g_template.c

/* Copyright (c) 1997-1999 Miller Puckette.
* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt," in this distribution.  */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <math.h>  /* for matrix transforms */

#include "m_pd.h"
#include "s_stuff.h"    /* for sys_hostfontsize */
#include "g_canvas.h"

void array_redraw(t_array *a, t_glist *glist);
void graph_graphrect(t_gobj *z, t_glist *glist,
    int *xp1, int *yp1, int *xp2, int *yp2);
/*
This file contains text objects you would put in a canvas to define a
template.  Templates describe objects of type "array" (g_array.c) and
"scalar" (g_scalar.c).
*/

    /* the structure of a "struct" object (also the obsolete "gtemplate"
    you get when using the name "template" in a box.) */

struct _gtemplate
{
    t_object x_obj;
    t_template *x_template;
    t_canvas *x_owner;
    t_symbol *x_sym;
    struct _gtemplate *x_next;
    int x_argc;
    t_atom *x_argv;
};

/* ---------------- forward definitions ---------------- */

static void template_conformarray(t_template *tfrom, t_template *tto,
    int *conformaction, t_array *a);
static void template_conformglist(t_template *tfrom, t_template *tto,
    t_glist *glist,  int *conformaction);
t_canvas *canvas_templatecanvas_forgroup(t_canvas *c);
static int drawimage_getindex(void *z, t_template *template, t_word *data);

/* ---------------------- storage ------------------------- */

t_class *gtemplate_class;
static t_class *template_class;

/* there's a pre-defined "float" template.  LATER should we bind this
to a symbol such as "pd-float"??? */

    /* return true if two dataslot definitions match */
static int dataslot_matches(t_dataslot *ds1, t_dataslot *ds2,
    int nametoo)
{
    return ((!nametoo || ds1->ds_name == ds2->ds_name) &&
        ds1->ds_type == ds2->ds_type &&
            (ds1->ds_type != DT_ARRAY ||
                ds1->ds_fieldtemplate == ds2->ds_fieldtemplate));
}

/* -- templates, the active ingredient in gtemplates defined below. ------- */

t_template *template_new(t_symbol *templatesym, int argc, t_atom *argv)
{
    t_template *x = (t_template *)pd_new(template_class);
    //fprintf(stderr,"template_new %lx\n", x);
    x->t_n = 0;
    x->t_transformable = 0;
    x->t_vec = (t_dataslot *)t_getbytes(0);
    while (argc > 0)
    {
        int newtype, oldn, newn;
        t_symbol *newname, *newarraytemplate = &s_, *newtypesym;
        t_binbuf *newbinbuf = NULL;
        if (argc < 2 || argv[0].a_type != A_SYMBOL ||
            argv[1].a_type != A_SYMBOL)
                goto bad;
        newtypesym = argv[0].a_w.w_symbol;
        newname = argv[1].a_w.w_symbol;
        if (newtypesym == &s_float)
            newtype = DT_FLOAT;
        else if (newtypesym == &s_symbol)
            newtype = DT_SYMBOL;
//        else if (newtypesym == &s_list)
//            newtype = DT_LIST;
        else if (newtypesym == gensym("canvas"))
        {
            char filename[MAXPDSTRING+3];
            t_binbuf *b = binbuf_new();
            if (argc < 3 || argv[2].a_type != A_SYMBOL)
            {
                pd_error(x, "canvas lacks template or name");
                goto bad;
            }
//            filename = canvas_makebindsym(argv[2].a_w.w_symbol);
            sprintf(filename, "%s.pd", argv[2].a_w.w_symbol->s_name);
            if (binbuf_read_via_canvas(b, filename, canvas_getcurrent(), 0))
                post("warning: abstraction %s not found", filename);
            else
                newbinbuf = b;
            newtype = DT_LIST;
            argc--;
            argv++;
        }
        else if (newtypesym == gensym("array"))
        {
            if (argc < 3 || argv[2].a_type != A_SYMBOL)
            {
                pd_error(x, "array lacks element template or name");
                goto bad;
            }
            newarraytemplate = canvas_makebindsym(argv[2].a_w.w_symbol);
            newtype = DT_ARRAY;
            argc--;
            argv++;
        }
        else
        {
            pd_error(x, "%s: no such type", newtypesym->s_name);
            goto bad;
        }
        newn = (oldn = x->t_n) + 1;
        x->t_vec = (t_dataslot *)t_resizebytes(x->t_vec,
            oldn * sizeof(*x->t_vec), newn * sizeof(*x->t_vec));
        x->t_n = newn;
        x->t_vec[oldn].ds_type = newtype;
        x->t_vec[oldn].ds_name = newname;
        x->t_vec[oldn].ds_fieldtemplate = newarraytemplate;
        x->t_vec[oldn].ds_binbuf = newbinbuf;
    bad: 
        argc -= 2; argv += 2;
    }
    if (*templatesym->s_name)
    {
        x->t_sym = templatesym;
        pd_bind(&x->t_pdobj, x->t_sym);
    }
    else x->t_sym = templatesym;
    return (x);
}

