+2))
    --          + string.byte(s,i+1)) + string.byte(s,i))
  end

  -- dbg('PsPdf:eps_clean '..self.path)
  if self.type~='eps' and self.type~='epsPreview' then
    errror('epsclean called with non-eps file ' .. self.path)
  end
  local offset, ps_length = false, false
  local fin, fout
  if self.type=='eps' then
    offset = 0
    ps_length = lfs.attributes(self.path, 'size')
  else
    -- read TOC; see Adobe EPS specification
    -- interpret byte for byte, in case the platform is not little-endian
    fin = io.open(self.path, 'rb')
    if fin then
      local toc = fin:read(12)
      fin:close()
      if toc and string.len(toc)==12 then
        offset = bytes2num(toc, 5)
        ps_length = bytes2num(toc, 9)
      end
    end
    if not offset then
      errror('Could not read preview header of ' .. self.path)
    end
    -- dbg(tostring(offset)..' '..tostring(ps_length))
  end

  -- create the PsPdf object which is to be returned

  local psp
  psp = PsPdf:new('eps')
  -- dbg(psp.path)

  -- read an initial and if necessary a final chunk of the file
  -- to find boundingbox comments.

  local atend = false
  local hr_atend = false
  local slurp -- the read buffer
  local l -- contains current scanned line; split off from slurp
  -- pre_lines: scanned header lines; alternately lines and eols
  local pre_lines = {}
  -- new_offset: offset plus combined length of scanned header lines
  local new_offset = offset
  -- post_lines: scanned trailer lines
  local post_lines = {}
  -- middle_length: ps_length minus scanned header- and and maybe trailer parts
  -- this is the length of file that will be copied wholesale.
  local middle_length
  local i, i_bb, i_hrbb
  local j, j_bb, j_hrbb, j_end
  -- j_end: index of final scanned trailer line
  -- no i_end necessary: for header lines we can use #pre_lines.

  fin = io.open(self.path, 'rb')
  if not fin then errror('Cannot read '..self.path) end
  fin:seek('set', offset)

  -- remaining, unscanned length of input buffer slurp
  local unscanned = math.min(ps_length,bufsize)
  -- dbg('bytes to be read: '..tostring(unscanned))
  slurp = fin:read(unscanned)
  -- dbg('Read from '..self.path..': '..string.len(slurp)..' bytes')

  -- unnecessary:
  psp.bb = nil
  psp.hrbb = nil

  i, i_bb, i_hrbb = 0, false, false
  while unscanned>0 do
    i = i+1
    if string.find(slurp,'[\n\r]')==1 then
      l,slurp = string.match(slurp, '^([\n\r]+)(.*)$')
    else
      l,slurp = string.match(slurp, '^([^\n\r]+)(.*)$')
      if string.match(l, Bb.bb_end) then
        atend = true
        i_bb = i
      elseif string.match(l, Bb.bb_pat) then
        -- dbg(l)
        psp.bb = Bb:from_comment(l)
        -- dbg(psp.bb:comment())
        -- from_comment errors out on failure; no need to check return value
        i_bb = i
      elseif string.match(l, HRBb.bb_end) then
        hr_atend = true
        i_hrbb = i
      elseif string.match(l, HRBb.bb_pat) then
        -- dbg(l)
        psp.hrbb = HRBb:from_comment(l)
        -- dbg(psp.hrbb:comment())
        i_hrbb = i
      end -- bbox line
    end -- eol/non-eol
    pre_lines[i] = l
    unscanned = unscanned - string.len(l)
    if (i_bb and (i_hrbb or (i_bb<(i-1)))) or unscanned<=0 then
      -- condition i_bb<i-1:
      -- We do not want to find the hrbb of an included eps.
      -- Therefore we stop looking for hrbb if it is not next to bb
      -- (with an intervening eol)
      -- Note that the header comments are not necessarily terminated
      -- with a %%EndComments line; see Adobe DSC spec 5001
      break
    end -- deciding whether to stop
  end -- while
  new_offset = offset + string.len(table.concat(pre_lines))
  middle_length = ps_length - string.len(table.concat(pre_lines))

  if atend or hr_atend then
    -- find boundingbox comments, starting from end of postscript
    if ps_length>bufsize then
      fin:seek('set',offset+ps_length-bufsize)
      unscanned = bufsize
      slurp = fin:read(unscanned)
    else
      -- use what is left from old slurp
      unscanned = string.len(slurp)
    end
    j = 1 -- count down from 0
    j_bb, j_hrbb, j_end = false, false, false
    while unscanned>0 do
      j = j - 1
      -- dbg(j)
      if string.find(slurp,'[\n\r]', string.len(slurp)) then
        -- dbg('eol(s)')
        slurp,l = string.match(slurp, '^(.-)([\n\r]+)$')
        -- '-': non-greedy matching
      else
        slurp,l = string.match(slurp, '^(.-)([^\n\r]+)$')
        -- dbg(l)
        if string.match(l, Bb.bb_pat) then
          psp.bb = Bb:from_comment(l)
          j_bb = j
        elseif string.match(l, HRBb.bb_pat) then
          psp.hrbb = HRBb:from_comment(l)
          j_hrbb = j
        end -- bbox line
      end -- eol/non-eol
      post_lines[j] = l
      unscanned = unscanned - string.len(l)
      if (psp.bb and
          (psp.hrbb or not hr_atend or j_bb>(j+1))) or unscanned<=0 then
        -- stop looking
        j_end = j
        break
      end -- deciding whether to stop
    end -- while
    middle_length = middle_length -
      string.len(table.concat(post_lines, '', j_end, 0))
  end --if atend
  fin:close()
  -- fix boundingbox lines
  if atend and j_bb then
    -- pre_lines[i_bb] = post_lines[j_bb]
    pre_lines[i_bb] = psp.bb:comment() -- WHY DOESNT THIS WORK ????
    post_lines[j_bb] = ''
    post_lines[j_bb+1] = ''
  end
  if hr_atend and j_hrbb then
    -- dbg(psp.hrbb:comment())
    -- pre_lines[i_hrbb] = post_lines[j_hrbb]
    pre_lines[i_hrbb] = psp.hrbb:comment()
    post_lines[j_hrbb] = ''
    post_lines[j_hrbb+1] = ''
  end
  -- create cleaned eps file
  fout = io.open(psp.path, 'wb')
  if not fout then errror('Cannot create new file '..psp.path) end
  fout:write(table.concat(pre_lines))
  fout:close()
  slice_file(self.path, psp.path, middle_length, new_offset, 'ab')
  fout = io.open(psp.path, 'ab')
  fout:write(table.concat(post_lines, '', j_end, 0))
  fout:close()
  return psp
end -- eps_clean

-- tight boundingbox (new file & object)

function PsPdf:eps_crop()

  -- not a proper conversion, although
  -- we use the Ghostscript bbox device for a tight boundingbox.
  -- We use both the regular and the hires boundingbox from gs.
  -- The eps should already have been cleaned up by eps_clean,
  -- and the current boundingbox should not contain negative coordinates,
  -- otherwise the bbox output device may give incorrect results.
  -- Only the boundingbox in the eps is rewritten.

