4. VM State

<<typedefs>>=

typedef struct trig_state trig_state;

The idea here is to have a component that allows multiple readers to read from one pool. This sort of functionality would make it easier for a single Trig instance to play multiple sequences.

It is initialized with trig_state_init.

<<funcdefs>>=

void trig_state_init(trig_state *ts);

<<funcs>>=

void trig_state_init(trig_state *ts)
{
<<trig_state_init>>
}

Two big things that an independent VM state would need: counter + cell position.

For convenience purposes, an optional pointer holding trig_vm is also part of the state. This makes it easier to wrap a graforge node around a reader.

<<trig_state>>=

struct trig_state {
    int counter;
    int pos;
    int ipos;
    void *ud;
};

<<trig_state_init>>=

ts->counter = -1;
ts->pos = 0;
ts->ipos = 0;
ts->ud = NULL;

The data in the trig_state struct can be set/get with trig_state_ud_set and trig_state_ud_get.

<<funcdefs>>=

void trig_state_ud_set(trig_state *state, void *ud);
void * trig_state_ud_get(trig_state *state);

<<funcs>>=

void trig_state_ud_set(trig_state *state, void *ud)
{
    state->ud = ud;
}

void * trig_state_ud_get(trig_state *state)
{
    return state->ud;
}

If vm is not empty, trig_state_step can run trig_vm_state_step internally.

An initial position, ipos, dictates where to start. Internally, this is represented as an 0-indexed array offset. Externally, the values are 1-indexed in order for it to make it align more with the visuals.

<<funcdefs>>=

void trig_state_ipos(trig_state *state, int ipos);

<<funcs>>=

void trig_state_ipos(trig_state *state, int ipos)
{
    if (ipos < 1 || ipos > 32) return;
    state->ipos = ipos - 1;
}

A state can be reset with trig_state_reset. This sets the pos to be ipos.

<<funcdefs>>=

void trig_state_reset(trig_state *state);

<<funcs>>=

void trig_state_reset(trig_state *state)
{
    state->pos = state->ipos;
    state->counter = -1;
}

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