#!/bin/sh

# Script to undescribe a GCC revision

o=$(git config --get gcc-config.upstream);
r=$(echo $1 | sed -n 's,^r\([0-9]\+\)-[0-9]\+\(-g[0-9a-f]\+\)\?$,\1,p');
n=$(echo $1 | sed -n 's,^r[0-9]\+-\([0-9]\+\)\(-g[0-9a-f]\+\)\?$,\1,p');

test -z $r && echo Invalid id $1 && exit 1;
h=$(git rev-parse --verify --quiet ${o:-origin}/releases/gcc-$r);
test -z $h && h=$(git rev-parse --verify --quiet ${o:-origin}/master);
p=$(git describe --all --match 'basepoints/gcc-'$r $h | sed -n 's,^\(tags/\)\?basepoints/gcc-[0-9]\+-\([0-9]\+\)-g[0-9a-f]*$,\2,p;s,^\(tags/\)\?basepoints/gcc-[0-9]\+$,0,p');
git rev-parse --verify $h~$(expr $p - $n);