  -- dbg('PsPdf:eps_crop '..self.path)
  if self.type~='eps' then
    errror('eps_crop called with non-eps file ' .. self.path)
  end

  -- create the PsPdf object which is to be returned

  local psp = PsPdf:new('eps')

  -- read new bbox from ghostscript output

  psp.bb, psp.hrbb = self:bb_from_gs()

  -- rewrite header with new boundingboxes

  local slurp -- the read buffer
  local l -- contains current scanned line; split off from slurp
  -- pre_lines: scanned header lines; alternately lines and eols
  local pre_lines = {}
  -- offset: combined length of scanned header lines
  local offset = 0
  local ps_length = lfs.attributes(self.path, 'size')
  local i, i_bb, i_hrbb

  fin = io.open(self.path, 'rb')
  if not fin then errror('Cannot read '..self.path) end

  -- remaining, unscanned length of input buffer slurp
  local unscanned = math.min(ps_length,bufsize)
  -- dbg('bytes to be read: '..tostring(unscanned))
  slurp = fin:read(unscanned)
  -- dbg('Read from '..self.path..': '..string.len(slurp)..' bytes')
  i, i_bb, i_hrbb = 0, false, false
  while unscanned>0 do
    i = i+1
    if string.find(slurp,'[\n\r]')==1 then
      l,slurp = string.match(slurp, '^([\n\r]+)(.*)$')
    else
      l,slurp = string.match(slurp, '^([^\n\r]+)(.*)$')
      if string.match(l, Bb.bb_pat) then
        i_bb = i
      elseif string.match(l, HRBb.bb_pat) then
        i_hrbb = i
      end -- bbox line
    end -- eol/non-eol
    pre_lines[i] = l
    unscanned = unscanned - string.len(l)
    if (i_bb and (i_hrbb or (i_bb<(i-1)))) or unscanned<=0 then
      break
    end
  end -- while
  fin:close()
  offset = string.len(table.concat(pre_lines))

  if i_hrbb then
    pre_lines[i_bb] = psp.bb:comment()
    pre_lines[i_hrbb] = psp.hrbb:comment()
  else
    -- jam both bbox comments into one slot, with an intervening eol.
    -- for the sake of conformity, we copy an existing eol.
    pre_lines[i_bb] = psp.bb:comment() .. pre_lines[i_bb-1] ..
        psp.hrbb:comment()
  end

  -- write a new eps file

  fout = io.open(psp.path, 'wb')
  if not fout then errror('Cannot write new file '.. psp.path) end
  fout:write(table.concat(pre_lines))
  fout:close()
  slice_file(self.path, psp.path,
      lfs.attributes(self.path,'size') - offset, offset, 'ab')
  options.bbox = false
  -- dbg('eps_crop from '..self.path..' to '..psp.path)
  return psp
end -- eps_crop

--[===[ real conversions involving a single call of gs or pdftops --------

Each conversion fullfills all options that it can: gray, bbox and
page. gray when converting to pdf, bbox when converting from eps or
from pdf to pdf and page when converting from pdf. It then sets the
fullfilled option(s) to false.

We like to preserve fonts as fonts. gs does this when generating
pdf, but may fail for fonts such as cid and large truetype when
generating PostScript. In such cases, pdftops may succeed. However,
it seems that if the page contains an element that does not cleanly
convert, pdftops simply rasterizes the entire page, and that this
choice is made per page.

--]===]

-- TODO: multiple pages?
-- (means additional parameter checking)

-- Converting from pdf to pdf using luatex; no grayscaling

function PsPdf:pdf_crop()

  -- options to be fulfilled: page, boundingbox
  -- only called directly.
  -- embeds the pdf with crop parameters into a new (lua)tex document
  -- dbg('PsPdf:pdf_crop '..self.path)
  if not (options.bbox or options.page) then
    return self
  end
  if options.page and options.page > self.pages then
    errror('PsPdf:pdf_crop called with non-existent page '.. options.page)
  end
  local pg = options.page or 1
  local bb, hrbb
  if options.bbox then
    bb, hrbb = self:bb_from_gs(pg)
  else
    -- dbg('about to use epdf')
    -- use [Trim|Crop|Media]Box instead
    -- if os.type=='windows' then waitasec() end
    local dummy = epdf.open(self.path)
    -- if os.type=='windows' then waitasec() end
    if not dummy then
      errror('Epdf: cannot open '..self.path)
    end
    -- dbg('about to get catalog')
    dummy = dummy:getCatalog()
    if not dummy then
      errror('Cannot open catalog of '..self.path)
    end
    -- dbg('got catalog')
    dummy = dummy:getPage(pg)
    if not dummy then
      errror('Epdf: cannot open page object '..tostring(pg)..' of '..self.path)
    end
    hrbb = dummy:getTrimBox()
    if not hrbb then
      hrbb = dummy:getCropBox()
    end
    if not hrbb then
      hrbb = dummy:getMediaBox()
    end
    -- further checks, including for non-nil, by Bb:from_rect,
    -- which errors out on failures
    hrbb = HRBb:from_rect(hrbb)
  end

  -- luatex on searchpath
  local luatex_prog = 'luatex'

  -- write TeX file which includes cropped pdf page
  -- adapted from Heiko Oberdiek's pdfcrop utility.
  -- first, create a table with the component strings for the tex source
  dummy = {}
  dummy[1] = [[
\catcode37 14 % percent
\catcode33 12 % exclam
\catcode34 12 % quote
\catcode35  6 % hash
\catcode39 12 % apostrophe
\catcode40 12 % left parenthesis
\catcode41 12 % right parenthesis
\catcode45 12 % minus
\catcode46 12 % period
\catcode60 12 % less
\catcode61 12 % equals
\catcode62 12 % greater
\catcode64 12 % at
\catcode91 12 % left square
\catcode93 12 % right square
\catcode96 12 % back tick
\catcode123 1 % left curly brace
\catcode125 2 % right curly brace
\catcode126 12 % tilde
\catcode`\#=6 %
\escapechar=92 %
\def\IfUndefined#1#2#3{%
  \begingroup\expandafter\expandafter\expandafter\endgroup
  \expandafter\ifx\csname#1\endcsname\relax
    #2%
  \else
    #3%
  \fi
}
\begingroup
  \newlinechar=10 %
  \endlinechar=\newlinechar %
  \ifnum0%
      \directlua{%
        if tex.enableprimitives then
          tex.enableprimitives('TEST', {
            'luatexversion',
            'pdfoutput',
            'pdfcompresslevel',
            'pdfhorigin',
            'pdfvorigin',
            'pdfpagewidth',
            'pdfpageheight',
            'pdfmapfile',
            'pdfximage',
            'pdflastximage',
            'pdfrefximage',
            'pdfminorversion',
            'pdfobjcompresslevel',
          })
          tex.print('1')
        end
      }%
      \ifx\TESTluatexversion\UnDeFiNeD\else 1\fi %
      =11 %
    \global\let\luatexversion\luatexversion %
    \global\let\pdfoutput\TESTpdfoutput %
    \global\let\pdfcompresslevel\TESTpdfcompresslevel %
    \global\let\pdfhorigin\TESTpdfhorigin %
    \global\let\pdfvorigin\TESTpdfvorigin %
    \global\let\pdfpagewidth\TESTpdfpagewidth %
    \global\let\pdfpageheight\TESTpdfpageheight %
    \global\let\pdfmapfile\TESTpdfmapfile %
    \global\let\pdfximage\TESTpdfximage %
    \global\let\pdflastximage\TESTpdflastximage %
    \global\let\pdfrefximage\TESTpdfrefximage %
    \global\let\pdfminorversion\TESTpdfminorversion %
    \global\let\pdfobjcompresslevel\TESTpdfobjcompresslevel %
  \else %
    \errmessage{%
      Missing \string\luatexversion %
    }%
  \fi %
\endgroup %