int template_size(t_template *x)
{
    return (x->t_n * sizeof(t_word));
}

int template_find_field(t_template *x, t_symbol *name, int *p_onset,
    int *p_type, t_symbol **p_arraytype)
{
    int i, n;
    if (!x)
    {
        bug("template_find_field");
        return (0);
    }
    n = x->t_n;
    for (i = 0; i < n; i++)
        if (x->t_vec[i].ds_name == name)
    {
        *p_onset = i * sizeof(t_word);
        *p_type = x->t_vec[i].ds_type;
        *p_arraytype = x->t_vec[i].ds_fieldtemplate;
        return (1);
    }
    return (0);
}

t_float template_getfloat(t_template *x, t_symbol *fieldname, t_word *wp,
    int loud)
{
    int onset, type;
    t_symbol *arraytype;
    t_float val = 0;
    if (template_find_field(x, fieldname, &onset, &type, &arraytype))
    {
        if (type == DT_FLOAT)
            val = *(t_float *)(((char *)wp) + onset);
        else if (loud) error("%s.%s: not a number",
            x->t_sym->s_name, fieldname->s_name);
    }
    else if (loud) error("%s.%s: no such field",
        x->t_sym->s_name, fieldname->s_name);
    return (val);
}

void template_setfloat(t_template *x, t_symbol *fieldname, t_word *wp, 
    t_float f, int loud)
{
    int onset, type;
    t_symbol *arraytype;
    if (template_find_field(x, fieldname, &onset, &type, &arraytype))
     {
        if (type == DT_FLOAT)
            *(t_float *)(((char *)wp) + onset) = f;
        else if (loud) error("%s.%s: not a number",
            x->t_sym->s_name, fieldname->s_name);
    }
    else if (loud) error("%s.%s: no such field",
        x->t_sym->s_name, fieldname->s_name);
}

t_symbol *template_getsymbol(t_template *x, t_symbol *fieldname, t_word *wp,
    int loud)
{
    int onset, type;
    t_symbol *arraytype;
    t_symbol *val = &s_;
    if (template_find_field(x, fieldname, &onset, &type, &arraytype))
    {
        if (type == DT_SYMBOL)
            val = *(t_symbol **)(((char *)wp) + onset);
        else if (loud) error("%s.%s: not a symbol",
            x->t_sym->s_name, fieldname->s_name);
    }
    else if (loud) error("%s.%s: no such field",
        x->t_sym->s_name, fieldname->s_name);
    return (val);
}

void template_setsymbol(t_template *x, t_symbol *fieldname, t_word *wp, 
    t_symbol *s, int loud)
{
    int onset, type;
    t_symbol *arraytype;
    if (template_find_field(x, fieldname, &onset, &type, &arraytype))
     {
        if (type == DT_SYMBOL)
            *(t_symbol **)(((char *)wp) + onset) = s;
        else if (loud) error("%s.%s: not a symbol",
            x->t_sym->s_name, fieldname->s_name);
    }
    else if (loud) error("%s.%s: no such field",
        x->t_sym->s_name, fieldname->s_name);
}

    /* stringent check to see if a "saved" template, x2, matches the current
        one (x1).  It's OK if x1 has additional scalar elements but not (yet)
        arrays or lists.  This is used for reading in "data files". */
int template_match(t_template *x1, t_template *x2)
{
    int i;
    if (x1->t_n < x2->t_n)
        return (0);
    for (i = x2->t_n; i < x1->t_n; i++)
    {
        if (x1->t_vec[i].ds_type == DT_ARRAY || 
            x1->t_vec[i].ds_type == DT_LIST)
                return (0);
    }
    //if (x2->t_n > x1->t_n)
    //    post("add elements...");
    for (i = 0; i < x2->t_n; i++)
        if (!dataslot_matches(&x1->t_vec[i], &x2->t_vec[i], 1))
            return (0);
    return (1);
}

