shithub: puzzles

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Actually make DSF an opaque structure type.

This makes good on all the previous preparatory commits, which I did
separately so that each one individually has a reasonably readable
diff, and all the mechanical changes are separated out from the
rewrites that needed actual thought.

Still no functional change, however: the DSF type wraps nothing but
the same int pointer that 'DSF *' used to store directly.

--- a/dsf.c

+++ b/dsf.c

@@ -9,6 +9,10 @@

 #include "puzzles.h"

+struct DSF {

+    int *p;

+};

+

 /*void print_dsf(int *dsf, int size)

 {

     int *printed_elements = snewn(size, int);

@@ -65,7 +69,7 @@

 {

     int i;

-    for (i = 0; i < size; i++) dsf[i] = 6;

+    for (i = 0; i < size; i++) dsf->p[i] = 6;

     /* Bottom bit of each element of this array stores whether that

      * element is opposite to its parent, which starts off as

      * false. Second bit of each element stores whether that element

@@ -76,14 +80,14 @@

 void dsf_copy(DSF *to, DSF *from, int size)

 {

-    memcpy(to, from, size * sizeof(int));

+    memcpy(to->p, from->p, size * sizeof(int));

 }

 DSF *snew_dsf(int size)

 {

-    int *ret;

-    

-    ret = snewn(size, int);

+    DSF *ret = snew(DSF);

+    ret->p = snewn(size, int);

+

     dsf_init(ret, size);

     /*print_dsf(ret, size); */

@@ -93,7 +97,10 @@

 void dsf_free(DSF *dsf)

 {

-    sfree(dsf);

+    if (dsf) {

+        sfree(dsf->p);

+        sfree(dsf);

+    }

 }

 int dsf_canonify(DSF *dsf, int index)

@@ -107,7 +114,7 @@

 }

 int dsf_size(DSF *dsf, int index) {

-    return dsf[dsf_canonify(dsf, index)] >> 2;

+    return dsf->p[dsf_canonify(dsf, index)] >> 2;

 }

 int edsf_canonify(DSF *dsf, int index, bool *inverse_return)

@@ -123,9 +130,9 @@

     /* Find the index of the canonical element of the 'equivalence class' of

      * which start_index is a member, and figure out whether start_index is the

      * same as or inverse to that. */

-    while ((dsf[index] & 2) == 0) {

-        inverse ^= (dsf[index] & 1);

-	index = dsf[index] >> 2;

+    while ((dsf->p[index] & 2) == 0) {

+        inverse ^= (dsf->p[index] & 1);

+	index = dsf->p[index] >> 2;

 /*        fprintf(stderr, "index = %2d, ", index); */

 /*        fprintf(stderr, "inverse = %d\n", inverse); */

     }

@@ -138,9 +145,9 @@

      * canonical member. */

     index = start_index;

     while (index != canonical_index) {

-	int nextindex = dsf[index] >> 2;

-        bool nextinverse = inverse ^ (dsf[index] & 1);

-	dsf[index] = (canonical_index << 2) | inverse;

+	int nextindex = dsf->p[index] >> 2;

+        bool nextinverse = inverse ^ (dsf->p[index] & 1);

+	dsf->p[index] = (canonical_index << 2) | inverse;

         inverse = nextinverse;

 	index = nextindex;

     }

@@ -160,10 +167,10 @@

 /*    fprintf(stderr, "Merge [%2d,%2d], %d\n", v1, v2, inverse); */

     v1 = edsf_canonify(dsf, v1, &i1);

-    assert(dsf[v1] & 2);

+    assert(dsf->p[v1] & 2);

     inverse ^= i1;

     v2 = edsf_canonify(dsf, v2, &i2);

-    assert(dsf[v2] & 2);

+    assert(dsf->p[v2] & 2);

     inverse ^= i2;

 /*    fprintf(stderr, "Doing [%2d,%2d], %d\n", v1, v2, inverse); */

@@ -190,8 +197,8 @@

 	    v1 = v2;

 	    v2 = v3;

 	}

-	dsf[v1] += (dsf[v2] >> 2) << 2;

-	dsf[v2] = (v1 << 2) | inverse;

+	dsf->p[v1] += (dsf->p[v2] >> 2) << 2;

+	dsf->p[v2] = (v1 << 2) | inverse;

     }

     v2 = edsf_canonify(dsf, v2, &i2);

@@ -198,5 +205,5 @@

     assert(v2 == v1);

     assert(i2 == inverse);

-/*    fprintf(stderr, "dsf[%2d] = %2d\n", v2, dsf[v2]); */

+/*    fprintf(stderr, "dsf[%2d] = %2d\n", v2, dsf->p[v2]); */

 }

--- a/puzzles.h

+++ b/puzzles.h

@@ -426,7 +426,7 @@

 /*

  * dsf.c

  */

-typedef int DSF;

+typedef struct DSF DSF;

 DSF *snew_dsf(int size);

 void dsf_free(DSF *dsf);

-- 

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