\pdfoutput=1 %
\pdfcompresslevel=9 %
\csname pdfmapfile\endcsname{}
\def\setpdfversion#1#2{%
  \ifnum#2>1 %
    \pdfobjcompresslevel=2 %
    % including unsupported pdf version!
    \pdfinclusionerrorlevel=0
    \pdfminorversion=9\relax
  \else
    \ifnum#1>4 %
      \pdfobjcompresslevel=2 %
    \else
      \pdfobjcompresslevel=0 %
    \fi
    \pdfminorversion=#1\relax
  \fi
}
\def\page #1 [#2 #3 #4 #5]{%
  \count0=#1\relax
  \setbox0=\hbox{%
    \pdfximage page #1 mediabox{]]
  dummy[2] = self.path
  dummy[3] = [[}%
    \pdfrefximage\pdflastximage
  }%
  \pdfhorigin=-#2bp\relax
  \pdfvorigin=#3bp\relax
  \pdfpagewidth=#4bp\relax
  \advance\pdfpagewidth by -#2bp\relax
  \pdfpageheight=#5bp\relax
  \advance\pdfpageheight by -#3bp\relax
  \ht0=\pdfpageheight
  \shipout\box0\relax
}
]]
  -- pdf minor version to write to tex header
  local tex_miver = false
  if settings.pdf_version=='default' then
    tex_miver = self.miver
  else
    -- in this case, gs should already have converted to
    -- a sufficiently low version
    tex_miver = tonumber(settings.pdf_version)
    if tex_miver>self.miver then
      errror('Pdf_crop: forgot to reduce pdf version')
    end
  end
  dummy[4] = string.format([[
\setpdfversion{%d}{%d}
\page %d [%f %f %f %f]
\csname @@end\endcsname
\end
]],
  tex_miver, self.maver, options.page or 1,
  hrbb.x1, hrbb.y1, hrbb.x2, hrbb.y2)

  local textemp = mktemp('tex') -- this also takes care of pdf:
  local pdftemp = string.gsub(textemp, 'tex$', 'pdf')
  -- if os.type=='windows' then waitasec() end
  local f = io.open(textemp, 'w')
  -- if os.type=='windows' then waitasec() end
  f:write(table.concat(dummy, ''))
  f:close()
  local cmd, res, psp
  if os.type=='unix' then
    cmd = {luatex_prog, '--safer', '--no-shell-escape', textemp}
    log_cmd(cmd)
    res = os.spawn(cmd)
  else
    cmd = luatex_prog..' --safer --no-shell-escape '..textemp
    log_cmd({cmd})
    -- os.execute('timeout /t 1 /nobreak >nul')
    res = os.execute(cmd)
  end
  if res and res==0 and lfs.attributes(pdftemp, 'size')>0 then
    psp = PsPdf:from_path(pdftemp)
    return psp
  else
    errror('pdf_crop failed on '..self.path)
  end
end

function PsPdf:eps_to_pdf()

  -- option to be fulfilled: gray
  -- set target and pdf version if applicable
  -- dbg('PsPdf:eps_to_pdf '..self.path)
  if self.type~='eps' then
    errror('PsPdf:eps_to_pdf called for non-eps file '.. self.path)
  end
  local cmd
  if options.bbox and self.bb:nonnegative() then
    self = self:eps_crop() -- this sets options.bbox to false
  end
  cmd = tab_combine({{gs_prog}, gs_options, pdf_options})
  -- dbg(table.concat(cmd,' '))
  if options.gray then
    cmd = tab_combine({cmd, gray_options})
  -- dbg(table.concat(cmd,' '))
    options.gray = false
  end
  table.insert(cmd, '-dEPSCrop') -- always hires bb
  -- dbg(table.concat(cmd,' '))
  local psp = PsPdf:new('pdf')
  table.insert(cmd, '-sOutputFile#'..psp.path)
  -- dbg(table.concat(cmd,' '))
  cmd = tab_combine({cmd, pdf_tail_options, {self.path}})
  -- dbg(table.concat(cmd,' '))
  log_cmd(cmd)
  local res = os.spawn(cmd)
  if res and res==0 and lfs.attributes(psp.path, 'size')>0 then
    psp.pages, psp.miver, psp.maver = pdf_props(psp.path)
    return psp
  else
    errror('eps_to_pdf failed on '..self.path)
  end
end -- eps_to_pdf

-- Converting from pdf to pdf with grayscaling and/or page selection

function PsPdf:pdf_to_pdf()

  -- option to be fulfilled: gray and optionally page.
  -- do not call this just for page selection because
  -- pdf_crop can do this in a less invasive manner
  -- dbg('PsPdf:pdf_to_pdf '..self.path)
  if self.type~='pdf' then
    errror('PsPdf:pdf_to_pdf called for non-pdf file '.. self.path)
  end
  local cmd
  if options.page and options.page > self.pages then
    errror('PsPdf:pdf_to_pdf called with non-existent page '.. options.page)
  end
  cmd = tab_combine({{gs_prog}, gs_options, pdf_options})
  -- dbg(table.concat(cmd,' '))
  if options.gray then
    cmd = tab_combine({cmd, gray_options})
    -- dbg(table.concat(cmd,' '))
    options.gray = false
  end
  if options.page then
    table.insert(cmd, '-dFirstPage#'..tostring(options.page))
    table.insert(cmd, '-dLastPage#'..tostring(options.page))
    -- dbg(table.concat(cmd,' '))
    options.page = false
  end
  local psp = PsPdf:new('pdf')
  table.insert(cmd, '-sOutputFile#'..psp.path)
  cmd = tab_combine({cmd, pdf_tail_options})
  -- dbg(table.concat(cmd,' '))
  table.insert(cmd, self.path)
  -- dbg(table.concat(cmd,' '))
  log_cmd(cmd)
  local res = os.spawn(cmd)
  if res and res==0 and lfs.attributes(psp.path, 'size')>0 then
    psp.pages, psp.miver, psp.maver = pdf_props(psp.path)
    return psp
  else
    errror('pdf_to_pdf failed on '..self.path)
  end
end -- pdf_to_pdf

function PsPdf:pdf_to_eps()

