feat: skip empty regions

src/pileup.rs

@@ -390,8 +390,16 @@ fn run_rgn(
     let chrom_len = bam.header().target_len(tid).unwrap() as usize;
 
     let windows = split_fetch_definition(&rgn, chrom_len, WINDOW_SIZE);
-    log::debug!("Splitting region into {} windows", windows.len());
+    log::debug!("Splitting {} into {} windows", chrom, windows.len());
     for (chrom_start, chrom_end) in windows {
+        // check if region has data
+        bam.fetch((chrom, chrom_start, chrom_end))?;
+        let mut tmp_records = bam.records();
+        let tmp_rec = tmp_records.next();
+        if tmp_rec.is_none() {
+            continue;
+        }
+        // fetch the data
         bam.fetch((chrom, chrom_start, chrom_end))?;
         let records = bam.records();
         // make the pileup