example.c

// To compile:
//   gcc -g -O2 example.c libminimap2.a -lz

#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <zlib.h>
#include "minimap.h"
#include "kseq.h"
KSEQ_INIT(gzFile, gzread)

int main(int argc, char *argv[])
{
	mm_idxopt_t iopt;
	mm_mapopt_t mopt;
	int n_threads = 3;

	mm_verbose = 2; // disable message output to stderr
	mm_set_opt(0, &iopt, &mopt);
	mopt.flag |= MM_F_CIGAR; // perform alignment

	if (argc < 3) {
		fprintf(stderr, "Usage: minimap2-lite <target.fa> <query.fa>\n");
		return 1;
	}

	// open query file for reading; you may use your favorite FASTA/Q parser
	gzFile f = gzopen(argv[2], "r");
	assert(f);
	kseq_t *ks = kseq_init(f);

	// open index reader
	mm_idx_reader_t *r = mm_idx_reader_open(argv[1], &iopt, 0);
	mm_idx_t *mi;
	while ((mi = mm_idx_reader_read(r, n_threads)) != 0) { // traverse each part of the index
		mm_mapopt_update(&mopt, mi); // this sets the maximum minimizer occurrence; TODO: set a better default in mm_mapopt_init()!
		mm_tbuf_t *tbuf = mm_tbuf_init(); // thread buffer; for multi-threading, allocate one tbuf for each thread
		gzrewind(f);
		kseq_rewind(ks);
		while (kseq_read(ks) >= 0) { // each kseq_read() call reads one query sequence
			mm_reg1_t *reg;
			int j, i, n_reg;
			reg = mm_map(mi, ks->seq.l, ks->seq.s, &n_reg, tbuf, &mopt, 0); // get all hits for the query
			for (j = 0; j < n_reg; ++j) { // traverse hits and print them out
				mm_reg1_t *r = &reg[j];
				assert(r->p); // with MM_F_CIGAR, this should not be NULL
				printf("%s\t%d\t%d\t%d\t%c\t", ks->name.s, ks->seq.l, r->qs, r->qe, "+-"[r->rev]);
				printf("%s\t%d\t%d\t%d\t%d\t%d\t%d\tcg:Z:", mi->seq[r->rid].name, mi->seq[r->rid].len, r->rs, r->re, r->mlen, r->blen, r->mapq);
				for (i = 0; i < r->p->n_cigar; ++i) // IMPORTANT: this gives the CIGAR in the aligned regions. NO soft/hard clippings!
					printf("%d%c", r->p->cigar[i]>>4, "MIDNSH"[r->p->cigar[i]&0xf]);
				putchar('\n');
				free(r->p);
			}
			free(reg);
		}
		mm_tbuf_destroy(tbuf);
		mm_idx_destroy(mi);
	}
	mm_idx_reader_close(r); // close the index reader
	kseq_destroy(ks); // close the query file
	gzclose(f);
	return 0;
}