libhts-dev 1.7-2 / usr / include / htslib / sam.h

/// @file htslib/sam.h
/// High-level SAM/BAM/CRAM sequence file operations.
/*
    Copyright (C) 2008, 2009, 2013-2017 Genome Research Ltd.
    Copyright (C) 2010, 2012, 2013 Broad Institute.

    Author: Heng Li <lh3@sanger.ac.uk>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.  */

#ifndef HTSLIB_SAM_H
#define HTSLIB_SAM_H

#include <stdint.h>
#include "hts.h"

#ifdef __cplusplus
extern "C" {
#endif

/// Highest SAM format version supported by this library
#define SAM_FORMAT_VERSION "1.5"

/**********************
 *** SAM/BAM header ***
 **********************/

/*! @typedef
 @abstract Structure for the alignment header.
 @field n_targets   number of reference sequences
 @field l_text      length of the plain text in the header
 @field target_len  lengths of the reference sequences
 @field target_name names of the reference sequences
 @field text        plain text
 @field sdict       header dictionary
 */

typedef struct {
    int32_t n_targets, ignore_sam_err;
    uint32_t l_text;
    uint32_t *target_len;
    int8_t *cigar_tab;
    char **target_name;
    char *text;
    void *sdict;
} bam_hdr_t;

/****************************
 *** CIGAR related macros ***
 ****************************/

#define BAM_CMATCH      0
#define BAM_CINS        1
#define BAM_CDEL        2
#define BAM_CREF_SKIP   3
#define BAM_CSOFT_CLIP  4
#define BAM_CHARD_CLIP  5
#define BAM_CPAD        6
#define BAM_CEQUAL      7
#define BAM_CDIFF       8
#define BAM_CBACK       9

#define BAM_CIGAR_STR   "MIDNSHP=XB"
#define BAM_CIGAR_SHIFT 4
#define BAM_CIGAR_MASK  0xf
#define BAM_CIGAR_TYPE  0x3C1A7

#define bam_cigar_op(c) ((c)&BAM_CIGAR_MASK)
#define bam_cigar_oplen(c) ((c)>>BAM_CIGAR_SHIFT)
// Note that BAM_CIGAR_STR is padded to length 16 bytes below so that
// the array look-up will not fall off the end.  '?' is chosen as the
// padding character so it's easy to spot if one is emitted, and will
// result in a parsing failure (in sam_parse1(), at least) if read.
#define bam_cigar_opchr(c) (BAM_CIGAR_STR "??????" [bam_cigar_op(c)])
#define bam_cigar_gen(l, o) ((l)<<BAM_CIGAR_SHIFT|(o))

/* bam_cigar_type returns a bit flag with:
 *   bit 1 set if the cigar operation consumes the query
 *   bit 2 set if the cigar operation consumes the reference
 *
 * For reference, the unobfuscated truth table for this function is:
 * BAM_CIGAR_TYPE  QUERY  REFERENCE
 * --------------------------------
 * BAM_CMATCH      1      1
 * BAM_CINS        1      0
 * BAM_CDEL        0      1
 * BAM_CREF_SKIP   0      1
 * BAM_CSOFT_CLIP  1      0
 * BAM_CHARD_CLIP  0      0
 * BAM_CPAD        0      0
 * BAM_CEQUAL      1      1
 * BAM_CDIFF       1      1
 * BAM_CBACK       0      0
 * --------------------------------
 */
#define bam_cigar_type(o) (BAM_CIGAR_TYPE>>((o)<<1)&3) // bit 1: consume query; bit 2: consume reference

/*! @abstract the read is paired in sequencing, no matter whether it is mapped in a pair */
#define BAM_FPAIRED        1
/*! @abstract the read is mapped in a proper pair */
#define BAM_FPROPER_PAIR   2
/*! @abstract the read itself is unmapped; conflictive with BAM_FPROPER_PAIR */
#define BAM_FUNMAP         4
/*! @abstract the mate is unmapped */
#define BAM_FMUNMAP        8
/*! @abstract the read is mapped to the reverse strand */
#define BAM_FREVERSE      16
/*! @abstract the mate is mapped to the reverse strand */
#define BAM_FMREVERSE     32
/*! @abstract this is read1 */
#define BAM_FREAD1        64
/*! @abstract this is read2 */
#define BAM_FREAD2       128
/*! @abstract not primary alignment */
#define BAM_FSECONDARY   256
/*! @abstract QC failure */
#define BAM_FQCFAIL      512
/*! @abstract optical or PCR duplicate */
#define BAM_FDUP        1024
/*! @abstract supplementary alignment */
#define BAM_FSUPPLEMENTARY 2048

