func (r *Record) Start() int {
	return r.Pos
}
Start returns the lower-coordinate end of the alignment.
package sam
import (
	"bytes"
	"errors"
	"fmt"
	"strconv"
	"github.com/biogo/hts/internal"
)
type Record struct {
	Name      string
	Ref       *Reference
	Pos       int
	MapQ      byte
	Cigar     Cigar
	Flags     Flags
	MateRef   *Reference
	MatePos   int
	TempLen   int
	Seq       Seq
	Qual      []byte
	AuxFields AuxFields
}
func NewRecord(name string, ref, mRef *Reference, p, mPos, tLen int, mapQ byte, co []CigarOp, seq, qual []byte, aux []Aux) (*Record, error) {
	if !(validPos(p) && validPos(mPos) && validTmpltLen(tLen) && validLen(len(seq)) && (qual == nil || validLen(len(qual)))) {
		return nil, errors.New("sam: value out of range")
	}
	if len(name) == 0 || len(name) > 254 {
		return nil, errors.New("sam: name absent or too long")
	}
	if qual != nil && len(qual) != len(seq) {
		return nil, errors.New("sam: sequence/quality length mismatch")
	}
	if ref != nil {
		if ref.id < 0 {
			return nil, errors.New("sam: linking to invalid reference")
		}
	} else {
		if p != -1 {
			return nil, errors.New("sam: specified position != -1 without reference")
		}
	}
	if mRef != nil {
		if mRef.id < 0 {
			return nil, errors.New("sam: linking to invalid mate reference")
		}
	} else {
		if mPos != -1 {
			return nil, errors.New("sam: specified mate position != -1 without mate reference")
		}
	}
	r := &Record{
		Name:      name,
		Ref:       ref,
		Pos:       p,
		MapQ:      mapQ,
		Cigar:     co,
		MateRef:   mRef,
		MatePos:   mPos,
		TempLen:   tLen,
		Seq:       NewSeq(seq),
		Qual:      qual,
		AuxFields: aux,
	}
	return r, nil
}
func IsValidRecord(r *Record) bool {
	if (r.Ref == nil || r.Pos == -1) && r.Flags&Unmapped == 0 {
		return false
	}
	if r.Flags&Paired != 0 && (r.MateRef == nil || r.MatePos == -1) && r.Flags&MateUnmapped == 0 {
		return false
	}
	if r.Flags&(Unmapped|ProperPair) == Unmapped|ProperPair {
		return false
	}
	if r.Flags&(Paired|MateUnmapped|ProperPair) == Paired|MateUnmapped|ProperPair {
		return false
	}
	if len(r.Qual) != 0 && r.Seq.Length != len(r.Qual) {
		return false
	}
	if r.Seq.Length != 0 && r.Seq.Length != r.queryLen() {
		return false
	}
	return true
}
func (r *Record) queryLen() int {
	var l int
	for _, co := range r.Cigar {
		l += co.Len() * co.Type().Consumes().Query
	}
	return l
}
func (r *Record) Tag(tag []byte) (v Aux, ok bool) {
	if len(tag) < 2 {
		panic("sam: tag too short")
	}
	for _, aux := range r.AuxFields {
		if aux.matches(tag) {
			return aux, true
		}
	}
	return nil, false
}
func (r *Record) RefID() int {
	return r.Ref.ID()
}