  -- options to be fulfilled: bbox and page
  -- dbg(tostring(settings.pdftops_prog))
  -- dbg('pdf_to_eps '..self.path)
  local psp = PsPdf:new('eps')
  local cmd, res
  local page = false
  if self.pages > 1 then
    if options.page then
      page = options.page
      if page > self.pages then
        errror('PsPdf:pdf_to_eps called with non-existant page '..
            tostring(page))
      end
    else
      page = 1
    end
    page = tostring(page)
  end -- self.pages > 1
  if pdftops then
    if page then
      cmd = tab_combine({{pdftops}, ps_options,
        {'-f', page, '-l', page,
         '-eps', self.path, psp.path}})
    else
      cmd = tab_combine({{pdftops}, ps_options,
        {'-eps', self.path, psp.path}})
    end
    options.page = false
    log_cmd(cmd)
    if os.type=='windows' then
      -- suppress console output of 'No display font for...' messages,
      -- which are usually harmless and for which I know no easy fix
      -- pdftops -q does not do the trick on Windows,
      -- and redirection to logfile gives access denied under miktex
      -- res = os.spawn({'cmd', '/c', table.concat(cmd, ' ')..' 2>>'..log_bsl})
      res = os.execute(table.concat(cmd, ' ')..' 2>nul')
    else
      res = os.spawn(cmd)
    end
    if res and res==0 and lfs.attributes(psp.path, 'size')>0 then
      psp.pages = 1
    else
      errror('pdf_to_eps failed on '..self.path)
    end
    -- fix for incorrect DSC header produced by some versions of pdftops:
    -- if necessary, change line `% Produced by ...' into `%%Produced by ...'
    -- this is usually the second line.
    -- otherwise the DSC header would be terminated before the bbox comment.
    -- this problem exists with pdftops from TL2011/w32.
    local slurp -- input buffer
    local fin = io.open(psp.path, 'rb')
    if not fin then errror('Cannot read '..psp.path) end

    -- remaining, unscanned length of input buffer slurp
    local unscanned = math.min(lfs.attributes(psp.path, 'size'),bufsize)
    slurp = fin:read(unscanned)
    local i, i_bb = 0, false
    local needs_fixing = false
    local pre_lines = {}
    local offset = 0
    while unscanned>0 do
      i = i+1
      if string.find(slurp,'[\n\r]')==1 then
        l,slurp = string.match(slurp, '^([\n\r]+)(.*)$')
      else
        l,slurp = string.match(slurp, '^([^\n\r]+)(.*)$')
        if string.match(l, Bb.bb_pat) then
          -- bbox line
          i_bb = i
        elseif string.match(l, '^%%%s') then -- `%' is escape char: doubled
          -- %X with X printable would be ok
          needs_fixing = true
          -- fix rightaway
          l = string.gsub(l, '^%%%s', '%%%%') -- same length
        end
      end -- eol/non-eol
      pre_lines[i] = l
      unscanned = unscanned - string.len(l)
      offset = offset + string.len(l)
      if i_bb then break end
    end -- while
    fin:close()
    if needs_fixing then
      -- write a new eps file
      local newfile = mktemp('eps')
      fout = io.open(newfile, 'wb')
      if not fout then errror('Cannot write new file '.. newfile) end
      fout:write(table.concat(pre_lines))
      fout:close()
      -- dbg('fixing '..psp.path..' to '..newfile)
      slice_file(psp.path, newfile,
        lfs.attributes(psp.path,'size') - offset, offset, 'ab')
      psp.path = newfile
    end -- needs_fixing
  else -- use ghostscript
    local epsdev = epsdevice()
    if not epsdev then
      errror('Conversion to eps not supported by this ghostscript')
    end
    cmd = tab_combine({{gs_prog}, gs_options,
      {'-sDEVICE#'..epsdev, '-dHaveTrueTypes=true', '-dLanguageLevel#3'}})
    -- the restrictions on eps files are apparently
    -- incompatible with grayscaling
    if options.page then
      table.insert(cmd, '-dFirstPage='..options.page)
      table.insert(cmd, '-dLastPage='..options.page)
    end
    table.insert(cmd, '-sOutputFile='..psp.path)
    table.insert(cmd, self.path)
    options.page = false
    log_cmd(cmd)
    res = os.spawn(cmd)
    if res and res==0 and lfs.attributes(psp.path, 'size')>0 then
      psp.pages = 1
    else
      errror('pdf_to_eps failed on '..self.path)
    end
  end -- use ghostscript
  psp:find_bb_simple()
  if options.bbox then psp = psp:eps_crop() end
  return psp

end -- pdf_to_eps

function PsPdf:ps_to_pdf()

  -- options to be fulfilled: gray
  -- dbg('PsPdf:ps_to_pdf '..self.path)
  if self.type~='ps' then
    errror('PsPdf:ps_to_pdf called for non-ps file '.. self.path)
  end
  local cmd
  cmd = tab_combine({{gs_prog}, gs_options, pdf_options})
  if options.gray then
    cmd = tab_combine({cmd, gray_options})
    options.gray = false
  end
  local psp = PsPdf:new('pdf')
  table.insert(cmd, '-sOutputFile#'..psp.path)
  cmd = tab_combine({cmd, pdf_tail_options})
  table.insert(cmd, self.path)
  log_cmd(cmd)
  local res = os.spawn(cmd)
  if res and res==0 and lfs.attributes(psp.path, 'size')>0 then
    psp.pages, psp.miver, psp.maver = pdf_props(psp.path)
    return psp
  else
    errror('ps_to_pdf failed on '..self.path)
  end

end -- PsPdf:ps_to_pdf

function PsPdf:pdf_to_ps()

  -- options to be fulfilled: page and, if not using pdftops, also gray
  -- dbg('PsPdf:pdf_to_ps '..self.path)
  local psp = PsPdf:new('ps')
  local page = false
  if self.pages>1 then
    if options.page and options.page > self.pages then
      errror('PsPdf:pdf_to_ps called with non-existant page '.. options.page)
    elseif options.page then
      page = tostring(options.page)
      psp.pages = 1
    end
  else
    psp.pages = self.pages
  end
  local cmd, res
  if pdftops then
    cmd = tab_combine({{pdftops}, ps_options})
    if page then
      cmd = tab_combine({cmd, {'-f', page, '-l', page}})
    end
    cmd = tab_combine({cmd, {'-paper', 'match', self.path, psp.path}})
  else -- use ghostscript
    cmd = tab_combine({{gs_prog}, gs_options,
        {'-sDEVICE#ps2write', '-dHaveTrueTypes=true', '-dLanguageLevel#3'}})
    if options.gray then
      cmd = tab_combine({cmd, gray_options})
    -- dbg(table.concat(cmd,' '))
      options.gray = false
    end
    if page then
      cmd = tab_combine({cmd, {'-dFirstPage#'..page, '-dLastPage#'..page}})
    end
    table.insert(cmd, '-sOutputFile#'..psp.path)
    -- table.insert(cmd, '-f')
    table.insert(cmd, self.path)
  end
  options.page = false
  log_cmd(cmd)
  if os.type=='windows' and pdftops then
    -- suppress console output of 'No display font for...' messages,
    -- which are usually harmless and for which I know no easy fix
    -- pdftops -q does not do the trick on Windows,
    -- and redirection to logfile gives access denied under miktex
    -- res = os.spawn({'cmd', '/c', table.concat(cmd, ' ')..' 2>>'..log_bsl})
    res = os.execute(table.concat(cmd, ' ')..' 2>nul')
  else
    res = os.spawn(cmd)
  end
  if res and res==0 and lfs.attributes(psp.path, 'size')>0 then
    return psp
  else
    errror('pdf_to_ps failed on '..self.path)
  end
end -- PsPdf:pdf_to_ps

function PsPdf:any_to_any()

