1 files changed, 491 insertions, 0 deletions
diff --git a/ccan/ccan/htable/htable.c b/ccan/ccan/htable/htable.c
new file mode 100644
index 0000000..f631ffe
--- /dev/null
+++ b/ccan/ccan/htable/htable.c
@@ -0,0 +1,491 @@
+/* Licensed under LGPLv2+ - see LICENSE file for details */
+#include <ccan/htable/htable.h>
+#include <ccan/compiler/compiler.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <string.h>
+
+/* We use 0x1 as deleted marker. */
+#define HTABLE_DELETED (0x1)
+
+/* perfect_bitnum 63 means there's no perfect bitnum */
+#define NO_PERFECT_BIT (sizeof(uintptr_t) * CHAR_BIT - 1)
+
+static void *htable_default_alloc(struct htable *ht, size_t len)
+{
+	return calloc(len, 1);
+}
+
+static void htable_default_free(struct htable *ht, void *p)
+{
+	free(p);
+}
+
+static void *(*htable_alloc)(struct htable *, size_t) = htable_default_alloc;
+static void (*htable_free)(struct htable *, void *) = htable_default_free;
+
+void htable_set_allocator(void *(*alloc)(struct htable *, size_t len),
+			  void (*free)(struct htable *, void *p))
+{
+	if (!alloc)
+		alloc = htable_default_alloc;
+	if (!free)
+		free = htable_default_free;
+	htable_alloc = alloc;
+	htable_free = free;
+}
+
+/* We clear out the bits which are always the same, and put metadata there. */
+static inline uintptr_t get_extra_ptr_bits(const struct htable *ht,
+					   uintptr_t e)
+{
+	return e & ht->common_mask;
+}
+
+static inline void *get_raw_ptr(const struct htable *ht, uintptr_t e)
+{
+	return (void *)((e & ~ht->common_mask) | ht->common_bits);
+}
+
+static inline uintptr_t make_hval(const struct htable *ht,
+				  const void *p, uintptr_t bits)
+{
+	return ((uintptr_t)p & ~ht->common_mask) | bits;
+}
+
+static inline bool entry_is_valid(uintptr_t e)
+{
+	return e > HTABLE_DELETED;
+}
+
+static inline uintptr_t ht_perfect_mask(const struct htable *ht)
+{
+	return (uintptr_t)2 << ht->perfect_bitnum;
+}
+
+static inline uintptr_t get_hash_ptr_bits(const struct htable *ht,
+					  size_t hash)
+{
+	/* Shuffling the extra bits (as specified in mask) down the
+	 * end is quite expensive.  But the lower bits are redundant, so
+	 * we fold the value first. */
+	return (hash ^ (hash >> ht->bits))
+		& ht->common_mask & ~ht_perfect_mask(ht);
+}
+
+void htable_init(struct htable *ht,
+		 size_t (*rehash)(const void *elem, void *priv), void *priv)
+{
+	struct htable empty = HTABLE_INITIALIZER(empty, NULL, NULL);
+	*ht = empty;
+	ht->rehash = rehash;
+	ht->priv = priv;
+	ht->table = &ht->common_bits;
+}
+
+/* Fill to 87.5% */
+static inline size_t ht_max(const struct htable *ht)
+{
+	return ((size_t)7 << ht->bits) / 8;
+}
+
+/* Clean deleted if we're full, and more than 12.5% deleted */
+static inline size_t ht_max_deleted(const struct htable *ht)
+{
+	return ((size_t)1 << ht->bits) / 8;
+}
+
+bool htable_init_sized(struct htable *ht,
+		       size_t (*rehash)(const void *, void *),
+		       void *priv, size_t expect)
+{
+	htable_init(ht, rehash, priv);
+
+	/* Don't go insane with sizing. */
+	for (ht->bits = 1; ht_max(ht) < expect; ht->bits++) {
+		if (ht->bits == 30)
+			break;
+	}
+