/* --------------- CONFORMING TO CHANGES IN A TEMPLATE ------------ */

/* the following routines handle updating scalars to agree with changes
in their template.  The old template is assumed to be the "installed" one
so we can delete old items; but making new ones we have to avoid scalar_new
which would make an old one whereas we will want a new one (but whose array
elements might still be old ones.)
    LATER deal with graphics updates too... */

    /* conform the word vector of a scalar to the new template */    
static void template_conformwords(t_template *tfrom, t_template *tto,
    int *conformaction, t_word *wfrom, t_word *wto)
{
    int nto = tto->t_n, i;
    for (i = 0; i < nto; i++)
    {
        if (conformaction[i] >= 0)
        {
                /* we swap the two, in case it's an array or list, so that
                when "wfrom" is deleted the old one gets cleaned up. */
            t_word wwas = wto[i];
            wto[i] = wfrom[conformaction[i]];
            wfrom[conformaction[i]] = wwas;
        }
    }
}

    /* conform a scalar, recursively conforming sublists and arrays  */
static t_scalar *template_conformscalar(t_template *tfrom, t_template *tto,
    int *conformaction, t_glist *glist, t_scalar *scfrom)
{
    t_scalar *x;
    t_gpointer gp;
    int i;
    t_template *scalartemplate;
    /* post("conform scalar"); */
        /* possibly replace the scalar */
    if (scfrom->sc_template == tfrom->t_sym)
    {
            /* see scalar_new() for comment about the gpointer. */
        gpointer_init(&gp);
        x = (t_scalar *)getbytes(sizeof(t_scalar) +
            (tto->t_n - 1) * sizeof(*x->sc_vec));
        x->sc_gobj.g_pd = scalar_class;
        x->sc_template = tfrom->t_sym;
        gpointer_setglist(&gp, glist, &x->sc_gobj);
            /* Here we initialize to the new template, but array and list
            elements will still belong to old template. */
        word_init(x->sc_vec, tto, &gp);

        template_conformwords(tfrom, tto, conformaction,
            scfrom->sc_vec, x->sc_vec);
            
            /* replace the old one with the new one in the list */
        if (glist->gl_list == &scfrom->sc_gobj)
        {
            glist->gl_list = &x->sc_gobj;
            x->sc_gobj.g_next = scfrom->sc_gobj.g_next;
        }
        else
        {
            t_gobj *y, *y2;
            for (y = glist->gl_list; y2 = y->g_next; y = y2)
                if (y2 == &scfrom->sc_gobj)
            {
                x->sc_gobj.g_next = y2->g_next;
                y->g_next = &x->sc_gobj;
                goto nobug;
            }
            bug("template_conformscalar");
        nobug: ;
        }
            /* burn the old one */
        pd_free(&scfrom->sc_gobj.g_pd);
        scalartemplate = tto;
    }
    else
    {
        x = scfrom;
        scalartemplate = template_findbyname(x->sc_template);
    }
        /* convert all array elements and sublists */
    for (i = 0; i < scalartemplate->t_n; i++)
    {
        t_dataslot *ds = scalartemplate->t_vec + i;
        if (ds->ds_type == DT_LIST)
        {
            t_glist *gl2 = x->sc_vec[i].w_list;
            template_conformglist(tfrom, tto, gl2, conformaction);
        }
        else if (ds->ds_type == DT_ARRAY)
        {
            t_symbol *arraytemplate = ds->ds_fieldtemplate;
            if (arraytemplate == tfrom->t_sym ||
                arraytemplate == tto->t_sym)
            {
                return 0;
            }
            template_conformarray(tfrom, tto, conformaction, 
                x->sc_vec[i].w_array);
        }
    }
    return (x);
}

