-# Copyright (C) 2007-2011 Martin A. Hansen.
+# Copyright (C) 2007-2013 Martin A. Hansen.
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
require 'pp'
require 'maasha/filesys'
require 'maasha/seq'
-
-# Error class for all exceptions to do with Genbank.
-class SamError < StandardError; end
+require 'maasha/cigar'
REGEX_HEADER = Regexp.new(/^@[A-Za-z][A-Za-z](\t[A-Za-z][A-Za-z0-9]:[ -~]+)+$/)
REGEX_COMMENT = Regexp.new(/^@CO\t.*/)
+FLAG_MULTI = 0x1 # Template having multiple fragments in sequencing
+FLAG_ALIGNED = 0x2 # Each fragment properly aligned according to the aligner
+FLAG_UNMAPPED = 0x4 # Fragment unmapped
+FLAG_NEXT_UNMAPPED = 0x8 # Next fragment in the template unmapped
+FLAG_REVCOMP = 0x10 # SEQ being reverse complemented
+FLAG_NEXT_REVCOMP = 0x20 # SEQ of the next fragment in the template being reversed
+FLAG_FIRST = 0x40 # The first fragment in the template
+FLAG_LAST = 0x80 # The last fragment in the template
+FLAG_SECONDARY_ALIGNMENT = 0x100 # Secondary alignment
+FLAG_QUALITY_FAIL = 0x200 # Not passing quality controls
+FLAG_DUPLICATES = 0x400 # PCR or optical duplicate
+
+# Error class for all exceptions to do with Genbank.
+class SamError < StandardError; end
+
# Class to parse and write SAM files.
class Sam < Filesys
attr_accessor :io, :header
+ # Class method to convert a SAM entry
+ # to a Biopiece record.
+ def self.to_bp(sam)
+ bp = {}
+
+ bp[:REC_TYPE] = 'SAM'
+ bp[:Q_ID] = sam[:QNAME]
+ bp[:STRAND] = sam[:FLAG].revcomp? ? '-' : '+'
+ bp[:S_ID] = sam[:RNAME]
+ bp[:S_BEG] = sam[:POS]
+ bp[:S_END] = sam[:POS] + sam[:SEQ].length - 1
+ bp[:MAPQ] = sam[:MAPQ]
+ bp[:CIGAR] = sam[:CIGAR].to_s
+
+ unless sam[:RNEXT] == '*'
+ bp[:Q_ID2] = sam[:RNEXT]
+ bp[:S_BEG2] = sam[:PNEXT]
+ bp[:TLEN] = sam[:TLEN]
+ end
+
+ bp[:SEQ] = sam[:SEQ].seq
+
+ unless sam[:SEQ].qual.nil?
+ bp[:SCORES] = sam[:SEQ].convert_phred2illumina!.qual
+ end
+
+ if sam.has_key? :NM and sam[:NM].to_i > 0
+ bp[:NM] = sam[:NM]
+ bp[:MD] = sam[:MD]
+ bp[:ALIGN] = self.align_descriptors(sam)
+ end
+
+ bp
+ end
+
+ # Class method to create a new SAM entry from a Biopiece record.
+ # FIXME
+ def self.new_bp(bp)
+ qname = bp[:Q_ID]
+ flag = 0
+ rname = bp[:S_ID]
+ pos = bp[:S_BEG]
+ mapq = bp[:MAPQ]
+ cigar = bp[:CIGAR]
+ rnext = bp[:Q_ID2] || '*'
+ pnext = bp[:S_BEG2] || 0
+ tlen = bp[:TLEN] || 0
+ seq = bp[:SEQ]
+ qual = bp[:SCORES] || '*'
+ nm = "NM:i:#{bp[:NM]}" if bp[:NM]
+ md = "MD:Z:#{bp[:MD]}" if bp[:MD]
+
+ flag |= FLAG_REVCOMP if bp[:STRAND] == '+'
+
+ if qname && flag && rname && pos && mapq && cigar && rnext && pnext && tlen && seq && qual
+ ary = [qname, flag, rname, pos, mapq, cigar, rnext, pnext, tlen, seq, qual]
+ ary << nm if nm
+ ary << md if md
+
+ ary.join("\t")
+ end
+ end
+
+ # Create alignment descriptors according to the KISS
+ # format description:
+ # http://code.google.com/p/biopieces/wiki/KissFormat
+ def self.align_descriptors(sam)
+ offset = 0
+ align = []
+
+ # Insertions
+ sam[:CIGAR].each do |len, op|
+ if op == 'I'
+ (0 ... len).each_with_index do |i|
+ nt = sam[:SEQ].seq[offset + i]
+
+ align << [offset + i, "->#{nt}"]
+ end
+ end
+
+ offset += len
+ end
+
+ offset = 0
+ deletions = 0
+
+ sam[:MD].scan(/\d+|\^[A-Z]+|[A-Z]+/).each do |m|
+ if m =~ /\d+/ # Matches
+ offset += m.to_i
+ elsif m[0] == '^' # Deletions
+ m.each_char do |nt|
+ unless nt == '^'
+ align << [offset, "#{nt}>-"]
+ deletions += 1
+ offset += 1
+ end
+ end
+ else # Mismatches
+ m.each_char do |nt|
+ nt2 = sam[:SEQ].seq[offset - deletions]
+
+ align << [offset, "#{nt}>#{nt2}"]
+
+ offset += 1
+ end
+ end
+ end
+
+ align.sort_by { |a| a.first }.map { |k, v| "#{k}:#{v}" }.join(",")
