fixes #1345 Restructure the source tree

This is not quite complete, but it sets the stage for other
protocols (such as zmq or mqtt) to be added to the project.

1 files changed, 302 insertions, 0 deletions

diff --git a/src/sp/transport/zerotier/zthash.c b/src/sp/transport/zerotier/zthash.c
new file mode 100644
index 00000000..ca46b373
--- /dev/null
+++ b/src/sp/transport/zerotier/zthash.c
@@ -0,0 +1,302 @@
+//
+// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#include "core/nng_impl.h"
+#include "zthash.h"
+
+struct zt_hash_entry {
+	uint64_t key;
+	void *   val;
+	uint32_t skips;
+};
+
+int
+zt_hash_init(zt_hash **hp)
+{
+	zt_hash *h;
+
+	if ((h = NNI_ALLOC_STRUCT(h)) == NULL) {
+		return (NNG_ENOMEM);
+	}
+	h->ih_entries = NULL;
+	h->ih_count   = 0;
+	h->ih_load    = 0;
+	h->ih_cap     = 0;
+	h->ih_maxload = 0;
+	h->ih_minload = 0; // never shrink below this
+	h->ih_minval  = 0;
+	h->ih_maxval  = 0xffffffff;
+	h->ih_dynval  = 0;
+
+	*hp = h;
+	return (0);
+}
+
+void
+zt_hash_fini(zt_hash *h)
+{
+	if (h != NULL) {
+		if (h->ih_entries != NULL) {
+			NNI_FREE_STRUCTS(h->ih_entries, h->ih_cap);
+			h->ih_entries = NULL;
+			h->ih_cap = h->ih_count = 0;
+			h->ih_load = h->ih_minload = h->ih_maxload = 0;
+		}
+
+		NNI_FREE_STRUCT(h);
+	}
+}
+
+void
+zt_hash_limits(zt_hash *h, uint64_t minval, uint64_t maxval, uint64_t start)
+{
+	if (start < minval) {
+		start = minval;
+	}
+	if (start > maxval) {
+		start = maxval;
+	}
+
+	h->ih_minval = minval;
+	h->ih_maxval = maxval;
+	h->ih_dynval = start;
+	NNI_ASSERT(minval < maxval);
+	NNI_ASSERT(start >= minval);
+	NNI_ASSERT(start <= maxval);
+}
+
+// Inspired by Python dict implementation.  This probe will visit every
+// cell.  We always hash consecutively assigned IDs.
+#define ZT_HASH_NEXT(h, j) ((((j) *5) + 1) & (h->ih_cap - 1))
+#define ZT_HASH_INDEX(h, j) ((j) & (h->ih_cap - 1))
+
+static size_t
+zt_hash_find_index(zt_hash *h, uint64_t id)
+{
+	size_t index;
+	size_t start;
+	if (h->ih_count == 0) {
+		return ((size_t) -1);
+	}
+
+	index = ZT_HASH_INDEX(h, id);
+	start = index;
+	for (;;) {
+		// The value of ihe_key is only valid if ihe_val is not NULL.
+		if ((h->ih_entries[index].key == id) &&
+		    (h->ih_entries[index].val != NULL)) {
+			return (index);
+		}
+		if (h->ih_entries[index].skips == 0) {
+			return ((size_t) -1);
+		}
+		index = ZT_HASH_NEXT(h, index);
+
+		if (index == start) {
+			break;
+		}
+	}
+
+	return ((size_t) -1);
+}
+
+int
+zt_hash_find(zt_hash *h, uint64_t id, void **vp)
+{
+	size_t index;
+	if ((index = zt_hash_find_index(h, id)) == (size_t) -1) {
+		return (NNG_ENOENT);
+	}
+	*vp = h->ih_entries[index].val;
+	return (0);
+}
+
+static int
+zt_hash_resize(zt_hash *h)
+{
+	size_t         newsize;
+	size_t         oldsize;
+	zt_hash_entry *newents;
+	zt_hash_entry *oldents;
+	uint32_t       i;
+
+	if ((h->ih_load < h->ih_maxload) && (h->ih_load >= h->ih_minload)) {
+		// No resize needed.
+		return (0);
+	}
+
+	oldsize = h->ih_cap;
+
+	newsize = 8;
+	while (newsize < (h->ih_count * 2)) {
+		newsize *= 2;
+	}
+	if (newsize == oldsize) {
+		// Same size.
+		return (0);
+	}
+
+	oldents = h->ih_entries;
+	newents = NNI_ALLOC_STRUCTS(newents, newsize);
+	if (newents == NULL) {
+		return (NNG_ENOMEM);
+	}
+
+	h->ih_entries = newents;
+	h->ih_cap     = newsize;
+	h->ih_load    = 0;
+	if (newsize > 8) {
+		h->ih_minload = newsize / 8;
+		h->ih_maxload = newsize * 2 / 3;
+	} else {
