Imported Upstream version 4.2-build2006upstream/4.2-build2006upstream

1 files changed, 316 insertions, 0 deletions

diff --git a/tutorials/sndkit/morse/morse.c b/tutorials/sndkit/morse/morse.c
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+/*
+ * Purpose: Simple audio programming example that plays morse code.
+ * Copyright (C) 4Front Technologies, 2002-2004. Released under GPLv2/CDDL.
+ *
+ * Description:
+ * This program reads stdin and plays the input to an audio device using morse
+ * code. The stdin input is supposed to be originated from a file. This
+ * program is not capable to play live keyboard input.
+ *
+ * This is a great OSS programming example because it shows how simple
+ * audio programming can be with OSS.
+ *
+ * You can use this program as a template. Just replace the
+ * while loop of the main routine by your own code.
+ *
+ * The {!nlink morse2.c} and {!nlink morse3.c} programs are more complex
+ * versions of the same program. They demonstrate how the {!nlink select}
+ * system call can be used for serving the audio device in parallel 
+ * while handling terminal input.
+ *
+ * This program was tuned to be used when practising for the 
+ * finnish morse code test for radio amateurs. It supports the
+ * scandinavian version of the morse code alphabet used in this test.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/soundcard.h>
+#include <math.h>
+#include <signal.h>
+#include <sys/time.h>
+#include <sys/types.h>
+
+#define BUFSZ (16*1024)
+#define SRATE 48000
+#define ATTACK 100
+#define CHARDELAY 3
+
+int charspeed = 25;
+
+int dotsize, charsize;
+int audiofd = -1;
+
+char randomlist[256];
+int nrandom;
+
+static int ncodes;
+
+double a, step;
+
+/*
+ * The genpulse() routine converts generates a single dot, dash or
+ * a pause between the symbols. this is done by generating sine wave 
+ * (using cos()). It's pretty slow but works for us.
+ */
+#include "charlist.h"
+
+static int
+genpulse (short *buf, int w, int state)
+{
+  int i, l;
+  a = 0.0;
+
+  l = w * dotsize;
+
+  for (i = 0; i < ATTACK; i++)
+    {
+      double tmp = 0x7fff * cos (a * M_PI / 180.0);
+      tmp *= (double) (i) / (double) ATTACK;
+
+      *buf++ = (int) tmp *state;
+
+      a += step;
+      if (a > 360.0)
+	a -= 360.0;
+    }
+
+  for (i = ATTACK; i < l - ATTACK; i++)
+    {
+      double tmp = 0x7fff * cos (a * M_PI / 180.0);
+
+      *buf++ = (int) tmp *state;
+
+      a += step;
+      if (a > 360.0)
+	a -= 360.0;
+    }
+
+  for (i = l - ATTACK; i < l; i++)
+    {
+      double tmp = 0x7fff * cos (a * M_PI / 180.0);
+
+      tmp *= (double) (l - i) / (double) ATTACK;
+
+      *buf++ = (int) tmp *state;
+
+      a += step;
+      if (a > 360.0)
+	a -= 360.0;
+    }
+
+  return l;
+}
+
+/*
+ * The genmorse() routine converts an ASCII character to the
+ * equivivalent audio morse code signal.
+ */
+static int
+genmorse (short *buf, char c)
+{
+  int l = 0, i;
+  const char *s;
+
+  //printf("%c", c);
+  //fflush(stdout);
+
+  if (c == ' ')
+    return genpulse (buf, 4, 0);
+
+  for (i = 0; i < ncodes; i++)
+    if (Chars[i] == c)
+      {
+	s = Codes[i];
+
+	while (*s)
+	  {
+	    if (*s++ == '.')
+	      l += genpulse (&buf[l], 1, 1);
+	    else
+	      l += genpulse (&buf[l], 3, 1);
+
+	    l += genpulse (&buf[l], 1, 0);
+	  }
+
+	l += genpulse (&buf[l], CHARDELAY, 0);
+	return l;
+      }
+
+  return 0;
+}
+
+/*
+ * The playchar() routine handles some special characters that are not
+ * included in the international morse aplhabet. Characters are then played by
+ * calling the genmorse() routine.