+ end
+
# Method to initialize a Sam object.
def initialize(io = nil)
@io = io
check_rname(rname)
check_pos(pos)
check_mapq(mapq)
- check_cigar(cigar, seq)
check_rnext(rnext)
check_pnext(pnext)
check_tlen(tlen)
entry = {}
entry[:QNAME] = qname
- entry[:FLAG] = flag
+ entry[:FLAG] = Flag.new(flag)
entry[:RNAME] = rname
entry[:POS] = pos
entry[:MAPQ] = mapq
- entry[:CIGAR] = cigar
+ entry[:CIGAR] = Cigar.new(cigar)
entry[:RNEXT] = rnext
entry[:PNEXT] = pnext
entry[:TLEN] = tlen
- entry[:SEQ] = Seq.new(qname, seq)
+ entry[:SEQ] = (qual == '*') ? Seq.new(qname, seq) : Seq.new(qname, seq, qual)
entry[:QUAL] = qual
+ # Optional fields - where some are really important! HATE HATE HATE SAM!!!
+
+ fields[11 .. -1].each do |field|
+ tag, type, val = field.split(':')
+
+ raise SamError, "Non-unique optional tag: #{tag}" if entry.has_key? tag.to_sym
+
+ # A [!-~] Printable character
+
+ # i [-+]?[0-9]+ Singed 32-bit integer
+ if type == 'i'
+ raise SamError, "Bad tag in optional field: #{field}" unless val =~ /^[-+]?[0-9]+$/
+ val = val.to_i
+ end
+
+ # f [-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)? Single-precision floating number
+ # Z [ !-~]+ Printable string, including space
+ # H [0-9A-F]+ Byte array in the Hex format
+ # B [cCsSiIf](,[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?)+ Integer or numeric array
+
+ entry[tag.to_sym] = val
+ end
+
entry
end
raise SamError, "Bad mapq: #{mapq}" unless (0 .. 2**8 - 1).include? mapq
end
- # Method to check cigar.
- def check_cigar(cigar, seq)
- raise SamError, "Bad cigar: #{cigar}" unless cigar =~ /^(\*|([0-9]+[MIDNSHPX=])+)$/
-
- # Check cigar hard clipping only at ends.
- if cigar.gsub(/^[0-9]+H|[0-9]+H$/, "").match('H')
- raise SamError, "Bad cigar with internal H: #{cigar}"
- end
-
- # Check cigar length matches sequence length.
- unless cigar == '*' or seq == '*'
- cigar_len = 0
-
- cigar.scan(/([0-9]+)([MIDNSHPX=])/).each do |len, op|
- cigar_len += len.to_i if op =~ /[MISX=]/
- end
-
- if cigar_len != seq.length
- raise SamError, "cigar and sequence length mismatch: #{cigar_len} != #{seq.length}"
- end
- end
- end
-
# Method to check if rnext, when not '*' or '='
# and @SQ header lines are present, is located
# in the header hash.
def check_qual(qual)
raise SamError, "Bad qual: #{qual}" unless qual =~ /^[!-~]+$/
end
+
+ # Method to deconvolute the SAM flag field.
+ class Flag
+ attr_reader :flag
+
+ # Method to initialize a Flag object.
+ def initialize(flag)
+ @flag = flag
+ end
+
+ # Method to test if template have
+ # multiple fragments in sequencing.
+ def multi?
+ (flag & FLAG_MULTI) == 0
+ end
+
+ # Method to test if each fragment
+ # properly aligned according to the aligner.
+ def aligned?
+ (flag & FLAG_ALIGNED) == 0
+ end
+
+ # Method to test if the fragment was unmapped.
+ def unmapped?
+ (flag & FLAG_UNMAPPED) == 0
+ end
+
+ # Method to test if the next fragment was unmapped.
+ def next_unmapped?
+ (flag & FLAG_NEXT_UNMAPPED) == 0
+ end
+
+ # Method to test if the fragment was reverse complemented.
+ def revcomp?
+ (flag & FLAG_REVCOMP) == 0
+ end
+
+ # Method to test if the next fragment was reverse complemented.
+ def next_revcomp?
+ (flag & FLAG_NEXT_REVCOMP) == 0
+ end
+
+ # Method to test if the fragment was first in the template.
+ def first?
+ (flag & FLAG_FIRST) == 0
+ end
+
+ # Method to test if the fragment was last in the template.
+ def last?
+ (flag & FLAG_LAST) == 0
+ end
+
+ # Method to test for secondary alignment.
+ def secondary_alignment?
+ (flag & FLAG_SECONDARY_ALIGNMENT) == 0
+ end
+
+ # Method to test for quality fail.
+ def quality_fail?
+ (flag & FLAG_QUALITY_FAIL) == 0
+ end
+
+ # Method to test for PCR or optical duplicates.
+ def duplicates?
+ (flag & FLAG_DUPLICATES) == 0
+ end
+ end
end