From b524cec0d86da22a3ff8fdb93328f54d7ccbdf29 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Mon, 19 Jan 2015 09:36:44 +0000
Subject: Revert "fadefx: remove module"

This reverts commit 3471463325be6c990b3abd18b4d34f723440d19a.

While not strictly necessary, it makes the user syntax in splitfx
files much terser.  Changes from the original version should make it
easier-to-read and the diagram should help a lot with understanding.
---
 lib/dtas/fadefx.rb  | 44 ++++++++++++++++++++++++++++++++++++++++++++
 test/test_fadefx.rb | 28 ++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+)
 create mode 100644 lib/dtas/fadefx.rb
 create mode 100644 test/test_fadefx.rb

diff --git a/lib/dtas/fadefx.rb b/lib/dtas/fadefx.rb
new file mode 100644
index 0000000..1ef79ef
--- /dev/null
+++ b/lib/dtas/fadefx.rb
@@ -0,0 +1,44 @@
+# Copyright (C) 2013-2015, all contributors <dtas-all@nongnu.org>
+# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
+require_relative '../dtas'
+require_relative 'parse_time'
+
+# --------- time --------->
+# _____   _______   ______
+#      \ /       \ /
+# prev  X   cur   X   next
+# _____/ \_______/ \______
+#
+# out_prev - controls the downward slope from prev
+# in_cur   - controls the upward slope into cur
+# out_cur  - controls the downward slope from cur
+# in_next  - controls the upward slope into next
+class DTAS::FadeFX # :nodoc:
+  include DTAS::ParseTime
+
+  attr_reader :out_prev, :in_cur, :out_cur, :in_next
+  F = Struct.new(:type, :flen)
+
+  def initialize(args)
+    args =~ /\A([^,]*),([^,]*);([^,]*),([^,]*)\z/ or
+      raise ArgumentError, "bad fade format"
+    fades = [ $1, $2, $3, $4 ]
+    %w(out_prev in_cur out_cur in_next).each do |iv|
+      instance_variable_set("@#{iv}", parse!(fades.shift))
+    end
+  end
+
+  # q - quarter of a sine wave
+  # h - half a sine wave
+  # t - linear (`triangular') slope
+  # l - logarithmic
+  # p - inverted parabola
+  # default is 't' (sox defaults to 'l', but triangular makes more sense
+  # when concatenating
+  def parse!(str)
+    return nil if str.empty?
+    type = "t"
+    str.sub!(/\A([a-z])/, "") and type = $1
+    F.new(type, parse_time(str))
+  end
+end
diff --git a/test/test_fadefx.rb b/test/test_fadefx.rb
new file mode 100644
index 0000000..e4f34fd
--- /dev/null
+++ b/test/test_fadefx.rb
@@ -0,0 +1,28 @@
+# Copyright (C) 2013-2015, all contributors <dtas-all@nongnu.org>
+# License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
+require_relative 'helper'
+require 'dtas/fadefx'
+
+class TestFadeFX < Testcase
+  def test_fadefx
+    ffx = DTAS::FadeFX.new("t1,t3.1;l4,t1")
+    assert_equal 't', ffx.out_prev.type
+    assert_equal 1, ffx.out_prev.flen
+    assert_equal 't', ffx.in_cur.type
+    assert_equal 3.1, ffx.in_cur.flen
+    assert_equal 'l', ffx.out_cur.type
+    assert_equal 4, ffx.out_cur.flen
+    assert_equal 't', ffx.in_next.type
+    assert_equal 1, ffx.in_next.flen
+  end
+
+  def test_fadefx_no_cur
+    ffx = DTAS::FadeFX.new("t1,;,t1")
+    assert_equal 't', ffx.out_prev.type
+    assert_equal 1, ffx.out_prev.flen
+    assert_nil ffx.in_cur
+    assert_nil ffx.out_cur
+    assert_equal 't', ffx.in_next.type
+    assert_equal 1, ffx.in_next.flen
+  end
+end
-- 
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