h48

A prototype for an optimal Rubik's cube solver, work in progress.
git clone https://git.tronto.net/h48
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coordinate.h (1651B)


      1 /* Macros defined in a separate file for easier testing */
      2 #include "coordinate_macros.h"
      3 
      4 STATIC_INLINE int64_t coord_h48(cube_t, const uint32_t *, uint8_t);
      5 STATIC_INLINE int64_t coord_h48_edges(cube_t, int64_t, uint8_t, uint8_t);
      6 STATIC_INLINE cube_t invcoord_h48(int64_t, const cube_t *, uint8_t);
      7 
      8 STATIC_INLINE int64_t
      9 coord_h48(cube_t c, const uint32_t *cocsepdata, uint8_t h)
     10 {
     11 	int64_t cocsep, coclass;
     12 	uint32_t data;
     13 	uint8_t ttrep;
     14 
     15 	DBG_ASSERT(h <= 11, -1, "coord_h48: h must be between 0 and 11\n");
     16 
     17 	cocsep = coord_cocsep(c);
     18 	data = cocsepdata[cocsep];
     19 	coclass = (int64_t)COCLASS(data);
     20 	ttrep = (int64_t)TTREP(data);
     21 
     22 	return coord_h48_edges(c, coclass, ttrep, h);
     23 }
     24 
     25 STATIC_INLINE int64_t
     26 coord_h48_edges(cube_t c, int64_t coclass, uint8_t ttrep, uint8_t h)
     27 {
     28 	cube_t d;
     29 	int64_t esep, eo, edges;
     30 
     31 	d = transform_edges(c, ttrep);
     32 	esep = coord_esep(d);
     33 	eo = coord_eo(d);
     34 	edges = (esep << 11) + eo;
     35 
     36 	return (coclass * H48_ESIZE(11) + edges) >> (11 - (int64_t)h);
     37 }
     38 
     39 /*
     40 This function does not necessarily return a cube whose coordinate is
     41 the given value, because it works up to symmetry. This means that the
     42 returned cube is a transformed cube of one that gives the correct value.
     43 */
     44 STATIC_INLINE cube_t
     45 invcoord_h48(int64_t i, const cube_t *crep, uint8_t h)
     46 {
     47 	cube_t ret;
     48 	int64_t hh, coclass, ee, esep, eo;
     49 
     50 	DBG_ASSERT(h <= 11, ZERO_CUBE,
     51 	    "invcoord_h48: h must be between 0 and 11\n");
     52 
     53 	hh = (int64_t)h;
     54 	coclass = i / H48_ESIZE(h);
     55 	ee = i % H48_ESIZE(h);
     56 	esep = ee >> hh;
     57 	eo = (ee & ((1 << hh) - 1)) << (11 - hh);
     58 
     59 	ret = invcoord_esep(esep);
     60 	copy_corners(&ret, crep[coclass]);
     61 	set_eo(&ret, eo);
     62 
     63 	return ret;
     64 }