Implemented compose; some cleanup

4 files changed, 110 insertions, 45 deletions

diff --git a/src/constants.h b/src/constants.h
new file mode 100644
index 0000000..6a7e3f9
--- /dev/null
+++ b/src/constants.h
@@ -0,0 +1,71 @@
+/* Standard moves */
+#define U  0U
+#define U2 1U
+#define U3 2U
+#define D  3U
+#define D2 4U
+#define D3 5U
+#define R  6U
+#define R2 7U
+#define R3 8U
+#define L  9U
+#define L2 10U
+#define L3 11U
+#define F  12U
+#define F2 13U
+#define F3 14U
+#define B  15U
+#define B2 16U
+#define B3 17U
+
+/* Regular transformations (rotations) */
+#define UF_i 0
+#define UL_i 1
+#define UB_i 2
+#define UR_i 3
+#define DF_i 4
+#define DL_i 5
+#define DB_i 6
+#define DR_i 7
+#define RU_i 8
+#define RF_i 9
+#define RD_i 10
+#define RB_i 11
+#define LU_i 12
+#define LF_i 13
+#define LD_i 14
+#define LB_i 15
+#define FU_i 16
+#define FR_i 16
+#define FD_i 18
+#define FL_i 19
+#define BU_i 20
+#define BR_i 21
+#define BD_i 22
+#define BL_i 23
+
+/* Mirrored transformations */
+#define UF_m 24
+#define UL_m 25
+#define UB_m 26
+#define UR_m 27
+#define DF_m 28
+#define DL_m 29
+#define DB_m 30
+#define DR_m 31
+#define RU_m 32
+#define RF_m 33
+#define RD_m 34
+#define RB_m 35
+#define LU_m 36
+#define LF_m 37
+#define LD_m 38
+#define LB_m 39
+#define FU_m 40
+#define FR_m 41
+#define FD_m 42
+#define FL_m 43
+#define BU_m 44
+#define BR_m 45
+#define BD_m 46
+#define BL_m 47
diff --git a/src/cube.h b/src/cube.h
index e5434e3..fcc76dc 100644
--- a/src/cube.h
+++ b/src/cube.h
@@ -1,52 +1,13 @@
-typedef enum {
-        U = 0, U2, U3, D, D2, D3,
-        R, R2, R3, L, L2, L3,
-        F, F2, F3, B, B2, B3
-} move_t;
+/* TODO: ifdef for different implementations */
+#include "cube_array.h"
 
-typedef enum {
-        UF_i = 0, UL_i, UB_i, UR_i, DF_i, DL_i, DB_i, DR_i,
-        UF_m, UL_m, UB_m, UR_m, DF_m, DL_m, DB_m, DR_m,
-        RU_i, RF_i, RD_i, RB_i, LU_i, LF_i, LD_i, LB_i,
-        RU_m, RF_m, RD_m, RB_m, LU_m, LF_m, LD_m, LB_m,
-        FU_i, FR_i, FD_i, FL_i, BU_i, BR_i, BD_i, BL_i,
-        FU_m, FR_m, FD_m, FL_m, BU_m, BR_m, BD_m, BL_m
-} trans_t;
-
-typedef struct {
-        uint8_t c[8];
-        uint8_t e[12];
-} cube_t;
+/* For moves and transformations, see constants.h */
+typedef uint8_t move_t;
+typedef uint8_t trans_t;
 
 extern cube_t solvedcube;
 
-/*
-The functions readcube() and writecube() use the following format.
-
-Each edge is represented by two letters denoting the sides it belongs to
-and one number denoting its orientation (0 oriented, 1 mis-oriented).
-Similarly, each corner is represented by three letters and a number
-(0 oriented, 1 twisted clockwise, 2 twisted counter-clockwise).
-Edge orientation is relative to the F / B axis, corner orientation is
-relative to the U / D axis.
-
-The pieces are ordered such that the solved cube looks like this:
-
-UF0 UB0 DB0 DF0 UR0 UL0 DL0 DR0 FR0 FL0 BL0 BR0
-UFR0 UBL0 DFL0 DBR0 UFL0 UBR0 DFR0 DBL0
-
-Whitespace (including newlines) between pieces is ignored when reading
-the cube, and a single whitespace character is added between pieces
-when writing.
-
-The cube after the moves R'U'F looks like this:
-
-FL1 BR0 DB0 UR1 UF0 UB0 DL0 FR0 UL1 DF1 BL0 DR0
-UBL1 DBR1 UFR2 DFR2 DFL2 UBL2 UFL2 DBL0
-
-More formats might be supported in the future.
-*/
-
+/* For the textual representation of the cube, see utils/FORMAT.txt */
 cube_t readcube(char *);
 void writecube(cube_t, char *);
 
diff --git a/src/cube_array.c b/src/cube_array.c
index a051610..b0b5e1e 100644
--- a/src/cube_array.c
+++ b/src/cube_array.c
@@ -25,6 +25,7 @@ The third bit is needed because x+y+1 can exceed 4.
 #include <stdio.h>
 #endif
 
+#include "constants.h"
 #include "cube.h"
 
 #define _c_ufr      0U
@@ -713,6 +714,32 @@ inverse_inconsistent:
 cube_t
 compose(cube_t c1, cube_t c2)
 {
+        uint8_t i, piece, orien, aux, auy;
+        cube_t ret = {0};
+
+#ifdef DEBUG
+        if (!isconsistent(c1) || !isconsistent(c2))
+                goto compose_inconsistent;
+#endif
+
+        for (i = 0; i < 12; i++) {
+                piece = c2.e[i] & _pbits;
+                orien = (c2.e[i] ^ c1.e[piece]) & _eobit;
+                ret.e[i] = (c1.e[piece] & _pbits) | orien;
+        }
+
+        for (i = 0; i < 8; i++) {
+                piece = c2.c[i] & _pbits;
+                aux = (c2.c[i] & _cobits) + (c1.c[piece] & _cobits);
+                auy = (aux + _ctwist_cw) >> 2U;
+                orien = (aux + auy) & _cobits2;
+                ret.c[i] = (c1.c[piece] & _pbits) | orien;
+        }
+
+        return ret;
+
+compose_inconsistent:
+        fprintf(stderr, "compose error, inconsistent cube\n");
         return errorcube;
 }
 
diff --git a/src/cube_array.h b/src/cube_array.h
new file mode 100644
index 0000000..6d9603b
--- /dev/null
+++ b/src/cube_array.h
@@ -0,0 +1,6 @@
+/* Public properties specific to the array implementation */
+
+typedef struct {
+        uint8_t c[8];
+        uint8_t e[12];
+} cube_t;