  -- weed out nonsense options

  -- dbg('PsPdf:any_to_any '..self.path)
  if options.type=='ps' then
    options.bbox = false
    -- dbg('Ignoring bbox option for ps output')
  end
  if options.bbox and not options.page then
    options.page = 1
    -- dbg('Selecting page 1 for bbox')
  end
  if self.pages==1 then
    options.page = false
    -- dbg('dropping page selection; source is already a 1-page document')
  end
  -- for _,o in ipairs({'page', 'gray', 'bbox'}) do
  --   -- if options[o] then dbg('Do option '..o) end
  -- end

  -- `distiller' settings depend on whether final output is pdf
  -- '.setpdfwrite' is just some optimization option for ghostscript
  if options.type=='pdf' then
    if settings.pdf_version~='default' then
      table.insert(pdf_options, '-dCompatibilityLevel#'..settings.pdf_version)
    end
    -- below, consider adding <</NeverEmbed [/Times-Roman /TimesBold ...]>>
    if settings.pdf_target=='screen' or settings.pdf_target=='ebook' then
      pdf_tailoptions = {'-c', '.setpdfwrite', '-f'}
      -- -f ensures that the input filename is not added to the -c string
    else
      pdf_tailoptions = {
          '-c', '.setpdfwrite <</NeverEmbed [ ] >> setdistillerparams', '-f'}
    end
  else
    pdf_tailoptions = {
        '-c', '.setpdfwrite <</NeverEmbed [ ] >> setdistillerparams', '-f'}
  end

  if options.type=='pdf' then
    table.insert(pdf_options, '-dPDFSETTINGS#/'..settings.pdf_target)
    if settings.pdf_version~='default' then
      table.insert(pdf_options, '-dCompatibilityLevel#'..settings.pdf_version)
    end
  else
    table.insert(pdf_options, '-dPDFSETTINGS#/default')
  end

  --[[
  each single-step conversion takes care of options it can handle
  and sets those options to false.
  for boundingboxes, eps_crop is either called explicitly
  or called implicitly by another converter.
  pdf_crop is always called explicitly and always as the last step

  all calls to external programs work on temporary files
  in the then-current temporary directory, with a simple generated
  filename. So no need to quote names of input- and output filenames.
  --]]

  local psp = self
  local newfile

  if psp.type=='eps' or psp.type=='epsPreview' then
    -- As a side effect of eps_clean, the modified source file is copied
    -- to the temp subdirectory.
    psp = psp:eps_clean()
    if options.bbox and psp.bb:nonnegative() then
      psp = psp:eps_crop()
    end
    if options.type=='eps' then
      if options.gray or options.bbox then
        -- bbox: eps_crop was apparently not applicable: pdf roundtrip
        psp = psp:eps_to_pdf():pdf_to_eps()
      end
    elseif options.type=='pdf' then
      psp = psp:eps_to_pdf()
      if options.bbox then
        psp = psp:pdf_crop()
      end
    elseif options.type=='ps' then
      psp = psp:eps_to_pdf():pdf_to_ps()
    end
    return psp

  elseif psp.type=='ps' then
    -- preliminary:
    -- copy infile to a file in the temp directory, needed for gs -dSAFER
    newfile = mktemp(psp.type)
    slice_file(psp.path, newfile)
    -- dbg(psp.path..' copied to '..newfile..' in '..lfs.currentdir())
    psp.path = newfile

    -- actual conversion
    if options.type=='eps' then
      return psp:ps_to_pdf():pdf_to_eps()
    elseif options.type=='pdf' then
      if options.bbox or options.page then
        return psp:ps_to_pdf():pdf_crop()
      else
        return psp:ps_to_pdf()
      end
    elseif options.type=='ps' then
      if options.gray or options.page then
        return psp:ps_to_pdf():pdf_to_ps()
      else
        return psp -- no conversion necessary
      end
    end -- pdf => ps

  elseif psp.type=='pdf' then
    -- preliminary:
    -- copy infile to a file in the temp directory, for gs -dSAFER
    newfile = mktemp(psp.type)
    slice_file(psp.path, newfile)
    -- dbg(psp.path..' copied to '..newfile..' in '..lfs.currentdir())
    psp.path = newfile

    -- actual conversion
    if options.type=='eps' then
      if options.gray then
        -- one-step grayscaling available for gs/ps but not for gs/eps
        return psp:pdf_to_pdf():pdf_to_eps()
      else
        return psp:pdf_to_eps()
      end
    elseif options.type=='pdf' then
      -- pdf_crop can take care of bbox and page,
      -- but not of gray and not of target use or pdf version
      do
        local need_gs = false
        -- compare actual and required versions,
        -- allowing for rounding differences
        if settings.pdf_version~='default' and
            (psp.maver+0.1*psp.miver)>tonumber(settings.pdf_version)-0.01 then
          need_gs = true
        end
        if settings.pdf_target~='default' then
          need_gs = true
        end
        if options.gray then
          need_gs = true
        end
        local need_crop = false
        if options.bbox then
          need_crop = true
        end
        if (not need_gs) and options.page then
          need_crop = true
        end
        if need_gs then
          psp = psp:pdf_to_pdf()
        end
        if need_crop or (psp.pages>1 and options.page) then
          psp = psp:pdf_crop()
        end
        return psp
      end
    elseif options.type=='ps' then
      if options.gray and pdftops then
        return psp:pdf_to_pdf():pdf_to_ps()
      else
        return psp:pdf_to_ps()
      end
    end -- pdf => ps
  end -- psp.type=='ps'|'pdf'
end -- any_to_any

-- system-dependent initialization -----------------------------------

-- current directory, at program start
cwd = lfs.currentdir()
if os.type == 'windows' then cwd = string.gsub(cwd, '\\', '/') end

-- child searchpath initially set to parent searchpath
-- childpath = os.getenv('PATH')

-- prepend (lua)tex directory to searchpath, if not already there
maybe_add_path(os.selfdir, false)