/*************************
 *** Alignment records ***
 *************************/

/*! @typedef
 @abstract Structure for core alignment information.
 @field  tid     chromosome ID, defined by bam_hdr_t
 @field  pos     0-based leftmost coordinate
 @field  bin     bin calculated by bam_reg2bin()
 @field  qual    mapping quality
 @field  l_qname length of the query name
 @field  flag    bitwise flag
 @field  l_extranul length of extra NULs between qname & cigar (for alignment)
 @field  n_cigar number of CIGAR operations
 @field  l_qseq  length of the query sequence (read)
 @field  mtid    chromosome ID of next read in template, defined by bam_hdr_t
 @field  mpos    0-based leftmost coordinate of next read in template
 */
typedef struct {
    int32_t tid;
    int32_t pos;
    uint16_t bin;
    uint8_t qual;
    uint8_t l_qname;
    uint16_t flag;
    uint8_t unused1;
    uint8_t l_extranul;
    uint32_t n_cigar;
    int32_t l_qseq;
    int32_t mtid;
    int32_t mpos;
    int32_t isize;
} bam1_core_t;

/*! @typedef
 @abstract Structure for one alignment.
 @field  core       core information about the alignment
 @field  l_data     current length of bam1_t::data
 @field  m_data     maximum length of bam1_t::data
 @field  data       all variable-length data, concatenated; structure: qname-cigar-seq-qual-aux

 @discussion Notes:

 1. qname is terminated by one to four NULs, so that the following
 cigar data is 32-bit aligned; core.l_qname includes these trailing NULs,
 while core.l_extranul counts the excess NULs (so 0 <= l_extranul <= 3).
 2. l_qseq is calculated from the total length of an alignment block
 on reading or from CIGAR.
 3. cigar data is encoded 4 bytes per CIGAR operation.
 4. seq is nybble-encoded according to bam_nt16_table.
 */
typedef struct {
    bam1_core_t core;
    int l_data;
    uint32_t m_data;
    uint8_t *data;
#ifndef BAM_NO_ID
    uint64_t id;
#endif
} bam1_t;

/*! @function
 @abstract  Get whether the query is on the reverse strand
 @param  b  pointer to an alignment
 @return    boolean true if query is on the reverse strand
 */
#define bam_is_rev(b) (((b)->core.flag&BAM_FREVERSE) != 0)
/*! @function
 @abstract  Get whether the query's mate is on the reverse strand
 @param  b  pointer to an alignment
 @return    boolean true if query's mate on the reverse strand
 */
#define bam_is_mrev(b) (((b)->core.flag&BAM_FMREVERSE) != 0)
/*! @function
 @abstract  Get the name of the query
 @param  b  pointer to an alignment
 @return    pointer to the name string, null terminated
 */
#define bam_get_qname(b) ((char*)(b)->data)
/*! @function
 @abstract  Get the CIGAR array
 @param  b  pointer to an alignment
 @return    pointer to the CIGAR array

 @discussion In the CIGAR array, each element is a 32-bit integer. The
 lower 4 bits gives a CIGAR operation and the higher 28 bits keep the
 length of a CIGAR.
 */
#define bam_get_cigar(b) ((uint32_t*)((b)->data + (b)->core.l_qname))
/*! @function
 @abstract  Get query sequence
 @param  b  pointer to an alignment
 @return    pointer to sequence

