urbit/j/c/cut.c
2015-02-10 15:13:17 -08:00

74 lines
1.4 KiB
C

/* j/3/cut.c
**
*/
#include "all.h"
/* functions
*/
u3_noun
u3qc_cut(
u3_atom a,
u3_atom b,
u3_atom c,
u3_atom d)
{
if ( !_(u3a_is_cat(a)) || (a >= 32) ) {
return u3m_bail(c3__fail);
}
if ( !_(u3a_is_cat(b)) ) {
return 0;
}
if ( !_(u3a_is_cat(c)) ) {
c = 0x7fffffff;
}
{
c3_g a_g = a;
c3_w b_w = b;
c3_w c_w = c;
c3_w len_w = u3r_met(a_g, d);
if ( (0 == c_w) || (b_w >= len_w) ) {
return 0;
}
if ( b_w + c_w > len_w ) {
c_w = (len_w - b_w);
}
if ( (b_w == 0) && (c_w == len_w) ) {
return u3k(d);
}
else {
c3_w* sal_w = u3a_slaq(a_g, c_w);
if ( 0 == sal_w ) {
return u3m_bail(c3__fail);
}
u3r_chop(a_g, b_w, c_w, 0, sal_w, d);
return u3a_malt(sal_w);
}
}
}
u3_noun
u3wc_cut(
u3_noun cor)
{
u3_noun a, b, c, d;
if ( (c3n == u3r_mean(cor, u3x_sam_2, &a,
u3x_sam_12, &b,
u3x_sam_13, &c,
u3x_sam_7, &d, 0)) ||
(c3n == u3ud(a)) ||
(c3n == u3ud(b)) ||
(c3n == u3ud(c)) ||
(c3n == u3ud(d)) )
{
return u3m_bail(c3__exit);
} else {
return u3qc_cut(a, b, c, d);
}
}