typedef struct { // auxiliary data structure
bamFile fp; // the file handler
bam_iter_t iter; // NULL if a region not specified
+ int min_mapQ, min_len; // mapQ filter; length filter
} aux_t;
void *bed_read(const char *fn); // read a BED or position list file
int bed_overlap(const void *_h, const char *chr, int beg, int end); // test if chr:beg-end overlaps
// This function reads a BAM alignment from one BAM file.
-static int read_bam(void *data, bam1_t *b)
+static int read_bam(void *data, bam1_t *b) // read level filters better go here to avoid pileup
{
aux_t *aux = (aux_t*)data; // data in fact is a pointer to an auxiliary structure
- return aux->iter? bam_iter_read(aux->fp, aux->iter, b) : bam_read1(aux->fp, b);
+ int ret = aux->iter? bam_iter_read(aux->fp, aux->iter, b) : bam_read1(aux->fp, b);
+ if (!(b->core.flag&BAM_FUNMAP)) {
+ if ((int)b->core.qual < aux->min_mapQ) b->core.flag |= BAM_FUNMAP;
+ else if (aux->min_len && bam_cigar2qlen(&b->core, bam1_cigar(b)) < aux->min_len) b->core.flag |= BAM_FUNMAP;
+ }
+ return ret;
}
#ifdef _MAIN_BAM2DEPTH
int main_depth(int argc, char *argv[])
#endif
{
- int i, n, tid, beg, end, pos, *n_plp, baseQ = 0;
+ int i, n, tid, beg, end, pos, *n_plp, baseQ = 0, mapQ = 0, min_len = 0;
const bam_pileup1_t **plp;
char *reg = 0; // specified region
void *bed = 0; // BED data structure
bam_mplp_t mplp;
// parse the command line
- while ((n = getopt(argc, argv, "r:b:q:")) >= 0) {
+ while ((n = getopt(argc, argv, "r:b:q:Q:l:")) >= 0) {
switch (n) {
+ case 'l': min_len = atoi(optarg); break; // minimum query length
case 'r': reg = strdup(optarg); break; // parsing a region requires a BAM header
case 'b': bed = bed_read(optarg); break; // BED or position list file can be parsed now
case 'q': baseQ = atoi(optarg); break; // base quality threshold
+ case 'Q': mapQ = atoi(optarg); break; // mapping quality threshold
}
}
if (optind == argc) {
- fprintf(stderr, "Usage: bam2depth [-r reg] [-q baseQthres] [-b in.bed] <in1.bam> [...]\n");
+ fprintf(stderr, "Usage: bam2depth [-r reg] [-q baseQthres] [-Q mapQthres] [-l minQLen] [-b in.bed] <in1.bam> [...]\n");
return 1;
}
// initialize the auxiliary data structures
n = argc - optind; // the number of BAMs on the command line
- data = calloc(n, sizeof(void*));
- beg = 0; end = 1<<30; tid = -1;
+ data = calloc(n, sizeof(void*)); // data[i] for the i-th input
+ beg = 0; end = 1<<30; tid = -1; // set the default region
for (i = 0; i < n; ++i) {
bam_header_t *htmp;
data[i] = calloc(1, sizeof(aux_t));
data[i]->fp = bam_open(argv[optind+i], "r"); // open BAM
+ data[i]->min_mapQ = mapQ; // set the mapQ filter
+ data[i]->min_len = min_len; // set the qlen filter
htmp = bam_header_read(data[i]->fp); // read the BAM header
if (i == 0) {
- h = htmp; // keep the header for the 1st BAM
+ h = htmp; // keep the header of the 1st BAM
if (reg) bam_parse_region(h, reg, &tid, &beg, &end); // also parse the region
} else bam_header_destroy(htmp); // if not the 1st BAM, trash the header
if (tid >= 0) { // if a region is specified and parsed successfully
while (bam_mplp_auto(mplp, &tid, &pos, n_plp, plp) > 0) { // come to the next covered position
if (pos < beg || pos >= end) continue; // out of range; skip
if (bed && bed_overlap(bed, h->target_name[tid], pos, pos + 1) == 0) continue; // not in BED; skip
- fputs(h->target_name[tid], stdout); printf("\t%d", pos+1);
- for (i = 0; i < n; ++i) {
+ fputs(h->target_name[tid], stdout); printf("\t%d", pos+1); // a customized printf() would be faster
+ for (i = 0; i < n; ++i) { // base level filters have to go here
int j, m = 0;
for (j = 0; j < n_plp[i]; ++j) {
const bam_pileup1_t *p = plp[i] + j; // DON'T modfity plp[][] unless you really know
if (p->is_del || p->is_refskip) ++m; // having dels or refskips at tid:pos
else if (bam1_qual(p->b)[p->qpos] < baseQ) ++m; // low base quality
}
- printf("\t%d", n_plp[i] - m);
+ printf("\t%d", n_plp[i] - m); // this the depth to output
}
putchar('\n');
}