src/cdrom/SDL_cdrom.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* This is the CD-audio control API for Simple DirectMedia Layer */

#include "SDL_cdrom.h"
#include "SDL_syscdrom.h"

#if !defined(__MACOS__)
#define CLIP_FRAMES	10      /* Some CD-ROMs won't go all the way */
#endif

static int SDL_cdinitted = 0;
static SDL_CD *default_cdrom;

/* The system level CD-ROM control functions */
struct CDcaps SDL_CDcaps = {
    NULL,                       /* Name */
    NULL,                       /* Open */
    NULL,                       /* GetTOC */
    NULL,                       /* Status */
    NULL,                       /* Play */
    NULL,                       /* Pause */
    NULL,                       /* Resume */
    NULL,                       /* Stop */
    NULL,                       /* Eject */
    NULL,                       /* Close */
};
int SDL_numcds;

int
SDL_CDROMInit (void)
{
    int retval;

    SDL_numcds = 0;
    retval = SDL_SYS_CDInit ();
    if (retval == 0) {
        SDL_cdinitted = 1;
    }
    default_cdrom = NULL;
    return (retval);
}

/* Check to see if the CD-ROM subsystem has been initialized */
static int
CheckInit (int check_cdrom, SDL_CD ** cdrom)
{
    int okay;

    okay = SDL_cdinitted;
    if (check_cdrom && (*cdrom == NULL)) {
        *cdrom = default_cdrom;
        if (*cdrom == NULL) {
            SDL_SetError ("CD-ROM not opened");
            okay = 0;
        }
    }
    if (!SDL_cdinitted) {
        SDL_SetError ("CD-ROM subsystem not initialized");
    }
    return (okay);
}

int
SDL_CDNumDrives (void)
{
    if (!CheckInit (0, NULL)) {
        return (-1);
    }
    return (SDL_numcds);
}

const char *
SDL_CDName (int drive)
{
    if (!CheckInit (0, NULL)) {
        return (NULL);
    }
    if (drive >= SDL_numcds) {
        SDL_SetError ("Invalid CD-ROM drive index");
        return (NULL);
    }
    if (SDL_CDcaps.Name) {
        return (SDL_CDcaps.Name (drive));
    } else {
        return ("");
    }
}

SDL_CD *
SDL_CDOpen (int drive)
{
    struct SDL_CD *cdrom;

    if (!CheckInit (0, NULL)) {
        return (NULL);
    }
    if (drive >= SDL_numcds) {
        SDL_SetError ("Invalid CD-ROM drive index");
        return (NULL);
    }
    cdrom = (SDL_CD *) SDL_malloc (sizeof (*cdrom));
    if (cdrom == NULL) {
        SDL_OutOfMemory ();
        return (NULL);
    }
    SDL_memset (cdrom, 0, sizeof (*cdrom));
    cdrom->id = SDL_CDcaps.Open (drive);
    if (cdrom->id < 0) {
        SDL_free (cdrom);
        return (NULL);
    }
    default_cdrom = cdrom;
    return (cdrom);
}

CDstatus
SDL_CDStatus (SDL_CD * cdrom)
{
    CDstatus status;
    int i;
    Uint32 position;

    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }

    /* Get the current status of the drive */
    cdrom->numtracks = 0;
    cdrom->cur_track = 0;
    cdrom->cur_frame = 0;
    status = SDL_CDcaps.Status (cdrom, &i);
    position = (Uint32) i;
    cdrom->status = status;

    /* Get the table of contents, if there's a CD available */
    if (CD_INDRIVE (status)) {
        if (SDL_CDcaps.GetTOC (cdrom) < 0) {
            status = CD_ERROR;
        }
        /* If the drive is playing, get current play position */
        if ((status == CD_PLAYING) || (status == CD_PAUSED)) {
            for (i = 1; cdrom->track[i].offset <= position; ++i) {
                /* Keep looking */ ;
            }
#ifdef DEBUG_CDROM
            fprintf (stderr,
                     "Current position: %d, track = %d (offset is %d)\n",
                     position, i - 1, cdrom->track[i - 1].offset);
#endif
            cdrom->cur_track = i - 1;
            position -= cdrom->track[cdrom->cur_track].offset;
            cdrom->cur_frame = position;
        }
    }
    return (status);
}

int
SDL_CDPlayTracks (SDL_CD * cdrom,
                  int strack, int sframe, int ntracks, int nframes)
{
    int etrack, eframe;
    int start, length;