+	ht->table = htable_alloc(ht, sizeof(size_t) << ht->bits);
+	if (!ht->table) {
+		ht->table = &ht->common_bits;
+		return false;
+	}
+	(void)htable_debug(ht, HTABLE_LOC);
+	return true;
+}
+	
+void htable_clear(struct htable *ht)
+{
+	if (ht->table != &ht->common_bits)
+		htable_free(ht, (void *)ht->table);
+	htable_init(ht, ht->rehash, ht->priv);
+}
+
+bool htable_copy_(struct htable *dst, const struct htable *src)
+{
+	uintptr_t *htable = htable_alloc(dst, sizeof(size_t) << src->bits);
+
+	if (!htable)
+		return false;
+
+	*dst = *src;
+	dst->table = htable;
+	memcpy(dst->table, src->table, sizeof(size_t) << src->bits);
+	return true;
+}
+
+static size_t hash_bucket(const struct htable *ht, size_t h)
+{
+	return h & ((1 << ht->bits)-1);
+}
+
+static void *htable_val(const struct htable *ht,
+			struct htable_iter *i, size_t hash, uintptr_t perfect)
+{
+	uintptr_t h2 = get_hash_ptr_bits(ht, hash) | perfect;
+
+	while (ht->table[i->off]) {
+		if (ht->table[i->off] != HTABLE_DELETED) {
+			if (get_extra_ptr_bits(ht, ht->table[i->off]) == h2)
+				return get_raw_ptr(ht, ht->table[i->off]);
+		}
+		i->off = (i->off + 1) & ((1 << ht->bits)-1);
+		h2 &= ~perfect;
+	}
+	return NULL;
+}
+
+void *htable_firstval_(const struct htable *ht,
+		       struct htable_iter *i, size_t hash)
+{
+	i->off = hash_bucket(ht, hash);
+	return htable_val(ht, i, hash, ht_perfect_mask(ht));
+}
+
+void *htable_nextval_(const struct htable *ht,
+		      struct htable_iter *i, size_t hash)
+{
+	i->off = (i->off + 1) & ((1 << ht->bits)-1);
+	return htable_val(ht, i, hash, 0);
+}
+
+void *htable_first_(const struct htable *ht, struct htable_iter *i)
+{
+	for (i->off = 0; i->off < (size_t)1 << ht->bits; i->off++) {
+		if (entry_is_valid(ht->table[i->off]))
+			return get_raw_ptr(ht, ht->table[i->off]);
+	}
+	return NULL;
+}
+
+void *htable_next_(const struct htable *ht, struct htable_iter *i)
+{
+	for (i->off++; i->off < (size_t)1 << ht->bits; i->off++) {
+		if (entry_is_valid(ht->table[i->off]))
+			return get_raw_ptr(ht, ht->table[i->off]);
+	}
+	return NULL;
+}
+
+void *htable_prev_(const struct htable *ht, struct htable_iter *i)
+{
+	for (;;) {
+		if (!i->off)
+			return NULL;
+		i->off--;
+		if (entry_is_valid(ht->table[i->off]))
+			return get_raw_ptr(ht, ht->table[i->off]);
+	}
+}
+
+/* Another bit currently in mask needs to be exposed, so that a bucket with p in
+ * it won't appear invalid */
+static COLD void unset_another_common_bit(struct htable *ht,
+					  uintptr_t *maskdiff,
+					  const void *p)
+{
+	size_t i;
+
+	for (i = sizeof(uintptr_t) * CHAR_BIT - 1; i > 0; i--) {
+		if (((uintptr_t)p & ((uintptr_t)1 << i))
+		    && ht->common_mask & ~*maskdiff & ((uintptr_t)1 << i))
+			break;
+	}
+	/* There must have been one, right? */
+	assert(i > 0);
+
+	*maskdiff |= ((uintptr_t)1 << i);
+}
+
+/* We want to change the common mask: this fixes up the table */
+static COLD void fixup_table_common(struct htable *ht, uintptr_t maskdiff)
+{
+	size_t i;
+	uintptr_t bitsdiff;
+
+again:
+	bitsdiff = ht->common_bits & maskdiff;
+
+	for (i = 0; i < (size_t)1 << ht->bits; i++) {