    /* conform an array, recursively conforming sublists and arrays  */
static void template_conformarray(t_template *tfrom, t_template *tto,
    int *conformaction, t_array *a)
{
    int i, j;
    t_template *scalartemplate = 0;
    if (a->a_templatesym == tfrom->t_sym)
    {
        /* the array elements must all be conformed */
        int oldelemsize = sizeof(t_word) * tfrom->t_n,
            newelemsize = sizeof(t_word) * tto->t_n;
        char *newarray = getbytes(newelemsize * a->a_n);
        char *oldarray = a->a_vec;
        if (a->a_elemsize != oldelemsize)
            bug("template_conformarray");
        for (i = 0; i < a->a_n; i++)
        {
            t_word *wp = (t_word *)(newarray + newelemsize * i);
            word_init(wp, tto, &a->a_gp);
            template_conformwords(tfrom, tto, conformaction,
                (t_word *)(oldarray + oldelemsize * i), wp);
            word_free((t_word *)(oldarray + oldelemsize * i), tfrom);
        }
        scalartemplate = tto;
        a->a_vec = newarray;
        freebytes(oldarray, oldelemsize * a->a_n);
    }
    else scalartemplate = template_findbyname(a->a_templatesym);
        /* convert all arrays and sublist fields in each element of the array */
    for (i = 0; i < a->a_n; i++)
    {
        t_word *wp = (t_word *)(a->a_vec + sizeof(t_word) * a->a_n * i);
        for (j = 0; j < scalartemplate->t_n; j++)
        {
            t_dataslot *ds = scalartemplate->t_vec + j;
            if (ds->ds_type == DT_LIST)
            {
                t_glist *gl2 = wp[j].w_list;
                template_conformglist(tfrom, tto, gl2, conformaction);
            }
            else if (ds->ds_type == DT_ARRAY)
            {
                template_conformarray(tfrom, tto, conformaction, 
                    wp[j].w_array);
            }
        }
    }
}

    /* this routine searches for every scalar in the glist that belongs
    to the "from" template and makes it belong to the "to" template.  Descend
    glists recursively.
    We don't handle redrawing here; this is to be filled in LATER... */

t_array *garray_getarray(t_garray *x);

static void template_conformglist(t_template *tfrom, t_template *tto,
    t_glist *glist,  int *conformaction)
{
    t_gobj *g;
    /* post("conform glist %s", glist->gl_name->s_name); */
    for (g = glist->gl_list; g; g = g->g_next)
    {
        if (pd_class(&g->g_pd) == scalar_class)
            g = &template_conformscalar(tfrom, tto, conformaction,
                glist, (t_scalar *)g)->sc_gobj;
        else if (pd_class(&g->g_pd) == canvas_class)
            template_conformglist(tfrom, tto, (t_glist *)g, conformaction);
        else if (pd_class(&g->g_pd) == garray_class)
            template_conformarray(tfrom, tto, conformaction,
                garray_getarray((t_garray *)g));
    }
}

    /* globally conform all scalars from one template to another */ 
void template_conform(t_template *tfrom, t_template *tto)
{
    int nto = tto->t_n, nfrom = tfrom->t_n, i, j,
        *conformaction = (int *)getbytes(sizeof(int) * nto),
        *conformedfrom = (int *)getbytes(sizeof(int) * nfrom), doit = 0;
    for (i = 0; i < nto; i++)
        conformaction[i] = -1;
    for (i = 0; i < nfrom; i++)
        conformedfrom[i] = 0;
    for (i = 0; i < nto; i++)
    {
        t_dataslot *dataslot = &tto->t_vec[i];
        for (j = 0; j < nfrom; j++)
        {
            t_dataslot *dataslot2 = &tfrom->t_vec[j];
            if (dataslot_matches(dataslot, dataslot2, 1))
            {
                conformaction[i] = j;
                conformedfrom[j] = 1;
            }
        }
    }
    for (i = 0; i < nto; i++)
        if (conformaction[i] < 0)
    {
        t_dataslot *dataslot = &tto->t_vec[i];
        for (j = 0; j < nfrom; j++)
            if (!conformedfrom[j] &&
                dataslot_matches(dataslot, &tfrom->t_vec[j], 0))
        {
            conformaction[i] = j;
            conformedfrom[j] = 1;
        }
    }
    if (nto != nfrom)
        doit = 1;
    else for (i = 0; i < nto; i++)
        if (conformaction[i] != i)
            doit = 1;