    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }

    /* Determine the starting and ending tracks */
    if ((strack < 0) || (strack >= cdrom->numtracks)) {
        SDL_SetError ("Invalid starting track");
        return (CD_ERROR);
    }
    if (!ntracks && !nframes) {
        etrack = cdrom->numtracks;
        eframe = 0;
    } else {
        etrack = strack + ntracks;
        if (etrack == strack) {
            eframe = sframe + nframes;
        } else {
            eframe = nframes;
        }
    }
    if (etrack > cdrom->numtracks) {
        SDL_SetError ("Invalid play length");
        return (CD_ERROR);
    }

    /* Skip data tracks and verify frame offsets */
    while ((strack <= etrack) &&
           (cdrom->track[strack].type == SDL_DATA_TRACK)) {
        ++strack;
    }
    if (sframe >= (int) cdrom->track[strack].length) {
        SDL_SetError ("Invalid starting frame for track %d", strack);
        return (CD_ERROR);
    }
    while ((etrack > strack) &&
           (cdrom->track[etrack - 1].type == SDL_DATA_TRACK)) {
        --etrack;
    }
    if (eframe > (int) cdrom->track[etrack].length) {
        SDL_SetError ("Invalid ending frame for track %d", etrack);
        return (CD_ERROR);
    }

    /* Determine start frame and play length */
    start = (cdrom->track[strack].offset + sframe);
    length = (cdrom->track[etrack].offset + eframe) - start;
#ifdef CLIP_FRAMES
    /* I've never seen this necessary, but xmcd does it.. */
    length -= CLIP_FRAMES;      /* CLIP_FRAMES == 10 */
#endif
    if (length < 0) {
        return (0);
    }

    /* Play! */
#ifdef DEBUG_CDROM
    fprintf (stderr, "Playing %d frames at offset %d\n", length, start);
#endif
    return (SDL_CDcaps.Play (cdrom, start, length));
}

int
SDL_CDPlay (SDL_CD * cdrom, int sframe, int length)
{
    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }

    return (SDL_CDcaps.Play (cdrom, sframe, length));
}

int
SDL_CDPause (SDL_CD * cdrom)
{
    CDstatus status;
    int retval;

    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }

    status = SDL_CDcaps.Status (cdrom, NULL);
    switch (status) {
    case CD_PLAYING:
        retval = SDL_CDcaps.Pause (cdrom);
        break;
    default:
        retval = 0;
        break;
    }
    return (retval);
}

int
SDL_CDResume (SDL_CD * cdrom)
{
    CDstatus status;
    int retval;

    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }

    status = SDL_CDcaps.Status (cdrom, NULL);
    switch (status) {
    case CD_PAUSED:
        retval = SDL_CDcaps.Resume (cdrom);
    default:
        retval = 0;
        break;
    }
    return (retval);
}

int
SDL_CDStop (SDL_CD * cdrom)
{
    CDstatus status;
    int retval;

    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }

    status = SDL_CDcaps.Status (cdrom, NULL);
    switch (status) {
    case CD_PLAYING:
    case CD_PAUSED:
        retval = SDL_CDcaps.Stop (cdrom);
    default:
        retval = 0;
        break;
    }
    return (retval);
}

int
SDL_CDEject (SDL_CD * cdrom)
{
    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return (CD_ERROR);
    }
    return (SDL_CDcaps.Eject (cdrom));
}

void
SDL_CDClose (SDL_CD * cdrom)
{
    /* Check if the CD-ROM subsystem has been initialized */
    if (!CheckInit (1, &cdrom)) {
        return;
    }
    SDL_CDcaps.Close (cdrom);
    SDL_free (cdrom);
    default_cdrom = NULL;
}

void
SDL_CDROMQuit (void)
{
    SDL_SYS_CDQuit ();
    SDL_cdinitted = 0;
}

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