samtools, bam cigar to string cigar

This code fragment converts a bam style binary cigar string in to a normal cigar string.

    CigarLen = b->core.n_cigar;  // Cigar length
    uint32_t *cigar    = bam1_cigar(b);

    Cigar.clear();
    for(size_t n=0;n<cigar_len;n++) {
      uint32_t opcode = cigar[n] & 0x0000000F;
      uint32_t len    = cigar[n] & 0xFFFFFFF0;

      len = len >> 4;

      if(opcode == 0)  { Cigar += stringify(len); Cigar += "M"; }
      if(opcode == 1)  { Cigar += stringify(len); Cigar += "I"; }
      if(opcode == 2)  { Cigar += stringify(len); Cigar += "D"; }
      if(opcode == 3)  { Cigar += stringify(len); Cigar += "N"; }
      if(opcode == 4)  { Cigar += stringify(len); Cigar += "S"; }
      if(opcode == 5)  { Cigar += stringify(len); Cigar += "H"; }
      if(opcode == 6)  { Cigar += stringify(len); Cigar += "P"; }
      if(opcode == 7)  { Cigar += stringify(len); Cigar += "a"; }
      if(opcode == 8)  { Cigar += stringify(len); Cigar += "b"; }
      if(opcode == 9)  { Cigar += stringify(len); Cigar += "c"; }
      if(opcode == 10) { Cigar += stringify(len); Cigar += "d"; }
      if(opcode == 11) { Cigar += stringify(len); Cigar += "e"; }
      if(opcode == 12) { Cigar += stringify(len); Cigar += "f"; }
      if(opcode == 13) { Cigar += stringify(len); Cigar += "g"; }
      if(opcode == 14) { Cigar += stringify(len); Cigar += "h"; }
    }
  }