-- Windows: miktex, TL or neither
-- no support yet for separate ghostscript
is_miktex = false
is_tl_w32 = false
if os.type == 'windows' then
  if string.find (string.lower(kpse.version()), 'miktex') then
    is_miktex = true
  else
    local rt = string.gsub(os.selfdir,'[\\/][^\\/]+[\\/][^\\/]+$', '')
    if not rt then
      errror('Unrecognized TeX directory structure', 0)
    elseif lfs.isfile(rt..'/release-texlive.txt') then
      --[[
      -- TL version is easy to determine but is not needed
      local fin = io:open(rt..'release-texlive.txt', 'r')
      if fin then
        local l = fin:read('*line')
        tl_ver = string.match(l, 'version%s+(%d+)$')
        if tl_ver then tl_ver = tonumber(tl_ver) end
      end -- if fin
      --]]
      is_tl_w32 = true
    else
      errror('Not MikTeX and no file ' .. rt ..
          '/release-texlive.txt; TeX installation not supported.', 0)
    end -- if isfile
  end -- if not miktex
end -- if windows

-- without Ghostscript we are dead in the water.
-- TL/w32: add to searchpath
gs_prog = false
do
  local rt=''
  if os.type == 'unix' then
    if find_on_path('gs') then
      gs_prog = 'gs'
    else
      error('No ghostscript on searchpath!', 0)
    end
  elseif is_miktex then
    gs_prog = 'mgs.exe'
    -- neither MiKTeX's nor TL's ghostscript need GS_LIB to be set
  elseif is_tl_w32 then
    -- windows/TeX Live
    -- grandparent of texlua.exe directory .. ...
    rt = string.gsub(os.selfdir,'[\\/][^\\/]+[\\/][^\\/]+$', '')
        ..'/tlpkg/tlgs'
    maybe_add_path(rt..'/bin', false)
    gs_prog = 'gswin32c.exe'
    --[[ problems with (at least) grayscaling
    gs_prog = 'rungs.exe'
    --]]
  else
    errror('Only TeX Live and MikTeX supported!', 0)
  end
end -- do

-- directory for configuration and log
epsdir = ''
if os.type == 'windows' then
  epsdir = fw(ep_shortname(os.getenv('APPDATA'))) .. '/epspdf'
else
  epsdir = os.getenv('HOME')..'/.epspdf'
end
-- dbg('epsdir: '..epsdir)
rcfile = epsdir .. '/config'
logfile = epsdir .. '/epspdf.log'

-- create epsdir if necessary
if lfs.isfile(epsdir) then
  error('Cannot continue; epspdf directory ' .. epsdir .. ' is a file')
elseif not lfs.isdir(epsdir) then
  if not lfs.mkdir(epsdir) then
    error('Failed to create epspdf directory ' .. epsdir)
  end
end

-- start logging ---------------------------------

-- log rotate if logfile too big
if lfs.attributes(logfile) and lfs.attributes(logfile).size > 100000 then
  local oldlog = logfile .. '.old'
  if lfs.attributes(oldlog) then
    if os.remove(oldlog) then os.rename(logfile,oldlog) end
  elseif lfs.attributes(logfile) then do
    -- separate epsdir runs with empty lines
    print_log('\n\nNew run')
  end end -- do elseif
end -- if lfs...logfile

write_log('epspdf '..table.concat(arg, ' '))

--[[ some debug output

dbg ('os is ' .. os.type .. ' and ' .. os.name)
dbg ('texlua in ' .. os.selfdir)
dbg('Ghostscript: ' .. gs_prog)
--]]

--[[

settings, initial values

The values in the settings array have lowest priority - lower than
autodetect and command-line options.  We go for false rather than
undefined, because this results in an actual settings entry.
We ignore illegal settings in the config file.

--]]

pdf_targets = {'screen', 'ebook', 'printer', 'prepress', 'default'}
pdf_versions = {'1.2', '1.3', '1.4', 'default'}

settings = {}
descriptions = {}

settings.pdf_target = 'default'
descriptions.pdf_target = 'One of ' .. join(pdf_targets, ', ', ' or ')

settings.pdf_version = 'default'
descriptions.pdf_version = 'One of ' .. join(pdf_versions, ', ', ' or ')

--[[
-- is bb_spread still a useful setting?
-- look at gs options wrt boundingbox
-- settings.bb_spread = 1
-- descriptions.bb_spread = 'Safety margin in points for (low-res) boundingbox'

settings.use_hires_bb = false
-- descriptions.use_hires_bb = 'Use high-resolution boundingbox if available'
-- Ignored; hires bb always used
--]]

-- because pdftops_prog is sometimes configurable, it is stored in settings.
-- it will not be used for TeX Live and only be read and written on Windows.

settings.pdftops_prog = false
descriptions.pdftops_prog = 'Full path to pdftops.exe (not used with TeX Live)'

settings.use_pdftops = true
descriptions.use_pdftops = 'Use pdftops if available'

-- epspdf stores ps- and pdf viewer settings on behalf of the gui interface
-- but does not use them itself.
-- They won't be used at all under osx or windows.

settings.ps_viewer = false
descriptions.ps_viewer =
  'Epspdftk: viewer for PostScript files; not used on Windows or OS X'

settings.pdf_viewer = false
descriptions.pdf_viewer =
  'Epspdftk: viewer for pdf files; not used on Windows or OS X'

-- default_dir, which is used on all platforms, is only for the gui.

if os.type == 'windows' then
  settings.default_dir =
      string.gsub(ep_shortname(os.getenv('USERPROFILE')), '\\', '/')
else
  settings.default_dir = os.getenv('HOME')
end
descriptions.default_dir =
  'Epspdftk: initial directory; ignored by epspdf itself'

-- options -------------------------------------

-- besides settings, which can be saved, we also use options which are not.
-- these are mostly conversion options.

options = {}
options.page = false
options.gray = false
options.bbox = false
options.debug = false
options.type = false -- implied via output filename on command line

-- command-line fragments for conversions --------------------

-- We could make these `class attributes' for PsPdf but to what purpose?
-- For Windows shell commands, we need to substitute `#' for `='
-- when invoking Ghostscript. For simplicity, we do this across the board.

gs_options = {'-q', '-dNOPAUSE', '-dBATCH', '-P-', '-dSAFER'}

-- may add custom options later

pdf_options = {'-sDEVICE#pdfwrite'} -- '-dUseCIEColor' causes serious slowdown
-- options for final conversion to pdf;
-- will be completed after reading settings and options
pdf_tail_options = {'-c', '.setpdfwrite', '-f'}
gray_options = {'-dProcessColorModel#/DeviceGray',
  '-sColorConversionStrategy#Gray'}

pdftops = false
-- gets a value only if we are going to use pdftops

ps_options = {'-level3'}
-- may add custom options later

-- `main program' inside scope-creating block ----------------------

do -- main program

  local infile = false
  local in_dir = false -- directory of infile
  local outfile = false
  local out_dir = false -- directory of outfile