+		uintptr_t e;
+		if (!entry_is_valid(e = ht->table[i]))
+			continue;
+
+		/* Clear the bits no longer in the mask, set them as
+		 * expected. */
+		e &= ~maskdiff;
+		e |= bitsdiff;
+		/* If this made it invalid, restart with more exposed */
+		if (!entry_is_valid(e)) {
+			unset_another_common_bit(ht, &maskdiff, get_raw_ptr(ht, e));
+			goto again;
+		}
+		ht->table[i] = e;
+	}
+
+	/* Take away those bits from our mask, bits and perfect bit. */
+	ht->common_mask &= ~maskdiff;
+	ht->common_bits &= ~maskdiff;
+	if (ht_perfect_mask(ht) & maskdiff)
+		ht->perfect_bitnum = NO_PERFECT_BIT;
+}
+
+/* Limited recursion */
+static void ht_add(struct htable *ht, const void *new, size_t h);
+
+/* We tried to add this entry, but it looked invalid!  We need to
+ * let another pointer bit through mask */
+static COLD void update_common_fix_invalid(struct htable *ht, const void *p, size_t h)
+{
+	uintptr_t maskdiff;
+
+	assert(ht->elems != 0);
+
+	maskdiff = 0;
+	unset_another_common_bit(ht, &maskdiff, p);
+	fixup_table_common(ht, maskdiff);
+
+	/* Now won't recurse */
+	ht_add(ht, p, h);
+}
+
+/* This does not expand the hash table, that's up to caller. */
+static void ht_add(struct htable *ht, const void *new, size_t h)
+{
+	size_t i;
+	uintptr_t perfect = ht_perfect_mask(ht);
+
+	i = hash_bucket(ht, h);
+
+	while (entry_is_valid(ht->table[i])) {
+		perfect = 0;
+		i = (i + 1) & ((1 << ht->bits)-1);
+	}
+	ht->table[i] = make_hval(ht, new, get_hash_ptr_bits(ht, h)|perfect);
+	if (!entry_is_valid(ht->table[i]))
+		update_common_fix_invalid(ht, new, h);
+}
+
+static COLD bool double_table(struct htable *ht)
+{
+	unsigned int i;
+	size_t oldnum = (size_t)1 << ht->bits;
+	uintptr_t *oldtable, e;
+
+	oldtable = ht->table;
+	ht->table = htable_alloc(ht, sizeof(size_t) << (ht->bits+1));
+	if (!ht->table) {
+		ht->table = oldtable;
+		return false;
+	}
+	ht->bits++;
+
+	/* If we lost our "perfect bit", get it back now. */
+	if (ht->perfect_bitnum == NO_PERFECT_BIT && ht->common_mask) {
+		for (i = 0; i < sizeof(ht->common_mask) * CHAR_BIT; i++) {
+			if (ht->common_mask & ((size_t)2 << i)) {
+				ht->perfect_bitnum = i;
+				break;
+			}
+		}
+	}
+
+	if (oldtable != &ht->common_bits) {
+		for (i = 0; i < oldnum; i++) {
+			if (entry_is_valid(e = oldtable[i])) {
+				void *p = get_raw_ptr(ht, e);
+				ht_add(ht, p, ht->rehash(p, ht->priv));
+			}
+		}
+		htable_free(ht, oldtable);
+	}
+	ht->deleted = 0;
+
+	(void)htable_debug(ht, HTABLE_LOC);
+	return true;
+}
+
+static COLD void rehash_table(struct htable *ht)
+{
+	size_t start, i;
+	uintptr_t e, perfect = ht_perfect_mask(ht);
+
+	/* Beware wrap cases: we need to start from first empty bucket. */
+	for (start = 0; ht->table[start]; start++);
+
+	for (i = 0; i < (size_t)1 << ht->bits; i++) {
+		size_t h = (i + start) & ((1 << ht->bits)-1);
+		e = ht->table[h];
+		if (!e)
+			continue;
+		if (e == HTABLE_DELETED)
+			ht->table[h] = 0;
+		else if (!(e & perfect)) {
+			void *p = get_raw_ptr(ht, e);
+			ht->table[h] = 0;
+			ht_add(ht, p, ht->rehash(p, ht->priv));
+		}
+	}
+	ht->deleted = 0;
+	(void)htable_debug(ht, HTABLE_LOC);
+}
+
+/* We stole some bits, now we need to put them back... */
+static COLD void update_common(struct htable *ht, const void *p)
+{
+	uintptr_t maskdiff;
+
+	if (ht->elems == 0) {
+		ht->common_mask = -1;
+		ht->common_bits = ((uintptr_t)p & ht->common_mask);
+		ht->perfect_bitnum = 0;
+		(void)htable_debug(ht, HTABLE_LOC);
+		return;
+	}
+
+	/* Find bits which are unequal to old common set. */
+	maskdiff = ht->common_bits ^ ((uintptr_t)p & ht->common_mask);
+
+	fixup_table_common(ht, maskdiff);
+	(void)htable_debug(ht, HTABLE_LOC);
+}
+
+bool htable_add_(struct htable *ht, size_t hash, const void *p)
+{
+	/* Cannot insert NULL, or (void *)1. */
+	assert(p);
+	assert(entry_is_valid((uintptr_t)p));
+
+	/* Getting too full? */
+	if (ht->elems+1 + ht->deleted > ht_max(ht)) {
+		/* If we're more than 1/8 deleted, clean those,
+		 * otherwise double table size. */
+		if (ht->deleted > ht_max_deleted(ht))
+			rehash_table(ht);
+		else if (!double_table(ht))
+			return false;
+	}
+	if (((uintptr_t)p & ht->common_mask) != ht->common_bits)
+		update_common(ht, p);
+
+	ht_add(ht, p, hash);
+	ht->elems++;
+	return true;
+}
+
+bool htable_del_(struct htable *ht, size_t h, const void *p)
+{
+	struct htable_iter i;
+	void *c;
+
+	for (c = htable_firstval(ht,&i,h); c; c = htable_nextval(ht,&i,h)) {
+		if (c == p) {
+			htable_delval(ht, &i);
+			return true;
+		}
+	}
+	return false;
+}
+
+void htable_delval_(struct htable *ht, struct htable_iter *i)
+{
+	assert(i->off < (size_t)1 << ht->bits);
+	assert(entry_is_valid(ht->table[i->off]));
+
+	ht->elems--;
+	/* Cheap test: if the next bucket is empty, don't need delete marker */
+	if (ht->table[hash_bucket(ht, i->off+1)] != 0) {
+		ht->table[i->off] = HTABLE_DELETED;
+		ht->deleted++;
+	} else
+		ht->table[i->off] = 0;
+}
+
+void *htable_pick_(const struct htable *ht, size_t seed, struct htable_iter *i)
+{
+	void *e;
+	struct htable_iter unwanted;
+
+	if (!i)
+		i = &unwanted;
+	i->off = seed % ((size_t)1 << ht->bits);
+	e = htable_next(ht, i);
+	if (!e)
+		e = htable_first(ht, i);
+	return e;
+}
+
+struct htable *htable_check(const struct htable *ht, const char *abortstr)
+{
+	void *p;
+	struct htable_iter i;
+	size_t n = 0;
+
+	/* Use non-DEBUG versions here, to avoid infinite recursion with
+	 * CCAN_HTABLE_DEBUG! */
+	for (p = htable_first_(ht, &i); p; p = htable_next_(ht, &i)) {
+		struct htable_iter i2;
+		void *c;
+		size_t h = ht->rehash(p, ht->priv);
+		bool found = false;
+
+		n++;
+
+		/* Open-code htable_get to avoid CCAN_HTABLE_DEBUG */
+		for (c = htable_firstval_(ht, &i2, h);
+		     c;
+		     c = htable_nextval_(ht, &i2, h)) {
+			if (c == p) {
+				found = true;
+				break;
+			}
+		}
+
+		if (!found) {
+			if (abortstr) {
+				fprintf(stderr,
+					"%s: element %p in position %zu"
+					" cannot find itself\n",
+					abortstr, p, i.off);
+				abort();
+			}
+			return NULL;
+		}
+	}
+	if (n != ht->elems) {
+		if (abortstr) {
+			fprintf(stderr,
+				"%s: found %zu elems, expected %zu\n",
+				abortstr, n, ht->elems);
+			abort();
+		}
+		return NULL;
+	}
+
+	return (struct htable *)ht;
+}