scripts/relpath.sh

   1 #!/bin/sh
   2
   3 #   BSD LICENSE
   4 #
   5 #   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   6 #   All rights reserved.
   7 #
   8 #   Redistribution and use in source and binary forms, with or without
   9 #   modification, are permitted provided that the following conditions
  10 #   are met:
  11 #
  12 #     * Redistributions of source code must retain the above copyright
  13 #       notice, this list of conditions and the following disclaimer.
  14 #     * Redistributions in binary form must reproduce the above copyright
  15 #       notice, this list of conditions and the following disclaimer in
  16 #       the documentation and/or other materials provided with the
  17 #       distribution.
  18 #     * Neither the name of Intel Corporation nor the names of its
  19 #       contributors may be used to endorse or promote products derived
  20 #       from this software without specific prior written permission.
  21 #
  22 #   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23 #   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24 #   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  25 #   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  26 #   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  27 #   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  28 #   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29 #   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30 #   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31 #   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  32 #   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33
  34 #
  35 # print the relative path of $1 from $2 directory
  36 # $1 and $2 MUST be absolute paths
  37 #
  38
  39 if [ $# -ne 2 ]; then
  40         echo "Bad arguments"
  41         echo "Usage:"
  42         echo "  $0 path1 path2"
  43         exit 1
  44 fi
  45
  46 # get the real absolute path, derefencing symlinks
  47 ABS1=$(readlink -f $1)
  48 ABS2=$(readlink -f $2)
  49
  50 # remove leading slash
  51 REL1=${ABS1#/}
  52 REL2=${ABS2#/}
  53
  54 left1=${REL1%%/*}
  55 right1=${REL1#*/}
  56 prev_right1=$REL1
  57 prev_left1=
  58
  59 left2=${REL2%%/*}
  60 right2=${REL2#*/}
  61 prev_right2=$REL2
  62 prev_left2=
  63
  64 while [ "${right1}" != "" -a "${right2}" != "" ]; do
  65
  66         if [ "$left1" != "$left2" ]; then
  67                 break
  68         fi
  69
  70         prev_left1=$left1
  71         left1=$left1/${right1%%/*}
  72         prev_right1=$right1
  73         right1=${prev_right1#*/}
  74         if [ "$right1" = "$prev_right1" ]; then
  75                 right1=""
  76         fi
  77
  78         prev_left2=$left2
  79         left2=$left2/${right2%%/*}
  80         prev_right2=$right2
  81         right2=${prev_right2#*/}
  82         if [ "$right2" = "$prev_right2" ]; then
  83                 right2=""
  84         fi
  85 done
  86
  87 if [ "${left1}" != "${left2}" ]; then
  88         right2=${prev_right2}
  89         right1=${prev_right1}
  90 fi
  91
  92 while [ "${right2}" != "" ]; do
  93         prefix=${prefix}../
  94         prev_right2=$right2
  95         right2=${right2#*/}
  96         if [ "$right2" = "$prev_right2" ]; then
  97                 right2=""
  98         fi
  99 done
 100
 101 echo ${prefix}${right1}
 102
 103 exit 0