  -- dbg('\nSettings are:\n')
  for k,v in pairs(settings) do dbg(k .. ' = ' .. tostring(v)) end

  do -- Handle settings and command-line inside nested scope --------------

    read_settings(rcfile)

    -- dbg('Defining cmdline options')
    local opts = {}

    opts.page = {
      type = 'string', val = nil,
      forms = {'-p', '--page', '--pagenumber'},
      placeholder = 'PNUM',
      negforms = nil,
      help = 'Page number; must be a positive integer'
    }

    opts.gray = {
      type = 'boolean', val = nil,
      forms = {'-g', '--grey', '--gray', '-G', '--GREY', '--GRAY'},
      negforms = nil,
      help = 'Convert to grayscale'
    }

    opts.bbox = {
      type = 'boolean', val = nil,
      forms = {'-b', '--bbox', '--BoundingBox'},
      negforms = nil,
      help = 'Compute tight boundingbox'
    }

    ---[[ ignored; included for backward compatibility
    opts.use_hires_bb = {
      type = 'boolean', val = nil,
      forms = {'-r', '--hires'},
      negforms = {'-n', '--no-hires'},
    }

    opts.custom = {
      type = 'string', val = nil,
      forms = {'-C', '--custom', '-P', '--psoptions'},
      negforms = nil
    }
    --]]

    opts.pdf_target = {
      type = 'string', val = nil,
      forms = {'-T', '--target'},
      placeholder = 'TARGET',
      negforms = nil,
      help = descriptions.pdf_target
    }
    opts.pdf_version = {
      type = 'string', val = nil,
      forms = {'-N', '--pdfversion'},
      placeholder = 'VERSION',
      negforms = nil,
      help = descriptions.pdf_version
    }

    if os.type=='windows' and not is_tl_w32 then
      opts.pdftops_prog = {
        type = 'string', val = nil,
        forms = {'--pdftops'},
        placeholder = 'PATH',
        negforms = nil,
        help = descriptions.pdftops_prog
      }
    end

    opts.use_pdftops = {
      type = 'boolean', val = nil,
      forms = {'-U'},
      negforms = {'-I'},
      help = descriptions.use_pdftops
    }

    opts.info = {
      type = 'boolean', val = nil,
      forms = {'-i', '--info'},
      negforms = nil,
      help = 'Info: display detected filetype and exit'
    }

    opts.help = {
      type = 'boolean', val = nil,
      forms = {'-h', '--help'},
      negforms = nil,
      help = 'Display this help message and exit'
    }

    opts.version = {
      type = 'boolean', val = nil,
      forms = {'-v', '--version'},
      negforms = nil,
      help = 'Display version info and exit'
    }

    opts.save = {
      type = 'boolean', val = nil,
      forms = {'-s', '--save'},
      negforms = nil,
      help = 'Save some settings to configuration file'
    }

    opts.debug = {
      type = 'boolean', val = nil,
      forms = {'-d'},
      negforms = nil,
      help = 'Debug: do not remove temp files'
    }

    opts.gui = {
      type = 'string', val = nil,
      forms = {'--gui'},
      negforms = nil,
      help = nil -- reserved for use by epspdftk
    }

    -- a couple of functions only available during command-line parsing

    local function show_version ()
      print('Epspdf version '..ep_version..'\nCopyright (c) '
          ..ep_copyright..' Siep Kroonenberg')
    end

    local function help (mess) -- requires opts array
      if mess then print(mess..eol) end
      show_version()
      -- below, string.gsub unindents its long-string parameter.
      -- string.format removes the second return value of string.gsub.
      print(string.format('%s', string.gsub([[

      Convert between [e]ps and pdf formats
      Usage: epspdf[.tlu] [options] infile [outfile]
      Default for outfile is file.pdf if infile is file.eps or file.ps
      Default for outfile is file.eps if infile is file.pdf
      ]], '([\r\n]+)      ', '%1')))

      -- need to enforce an ordering, otherwise we could have used pairs(opts)
      -- omitted below: no-op options
      -- one line where possible
      local indent_n = 12
      local intent_sp = string.rep(' ', indent_n)
      local indent_fmt = '%-' .. tostring(indent_n) .. 's'
      for _, o in ipairs({'page', 'gray', 'bbox', 'pdf_target', 'pdf_version',
         'pdftops_prog', 'use_pdftops', 'save', 'info', 'debug',
         'version', 'help'}) do
        local v = opts[o]
        if v~='pdftops_prog' or is_miktex then
          if v and v.help then
            local synt = join(v.forms, ', ')
            if v.type ~= 'boolean' then synt = synt .. ' ' .. v.placeholder end
            if string.len(synt)<indent_n then
              print(string.format(indent_fmt, synt) .. v.help)
            else
              print(synt)
              print(intent_sp .. v.help)
            end
            if v.negforms then
              local neghelp = 'Reverses the above'
              synt = join(v.negforms, ', ')
              if string.len(synt)<indent_n then
                print(string.format(indent_fmt, synt) .. neghelp)
              else
                print(synt)
                print(intent_sp .. neghelp)
              end
            end
          end
        end -- ~=pdftops_prog or is_miktex
      end -- for
      if mess then os.exit(1) else os.exit() end
    end -- help

    if #arg < 1 then help('No parameters') end

    -- command-line parsing

    -- -r="tata tata" is parsed by [tex]lua as a single argument
    -- lua/linux retains the quotes,
    -- lua/windows strips them.
    -- texlua strips them, both on unix and on windows.

    local i=1
    while i<=#arg and string.sub(arg[i],1,1)=='-' do
      -- dbg('parse argument '..tostring(i)..': '..arg[i])
      local parsed = false
      local kk, vv = string.match(arg[i],'([^=]+)=(.*)$')
      if kk==nil then
        kk = arg[i] -- also vv==nil
      else
        vv = strip_outer_spaces(vv)
      end
      for p, o in pairs(opts) do
        -- dbg(' try '..p)
        if in_list(kk, o.forms) or in_list(kk, o.negforms) then
          parsed = true
          if o.type == 'boolean' then
            if vv then help(kk..' should not have a parameter.') end
            if in_list(kk, o.forms) then
              o.val = true
            else
              o.val = false
            end
          elseif vv then
            o.val = vv
          else
            i = i + 1
            if i>#arg then
              help('Missing parameter to '..kk)
            end
            o.val = strip_outer_spaces(arg[i])
          end -- testing for o.type or vv
          break -- for
        end -- if in_list
      end -- for
      if not parsed then help('illegal parameter '..kk) end
      i = i + 1
    end -- while

    -- some debug output

    --[[
    if i<=#arg then
      dbg('non-option arguments:')
      for j=i,#arg do dbg(arg[j]) end
      dbg(eol)
    else
      dbg('no non-option arguments')
    end

    for i=1,#arg do dbg(arg[i]) end

    dbg(eol..'Options from command-line:')
    for p, o in pairs(opts) do
      if o.val==nil then
        dbg(p..': undefined')
      else
        dbg(p..': '..tostring(o.val))
      end
    end
      --]]

    -- check and interpret opts.
    -- Copy to either settings or to options table.
    -- at syntax error, abort via help function.

