Add helpers for converting to/from normalized (perceptual) volume

These routines were taken from alsamixer and converted to fixed
point for Rockbox.

Change-Id: I64e8bf08da02b1e6e3ef10fdc78254bf8e87ff20

1 files changed, 22 insertions, 0 deletions

diff --git a/docs/LICENSES b/docs/LICENSES
index d340d3961b..4d676c82c0 100644
--- a/docs/LICENSES
+++ b/docs/LICENSES
@@ -143,3 +143,25 @@ From: https://github.com/cnSchwarzer/bsdiff-win
  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
+
+*************************************************************************
+In: apps/misc.c, to_normalized_volume and from_normalized_volume
+From: https://git.alsa-project.org/?p=alsa-utils.git
+      alsamixer/volume_mapping.c
+*************************************************************************
+
+/*
+ * Copyright (c) 2010 Clemens Ladisch <clemens@ladisch.de>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */