Merge pull request #315 from dcurrie/issue-#312
Fix for equal? bug #312
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commit
57c3bffc73
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@ -10,8 +10,10 @@ KHASH_DEFINE2(m, void *, int, 0, kh_ptr_hash_func, kh_ptr_hash_equal)
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static bool
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internal_equal_p(pic_state *pic, pic_value x, pic_value y, int depth, khash_t(m) *h)
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{
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pic_value local = pic_nil_value();
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int c = 0;
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pic_value localx = pic_nil_value();
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pic_value localy = pic_nil_value();
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int cx = 0;
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int cy = 0;
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if (depth > 10) {
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if (depth > 200) {
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@ -68,17 +70,30 @@ internal_equal_p(pic_state *pic, pic_value x, pic_value y, int depth, khash_t(m)
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return false;
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/* Floyd's cycle-finding algorithm */
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if (pic_nil_p(local)) {
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local = x;
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if (pic_nil_p(localx)) {
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localx = x;
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}
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x = pic_cdr(pic, x);
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cx++;
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if (pic_nil_p(localy)) {
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localy = y;
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}
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y = pic_cdr(pic, y);
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c++;
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if (c == 2) {
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c = 0;
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local = pic_cdr(pic, local);
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if (pic_eq_p(local, x)) {
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return true;
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cy++;
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if (cx == 2) {
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cx = 0;
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localx = pic_cdr(pic, localx);
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if (pic_eq_p(localx, x)) {
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if (cy < 0 ) return true; /* both lists circular */
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cx = INT_MIN; /* found a cycle on x */
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}
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}
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if (cy == 2) {
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cy = 0;
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localy = pic_cdr(pic, localy);
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if (pic_eq_p(localy, y)) {
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if (cx < 0 ) return true; /* both lists circular */
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cy = INT_MIN; /* found a cycle on y */
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}
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}
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goto LOOP; /* tail-call optimization */
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