    if (doit)
    {
        t_glist *gl;
        post("conforming template '%s' to new structure",
            tfrom->t_sym->s_name);
        //for (i = 0; i < nto; i++)
        //    post("... %d", conformaction[i]);
        for (gl = canvas_list; gl; gl = gl->gl_next)
            template_conformglist(tfrom, tto, gl, conformaction);
    }
    freebytes(conformaction, sizeof(int) * nto);
    freebytes(conformedfrom, sizeof(int) * nfrom);
}

t_template *template_findbyname(t_symbol *s)
{
    return ((t_template *)pd_findbyclass(s, template_class));
}

t_canvas *template_findcanvas(t_template *template)
{
    t_gtemplate *gt;
    if (!template)
    {
        bug("template_findcanvas");
        return (0);
    }
    if (!(gt = template->t_list))
        return (0);
    return (gt->x_owner);
    /* return ((t_canvas *)pd_findbyclass(template->t_sym, canvas_class)); */
}

void template_notify(t_template *template, t_symbol *s, int argc, t_atom *argv)
{
    if (template->t_list)
        outlet_anything(template->t_list->x_obj.ob_outlet, s, argc, argv);
}

    /* bash the first of (argv) with a pointer to a scalar, and send on
    to template as a notification message */
void template_notifyforscalar(t_template *template, t_glist *owner,
    t_scalar *sc, t_symbol *s, int argc, t_atom *argv)
{
    t_gpointer gp;
    gpointer_init(&gp);
    gpointer_setglist(&gp, owner, &sc->sc_gobj);
    SETPOINTER(argv, &gp);
    template_notify(template, s, argc, argv);
    gpointer_unset(&gp);
}

    /* call this when reading a patch from a file to declare what templates
    we'll need.  If there's already a template, check if it matches.
    If it doesn't it's still OK as long as there are no "struct" (gtemplate)
    objects hanging from it; we just conform everyone to the new template.
    If there are still struct objects belonging to the other template, we're
    in trouble.  LATER we'll figure out how to conform the new patch's objects
    to the pre-existing struct. */
static void *template_usetemplate(void *dummy, t_symbol *s,
    int argc, t_atom *argv)
{
    t_template *x;
    t_symbol *templatesym =
        canvas_makebindsym(atom_getsymbolarg(0, argc, argv));
    if (!argc)
        return (0);
    argc--; argv++;
            /* check if there's already a template by this name. */
    if ((x = (t_template *)pd_findbyclass(templatesym, template_class)))
    {
        t_template *y = template_new(&s_, argc, argv), *y2;
            /* If the new template is the same as the old one,
            there's nothing to do.  */
        if (!template_match(x, y))
        {
                /* Are there "struct" objects upholding this template? */
            if (x->t_list)
            {
                    /* don't know what to do here! */
                error("%s: template mismatch",
                    templatesym->s_name);
            }
            else
            {
                    /* conform everyone to the new template */
                template_conform(x, y);
                pd_free(&x->t_pdobj);
                y2 = template_new(templatesym, argc, argv);
                y2->t_list = 0;
            }
        }
        pd_free(&y->t_pdobj);
    }
        /* otherwise, just make one. */
    else template_new(templatesym, argc, argv);
    return (0);
}

    /* here we assume someone has already cleaned up all instances of this. */
void template_free(t_template *x)
{
    if (*x->t_sym->s_name)
        pd_unbind(&x->t_pdobj, x->t_sym);
    t_freebytes(x->t_vec, x->t_n * sizeof(*x->t_vec));
}

static void template_setup(void)
{
    template_class = class_new(gensym("template"), 0, (t_method)template_free,
        sizeof(t_template), CLASS_PD, 0);
    class_addmethod(pd_canvasmaker, (t_method)template_usetemplate,
        gensym("struct"), A_GIMME, 0);
        
