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ss.h

/*
 * Copyright (c) 1991-1993 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the Computer Systems
 *    Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * @(#) $Header: ss.h,v 1.10 96/03/16 13:12:53 van Exp $ (LBL)
 */

#ifndef vat_ss_h
#define vat_ss_h

#include <sys/types.h>
#ifdef WIN32
#include <winsock.h>
#endif
#include <memory.h>
#undef resource_h

#define ULAW_ZERO 0x7f
#define MEAN_FILTER 3

class SampleStream {
    public:
      SampleStream(int, int, int, int lvl = 0);
      SampleStream(const SampleStream&);
      void Mix(int delta, const u_char* in, int len);
      inline u_char *CurBlk() const { return &samples[now]; }
      inline u_char *BlkBack(u_int nsamp) const
                  {
                        if (nsamp > now)
                              nsamp -= totsize;
                        return (&samples[now - nsamp]);
                  }
      inline u_int Clock() const { return sclock; }
      inline int BlkSize() const { return blksize; }
      inline int MaxSamp() const { return maxsamp; }
      inline void Advance()
                  {
                        sclock += blksize;
                        now += blksize;
                        if (now >= totsize)
                              now = 0;
                        // clear out the oldest discardable frame
                        int i = int(now  - past);
                        if (i < 0)
                              i += totsize;
                        memcpy(&samples[i], zero, blksize);
                  }
      inline int Mean() const { return (smean); }
      inline int LTMean() const { return (sltmean); }
      inline int Silent(int t = 0) const {
            return (((smax - sltmean) >> MEAN_FILTER) < ssthresh_ + t);
      }
      inline int Max() const { return (smax); }
      void Compute();
      inline u_int Now() const { return now; }
      inline int Scale() const { return bias; }
      void SetScale(int s) { bias = s; }
      inline void AdjustScale(int s)
                  {
                        int b = bias + s;
                        if (b < 32 && b > -32)
                              bias = b;
                  }
      inline int AGC() const { return (doAGC); }
      inline void DoAGC(int v)
                  {
                        doAGC = v? 1 : 0;
                        if (doAGC == 0) {
                              oldbias = bias;
                              bias = 0;
                        } else {
                              bias = oldbias;
                              deadtime = sclock;
                        }
                  }
      inline void UpdateAGC()
                  {
                        if (doAGC)
                              _UpdateAGC();
                  }
      inline int AGCLevel() const { return (AGClevel); }
      inline void SetAGCLevel(int v) { AGClevel = v; }
      inline void ssthresh(int v) { ssthresh_ = v; }
    private:
      void _UpdateAGC();
      u_char *samples;
      const u_char *zero;
      u_int now;
      u_int sclock;
      const int past;
      const u_int blksize;
      const u_int totsize;
      const int maxsamp;

      int sltmean;
      int smean;
      int smax;

      int doAGC;
      int bias;
      int oldbias;
      int AGClevel;
      int AGCerr;
      u_int deadtime;
      int ssthresh_;
};

#endif

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