fastq/record: Split name from definition on first separator

This previously searched for the separator from the end of the
definition, which may contain part of the description if the separator
appears multiple times. It now searches from the beginning of the
definition.

Author: zaeleus

CHANGELOG.md

@@ -6,6 +6,12 @@
 
   * Log messages are written to `stderr` rather than `stdout`.
 
+  * fastq/record: Split name from definition on first separator.
+
+    This previously searched for the separator from the end of the definition,
+    which may contain part of the description if the separator appears multiple
+    times. It now searches from the beginning of the definition.
+
 ### Removed
 
   * Remove `--verbose` flag.

src/fastq/record.rs

@@ -79,16 +79,13 @@ impl Record {
         let definition = self.definition();
 
         let pos = if let Some(c) = separator {
-            definition.iter().rev().position(|&b| b == c)
+            definition.iter().position(|&b| b == c)
         } else {
-            definition
-                .iter()
-                .rev()
-                .position(|&b| b == b'/' || b == b' ')
+            definition.iter().position(|&b| b == b'/' || b == b' ')
         };
 
         if let Some(i) = pos {
-            self.name_end = definition.len() - i - 1;
+            self.name_end = i;
         }
     }
 }
@@ -129,16 +126,15 @@ mod tests {
 
     #[test]
     fn test_reset() {
-        let mut record = Record::new("@fqlib/1", "", "", "");
-        record.reset(None);
-        assert_eq!(record.name(), b"@fqlib");
-
-        let mut record = Record::new("@fqlib 1", "", "", "");
-        record.reset(None);
-        assert_eq!(record.name(), b"@fqlib");
+        fn t(definition: &str, separator: Option<u8>, expected: &[u8]) {
+            let mut record = Record::new(definition, "", "", "");
+            record.reset(separator);
+            assert_eq!(record.name(), expected);
+        }
 
-        let mut record = Record::new("@fqlib_1", "", "", "");
-        record.reset(Some(b'_'));
-        assert_eq!(record.name(), b"@fqlib");
+        t("@fqlib/1", None, b"@fqlib");
+        t("@fqlib 1", None, b"@fqlib");
+        t("@fqlib/1 RG:rg0", None, b"@fqlib");
+        t("@fqlib_1", Some(b'_'), b"@fqlib");
     }
 }