wip

Author: imaami

src/debruijn25.c

@@ -226,46 +226,6 @@ ror64 (uint64_t x,
 	return !(n &= 63U) ? x : (x >> n | x << (64U - n));
 }
 
-static uint64_t
-is_b26 (uint64_t  const x,
-        unsigned *const rot)
-{
-	uint64_t y = x << 6U | x >> (64U - 6U);
-	uint64_t m = 0U;
-	unsigned r = 0U;
-	unsigned n = 0U;
-
-	do {
-		y >>= 1U;
-		uint64_t b = UINT64_C(1) << (y & 63U);
-		uint64_t m_ = m;
-		m |= b;
-		if (m == m_)
-			return 0U;
-		++n;
-		if (b == 1U)
-			r = n & 63U;
-	} while (n < 6U);
-
-	y = x;
-	do {
-		y >>= 1U;
-		uint64_t b = UINT64_C(1) << (y & 63U);
-		uint64_t m_ = m;
-		m |= b;
-		if (m == m_)
-			return 0U;
-		++n;
-		if (b == 1U)
-			r = n & 63U;
-	} while (m != UINT64_MAX);
-
-	if (rot)
-		*rot = r;
-
-	return ror64(x, r);
-}
-
 static force_inline size_t
 mapping (struct ptab *tab,
          unsigned     idx)
@@ -947,8 +907,13 @@ bag_gen (struct bag *const a,
 }
 
 static int64_t
-b26_find (uint64_t const *ptr,
-          uint64_t        key);
+b26_find (uint64_t        seq,
+          uint64_t const *arr);
+
+static uint64_t
+b26_identify (uint64_t        x,
+              uint32_t       *id,
+              uint64_t const *arr);
 
 static void
 bags_scan (struct bag *const     b,
@@ -959,36 +924,33 @@ bags_scan (struct bag *const     b,
 	for (unsigned i = 0; i < 119U; ++i) {
 		for (unsigned j = i; j < 119U; ++j) {
 			for (unsigned r = 0U; r < 16U; ++r, bag_move_head(&b[j], 1, 1)) {
-				unsigned rot = 0;
-				uint64_t u64 = is_b26(bag_gen(&b[i], &b[j]), &rot);
+				uint32_t id = 0;
+				uint64_t u64 = b26_identify(bag_gen(&b[i], &b[j]), &id, b26);
 				if (u64) {
-					int64_t id = b26_find(b26, u64);
 					printf("a=%3u 0x%08" PRIx32 " b=%3u 0x%08" PRIx32
-					       " r=%2u 0x%016" PRIx64 " (%" PRId64 ",%u)\n", i, b[i].seq,
-					       j, b[j].seq, r, u64, id, rot);
+					       " r=%2u 0x%016" PRIx64 " (%" PRIu32 ",%" PRIu32 ")\n", i, b[i].seq,
+					       j, b[j].seq, r, u64, id >> 6U, id & 63U);
 				}
 				if (i == j)
 					continue;
-				rot = 0;
-				u64 = is_b26(bag_gen(&b[j], &b[i]), &rot);
+				id = 0;
+				u64 = b26_identify(bag_gen(&b[j], &b[i]), &id, b26);
 				if (u64) {
-					int64_t id = b26_find(b26, u64);
 					printf("a=%3u 0x%08" PRIx32 " b=%3u 0x%08" PRIx32
-					       " r=%2u 0x%016" PRIx64 " (%" PRId64 ",%u)\n", j, b[j].seq,
-					       i, b[i].seq, r, u64, id, rot);
+					       " r=%2u 0x%016" PRIx64 " (%" PRIu32 ",%" PRIu32 ")\n", j, b[j].seq,
+					       i, b[i].seq, r, u64, id >> 6U, id & 63U);
 				}
 			}
 			if (i == j)
 				continue;
 			for (unsigned r = 0U; r < 16U; ++r, bag_move_head(&b[i], 1, 1)) {
-				unsigned rot = 0;
-				uint64_t u64 = is_b26(bag_gen(&b[j], &b[i]), &rot);
-				if (u64) {
-					int64_t id = b26_find(b26, u64);
-					printf("a=%3u 0x%08" PRIx32 " b=%3u 0x%08" PRIx32
-					       " r=%2u 0x%016" PRIx64 " (%" PRId64 ",%u)\n", j, b[j].seq,
-					       i, b[i].seq, r, u64, id, rot);
-				}
+				uint32_t id = 0;
+				uint64_t u64 = b26_identify(bag_gen(&b[j], &b[i]), &id, b26);
+				if (!u64)
+					continue;
+				printf("a=%3u 0x%08" PRIx32 " b=%3u 0x%08" PRIx32
+				       " r=%2u 0x%016" PRIx64 " (%" PRIu32 ",%" PRIu32 ")\n",
+				       j, b[j].seq, i, b[i].seq, r, u64, id >> 6U, id & 63U);
 			}
 		}
 	}
@@ -1088,21 +1050,77 @@ b26_cmp (void const *pkey,
 }
 
 static int64_t
-b26_find (uint64_t const *const ptr,
-          uint64_t const        key)
+b26_find (uint64_t const        seq,
+          uint64_t const *const arr)
 {
-	if (!ptr)
+	if (!arr)
 		return -1;
 
 #if UINTPTR_MAX >= 0x3f79d71b4cb0a89
-	void const *k = (void const *)key;
+	void const *k = (void const *)seq;
 #else
-	void const *k = (void const *)&key;
+	void const *k = (void const *)&seq;
 #endif
-	uint64_t const *ret = bsearch(k, ptr, UINT64_C(1) << 26U,
-	                              sizeof *ptr, b26_cmp);
+	uint64_t const *ret = bsearch(k, arr, UINT64_C(1) << 26U,
+	                              sizeof *arr, b26_cmp);
 	if (!ret)
 		return -1;
 
-	return (int64_t)(ptrdiff_t)(ret - ptr);
+	return (int64_t)(ptrdiff_t)(ret - arr);
+}
+
+static uint64_t
+is_b26 (uint64_t  const x,
+        unsigned *const rot)
+{
+	uint64_t y = x << 6U | x >> (64U - 6U);
+	uint64_t m = 0U;
+	unsigned r = 0U;
+	unsigned n = 0U;
+
+	do {
+		y >>= 1U;
+		uint64_t b = UINT64_C(1) << (y & 63U);
+		uint64_t m_ = m;
+		m |= b;
+		if (m == m_)
+			return 0U;
+		++n;
+		if (b == 1U)
+			r = n & 63U;
+	} while (n < 6U);
+
+	y = x;
+	do {
+		y >>= 1U;
+		uint64_t b = UINT64_C(1) << (y & 63U);
+		uint64_t m_ = m;
+		m |= b;
+		if (m == m_)
+			return 0U;
+		++n;
+		if (b == 1U)
+			r = n & 63U;
+	} while (m != UINT64_MAX);
+
+	if (rot)
+		*rot = r;
+
+	return ror64(x, r);
+}
+
+static uint64_t
+b26_identify (uint64_t              x,
+              uint32_t *const       id,
+              uint64_t const *const arr)
+{
+	unsigned rot = 0;
+	x = is_b26(x, &rot);
+	if (x) {
+		int64_t i = b26_find(x, arr);
+		if (i < 0)
+			return 0U;
+		*id = ((uint32_t)i << 6U) | rot;
+	}
+	return x;
 }