}

/* ---------------- gtemplates.  One per canvas. ----------- */

/* "Struct": an object that searches for, and if necessary creates, 
a template (above).  Other objects in the canvas then can give drawing
instructions for the template.  The template doesn't go away when the
"struct" is deleted, so that you can replace it with
another one to add new fields, for example. */

static void gtemplate_free(t_gtemplate *x);

static void *gtemplate_donew(t_symbol *sym, int argc, t_atom *argv)
{
    t_canvas *cur = canvas_getcurrent();
    t_gobj *gob = cur->gl_list;
    while (gob)
    {
        if (pd_class(&gob->g_pd) == gtemplate_class)
        {
            error("%s: only one struct allowed per canvas.", cur->gl_name->s_name);
            return(0);
        }
        gob = gob->g_next;
    }
    t_gtemplate *x = (t_gtemplate *)pd_new(gtemplate_class);
    t_template *t = template_findbyname(sym);

    int i;
    x->x_owner = canvas_getcurrent();
    x->x_next = 0;
    x->x_sym = sym;
    x->x_argc = argc;
    x->x_argv = (t_atom *)getbytes(argc * sizeof(t_atom));
    for (i = 0; i < argc; i++)
        x->x_argv[i] = argv[i];

        /* already have a template by this name? */
    if (t)
    {
        x->x_template = t;
            /* if it's already got a "struct" object we
            just tack this one to the end of the list and leave it
            there. */
        if (t->t_list)
        {
            t_gtemplate *x2, *x3;
            for (x2 = x->x_template->t_list; x3 = x2->x_next; x2 = x3)
                ;
            x2->x_next = x;
            post("template %s: warning: already exists.", sym->s_name);
        }
        else
        {
                /* if there's none, we just replace the template with
                our own and conform it. */
            t_template *y = template_new(&s_, argc, argv);

            canvas_redrawallfortemplate(t, 2);
                /* Unless the new template is different from the old one,
                there's nothing to do.  */
            if (!template_match(t, y))
            {
                    /* conform everyone to the new template */
                template_conform(t, y);
                pd_free(&t->t_pdobj);
                t = template_new(sym, argc, argv);
            }
            pd_free(&y->t_pdobj);
            t->t_list = x;
            canvas_redrawallfortemplate(t, 1);
        }
    }
    else
    {
            /* otherwise make a new one and we're the only struct on it. */
        x->x_template = t = template_new(sym, argc, argv);
        t->t_list = x;
   }
    outlet_new(&x->x_obj, 0);
    return (x);
}

int template_check_array_fields(t_symbol *structname, t_template *template);

/* probably duplicating some code from template_new here... */
int gtemplate_cancreate(t_symbol *templatename, int argc, t_atom *argv)
{
    while (argc > 1)
    {
        t_symbol *typesym = argv[0].a_w.w_symbol;
        if (typesym == &s_float || typesym == &s_symbol)
        {
            argc -= 2;
            argv += 2; 
        }
        else if (typesym == gensym("array"))
        {
            if (argc > 2 && argv[2].a_type == A_SYMBOL)
            {
                /* check for cancreation here */
                t_template *elemtemplate =
                    template_findbyname(canvas_makebindsym(argv[2].a_w.w_symbol));
                if (!elemtemplate)
                {
                    post("warning: template %s does not exist",
                        argv[2].a_w.w_symbol->s_name);
                }
                else if (template_check_array_fields(
                        canvas_makebindsym(templatename), elemtemplate) == 0)
                {
                    return 0;
                }
                argc -= 3;
                argv += 3;
            }
            else
            {
                argc -= 2;
                argv += 2;
            }
        }
        else
        {
            argc -= 2;
            argv += 2;
        }
    }
    return 1;
}

static void *gtemplate_new(t_symbol *s, int argc, t_atom *argv)
{
    t_symbol *sym = atom_getsymbolarg(0, argc, argv);
    if (argc >= 1)
        argc--; argv++;
    if (gtemplate_cancreate(sym, argc, argv))
    {
        return (gtemplate_donew(canvas_makebindsym(sym), argc, argv));
    }
    else
        return (0);
}

    /* old version (0.34) -- delete 2003 or so */
static void *gtemplate_new_old(t_symbol *s, int argc, t_atom *argv)
{
    t_symbol *sym = canvas_makebindsym(canvas_getcurrent()->gl_name);
    static int warned;
    if (!warned)
    {
        post("warning -- 'template' (%s) is obsolete; replace with 'struct'",
            sym->s_name);
        warned = 1;
    }
    return (gtemplate_donew(sym, argc, argv));
}

