Extract read-ints as dedicated bytebuffer fn

chrovis · Jan 4, 2024 · bc6d442 · bc6d442
1 parent 3fad1b5
commit bc6d442
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Showing 3 changed files with 22 additions and 10 deletions.
diff --git a/src/cljam/io/cram/codecs/rans4x8.clj b/src/cljam/io/cram/codecs/rans4x8.clj
@@ -61,11 +61,7 @@
 (defn- decode0 [bb ^long n-out]
   (let [freqs (read-frequencies0 bb)
         cum-freqs (cumulative-frequencies freqs)
-        states (doto (int-array 4)
-                 (aset 0 (int (bb/read-uint bb)))
-                 (aset 1 (int (bb/read-uint bb)))
-                 (aset 2 (int (bb/read-uint bb)))
-                 (aset 3 (int (bb/read-uint bb))))
+        states (bb/read-ints bb 4)
         out (byte-array n-out)]
     (dotimes [i n-out]
       (let [j (rem i 4)
@@ -87,11 +83,7 @@
                               freqs))
         quarter (quot n-out 4)
         truncated (* 4 quarter)
-        states (doto (int-array 4)
-                 (aset 0 (int (bb/read-uint bb)))
-                 (aset 1 (int (bb/read-uint bb)))
-                 (aset 2 (int (bb/read-uint bb)))
-                 (aset 3 (int (bb/read-uint bb))))
+        states (bb/read-ints bb 4)
         last-syms (int-array 4)
         out (byte-array n-out)]
     (dotimes [i quarter]

diff --git a/src/cljam/io/util/byte_buffer.clj b/src/cljam/io/util/byte_buffer.clj
@@ -57,6 +57,15 @@
    (.get bb buffer (int offset) (int length))
    buffer))
 
+(defn read-ints
+  "Reads 'length' ints to buffer starting from offset ints. Returns a new int-array if called without buffer."
+  (^ints [bb length]
+   (read-ints bb (int-array length) 0 length))
+  (^ints [^ByteBuffer bb ^ints buffer ^long offset ^long length]
+   (dotimes [i length]
+     (aset buffer (+ offset i) (.getInt bb)))
+   buffer))
+
 (defn read-string
   "Reads 'length' bytes. Returns a String."
   [^ByteBuffer bb ^long length]

diff --git a/test/cljam/io/util/byte_buffer_test.clj b/test/cljam/io/util/byte_buffer_test.clj
@@ -61,6 +61,17 @@
       (is (= [0 0 0x34 0x12 0xF0 0]
              (map #(bit-and % 0xFF) (bb/read-bytes bb (byte-array 6) 2 3)))))
 
+    (testing "read-ints"
+      (.reset bb)
+      (let [arr (bb/read-ints bb 2)]
+        (is (instance? (class (int-array 0)) arr))
+        (is (= [0xF0123456 0x789ABCDE] (map #(bit-and % 0xFFFFFFFF) arr))))
+
+      (.reset bb)
+      (bb/skip bb 1)
+      (is (= [0 0 0xDEF01234 0]
+             (map #(bit-and % 0xFFFFFFFF) (bb/read-ints bb (int-array 4) 2 1)))))
+
     (testing "read-string"
       (.reset bb)
       (doseq [c "ABCDEFGH"]