+		h->ih_minload = 0;
+		h->ih_maxload = 5;
+	}
+	for (i = 0; i < oldsize; i++) {
+		size_t index;
+		if (oldents[i].val == NULL) {
+			continue;
+		}
+		index = oldents[i].key & (newsize - 1);
+		for (;;) {
+			// Increment the load unconditionally.  It counts
+			// once for every item stored, plus once for each
+			// hashing operation we use to store the item (i.e.
+			// one for the item, plus once for each rehash.)
+			h->ih_load++;
+			if (newents[index].val == NULL) {
+				// As we are hitting this entry for the first
+				// time, it won't have any skips.
+				NNI_ASSERT(newents[index].skips == 0);
+				newents[index].val = oldents[i].val;
+				newents[index].key = oldents[i].key;
+				break;
+			}
+			newents[index].skips++;
+			index = ZT_HASH_NEXT(h, index);
+		}
+	}
+	if (oldsize != 0) {
+		NNI_FREE_STRUCTS(oldents, oldsize);
+	}
+	return (0);
+}
+
+int
+zt_hash_remove(zt_hash *h, uint64_t id)
+{
+	size_t         index;
+	size_t         probe;
+
+	if ((index = zt_hash_find_index(h, id)) == (size_t) -1) {
+		return (NNG_ENOENT);
+	}
+
+	// Now we have found the index where the object exists.  We are going
+	// to restart the search, until the index matches, to decrement the
+	// skips counter.
+	probe = (int) ZT_HASH_INDEX(h, id);
+
+	for (;;) {
+                zt_hash_entry *entry;
+		// The load was increased once each hashing operation we used
+		// to place the the item.  Decrement it accordingly.
+		h->ih_load--;
+		entry = &h->ih_entries[probe];
+		if (probe == index) {
+			entry->val = NULL;
+			entry->key = 0;
+			break;
+		}
+		NNI_ASSERT(entry->skips > 0);
+		entry->skips--;
+		probe = ZT_HASH_NEXT(h, probe);
+	}
+
+	h->ih_count--;
+
+	// Shrink -- but it's ok if we can't.
+	(void) zt_hash_resize(h);
+
+	return (0);
+}
+
+int
+zt_hash_insert(zt_hash *h, uint64_t id, void *val)
+{
+	size_t         index;
+	zt_hash_entry *ent;
+
+	// Try to resize -- if we don't need to, this will be a no-op.
+	if (zt_hash_resize(h) != 0) {
+		return (NNG_ENOMEM);
+	}
+
+	// If it already exists, just overwrite the old value.
+	if ((index = zt_hash_find_index(h, id)) != (size_t) -1) {
+		ent      = &h->ih_entries[index];
+		ent->val = val;
+		return (0);
+	}
+
+	index = ZT_HASH_INDEX(h, id);
+	for (;;) {
+		ent = &h->ih_entries[index];
+
+		// Increment the load count.  We do this each time time we
+		// rehash.  This may over-count items that collide on the
+		// same rehashing, but this should just cause a table to
+		// grow sooner, which is probably a good thing.
+		h->ih_load++;
+		if (ent->val == NULL) {
+			h->ih_count++;
+			ent->key = id;
+			ent->val = val;
+			return (0);
+		}
+		// Record the skip count.  This being non-zero informs
+		// that a rehash will be necessary.  Without this we
+		// would need to scan the entire hash for the match.
+		ent->skips++;
+		index = ZT_HASH_NEXT(h, index);
+	}
+}
+
+int
+zt_hash_alloc(zt_hash *h, uint64_t *idp, void *val)
+{
+	uint64_t id;
+	int      rv;
+
+	NNI_ASSERT(val != NULL);
+
+	if (h->ih_count > (h->ih_maxval - h->ih_minval)) {
+		// Really more like ENOSPC.. the table is filled to max.
+		return (NNG_ENOMEM);
+	}
+
+	for (;;) {
+		id = h->ih_dynval;
+		h->ih_dynval++;
+		if (h->ih_dynval > h->ih_maxval) {
+			h->ih_dynval = h->ih_minval;
+		}
+
+		if (zt_hash_find_index(h, id) == (size_t) -1) {
+			break;
+		}
+	}
+
+	rv = zt_hash_insert(h, id, val);
+	if (rv == 0) {
+		*idp = id;
+	}
+	return (rv);
+}