Merge pull request #45 from ArcInstitute/21-return-error-immediately-in-parallel-implementations-when-n_threads-0

21 handle num threads equals zero by setting to max

Author: noamteyssier

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "binseq"
-version = "0.6.4"
+version = "0.6.5"
 edition = "2021"
 description = "A high efficiency binary format for sequencing data"
 license = "MIT"
@@ -17,6 +17,7 @@ bitnuc = "0.2.11"
 bytemuck = "1.21.0"
 byteorder = "1.5.0"
 memmap2 = "0.9.5"
+num_cpus = "1.17.0"
 rand = { version = "0.9.1", features = ["small_rng"] }
 thiserror = "2.0.8"
 zstd = { version = "0.13.3", features = ["zstdmt"] }

src/bq/reader.rs

@@ -629,6 +629,13 @@ impl ParallelReader for MmapReader {
         num_threads: usize,
         range: Range<usize>,
     ) -> Result<()> {
+        // Calculate the number of threads to use
+        let num_threads = if num_threads == 0 {
+            num_cpus::get()
+        } else {
+            num_threads.min(num_cpus::get())
+        };
+
         // Validate range
         let num_records = self.num_records();
         if range.start >= num_records || range.end > num_records || range.start >= range.end {

src/vbq/reader.rs

@@ -977,6 +977,13 @@ impl ParallelReader for MmapReader {
         num_threads: usize,
         range: Range<usize>,
     ) -> Result<()> {
+        // Calculate the number of threads to use
+        let num_threads = if num_threads == 0 {
+            num_cpus::get()
+        } else {
+            num_threads.min(num_cpus::get())
+        };
+
         // Generate or load the index first
         let index = self.load_index()?;