    -- page

    if opts.page.val then
      local pnum = tonumber(opts.page.val)
      if pnum<=0 or math.floor(pnum) ~= pnum then
        help(opts.page.val..' not a positive integer')
      else
        options.page = pnum
      end
    end

    -- grayscaling

    if opts.gray.val then
      options.gray = true
    else
      options.gray = false
    end

    -- boundingbox

    if opts.bbox.val then
      options.bbox = true
    else
      options.bbox = false
    end

    --[[
    -- using hires boundingbox

    if opts.use_hires_bb.val~=nil then
      settings.use_hires_bb = opts.use_hires_bb.val
    end
    --]]

    -- using pdftops

    if opts.use_pdftops.val~=nil then
      settings.use_pdftops = opts.use_pdftops.val
    end

    -- pdf target use

    if opts.pdf_target.val~=nil then
      if in_list(opts.pdf_target.val, pdf_targets) then
        settings.pdf_target = opts.pdf_target.val
      else
        help('Illegal value '..opts.pdf_target.val..' for pdf_target')
      end
    end

    -- pdf version

    if opts.pdf_version.val~=nil then
      if in_list(opts.pdf_version.val, pdf_versions) then
        settings.pdf_version = opts.pdf_version.val
      else
        help('Illegal value '..opts.pdf_version.val..' for pdf_version')
      end
    end

    -- pdftops program; pdftops has already been been initialized to false

    -- pdftops_prog as command-line option
    if os.type=='windows' and not is_tl_w32 and opts.pdftops_prog.val then
      settings.pdftops_prog = is_prog(opts.pdftops_prog.val)
    end

    -- pdftops should be on the path.
    -- for miktex, make it so if possible.
    if os.type=='windows' and not is_tl_w32 then
      if settings.use_pdftops then
        pdftops = is_prog(settings.pdftops_prog)
        if pdftops then
          -- strip path and modify searchpath, to avoid paths with spaces
          maybe_add_path(string.gsub(pdftops, '[\\/][^\\/]*$', ''), 'append')
          pdftops = string.gsub(settings.pdftops_prog, '^.*[\\/]', '')
        end
      end
    elseif os.type=='windows' then
      if settings.use_pdftops then
        pdftops = 'pdftops.exe'
      end
    else
      if settings.use_pdftops then
        pdftops = find_on_path('pdftops')
      end
    end
    -- dbg('Option handling; pdftops is '..tostring(pdftops))

    -- other options

    if opts.save.val then
      write_settings(rcfile)
    end

    if opts.debug.val then
      options.debug = true
    end

    if opts.help.val then
      help()
    end

    -- opts.info.val: need to get infile first

    if opts.version.val then
      show_version()
      os.exit()
    end

    if opts.gui.val then
      gui(opts.gui.val)
    end

    -- now we need 1 or 2 filenames, unless the user really only
    -- wanted to save options without further action.

    if i>#arg then
      if opts.save.val then os.exit() else help('No filenames') end
    end

    infile = arg[i]
    outfile = false
    if i<#arg then
      outfile = arg[i+1]
    end
    if (#arg>i and opts.info.val) or (#arg>i+1) then
      help('Surplus non-option parameters')
    end

    if not outfile and not opts.info.val then
      -- derive outfile from infile: [e]ps => pdf, pdf => eps
      if intype=='pdf' then
        outfile = string.gsub(infile,'%.[^%.]*$','eps')
      else
        outfile = string.gsub(infile,'%.[^%.]*$','.pdf')
      end
    end

    -- one final quick option
    if opts.info.val then
      info(infile)
    end

    -- add pdf_version and pdf_target to the options array,
    -- from where it will be set to false when realized
    if settings.pdf_target == 'default' then
      options.pdf_target = false
    else
      options.pdf_target = settings.pdf_target
    end
    if settings.pdf_version == 'default' then
      options.pdf_version = false
    else
      options.pdf_version = tonumber(settings.pdf_version)
    end

  end -- decoding command-line

  --[[
  dbg('After command-line processing\n Settings')
  -- print settings- and options array with dbg
  for k, v in pairs(settings) do
    dbg(k..': '..tostring(v))
  end
  dbg(' Options')
  for k, v in pairs(options) do
    dbg(k..': '..tostring(v))
  end
  --]]

  --[[

  Once it becomes clear that real work needs to be done,
  we shall create a temp directory.

    because of gs -dSAFER restrictions, infile must be in (a
    subdirectory of) the directory of the output file, e.g. in the
    temp directory.

    Also because of -dSAFER, we copy infile to the temp directory of
    it is not in the same directory as outfile.

  --]]

  source = io.open(infile)
  if not source then
    error(infile .. ' not readable')
  end
  source:close()
  -- if options.debug then
  --   warn('in: '..infile..'\nout: '..outfile..'\n\ncwd: '..cwd)
  -- end
  infile, in_dir = absolute_path(infile)
  outfile, out_dir = absolute_path(outfile)
  if not out_dir then
    errror('Invalid output directory for '.. outfile)
  end

  -- directory for temporary files

  -- previously, we used a subdirectory of the target directory.
  -- however, since under windows cleanup may fail, we now try to use
  -- a directory under a dedicated temp directory, which has a better chance
  -- of getting cleaned up by the system.

  lfs.chdir(system_tempdir() or out_dir)
  -- no check for failure; we create a subdirectory in
  -- whatever is the current directory
  tempdir = os.tmpdir()
  if not tempdir then
    errror('Cannot create directory for temporary files')
  else
    -- dbg('temp directory '..tempdir)
  end
  lfs.chdir(tempdir)

  intype = identify(infile)

  -- remaining cases: want a real conversion
  if not intype then
    error(infile..' has an unsupported filetype')
  end

  --sanity check on output filetype
  options.type = string.match(outfile, '.*%.([^%.]+)$')
  if not options.type or (options.type~='ps'
      and options.type~='eps' and options.type~='pdf') then
    errror('Output file '..outfile..
        ' should have extension .eps, .ps or .pdf')
  end

  if outfile==infile then
    local insave = infile .. '.luasave'
    move_or_copy(infile, insave)
    infile = insave
  end

  -- had some trouble under msw when removing outfile later so try it now
  if lfs.isfile(outfile) then
    os.remove(outfile)
    -- if removal fails but outfile is overwritable then no real problem
  end

  local fout = io.open(outfile, 'wb')
  if not fout then
    errror('Output file '..outfile..' not writable; aborting')
  else
    fout:close()
  end

  source = PsPdf:from_path(infile)
  dest = source:any_to_any()
  if not lfs.isfile(dest.path) then
    errror('Failed to generate '..dest.path)
  end
  write_log('Copying or moving '..dest.path..' to '..outfile)
  move_or_copy(dest.path, outfile)
  if not options.debug then
    cleantemp()
  end
  if lfs.isfile(outfile) and lfs.attributes(outfile, 'size')>0 then
    os.exit()
  else
    errror('Conversion failed')
  end
end