 @discussion Each base is encoded in 4 bits: 1 for A, 2 for C, 4 for G,
 8 for T and 15 for N. Two bases are packed in one byte with the base
 at the higher 4 bits having smaller coordinate on the read. It is
 recommended to use bam_seqi() macro to get the base.
 */
#define bam_get_seq(b)   ((b)->data + ((b)->core.n_cigar<<2) + (b)->core.l_qname)
/*! @function
 @abstract  Get query quality
 @param  b  pointer to an alignment
 @return    pointer to quality string
 */
#define bam_get_qual(b)  ((b)->data + ((b)->core.n_cigar<<2) + (b)->core.l_qname + (((b)->core.l_qseq + 1)>>1))
/*! @function
 @abstract  Get auxiliary data
 @param  b  pointer to an alignment
 @return    pointer to the concatenated auxiliary data
 */
#define bam_get_aux(b)   ((b)->data + ((b)->core.n_cigar<<2) + (b)->core.l_qname + (((b)->core.l_qseq + 1)>>1) + (b)->core.l_qseq)
/*! @function
 @abstract  Get length of auxiliary data
 @param  b  pointer to an alignment
 @return    length of the concatenated auxiliary data
 */
#define bam_get_l_aux(b) ((b)->l_data - ((b)->core.n_cigar<<2) - (b)->core.l_qname - (b)->core.l_qseq - (((b)->core.l_qseq + 1)>>1))
/*! @function
 @abstract  Get a base on read
 @param  s  Query sequence returned by bam_get_seq()
 @param  i  The i-th position, 0-based
 @return    4-bit integer representing the base.
 */
#define bam_seqi(s, i) ((s)[(i)>>1] >> ((~(i)&1)<<2) & 0xf)

/**************************
 *** Exported functions ***
 **************************/

    /***************
     *** BAM I/O ***
     ***************/

    bam_hdr_t *bam_hdr_init(void);
    bam_hdr_t *bam_hdr_read(BGZF *fp);
    int bam_hdr_write(BGZF *fp, const bam_hdr_t *h) HTS_RESULT_USED;
    void bam_hdr_destroy(bam_hdr_t *h);
    int bam_name2id(bam_hdr_t *h, const char *ref);
    bam_hdr_t* bam_hdr_dup(const bam_hdr_t *h0);

    bam1_t *bam_init1(void);
    void bam_destroy1(bam1_t *b);
    int bam_read1(BGZF *fp, bam1_t *b) HTS_RESULT_USED;
    int bam_write1(BGZF *fp, const bam1_t *b) HTS_RESULT_USED;
    bam1_t *bam_copy1(bam1_t *bdst, const bam1_t *bsrc);
    bam1_t *bam_dup1(const bam1_t *bsrc);

    int bam_cigar2qlen(int n_cigar, const uint32_t *cigar);
    int bam_cigar2rlen(int n_cigar, const uint32_t *cigar);

    /*!
      @abstract Calculate the rightmost base position of an alignment on the
      reference genome.

      @param  b  pointer to an alignment
      @return    the coordinate of the first base after the alignment, 0-based

      @discussion For a mapped read, this is just b->core.pos + bam_cigar2rlen.
      For an unmapped read (either according to its flags or if it has no cigar
      string), we return b->core.pos + 1 by convention.
    */
    int32_t bam_endpos(const bam1_t *b);

    int   bam_str2flag(const char *str);    /** returns negative value on error */
    char *bam_flag2str(int flag);   /** The string must be freed by the user */

    /*************************
     *** BAM/CRAM indexing ***
     *************************/

    // These BAM iterator functions work only on BAM files.  To work with either
    // BAM or CRAM files use the sam_index_load() & sam_itr_*() functions.
    #define bam_itr_destroy(iter) hts_itr_destroy(iter)
    #define bam_itr_queryi(idx, tid, beg, end) sam_itr_queryi(idx, tid, beg, end)
    #define bam_itr_querys(idx, hdr, region) sam_itr_querys(idx, hdr, region)
    #define bam_itr_next(htsfp, itr, r) hts_itr_next((htsfp)->fp.bgzf, (itr), (r), 0)

// Load/build .csi or .bai BAM index file.  Does not work with CRAM.
// It is recommended to use the sam_index_* functions below instead.
#define bam_index_load(fn) hts_idx_load((fn), HTS_FMT_BAI)
#define bam_index_build(fn, min_shift) (sam_index_build((fn), (min_shift)))

/// Load a BAM (.csi or .bai) or CRAM (.crai) index file
/** @param fp  File handle of the data file whose index is being opened
    @param fn  BAM/CRAM/etc filename to search alongside for the index file
    @return  The index, or NULL if an error occurred.
*/
hts_idx_t *sam_index_load(htsFile *fp, const char *fn);

