Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / audio-1.1.4 / au.m

diff --git a/octave_packages/audio-1.1.4/au.m b/octave_packages/audio-1.1.4/au.m
new file mode 100644 (file)
index 0000000..a194bfd
--- /dev/null
+++ b/octave_packages/audio-1.1.4/au.m
@@ -0,0 +1,51 @@
+## Copyright (C) 2000 Paul Kienzle
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; If not, see <http://www.gnu.org/licenses/>.
+
+## y = au(x, fs, lo [, hi])
+##
+## Extract data from x for time range lo to hi in milliseconds.  If lo
+## is [], start at the beginning.  If hi is [], go to the end.  If hi is
+## not specified, return the single element at lo.  If lo<0, prepad the
+## signal to time lo.  If hi is beyond the end, postpad the signal to
+## time hi.
+
+## TODO: modify prepad and postpad so that they accept matrices.
+function y=au(x,fs,lo,hi)
+  if nargin<3 || nargin>4,
+    usage("y = au(x, fs, lo [,hi])");
+  endif
+
+  if nargin<4, hi=lo; endif
+  if isempty(lo), 
+    lo=1; 
+  else
+    lo=fix(lo*fs/1000)+1;
+  endif
+  if isempty(hi),
+    hi=length(x);
+  else
+    hi=fix(hi*fs/1000)+1;
+  endif
+  if hi<lo, t=hi; hi=lo; lo=hi; endif
+  if (size(x,1)==1 || size(x,2)==1)
+    y=x(max(lo,1):min(hi,length(x)));
+    if (lo<1), y=prepad(y,length(y)-lo+1); endif
+    if (hi>length(x)), y=postpad(y,length(y)+hi-length(x)); endif
+  else
+    y=x(max(lo,1):min(hi,length(x)), :);
+    if (lo<1), y=[zeros(size(x,2),-lo+1) ; y]; endif
+    if (hi>length(x)), y=[y ; zeros(size(x,2),hi-length(x))]; endif
+  endif
+endfunction