#!/bin/bash

### min-expand.sh --- Minimal column-width expand command.

## Copyright (C) 2007 Aaron S. Hawley

## 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, either version 3 of the License, or
## (at your option) any later version.

## 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, see <http://www.gnu.org/licenses/>.

## $Id: min-expand,v 1.4 2007/07/19 20:42:33 aaronh Exp $

### Commentary

## Takes a tab-delimited file on standard input and outputs with only
## the minimal number of spaces between columns.  The are properly
## aligned, but as narrowly as is possible.

## First it reads the entire file and determines the maximum width of
## each column, then determines the proper 'tab stops', then runs the
## file through expand with the tab stop settintgs.

## Any command-line arguments passed to this script are sent to the
## cut command before maximum column widths are calculated.  However,
## the output of this command will contain all the columns.

### Example:

## $ EXAMPLE="First\tLast\tBirth year\tKOs\nEvander\tHolyfield\t1962\t27\n\
## Jack\tDempsey\t1895\t51\nJoe\tLouis\t1914\t55\nMuhammad\tAli\t1942\t37"

## $ echo -e "${EXAMPLE}"
## First   Last    Birth year      KOs
## Evander Holyfield       1962    27
## Jack    Dempsey 1895    51
## Joe     Louis   1914    55
## Muhammad        Ali     1942    37

## $ echo -e "${EXAMPLE}" | min-expand
## First    Last      Birth year KOs
## Evander  Holyfield 1962       27
## Jack     Dempsey   1895       51
## Joe      Louis     1914       55
## Muhammad Ali       1942       37

### Code:

## Awk script that calculates the tab stop widths.
#  First written for GNU Awk 3.1.5

SOURCE="\
BEGIN { \
    FS = \"\\t\"; \
    min_space = 1; \
} \
 \
{ \
    for (i = 1; i < NF; i++) { \
	field_size = length(\$i); \
	if (width[i] < field_size) { \
	    width[i] = field_size; \
	} \
    } \
} \
 \
END { \
    tabstop = tabstops = width[1] + min_space; \
    for (field = 2; field <= length(width); field++) { \
	tabstop += width[field] + min_space; \
	tabstops = tabstops  \",\" tabstop; \
    } \
    print tabstops; \
} \
";

TMPFILE=/tmp/min-expand.$$

if [ -z "$*" ] || [ $# = 0 ]; then
    TABSTOPS=`tee "${TMPFILE}" | awk "${SOURCE}"`;
else
    TABSTOPS=`tee "${TMPFILE}" | cut "$*" | awk "${SOURCE}"`;
fi

expand -t"${TABSTOPS}" "${TMPFILE}"
rm -f "${TMPFILE}"

### End of file