59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/* $Revision: 1.5 $
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*/
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#include "unroff.h"
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/* Functions to register Scheme objects in a vector that has been added
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* to the GC root set to avoid having to deal with weak pointers.
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* Code using these functions works with indexes into the vector.
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*
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* register_object(obj) -- registers an object and returns index
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* deregister_object(inx) -- deregisters object specified by index
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* get_object(inx) -- returns object specified by index
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*/
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static int max_objects = 32; /* initial size */
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static int num_objects;
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static Object objects;
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static int inx;
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int register_object(Object x) {
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Object v;
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int n;
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GC_Node;
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if (num_objects == max_objects) {
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max_objects *= 2;
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GC_Link(x);
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v = Make_Vector(max_objects, Null);
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GC_Unlink;
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memcpy(VECTOR(v)->data, VECTOR(objects)->data,
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num_objects * sizeof(Object));
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objects = v;
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inx = num_objects;
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}
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for (n = 0; !Nullp(VECTOR(objects)->data[inx]);
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inx++, inx %= max_objects) {
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n++;
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assert(n < max_objects);
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}
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VECTOR(objects)->data[inx] = x;
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num_objects++;
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return inx;
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}
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void deregister_object(int i) {
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VECTOR(objects)->data[i] = Null;
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--num_objects;
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assert(num_objects >= 0);
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}
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Object get_object(int i) {
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return VECTOR(objects)->data[i];
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}
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void init_gcroot(void) {
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objects = Make_Vector(max_objects, Null);
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Global_GC_Link(objects);
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}
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