t_template *gtemplate_get(t_gtemplate *x)
{
    return (x->x_template);
}

static void gtemplate_free(t_gtemplate *x)
{
        /* get off the template's list */
    t_template *t = x->x_template;
    t_gtemplate *y;
    if (x == t->t_list)
    {
        canvas_redrawallfortemplate(t, 2);
        if (x->x_next)
        {
                /* if we were first on the list, and there are others on
                the list, make a new template corresponding to the new
                first-on-list and replace the existing template with it. */
            t_template *z = template_new(&s_,
                x->x_next->x_argc, x->x_next->x_argv);
            template_conform(t, z);
            pd_free(&t->t_pdobj);
            pd_free(&z->t_pdobj);
            z = template_new(x->x_sym, x->x_next->x_argc, x->x_next->x_argv);
            z->t_list = x->x_next;
            for (y = z->t_list; y ; y = y->x_next)
                y->x_template = z;
        }
        else t->t_list = 0;
        canvas_redrawallfortemplate(t, 1);
    }
    else
    {
        t_gtemplate *x2, *x3;
        for (x2 = t->t_list; x3 = x2->x_next; x2 = x3)
        {
            if (x == x3)
            {
                x2->x_next = x3->x_next;
                break;
            }
        }
    }
    freebytes(x->x_argv, sizeof(t_atom) * x->x_argc);
}

static void gtemplate_setup(void)
{
    gtemplate_class = class_new(gensym("struct"),
        (t_newmethod)gtemplate_new, (t_method)gtemplate_free,
        sizeof(t_gtemplate), CLASS_NOINLET, A_GIMME, 0);
    class_addcreator((t_newmethod)gtemplate_new_old, gensym("template"),
        A_GIMME, 0);
}

/* ---------------  FIELD DESCRIPTORS ---------------------- */

/* a field descriptor can hold a constant or a variable; if a variable,
it's the name of a field in the template we belong to.  LATER, we might
want to cache the offset of the field so we don't have to search for it
every single time we draw the object.
*/

struct _fielddesc
{
    char fd_type;       /* LATER consider removing this? */
    char fd_var;
    union
    {
        t_float fd_float;       /* the field is a constant float */
        t_symbol *fd_symbol;    /* the field is a constant symbol */
        t_symbol *fd_varsym;    /* the field is variable and this is the name */
    } fd_un;
    float fd_v1;        /* min and max values */
    float fd_v2;
    float fd_screen1;   /* min and max screen values */
    float fd_screen2;
    float fd_quantum;   /* quantization in value */ 
};

static void fielddesc_setfloat_const(t_fielddesc *fd, t_float f)
{
    fd->fd_type = A_FLOAT;
    fd->fd_var = 0;
    fd->fd_un.fd_float = f;
    fd->fd_v1 = fd->fd_v2 = fd->fd_screen1 = fd->fd_screen2 =
        fd->fd_quantum = 0;
}

static void fielddesc_setsymbol_const(t_fielddesc *fd, t_symbol *s)
{
    fd->fd_type = A_SYMBOL;
    fd->fd_var = 0;
    fd->fd_un.fd_symbol = s;
    fd->fd_v1 = fd->fd_v2 = fd->fd_screen1 = fd->fd_screen2 =
        fd->fd_quantum = 0;
}

static void fielddesc_setfloat_var(t_fielddesc *fd, t_symbol *s)
{
    char *s1, *s2, *s3, strbuf[MAXPDSTRING];
    fd->fd_type = A_FLOAT;
    fd->fd_var = 1;
    if (!(s1 = strchr(s->s_name, '(')) || !(s2 = strchr(s->s_name, ')'))
        || (s1 > s2))
    {
        fd->fd_un.fd_varsym = s;
        fd->fd_v1 = fd->fd_v2 = fd->fd_screen1 = fd->fd_screen2 =
            fd->fd_quantum = 0;
    }
    else
    {
        int cpy = s1 - s->s_name, got;
        if (cpy > MAXPDSTRING-5)
            cpy = MAXPDSTRING-5;
        strncpy(strbuf, s->s_name, cpy);
        strbuf[cpy] = 0;
        fd->fd_un.fd_varsym = gensym(strbuf);
        got = sscanf(s1, "(%f:%f)(%f:%f)(%f)",
            &fd->fd_v1, &fd->fd_v2, &fd->fd_screen1, &fd->fd_screen2,
                &fd->fd_quantum);
        if (got < 2)
            goto fail;
        if (got == 3 || (got < 4 && strchr(s2, '(')))
            goto fail;
        if (got < 5 && (s3 = strchr(s2, '(')) && strchr(s3+1, '('))
            goto fail;
        if (got == 4)
            fd->fd_quantum = 0;
        else if (got == 2)
        {
            fd->fd_quantum = 0;
            fd->fd_screen1 = fd->fd_v1;
            fd->fd_screen2 = fd->fd_v2;
        }
        return;
    fail:
        post("parse error: %s", s->s_name);
        fd->fd_v1 = fd->fd_screen1 = fd->fd_v2 = fd->fd_screen2 =
            fd->fd_quantum = 0;
    }
}

