#!/usr/bin/mawk -We
# *********************************************************************
# rndtable: pick one or more records at random from a table.
# Copyright (c) 2001,2006 Carlo Strozzi
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 dated June, 1991.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# *********************************************************************
# $Id: rndtable,v 1.3 2006/03/10 11:26:13 carlo Exp $

BEGIN {
  NULL = ""; FS = OFS = "\t"; n = 1; srand()

  # Get local settings.
  nosql_install = ENVIRON["NOSQL_INSTALL"]
  stdout = ENVIRON["NOSQL_STDOUT"]
  stderr = ENVIRON["NOSQL_STDERR"]

  # Set default values if necessary.
  if (nosql_install == NULL) nosql_install = "/usr/local/nosql"
  if (stdout == NULL) stdout = "/dev/stdout"
  if (stderr == NULL) stderr = "/dev/stderr"

  while (ARGV[++i] != NULL) {
    if (ARGV[i] == "-L" || ARGV[i] == "--lines") n = ARGV[++i]
    else if (ARGV[i] == "-N" || ARGV[i] == "--no-header") no_hdr = 1
    else if (ARGV[i] == "-z" || ARGV[i] == "--zero") zero = 1
    else if (ARGV[i] == "-K" || ARGV[i] == "--key") key = 1
    else if (ARGV[i] == "-i" || ARGV[i] == "--input") i_file = ARGV[++i]
    else if (ARGV[i] == "-o" || ARGV[i] == "--output") o_file = ARGV[++i]
    else if (ARGV[i] == "-h" || ARGV[i] == "--help") {
       system("grep -v '^#' " nosql_install "/help/rndtable.txt")
       exit(rc=1)
    }
    else if (ARGV[i] == "--show-copying") {
       system("cat " nosql_install "/doc/COPYING")
       exit(rc=1)
    }
    else if (ARGV[i] == "--show-warranty") {
       system("cat " nosql_install "/doc/WARRANTY")
       exit(rc=1)
    }
  }

  ARGC = 1					# Fix argv[]

  if (o_file == NULL) o_file = stdout
  if (i_file != NULL) { ARGV[1] = i_file; ARGC = 2 }
}

#
# Main loop
#

NR == 1 {

   gsub(/ +/,"")			# trim blanks in names.

   if (!no_hdr) {
      if (key) print $1 > o_file
      else print $0 > o_file
   }
   next
}

NR == int(rand()*NR+1) {
   found++
   if (key) print $1 > o_file
   else print > o_file
   if (found == n) exit
}

END {
    if (NR > 1 && !zero && !found) {
       if (key) print $1 > o_file
       else print > o_file
    }
}

# End of program.
