From 7e702c3387d702374158c61ac6da4b3cb2452186 Mon Sep 17 00:00:00 2001 From: Sebastiano Tronto Date: Tue, 19 Sep 2023 23:22:07 +0200 Subject: Renamed file + added TODOs --- src/cube_array.c | 712 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 712 insertions(+) create mode 100644 src/cube_array.c (limited to 'src/cube_array.c') diff --git a/src/cube_array.c b/src/cube_array.c new file mode 100644 index 0000000..3445658 --- /dev/null +++ b/src/cube_array.c @@ -0,0 +1,712 @@ +/* +In this implementation of the cube.h interface, the cube is represented +by two arrays of 8-bit unsigned integers, one for centers and one for +corners. The 4 leas-significant digits of each bit determine the piece, +the other 4 are used for orientation or kept to 0. + +Edges: + xxxopppp (x = unused, o = orientation, p = piece) + +Corners: + xooxpppp (x = unused, o = orientation, p = piece) + +The two bits for CO are shifted to make it possible to perform mod 3 +operations (sum, inverse) using only addition and bitwise operators. +See below for details. + +The third bit is needed because x+y+1 can exceed 4. +*/ + +#include +#include +#include + +#ifdef DEBUG +#include +#endif + +#include "cube.h" + +#define _c_ufr 0U +#define _c_ubl 1U +#define _c_dfl 2U +#define _c_dbr 3U +#define _c_ufl 4U +#define _c_ubr 5U +#define _c_dfr 6U +#define _c_dbl 7U + +#define _e_uf 0U +#define _e_ub 1U +#define _e_db 2U +#define _e_df 3U +#define _e_ur 4U +#define _e_ul 5U +#define _e_dl 6U +#define _e_dr 7U +#define _e_fr 8U +#define _e_fl 9U +#define _e_bl 10U +#define _e_br 11U + +#define _eoshift 4U +#define _coshift 5U + +#define _pbits 0xFU +#define _eobit 0x10U +#define _cobits 0xF0U +#define _cobits2 0x60U +#define _ctwist_cw 0x20U +#define _ctwist_ccw 0x40U +#define _eflip 0x10U +#define _error 0xFFU + +static char *cornerstr[] = { + [_c_ufr] = "UFR", + [_c_ubl] = "UBL", + [_c_dfl] = "DFL", + [_c_dbr] = "DBR", + [_c_ufl] = "UFL", + [_c_ubr] = "UBR", + [_c_dfr] = "DFR", + [_c_dbl] = "DBL" +}; + +static char *cornerstralt[] = { + [_c_ufr] = "URF", + [_c_ubl] = "ULB", + [_c_dfl] = "DLF", + [_c_dbr] = "DRB", + [_c_ufl] = "ULF", + [_c_ubr] = "URB", + [_c_dfr] = "DRF", + [_c_dbl] = "DLB" +}; + +static char *edgestr[] = { + [_e_uf] = "UF", + [_e_ub] = "UB", + [_e_db] = "DB", + [_e_df] = "DF", + [_e_ur] = "UR", + [_e_ul] = "UL", + [_e_dl] = "DL", + [_e_dr] = "DR", + [_e_fr] = "FR", + [_e_fl] = "FL", + [_e_bl] = "BL", + [_e_br] = "BR" +}; + +static char *movestr[] = { + [U] = "U", + [U2] = "U2", + [U3] = "U'", + [D] = "D", + [D2] = "D2", + [D3] = "D'", + [R] = "R", + [R2] = "R2", + [R3] = "R'", + [L] = "L", + [L2] = "L2", + [L3] = "L'", + [F] = "F", + [F2] = "F2", + [F3] = "F'", + [B] = "B", + [B2] = "B2", + [B3] = "B'", +}; + +cube_t solvedcube = { + .c = { + [_c_ufr] = _c_ufr, + [_c_ubl] = _c_ubl, + [_c_dfl] = _c_dfl, + [_c_dbr] = _c_dbr, + [_c_ufl] = _c_ufl, + [_c_ubr] = _c_ubr, + [_c_dfr] = _c_dfr, + [_c_dbl] = _c_dbl + }, + .e = { + [_e_uf] = _e_uf, + [_e_ub] = _e_ub, + [_e_db] = _e_db, + [_e_df] = _e_df, + [_e_ur] = _e_ur, + [_e_ul] = _e_ul, + [_e_dl] = _e_dl, + [_e_dr] = _e_dr, + [_e_fr] = _e_fr, + [_e_fl] = _e_fl, + [_e_bl] = _e_bl, + [_e_br] = _e_br + } +}; + +static cube_t errorcube = { .e = {0}, .c = {0} }; + +static uint8_t readco(char *); +static uint8_t readcp(char *); +static uint8_t readeo(char *); +static uint8_t readep(char *); +static uint8_t readmove(char); +static uint8_t readmodifier(char); +static int permsign(uint8_t *, int); +static cube_t compose(cube_t, cube_t); + +static uint8_t +readco(char *str) +{ + if (*str == '0') + return 0; + if (*str == '1') + return _ctwist_cw; + if (*str == '2') + return _ctwist_ccw; + +#ifdef DEBUG + fprintf(stderr, "Error reading CO\n"); +#endif + return _error; +} + +static uint8_t +readcp(char *str) +{ + uint8_t c; + + for (c = 0; c < 8; c++) + if (!strncmp(str, cornerstr[c], 3) || + !strncmp(str, cornerstralt[c], 3)) + return c; + +#ifdef DEBUG + fprintf(stderr, "Error reading CP\n"); +#endif + return _error; +} + +static uint8_t +readeo(char *str) +{ + if (*str == '0') + return 0; + if (*str == '1') + return _eflip; + +#ifdef DEBUG + fprintf(stderr, "Error reading EO\n"); +#endif + return _error; +} + +static uint8_t +readep(char *str) +{ + uint8_t e; + + for (e = 0; e < 12; e++) + if (!strncmp(str, edgestr[e], 2)) + return e; + +#ifdef DEBUG + fprintf(stderr, "Error reading EP\n"); +#endif + return _error; +} + +cube_t +readcube(char *buf) +{ + int i; + uint8_t piece, orient; + cube_t ret = {0}; + char *b = buf; + + for (i = 0; i < 12; i++) { + while (*b == ' ' || *b == '\t' || *b == '\n') + b++; + if ((piece = readep(b)) == _error) + goto readcube_error; + b += 2; + if ((orient = readeo(b)) == _error) + goto readcube_error; + b++; + ret.e[i] = piece | orient; + } + for (i = 0; i < 8; i++) { + while (*b == ' ' || *b == '\t' || *b == '\n') + b++; + if ((piece = readcp(b)) == _error) + goto readcube_error; + b += 3; + if ((orient = readco(b)) == _error) + goto readcube_error; + b++; + ret.c[i] = piece | orient; + } + + return ret; + +readcube_error: +#ifdef DEBUG + fprintf(stderr, "readcube error\n"); +#endif + return errorcube; +} + +void +writecube(cube_t cube, char *buf) +{ + char *errormsg; + uint8_t piece, orient; + size_t len; + int i; + + if (!isconsistent(cube)) { + errormsg = "ERROR: cannot write inconsistent cube"; + goto writecube_error; + } + + for (i = 0; i < 12; i++) { + piece = cube.e[i] & _pbits; + orient = (cube.e[i] & _eobit) >> _eoshift; + buf[4*i ] = edgestr[piece][0]; + buf[4*i + 1] = edgestr[piece][1]; + buf[4*i + 2] = orient + '0'; + buf[4*i + 3] = ' '; + } + for (i = 0; i < 8; i++) { + piece = cube.c[i] & _pbits; + orient = (cube.c[i] & _cobits) >> _coshift; + buf[48 + 5*i ] = cornerstr[piece][0]; + buf[48 + 5*i + 1] = cornerstr[piece][1]; + buf[48 + 5*i + 2] = cornerstr[piece][2]; + buf[48 + 5*i + 3] = orient + '0'; + buf[48 + 5*i + 4] = ' '; + } + + buf[48+39] = '\0'; + + return; + +writecube_error: +#ifdef DEBUG + fprintf(stderr, "writecube error, see stdout for details\n"); +#endif + len = strlen(errormsg); + memcpy(buf, errormsg, len); + buf[len] = '\n'; + buf[len+1] = '\0'; +} + + +static uint8_t +readmove(char c) +{ + switch (c) { + case 'U': + return U; + case 'D': + return D; + case 'R': + return R; + case 'L': + return L; + case 'F': + return F; + case 'B': + return B; + default: + return _error; + } +} + +static uint8_t +readmodifier(char c) +{ + switch (c) { + case '1': /* Fallthrough */ + case '2': /* Fallthrough */ + case '3': + return c - '0' - 1; + case '\'': + return 2; + default: + return 0; + } +} + +int +readmoves(char *buf, move_t *m) +{ + int n; + uint64_t r; + char *b; + + for (b = buf, n = 0; *b != '\0'; b++) { + while (*b == ' ' || *b == '\t' || *b == '\n') + b++; + if (*b == '\0') + return n; + if ((r = readmove(*b)) == _error) + goto readmoves_error; + m[n] = (move_t)r; + if ((r = readmodifier(*(b+1))) != 0) { + b++; + m[n] += r; + } + n++; + } + + return n; + +readmoves_error: +#ifdef DEBUG + fprintf(stderr, "readmoves error\n"); +#endif + return -1; +} + +void +writemoves(move_t *m, int n, char *buf) +{ + int i; + size_t len; + char *b, *s; + + for (i = 0, b = buf; i < n; i++, b++) { + s = movestr[m[i]]; + len = strlen(s); + memcpy(b, s, len); + b += len; + *b = ' '; + } + *b = '\0'; +} + + +static int +permsign(uint8_t *a, int n) +{ + int i, j; + uint8_t ret = 0; + + for (i = 0; i < n; i++) + for (j = i+1; j < n; j++) + ret += (a[i] & _pbits) > (a[j] & _pbits) ? 1 : 0; + + return ret % 2; +} + +bool +isconsistent(cube_t cube) +{ + int8_t p, psum, eosum, co, cosum; + bool found[12]; + int i; + + psum = 0; + for (i = 0; i < 12; i++) + found[i] = false; + for (i = 0; i < 12; i++) { + p = cube.e[i] & _pbits; + if (p >= 12) + goto inconsistent_ep; + found[p] = true; + } + for (i = 0; i < 12; i++) + if (!found[i]) + goto inconsistent_ep; + psum = permsign(cube.e, 12); + + for (i = 0; i < 8; i++) + found[i] = false; + for (i = 0; i < 8; i++) { + p = cube.c[i] & _pbits; + if (p >= 8) + goto inconsistent_cp; + found[p] = true; + } + for (i = 0; i < 8; i++) + if (!found[i]) + goto inconsistent_cp; + psum += permsign(cube.c, 8); + + if (psum % 2 != 0) + goto inconsistent_parity; + + eosum = 0; + for (i = 0; i < 12; i++) + eosum += (cube.e[i] & _eobit) >> _eoshift; + if (eosum % 2 != 0) + goto inconsistent_eo; + + cosum = 0; + for (i = 0; i < 8; i++) { + co = (cube.c[i] & _cobits) >> _coshift; + if (co > 2) + goto inconsistent_co; + cosum += co; + } + if (cosum % 3 != 0) + goto inconsistent_co; + + return true; + +inconsistent_ep: +#ifdef DEBUG + fprintf(stderr, "Inconsistent EP\n"); +#endif + goto inconsistent_return; +inconsistent_cp: +#ifdef DEBUG + fprintf(stderr, "Inconsistent CP\n"); +#endif + goto inconsistent_return; +inconsistent_parity: +#ifdef DEBUG + fprintf(stderr, "Inconsistent parity\n"); +#endif + goto inconsistent_return; +inconsistent_eo: +#ifdef DEBUG + fprintf(stderr, "Inconsistent EO\n"); +#endif + goto inconsistent_return; +inconsistent_co: +#ifdef DEBUG + fprintf(stderr, "Inconsistent CO\n"); +#endif + goto inconsistent_return; +inconsistent_return: + return false; +} + +bool +equal(cube_t cube1, cube_t cube2) +{ + uint8_t i; + + for (i = 0; i < 12; i++) + if (cube1.e[i] != cube2.e[i]) + return false; + + for (i = 0; i < 8; i++) + if (cube1.c[i] != cube2.c[i]) + return false; + + return true; +} + +bool +issolved(cube_t cube) +{ + return equal(cube, solvedcube); +} + +bool +iserror(cube_t cube) +{ + return equal(cube, errorcube); +} + +cube_t +move(cube_t c, move_t m) +{ + cube_t ret; + uint8_t aux, auy, auz; + +#ifdef DEBUG + if (!isconsistent(c)) + goto move_inconsistent; +#endif + +#define PERM4(r, i, j, k, l) \ + aux = r[i]; \ + r[i] = r[l]; \ + r[l] = r[k]; \ + r[k] = r[j]; \ + r[j] = aux; +#define PERM22(r, i, j, k, l) \ + aux = r[i]; \ + r[i] = r[j]; \ + r[j] = aux; \ + aux = r[k]; \ + r[k] = r[l]; \ + r[l] = aux; +#define CO(a, b) \ + aux = (a & _cobits) + (b & _cobits); \ + auy = (aux + _ctwist_cw) >> 2U; \ + auz = (aux + auy) & _cobits2; \ + a = (a & _pbits) | auz; +#define CO4(r, i, j, k, l) \ + CO(r[i], _ctwist_cw) \ + CO(r[j], _ctwist_cw) \ + CO(r[k], _ctwist_ccw) \ + CO(r[l], _ctwist_ccw) +#define EO4(r, i, j, k, l) \ + r[i] ^= _eobit; \ + r[j] ^= _eobit; \ + r[k] ^= _eobit; \ + r[l] ^= _eobit; + + ret = c; + + switch (m) { + case U: + PERM4(ret.e, _e_uf, _e_ul, _e_ub, _e_ur) + PERM4(ret.c, _c_ufr, _c_ufl, _c_ubl, _c_ubr) + + return ret; + case U2: + PERM22(ret.e, _e_uf, _e_ub, _e_ul, _e_ur) + PERM22(ret.c, _c_ufr, _c_ubl, _c_ufl, _c_ubr) + + return ret; + case U3: + PERM4(ret.e, _e_uf, _e_ur, _e_ub, _e_ul) + PERM4(ret.c, _c_ufr, _c_ubr, _c_ubl, _c_ufl) + + return ret; + case D: + PERM4(ret.e, _e_df, _e_dr, _e_db, _e_dl) + PERM4(ret.c, _c_dfr, _c_dbr, _c_dbl, _c_dfl) + + return ret; + case D2: + PERM22(ret.e, _e_df, _e_db, _e_dr, _e_dl) + PERM22(ret.c, _c_dfr, _c_dbl, _c_dbr, _c_dfl) + + return ret; + case D3: + PERM4(ret.e, _e_df, _e_dl, _e_db, _e_dr) + PERM4(ret.c, _c_dfr, _c_dfl, _c_dbl, _c_dbr) + + return ret; + case