/// Load a specific BAM (.csi or .bai) or CRAM (.crai) index file
/** @param fp     File handle of the data file whose index is being opened
    @param fn     BAM/CRAM/etc data file filename
    @param fnidx  Index filename, or NULL to search alongside @a fn
    @return  The index, or NULL if an error occurred.
*/
hts_idx_t *sam_index_load2(htsFile *fp, const char *fn, const char *fnidx);

/// Generate and save an index file
/** @param fn        Input BAM/etc filename, to which .csi/etc will be added
    @param min_shift Positive to generate CSI, or 0 to generate BAI
    @return  0 if successful, or negative if an error occurred (usually -1; or
             -2: opening fn failed; -3: format not indexable; -4:
             failed to create and/or save the index)
*/
int sam_index_build(const char *fn, int min_shift) HTS_RESULT_USED;

/// Generate and save an index to a specific file
/** @param fn        Input BAM/CRAM/etc filename
    @param fnidx     Output filename, or NULL to add .bai/.csi/etc to @a fn
    @param min_shift Positive to generate CSI, or 0 to generate BAI
    @return  0 if successful, or negative if an error occurred (see
             sam_index_build for error codes)
*/
int sam_index_build2(const char *fn, const char *fnidx, int min_shift) HTS_RESULT_USED;
int sam_index_build3(const char *fn, const char *fnidx, int min_shift, int nthreads) HTS_RESULT_USED;

    #define sam_itr_destroy(iter) hts_itr_destroy(iter)
    hts_itr_t *sam_itr_queryi(const hts_idx_t *idx, int tid, int beg, int end);
    hts_itr_t *sam_itr_querys(const hts_idx_t *idx, bam_hdr_t *hdr, const char *region);
    hts_itr_multi_t *sam_itr_regions(const hts_idx_t *idx, bam_hdr_t *hdr, hts_reglist_t *reglist, unsigned int regcount);

    #define sam_itr_next(htsfp, itr, r) hts_itr_next((htsfp)->fp.bgzf, (itr), (r), (htsfp))
    #define sam_itr_multi_next(htsfp, itr, r) hts_itr_multi_next((htsfp), (itr), (r))

    /***************
     *** SAM I/O ***
     ***************/

    #define sam_open(fn, mode) (hts_open((fn), (mode)))
    #define sam_open_format(fn, mode, fmt) (hts_open_format((fn), (mode), (fmt)))
    #define sam_close(fp) hts_close(fp)

    int sam_open_mode(char *mode, const char *fn, const char *format);

    // A version of sam_open_mode that can handle ,key=value options.
    // The format string is allocated and returned, to be freed by the caller.
    // Prefix should be "r" or "w",
    char *sam_open_mode_opts(const char *fn,
                             const char *mode,
                             const char *format);

    typedef htsFile samFile;
    bam_hdr_t *sam_hdr_parse(int l_text, const char *text);
    bam_hdr_t *sam_hdr_read(samFile *fp);
    int sam_hdr_write(samFile *fp, const bam_hdr_t *h) HTS_RESULT_USED;
    int sam_hdr_change_HD(bam_hdr_t *h, const char *key, const char *val);

    int sam_parse1(kstring_t *s, bam_hdr_t *h, bam1_t *b) HTS_RESULT_USED;
    int sam_format1(const bam_hdr_t *h, const bam1_t *b, kstring_t *str) HTS_RESULT_USED;

    /*!
     *  @return >= 0 on successfully reading a new record, -1 on end of stream, < -1 on error
     **/
    int sam_read1(samFile *fp, bam_hdr_t *h, bam1_t *b) HTS_RESULT_USED;
    int sam_write1(samFile *fp, const bam_hdr_t *h, const bam1_t *b) HTS_RESULT_USED;

    /*************************************
     *** Manipulating auxiliary fields ***
     *************************************/

/// Return a pointer to an aux record
/** @param b   Pointer to the bam record
    @param tag Desired aux tag
    @return Pointer to the tag data, or NULL if tag is not present or on error
    If the tag is not present, this function returns NULL and sets errno to
    ENOENT.  If the bam record's aux data is corrupt (either a tag has an
    invalid type, or the last record is incomplete) then errno is set to
    EINVAL and NULL is returned.
 */
uint8_t *bam_aux_get(const bam1_t *b, const char tag[2]);

