Luigi Castelli

so I spent the last 4-5 hours reading every single thread in the

I have been keeping into consideration threads priority and buffer~'s

lightweight locking mechanism (b_valid and b_inuse flags).

I am writing a normalization routine to be used inside a more complex

// don't need to worry about threads priority

defer_low(x, (method)myobj_doscale,0L,0,0L);     

void myobj_doscale(t_myobj *x, double scale)

while (buf->b_inuse) ; // spin until buffer is no longer

buf->b_valid = 0;     // set b_valid to false to prevent

b->b_valid = 1;     // restore buffer~ access

b->b_modtime = gettime(); // set new modification time

So far the code seems to be working correctly but I am not sure it IS

1. Is it strictly necessary to defer methods that alter the buffer~

2. Am I supposed to be using deferlow as above or is defer more

3. Am I correctly understanding and using buffer~'s locking mechanism ?

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so I spent the last 4-5 hours reading every single thread in the
archives related to buffer~.

I have been keeping into consideration threads priority and buffer~'s
lightweight locking mechanism (b_valid and b_inuse flags).

I am writing a normalization routine to be used inside a more complex
object and here is what I came up with:

void myobj_normalize(t_myobj *x)
{
    t_buffer *b = x->buf;

        float *table = b->b_samples;
        long chan = x->chan;
        long frames = b->b_frames;
        long nc = b->b_nchans;
        int i;

        // don't need to worry about threads priority
        // when reading from a buffer~

        float maxval = 0.;
        for (i = 0; i < frames; ++i) {
            float val = table[i * nc + chan];
            float absval = fabsf(val);
            if (absval > maxval) {
                maxval = absval;
            }
        }

            // now I need to write to buffer
            // so threads priority become an issue

            float scale = 1. / maxval;
            defer_low(x, (method)myobj_doscale,0L,0,0L);	 
        }
    }
}

void myobj_doscale(t_myobj *x, double scale)
{
    t_buffer *b = x->buf;
    float *table = b->b_samples;
    long chan = x->chan;
    frames = b->b_frames;
    long nc = b->b_nchans;
    int i;

    while (buf->b_inuse) ;    // spin until buffer is no longer
                              // in use by the audio thread

    buf->b_valid = 0;	      // set b_valid to false to prevent
                              // buffer~ access while editing

    for (i = 0; i < frames; ++i) {
        table[i * nc + chan] *= scale;
    }

    b->b_valid = 1;	      // restore buffer~ access

    b->b_modtime = gettime(); // set new modification time
                              // so that any object referencing
                              // this buffer~ can update
}

So far the code seems to be working correctly but I am not sure it IS
correct.

1. Is it strictly necessary to defer methods that alter the buffer~
content in any way to low priority ?

2. Am I supposed to be using deferlow as above or is defer more
appropriate in this situation ?

------------------------------------------------------------
THIS E-MAIL MESSAGE IS FOR THE SOLE USE OF THE INTENDED RECIPIENT AND MAY CONTAIN CONFIDENTIAL AND/OR PRIVILEGED INFORMATION.  ANY UNAUTHORIZED REVIEW, USE, DISCLOSURE OR DISTRIBUTION IS PROHIBITED.  IF YOU ARE NOT THE INTENDED RECIPIENT, CONTACT THE SENDER BY E-MAIL AT SUPERBIGIO@YAHOO.COM AND DESTROY ALL COPIES OF THE ORIGINAL MESSAGE. WITHOUT PREJUDICE UCC1-207.
------------------------------------------------------------

Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games.
http://sims.yahoo.com/


buffer-questions

I am reviving this thread because my hopes in the new SDK have been disappointed. I wish there was the code of poke~ so I could see Cycling74 approved buffer writing etiquette.

Can someone give me the real practice of the inuse, valid and dirty flags?

I am reviving this thread because my hopes in the new SDK have been disappointed.  I wish there was the code of poke~ so I could see Cycling74 approved buffer writing etiquette.

did you see this, posted the other day by tim place?

http://blog.74objects.com/2009/03/22/accessing-buffers/

buffer~ questions