Re: [AD] Audio plugin function names

[Chris Robinson <chris.kcat@xxxxxxxxxx>]

On Sunday 05 October 2008 01:12:34 pm Thomas Fjellstrom wrote:
> With vorbis and ogg you CAN pass in read/write functions just fine, so I
> don't see the likeness. sndfile has a hack that somehow bypasses its
> incomplete fd handler..

I'm not sure what the issue is. sf_open_virtual takes a pointer to a struct 
that holds function pointers. The functions include read/write functions..

static sf_count_t snd_get_filelen(void *user_data)
{
    MemDataInfo *data = (MemDataInfo*)user_data;
    return data->Length;
}

static sf_count_t snd_seek(sf_count_t offset, int whence, void *user_data)
{
    ...
}

static sf_count_t snd_read(void *ptr, sf_count_t count, void *user_data)
{
    ...
}

static sf_count_t snd_write(const void *ptr, sf_count_t count, void 
*user_data)
{
    ...
}

static sf_count_t snd_tell(void *user_data)
{
    MemDataInfo *data = (MemDataInfo*)user_data;
    return data->Pos;
}

static SF_VIRTUAL_IO sndMemIO = {
    snd_get_filelen,
    snd_seek,
    snd_read,
    snd_write,
    snd_tell
};

...

SNDFILE *sndFile = sf_open_virtual(&sndMemIO, SFM_READ, &sndInfo, data);
...
sf_close(sndFile);

And it works just fine. VorbisFile is nearly identical, except it doesn't have 
get_filelen, has a close function, the function prototypes are 
ever-so-slightly different, and the struct is not passed by pointer. Granted, 
the internals could be a mess, but then so were APEG's custom IO callbacks 
(and could still be considered as so), and I'm sure Allegro's PACKFILE 
callbacks were, too. They still work just fine, though.