/// Get an integer aux value
/** @param s Pointer to the tag data, as returned by bam_aux_get()
    @return The value, or 0 if the tag was not an integer type
    If the tag is not an integer type, errno is set to EINVAL.  This function
    will not return the value of floating-point tags.
*/
int64_t bam_aux2i(const uint8_t *s);

/// Get an integer aux value
/** @param s Pointer to the tag data, as returned by bam_aux_get()
    @return The value, or 0 if the tag was not an integer type
    If the tag is not an numeric type, errno is set to EINVAL.  The value of
    integer flags will be returned cast to a double.
*/
double bam_aux2f(const uint8_t *s);

/// Get a character aux value
/** @param s Pointer to the tag data, as returned by bam_aux_get().
    @return The value, or 0 if the tag was not a character ('A') type
    If the tag is not a character type, errno is set to EINVAL.
*/
char bam_aux2A(const uint8_t *s);

/// Get a string aux value
/** @param s Pointer to the tag data, as returned by bam_aux_get().
    @return Pointer to the string, or NULL if the tag was not a string type
    If the tag is not a string type ('Z' or 'H'), errno is set to EINVAL.
*/
char *bam_aux2Z(const uint8_t *s);

/// Get the length of an array-type ('B') tag
/** @param s Pointer to the tag data, as returned by bam_aux_get().
    @return The length of the array, or 0 if the tag is not an array type.
    If the tag is not an array type, errno is set to EINVAL.
 */
uint32_t bam_auxB_len(const uint8_t *s);

/// Get an integer value from an array-type tag
/** @param s   Pointer to the tag data, as returned by bam_aux_get().
    @param idx 0-based Index into the array
    @return The idx'th value, or 0 on error.
    If the array is not an integer type, errno is set to EINVAL.  If idx
    is greater than or equal to  the value returned by bam_auxB_len(s),
    errno is set to ERANGE.  In both cases, 0 will be returned.
 */
int64_t bam_auxB2i(const uint8_t *s, uint32_t idx);

/// Get a floating-point value from an array-type tag
/** @param s   Pointer to the tag data, as returned by bam_aux_get().
    @param idx 0-based Index into the array
    @return The idx'th value, or 0.0 on error.
    If the array is not a numeric type, errno is set to EINVAL.  This can
    only actually happen if the input record has an invalid type field.  If
    idx is greater than or equal to  the value returned by bam_auxB_len(s),
    errno is set to ERANGE.  In both cases, 0.0 will be returned.
 */
double bam_auxB2f(const uint8_t *s, uint32_t idx);

/// Append tag data to a bam record
/* @param b    The bam record to append to.
   @param tag  Tag identifier
   @param type Tag data type
   @param len  Length of the data in bytes
   @param data The data to append
   @return 0 on success; -1 on failure.
If there is not enough space to store the additional tag, errno is set to
ENOMEM.  If the type is invalid, errno may be set to EINVAL.  errno is
also set to EINVAL if the bam record's aux data is corrupt.
*/
int bam_aux_append(bam1_t *b, const char tag[2], char type, int len, const uint8_t *data);

/// Delete tag data from a bam record
/* @param b The bam record to update
   @param s Pointer to the tag to delete, as returned by bam_aux_get().
   @return 0 on success; -1 on failure
   If the bam record's aux data is corrupt, errno is set to EINVAL and this
   function returns -1;
*/
int bam_aux_del(bam1_t *b, uint8_t *s);

/// Update a string-type tag
/* @param b    The bam record to update
   @param tag  Tag identifier
   @param len  The length of the new string
   @param data The new string
   @return 0 on success, -1 on failure
*/
int bam_aux_update_str(bam1_t *b, const char tag[2], int len, const char *data);

/**************************
 *** Pileup and Mpileup ***
 **************************/

#if !defined(BAM_NO_PILEUP)

/*! @typedef
 @abstract Generic pileup 'client data'.

 @discussion The pileup iterator allows setting a constructor and
 destructor function, which will be called every time a sequence is
 fetched and discarded.  This permits caching of per-sequence data in
 a tidy manner during the pileup process.  This union is the cached
 data to be manipulated by the "client" (the caller of pileup).
*/
typedef union {
    void *p;
    int64_t i;
    double f;
} bam_pileup_cd;

/*! @typedef
 @abstract Structure for one alignment covering the pileup position.
 @field  b          pointer to the alignment
 @field  qpos       position of the read base at the pileup site, 0-based
 @field  indel      indel length; 0 for no indel, positive for ins and negative for del
 @field  level      the level of the read in the "viewer" mode
 @field  is_del     1 iff the base on the padded read is a deletion
 @field  is_head    ???
 @field  is_tail    ???
 @field  is_refskip ???
 @field  aux        ???