#define CLOSED 1
#define BEZ 2
#define NOMOUSE 4
#define A_ARRAY 55      /* LATER decide whether to enshrine this in m_pd.h */

static void fielddesc_setfloatarg(t_fielddesc *fd, int argc, t_atom *argv)
{
        if (argc <= 0) fielddesc_setfloat_const(fd, 0);
        else if (argv->a_type == A_SYMBOL)
            fielddesc_setfloat_var(fd, argv->a_w.w_symbol);
        else fielddesc_setfloat_const(fd, argv->a_w.w_float);
}

static void fielddesc_setsymbolarg(t_fielddesc *fd, int argc, t_atom *argv)
{
        if (argc <= 0) fielddesc_setsymbol_const(fd, &s_);
        else if (argv->a_type == A_SYMBOL)
        {
            fd->fd_type = A_SYMBOL;
            fd->fd_var = 1;
            fd->fd_un.fd_varsym = argv->a_w.w_symbol;
            fd->fd_v1 = fd->fd_v2 = fd->fd_screen1 = fd->fd_screen2 =
                fd->fd_quantum = 0;
        }
        else fielddesc_setsymbol_const(fd, &s_);
}

static void fielddesc_setarrayarg(t_fielddesc *fd, int argc, t_atom *argv)
{
        if (argc <= 0) fielddesc_setfloat_const(fd, 0);
        else if (argv->a_type == A_SYMBOL)
        {
            fd->fd_type = A_ARRAY;
            fd->fd_var = 1;
            fd->fd_un.fd_varsym = argv->a_w.w_symbol;
        }
        else fielddesc_setfloat_const(fd, argv->a_w.w_float);
}

    /* getting and setting values via fielddescs -- note confusing names;
    the above are setting up the fielddesc itself. */
static t_float fielddesc_getfloat(t_fielddesc *f, t_template *template,
    t_word *wp, int loud)
{
    if (f->fd_type == A_FLOAT)
    {
        if (f->fd_var)
            return (template_getfloat(template, f->fd_un.fd_varsym, wp, loud));
        else return (f->fd_un.fd_float);
    }
    else
    {
        if (loud)
            error("symbolic data field used as number");
        return (0);
    }
}

    /* convert a variable's value to a screen coordinate via its fielddesc */
t_float fielddesc_cvttocoord(t_fielddesc *f, t_float val)
{
    t_float coord, extreme, div;
    if (f->fd_v2 == f->fd_v1)
        return (val);
    div = (f->fd_screen2 - f->fd_screen1)/(f->fd_v2 - f->fd_v1);
    coord = f->fd_screen1 + (val - f->fd_v1) * div;
    extreme = (f->fd_screen1 < f->fd_screen2 ?
        f->fd_screen1 : f->fd_screen2);
    if (coord < extreme)
        coord = extreme;
    extreme = (f->fd_screen1 > f->fd_screen2 ? 
        f->fd_screen1 : f->fd_screen2);
    if (coord > extreme)
        coord = extreme;
    return (coord);
}

    /* read a variable via fielddesc and convert to screen coordinate */
t_float fielddesc_getcoord(t_fielddesc *f, t_template *template,
    t_word *wp, int loud)
{
    if (f->fd_type == A_FLOAT)
    {
        if (f->fd_var)
        {
            t_float val = template_getfloat(template,
                f->fd_un.fd_varsym, wp, loud);
            return (fielddesc_cvttocoord(f, val));
        }
        else return (f->fd_un.fd_float);
    }
    else
    {
        if (loud)
            error("symbolic data field used as number");
        return (0);
    }
}

static t_symbol *fielddesc_getsymbol(t_fielddesc *f, t_template *template,
    t_word *wp, int loud)
{
    if (f->fd_type == A_SYMBOL)
    {
        if (f->fd_var)