+ */
+
+static void
+playchar (char c)
+{
+  short buf[16 * BUFSZ];
+  int l;
+
+  l = 0;
+
+  if (c <= 'Z' && c >= 'A')
+    c += 32;
+
+  switch (c)
+    {
+    case '\n':
+      return;
+      break;
+    case ' ':
+    case '\t':
+      l = genmorse (buf, ' ');
+      break;
+
+    case '\r':
+      break;
+
+    case 'Å':
+      l = genmorse (buf, 'å');
+      break;
+    case 'Ä':
+      l = genmorse (buf, 'ä');
+      break;
+    case 'Ö':
+      l = genmorse (buf, 'ö');
+      break;
+    case 'Ü':
+      l = genmorse (buf, 'ü');
+      break;
+
+    default:
+      l = genmorse (buf, c);
+    }
+
+  write (audiofd, buf, 2 * l);
+  if (2 * l < charsize)
+    {
+      char tmp[4 * 1024 * 1024];
+      l = charsize - 2 * l;
+      memset (tmp, 0, l);
+      write (audiofd, tmp, l);
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  char *devname = "/dev/dsp";
+  short buf[16 * BUFSZ];
+  char line[1024];
+  int i, parm;
+  int l, speed, charspeed, wpm = 8;
+
+/*
+ * Charcter rate (CPS/WPS) handling.
+ */
+
+  if (argc > 1)
+    {
+      wpm = atoi (argv[1]);
+      if (wpm == 0)
+	wpm = 12;
+    }
+
+  if (argc > 2)
+    charspeed = atoi (argv[2]);
+
+  speed = wpm;
+  charsize = 60 * SRATE * 2 / charspeed;
+
+  printf ("Words per minute %d. Characters per minute %d\n", wpm, wpm * 5);
+  printf ("Charrate %d chars/min -> (%d samples)\n", charspeed, charsize);
+  dotsize = SRATE / speed;
+
+  ncodes = strlen (Chars);
+
+/*
+ * Open the audio device and set up the parameters.
+ */
+
+  if ((audiofd = open (devname, O_WRONLY, 0)) == -1)
+    {
+      perror (devname);
+      exit (-1);
+    }
+
+  parm = AFMT_S16_LE;
+  if (ioctl (audiofd, SNDCTL_DSP_SETFMT, &parm) == -1)
+    {
+      perror ("SETFMT");
+      close (audiofd);
+      exit (-1);
+    }
+
+  if (parm != AFMT_S16_LE)
+    {
+      printf
+	("Error: 32/24 bit sample format is not supported by the device\n");
+      printf ("%08x/%08x\n", parm, AFMT_S16_LE);
+      close (audiofd);
+      exit (-1);
+    }
+
+  parm = SRATE;
+  if (ioctl (audiofd, SNDCTL_DSP_SPEED, &parm) == -1)
+    {
+      perror ("SPEED");
+      close (audiofd);
+      exit (-1);
+    }
+
+  if (parm != SRATE)
+    {
+      printf
+	("Error: %d Hz sampling rate is not supported by the device (%d)\n",
+	 SRATE, parm);
+      close (audiofd);
+      exit (-1);
+    }
+
+/*
+ * The setup phase is complete. After this moment we can forget that we are
+ * working on a device. The remainder of this program behaves just like
+ * it's writing to any (disk) file.
+ */
+  a = 0.0;
+
+  step = 360.0 * 600.0 / parm;
+
+  l = 0;
+  l += genpulse (&buf[l], 1, 0);
+  write (audiofd, buf, l * 2);
+
+  /* Some initial delay */
+  memset (buf, 0, 4096);
+  for (l = 0; l < 30; l++)
+    write (audiofd, buf, 4096);
+
+  while (fgets (line, sizeof (line), stdin) != NULL)
+    {
+
+      if (*line == '#')
+	continue;
+
+      for (i = 0; i < strlen (line); i++)
+	{
+	  playchar (line[i]);
+	}
+    }
+
+  /* Some final delay */
+  memset (buf, 0, 4096);
+  for (l = 0; l < 20; l++)
+    write (audiofd, buf, 4096);
+
+  close (audiofd);
+
+  exit (0);
+}