[linux-audio-dev] help with multiple control ports

[Lars Luthman]

On Wed, 2005-06-29 at 13:57 +0300, Artemio wrote:
> I have a problem with creating a plugin with more than one control 
> port. In the attachment you'll find "booster-simple.c" which has one 
> "Gain" port and my attempt to add a second port in "booster.c". For 
> some reason the latter cannot be used - the sources seem to be 
> correct, it compiles fine, but then if I test with "applyplugin" it 
> segfaults and other hosts complain about a malloc() error and hang.

From booster.c:

#define BOOSTER_INPUT1  0
#define BOOSTER_OUTPUT1 1
#define BOOSTER_INPUT2 2
#define BOOSTER_OUTPUT2 3
#define BOOSTER_GAIN 4
#define BOOSTER_ASYMMETRY 5

...

g_psMonoDescriptor->PortCount = 4;
piPortDescriptors = (LADSPA_PortDescriptor *)calloc(4,
sizeof(LADSPA_PortDescriptor));
g_psMonoDescriptor->PortDescriptors
      = (const LADSPA_PortDescriptor *)piPortDescriptors;
	  
piPortDescriptors[BOOSTER_GAIN] = LADSPA_PORT_INPUT|LADSPA_PORT_CONTROL;
piPortDescriptors[BOOSTER_ASYMMETRY] =
    LADSPA_PORT_INPUT|LADSPA_PORT_CONTROL;
piPortDescriptors[BOOSTER_INPUT1] = LADSPA_PORT_INPUT|LADSPA_PORT_AUDIO;
piPortDescriptors[BOOSTER_OUTPUT1] = 
    LADSPA_PORT_OUTPUT|LADSPA_PORT_AUDIO;


First you set the PortCount to 4 and allocate an array of 4
LADSPA_PortDescriptor variables, and then you try to access index
BOOSTER_GAIN and BOOSTER_ASYMMETRY in the array, which are defined as 4
and 5. That is bound to cause all sorts of problems.

-- 
Lars Luthman
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