This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

This library 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Sam Lantinga

/* This file supports an external command for playing music */

#include <sys/types.h>

#include <sys/wait.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <signal.h>

#include "music_cmd.h"

/* Unimplemented */

void MusicCMD_SetVolume(int volume)

{

Mix_SetError("No way to modify external player volume");

}

/* Load a music stream from the given file */

MusicCMD *MusicCMD_LoadSong(const char *cmd, const char *file)

{

MusicCMD *music;

/* Allocate and fill the music structure */

music = (MusicCMD *)malloc(sizeof *music);

if ( music == NULL ) {

Mix_SetError("Out of memory");

return(NULL);

}

strncpy(music->file, file, (sizeof music->file)-1);

music->file[(sizeof music->file)-1] = '\0';

strncpy(music->cmd, cmd, (sizeof music->cmd)-1);

music->cmd[(sizeof music->cmd)-1] = '\0';

music->pid = 0;

/* We're done */

return(music);

}

/* Parse a command line buffer into arguments */

static int ParseCommandLine(char *cmdline, char **argv)

{

char *bufp;

int argc;

argc = 0;

for ( bufp = cmdline; *bufp; ) {

/* Skip leading whitespace */

while ( isspace(*bufp) ) {

++bufp;

}

/* Skip over argument */

if ( *bufp == '"' ) {

++bufp;

if ( *bufp ) {

if ( argv ) {

argv[argc] = bufp;

}

++argc;

}

/* Skip over word */

while ( *bufp && (*bufp != '"') ) {

++bufp;

}

} else {

if ( *bufp ) {

if ( argv ) {

argv[argc] = bufp;

}

++argc;

}

/* Skip over word */

while ( *bufp && ! isspace(*bufp) ) {

++bufp;

}

}

if ( *bufp ) {

if ( argv ) {

*bufp = '\0';

}

++bufp;

}

}

if ( argv ) {

argv[argc] = NULL;

}

return(argc);

}

static char **parse_args(char *command, char *last_arg)

{

int argc;

char **argv;

/* Parse the command line */

argc = ParseCommandLine(command, NULL);

if ( last_arg ) {

++argc;

}

argv = (char **)malloc((argc+1)*(sizeof *argv));

if ( argv == NULL ) {

return(NULL);

}

argc = ParseCommandLine(command, argv);

/* Add last command line argument */

if ( last_arg ) {

argv[argc++] = last_arg;

}

argv[argc] = NULL;

/* We're ready! */

return(argv);

}

/* Start playback of a given music stream */

void MusicCMD_Start(MusicCMD *music)

{

music->pid = fork();

switch(music->pid) {

/* Failed fork() system call */

case -1:

Mix_SetError("fork() failed");

return;

/* Child process - executes here */

case 0: {

char command[PATH_MAX];

char **argv;

/* Execute the command */

strcpy(command, music->cmd);

argv = parse_args(command, music->file);

if ( argv != NULL ) {

execvp(argv[0], argv);

}

/* exec() failed */

perror(argv[0]);

_exit(-1);

}

break;

/* Parent process - executes here */

default:

break;

}

return;

}

/* Stop playback of a stream previously started with MusicCMD_Start() */

void MusicCMD_Stop(MusicCMD *music)

{

int status;

if ( music->pid > 0 ) {

while ( kill(music->pid, 0) == 0 ) {

kill(music->pid, SIGTERM);

sleep(1);

waitpid(music->pid, &status, WNOHANG);

}

music->pid = 0;

}

}

/* Pause playback of a given music stream */

void MusicCMD_Pause(MusicCMD *music)

{

if ( music->pid > 0 ) {

kill(music->pid, SIGSTOP);

}

}

/* Resume playback of a given music stream */

void MusicCMD_Resume(MusicCMD *music)

{

if ( music->pid > 0 ) {

kill(music->pid, SIGCONT);

}

}

/* Close the given music stream */

void MusicCMD_FreeSong(MusicCMD *music)

{

free(music);

}

/* Return non-zero if a stream is currently playing */

int MusicCMD_Active(MusicCMD *music)

{

int status;

int active;

active = 0;

if ( music->pid > 0 ) {

waitpid(music->pid, &status, WNOHANG);

if ( kill(music->pid, 0) == 0 ) {

active = 1;

}

}

return(active);

}

#endif /* unix */