BedProject

#!/usr/bin/gawk -f
# max 1/06

BEGIN { 
        if (ARGC==1 || ARGC>4) {
          print;
          print "Will change the seqname-fields of a bed file and"
          print "and will add a given offset to both start- and end-pos"
          print "fields of bed. Used to project results from a program"
          print "that returned coordinates from 0...x to a given chromosome"
          print "If you specify a fasta-file as parameter, we will "
          print "read seqname/offset from the seqname-line of the fasta-file"
          print "It has to be in UCSC-style format, eg:"
          print "  >seqname range=chr4:1012-1050"
          print "In this case seqname would be 'chr4' and offset '1012'. "
          print "If you add -r at the end, coordinates will be SUBSTRACTED"
          print "offset instead of added (reversed)"
          print ""
          print "SYNTAX:"
          print " bedproject <seqname> <offset>" 
          print " bedproject <seqname> <offset> -r" 
          print " bedproject <fasta-file>"
          print " bedproject <fasta-file> -r"
          print "EXAMPLE:"
          print " cat bla.bed | bedproject chr4 1204"
          print " cat bla.bed | bedproject bla.fa"
          exit 1
        }
        
        OFS="\t"
        if (ARGV[ARGC-1]=="-r") {
            rev=1;
            ARGC-=1;
        }

        if (ARGC==3) {
         seqname = ARGV[1]
         offset = ARGV[2]
         revOffset = ARGV[2]
        }

        if (ARGC==2) {
         FS = " "
         getline < ARGV[1]
         split($2, range, "=")
         split(range[2], coords, ":")
         seqname = coords[1]
         split(coords[2], positions, "-")
         offset = positions[1]
         revOffset = positions[2]
        }

         ARGV[1]="-"
         ARGC=2
      }

/track/ { print; next;}
/browser/ {print; next;}

/.*[a-z]+.*/    { 
         if ($2 < 0) {
            print "bedproject Error: negative position found!"  > "/dev/stderr"
            exit 1
          }
        if (rev==1) {
            if ($6=="+") {
                $6="-"
            }
            else if ($6=="-") {
                $6="+"
            }
            if (revOffset-$3 < 0) {
                dropped+=1;
                next;
                }
            print seqname, revOffset-$3, revOffset-$2, $4, $5, $6, $7, $8, $9, $10,$11,$12,$13,$14;
        }
        else { 
        if (offset+$2 < 0) {
            print "warning: dropping negative startpos feature" > "/dev/stderr";
            next
        }
        print seqname, offset+$2, offset+$3, $4, $5, $6, $7, $8, $9, $10, $11, $12,$13, $14;
    }
        }

END { if (dropped!=0) { 
                print "warning: dropped "dropped" negative startpos features" > /dev/stderr;
            }
        }