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57 lines
853 B
C
57 lines
853 B
C
/* j/3/tape.c
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**
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** This file is in the public domain.
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*/
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#include "all.h"
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/* functions
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*/
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static u3_noun
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_norm(
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u3_noun a)
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{
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if ( c3n == u3du(a) ) {
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return u3_nul;
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} else {
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return u3nc(((c3y == u3du(u3h(a))) ? u3_nul : u3k(u3h(a))),
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_norm(u3t(a)));
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}
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}
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static u3_noun
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_good(
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u3_noun a)
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{
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while ( 1 ) {
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if ( u3_nul == a ) {
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return c3y;
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}
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if ( c3n == u3ud(u3h(a)) ) {
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return c3n;
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}
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a = u3t(a);
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}
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}
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u3_noun
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u3qe_tape(u3_noun a)
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{
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if ( c3y == _good(a) ) {
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return u3k(a);
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} else {
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return _norm(a);
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}
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}
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u3_noun
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u3we_tape(u3_noun cor)
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{
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u3_noun a;
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if ( (u3_none == (a = u3r_at(u3x_sam, cor))) ) {
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return u3m_bail(c3__fail);
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} else {
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return u3qe_tape(a);
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}
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}
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