 @discussion See also bam_plbuf_push() and bam_lplbuf_push(). The
 difference between the two functions is that the former does not
 set bam_pileup1_t::level, while the later does. Level helps the
 implementation of alignment viewers, but calculating this has some
 overhead.
 */
typedef struct {
    bam1_t *b;
    int32_t qpos;
    int indel, level;
    uint32_t is_del:1, is_head:1, is_tail:1, is_refskip:1, aux:28;
    bam_pileup_cd cd; // generic per-struct data, owned by caller.
} bam_pileup1_t;

typedef int (*bam_plp_auto_f)(void *data, bam1_t *b);

struct __bam_plp_t;
typedef struct __bam_plp_t *bam_plp_t;

struct __bam_mplp_t;
typedef struct __bam_mplp_t *bam_mplp_t;

    /**
     *  bam_plp_init() - sets an iterator over multiple
     *  @func:      see mplp_func in bam_plcmd.c in samtools for an example. Expected return
     *              status: 0 on success, -1 on end, < -1 on non-recoverable errors
     *  @data:      user data to pass to @func
     */
    bam_plp_t bam_plp_init(bam_plp_auto_f func, void *data);
    void bam_plp_destroy(bam_plp_t iter);
    int bam_plp_push(bam_plp_t iter, const bam1_t *b);
    const bam_pileup1_t *bam_plp_next(bam_plp_t iter, int *_tid, int *_pos, int *_n_plp);
    const bam_pileup1_t *bam_plp_auto(bam_plp_t iter, int *_tid, int *_pos, int *_n_plp);
    void bam_plp_set_maxcnt(bam_plp_t iter, int maxcnt);
    void bam_plp_reset(bam_plp_t iter);

    /**
     *  bam_plp_constructor() - sets a callback to initialise any per-pileup1_t fields.
     *  @plp:       The bam_plp_t initialised using bam_plp_init.
     *  @func:      The callback function itself.  When called, it is given the
     *              data argument (specified in bam_plp_init), the bam structure and
     *              a pointer to a locally allocated bam_pileup_cd union.  This union
     *              will also be present in each bam_pileup1_t created.
     */
    void bam_plp_constructor(bam_plp_t plp,
                             int (*func)(void *data, const bam1_t *b, bam_pileup_cd *cd));
    void bam_plp_destructor(bam_plp_t plp,
                            int (*func)(void *data, const bam1_t *b, bam_pileup_cd *cd));

    bam_mplp_t bam_mplp_init(int n, bam_plp_auto_f func, void **data);
    /**
     *  bam_mplp_init_overlaps() - if called, mpileup will detect overlapping
     *  read pairs and for each base pair set the base quality of the
     *  lower-quality base to zero, thus effectively discarding it from
     *  calling. If the two bases are identical, the quality of the other base
     *  is increased to the sum of their qualities (capped at 200), otherwise
     *  it is multiplied by 0.8.
     */
    void bam_mplp_init_overlaps(bam_mplp_t iter);
    void bam_mplp_destroy(bam_mplp_t iter);
    void bam_mplp_set_maxcnt(bam_mplp_t iter, int maxcnt);
    int bam_mplp_auto(bam_mplp_t iter, int *_tid, int *_pos, int *n_plp, const bam_pileup1_t **plp);
    void bam_mplp_reset(bam_mplp_t iter);
    void bam_mplp_constructor(bam_mplp_t iter,
                              int (*func)(void *data, const bam1_t *b, bam_pileup_cd *cd));
    void bam_mplp_destructor(bam_mplp_t iter,
                             int (*func)(void *data, const bam1_t *b, bam_pileup_cd *cd));

#endif // ~!defined(BAM_NO_PILEUP)


/***********************************
 * BAQ calculation and realignment *
 ***********************************/

int sam_cap_mapq(bam1_t *b, const char *ref, int ref_len, int thres);
int sam_prob_realn(bam1_t *b, const char *ref, int ref_len, int flag);

#ifdef __cplusplus
}
#endif

#endif