Add efacf056cd

dockerdoom/trunk/pcsound/pcsound_linux.c

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+// Emacs style mode select   -*- C++ -*- 
+//-----------------------------------------------------------------------------
+//
+// Copyright(C) 2007 Simon Howard
+//
+// 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, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+// 02111-1307, USA.
+//
+// DESCRIPTION:
+//    PC speaker driver for Linux.
+//
+//-----------------------------------------------------------------------------
+
+#include "config.h"
+
+#ifdef HAVE_LINUX_KD_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <linux/kd.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "SDL.h"
+#include "SDL_thread.h"
+
+#include "pcsound.h"
+#include "pcsound_internal.h"
+
+#define CONSOLE_DEVICE "/dev/console"
+
+static int console_handle;
+static pcsound_callback_func callback;
+static int sound_thread_running = 0;
+static SDL_Thread *sound_thread_handle;
+static int sleep_adjust = 0;
+
+static void AdjustedSleep(unsigned int ms)
+{
+    unsigned int start_time;
+    unsigned int end_time;
+    unsigned int actual_time;
+
+    // Adjust based on previous error to keep the tempo right
+
+    if (sleep_adjust > ms)
+    {
+        sleep_adjust -= ms;
+        return;
+    }
+    else
+    {
+        ms -= sleep_adjust;
+    }
+
+    // Do the sleep and record how long it takes
+
+    start_time = SDL_GetTicks();
+
+    SDL_Delay(ms);
+    
+    end_time = SDL_GetTicks();
+
+    if (end_time > start_time)
+    {
+        actual_time = end_time - start_time;
+    }
+    else
+    {
+        actual_time = ms;
+    }
+
+    if (actual_time < ms)
+    {
+        actual_time = ms;
+    }
+
+    // Save sleep_adjust for next time
+
+    sleep_adjust = actual_time - ms;
+}
+
+static int SoundThread(void *unused)
+{
+    int frequency;
+    int duration;
+    int cycles;
+    
+    while (sound_thread_running)
+    {
+        callback(&duration, &frequency);
+
+        if (frequency != 0) 
+        {
+            cycles = PCSOUND_8253_FREQUENCY / frequency;
+        }
+        else
+        {
+            cycles = 0;
+        }
+
+        ioctl(console_handle, KIOCSOUND, cycles);
+
+        AdjustedSleep(duration);
+    }
+
+    return 0;
+}
+
+static int PCSound_Linux_Init(pcsound_callback_func callback_func)
+{
+    // Try to open the console
+
+    console_handle = open(CONSOLE_DEVICE, O_WRONLY);
+
+    if (console_handle == -1)
+    {
+        // Don't have permissions for the console device?
+
+	fprintf(stderr, "PCSound_Linux_Init: Failed to open '%s': %s\n",
+			CONSOLE_DEVICE, strerror(errno));
+        return 0;
+    }
+
+    if (ioctl(console_handle, KIOCSOUND, 0) < 0)
+    {
+        // KIOCSOUND not supported: non-PC linux?
+
+        close(console_handle);
+        return 0;
+    }
+
+    // Start a thread up to generate PC speaker output
+    
+    callback = callback_func;
+    sound_thread_running = 1;
+
+    sound_thread_handle = SDL_CreateThread(SoundThread, NULL);
+    
+    return 1;
+}
+
+static void PCSound_Linux_Shutdown(void)
+{
+    sound_thread_running = 0;
+    SDL_WaitThread(sound_thread_handle, NULL);
+    close(console_handle);
+}
+
+pcsound_driver_t pcsound_linux_driver =
+{
+    "Linux",
+    PCSound_Linux_Init,
+    PCSound_Linux_Shutdown,
+};
+
+#endif /* #ifdef HAVE_LINUX_KD_H */
+