R: + PERM4(ret.e, _e_ur, _e_br, _e_dr, _e_fr) + PERM4(ret.c, _c_ufr, _c_ubr, _c_dbr, _c_dfr) + + CO4(ret.c, _c_ubr, _c_dfr, _c_ufr, _c_dbr) + + return ret; + case R2: + PERM22(ret.e, _e_ur, _e_dr, _e_fr, _e_br) + PERM22(ret.c, _c_ufr, _c_dbr, _c_ubr, _c_dfr) + + return ret; + case R3: + PERM4(ret.e, _e_ur, _e_fr, _e_dr, _e_br) + PERM4(ret.c, _c_ufr, _c_dfr, _c_dbr, _c_ubr) + + CO4(ret.c, _c_ubr, _c_dfr, _c_ufr, _c_dbr) + + return ret; + case L: + PERM4(ret.e, _e_ul, _e_fl, _e_dl, _e_bl) + PERM4(ret.c, _c_ufl, _c_dfl, _c_dbl, _c_ubl) + + CO4(ret.c, _c_ufl, _c_dbl, _c_dfl, _c_ubl) + + return ret; + case L2: + PERM22(ret.e, _e_ul, _e_dl, _e_fl, _e_bl) + PERM22(ret.c, _c_ufl, _c_dbl, _c_ubl, _c_dfl) + + return ret; + case L3: + PERM4(ret.e, _e_ul, _e_bl, _e_dl, _e_fl) + PERM4(ret.c, _c_ufl, _c_ubl, _c_dbl, _c_dfl) + + CO4(ret.c, _c_ufl, _c_dbl, _c_dfl, _c_ubl) + + return ret; + case F: + PERM4(ret.e, _e_uf, _e_fr, _e_df, _e_fl) + PERM4(ret.c, _c_ufr, _c_dfr, _c_dfl, _c_ufl) + + EO4(ret.e, _e_uf, _e_fr, _e_df, _e_fl) + CO4(ret.c, _c_ufr, _c_dfl, _c_dfr, _c_ufl) + + return ret; + case F2: + PERM22(ret.e, _e_uf, _e_df, _e_fr, _e_fl) + PERM22(ret.c, _c_ufr, _c_dfl, _c_ufl, _c_dfr) + + return ret; + case F3: + PERM4(ret.e, _e_uf, _e_fl, _e_df, _e_fr) + PERM4(ret.c, _c_ufr, _c_ufl, _c_dfl, _c_dfr) + + EO4(ret.e, _e_uf, _e_fr, _e_df, _e_fl) + CO4(ret.c, _c_ufr, _c_dfl, _c_dfr, _c_ufl) + + return ret; + case B: + PERM4(ret.e, _e_ub, _e_bl, _e_db, _e_br) + PERM4(ret.c, _c_ubr, _c_ubl, _c_dbl, _c_dbr) + + EO4(ret.e, _e_ub, _e_br, _e_db, _e_bl) + CO4(ret.c, _c_ubl, _c_dbr, _c_dbl, _c_ubr) + + return ret; + case B2: + PERM22(ret.e, _e_ub, _e_db, _e_br, _e_bl) + PERM22(ret.c, _c_ubr, _c_dbl, _c_ubl, _c_dbr) + + return ret; + case B3: + PERM4(ret.e, _e_ub, _e_br, _e_db, _e_bl) + PERM4(ret.c, _c_ubr, _c_dbr, _c_dbl, _c_ubl) + + EO4(ret.e, _e_ub, _e_br, _e_db, _e_bl) + CO4(ret.c, _c_ubl, _c_dbr, _c_dbl, _c_ubr) + + return ret; + default: + goto move_unknown; + } + +move_inconsistent: + fprintf(stderr, "move error, inconsistent cube\n"); + goto move_error; +move_unknown: + fprintf(stderr, "mover error, unknown move\n"); + goto move_error; +move_error: + return errorcube; +} + +cube_t +inverse(cube_t c) +{ + uint8_t i, piece, orien; + cube_t ret = {0}; + +#ifdef DEBUG + if (!isconsistent(c)) + goto inverse_inconsistent; +#endif + + for (i = 0; i < 12; i++) { + piece = c.e[i & _pbits]; + orien = piece & _eobit; + ret.e[piece & _pbits] = i | orien; + } + + for (i = 0; i < 8; i++) { + piece = c.c[i & _pbits]; + orien = ((piece << 1) | (piece >> 1)) & _cobits2; + ret.c[piece & _pbits] = i | orien; + } + + return ret; + +inverse_inconsistent: + fprintf(stderr, "inverse error, inconsistent cube\n"); + return errorcube; +} -- cgit v1.3