unicode: use new faster htable

Replace the old shl_hashtable with shl_htable, which avoids the additional
allocations and is considerably faster. The underlying hash-table is still
the same, but our boilerplate code is reduced heavily.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

5 files changed, 1192 insertions, 23 deletions

diff --git a/LICENSE_htable b/LICENSE_htable
new file mode 100644
index 0000000..2d2d780
--- /dev/null
+++ b/LICENSE_htable
@@ -0,0 +1,510 @@
+
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diff --git a/Makefile.am b/Makefile.am
index e6dfdb7..d480820 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -95,9 +95,8 @@ noinst_LTLIBRARIES += libshl.la
 
 libshl_la_SOURCES = \
 	src/shl_array.h \
-	src/shl_hashtable.h \
-	external/htable.h \
-	external/htable.c \
+	src/shl_htable.h \
+	src/shl_htable.c \
 	src/shl_llog.h
 libshl_la_CPPFLAGS = $(AM_CPPFLAGS)
 libshl_la_LDFLAGS = $(AM_LDFLAGS)
diff --git a/src/shl_htable.c b/src/shl_htable.c
new file mode 100644
index 0000000..e79a7c0
--- /dev/null
+++ b/src/shl_htable.c
@@ -0,0 +1,428 @@
+/*
+ * SHL - Dynamic hash-table
+ *
+ * Written-by: Rusty Russell <rusty@rustcorp.com.au>
+ * Adjusted-by: David Herrmann <dh.herrmann@gmail.com>
+ * Licensed under LGPLv2+ - see LICENSE_htable file for details
+ */
+
+/*
+ * Please see ccan/htable/_info at:
+ *   https://github.com/rustyrussell/ccan/tree/master/ccan/htable
+ * for information on the hashtable algorithm. This file copies the code inline
+ * and is released under the same conditions.
+ *
+ * At the end of the file you can find some helpers to use this htable to store
+ * objects with "unsigned long" or "char*" keys.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include "shl_htable.h"
+
+#define COLD __attribute__((cold))
+
+struct htable {
+	/* KEEP IN SYNC WITH "struct shl_htable_int" */
+	size_t (*rehash)(const void *elem, void *priv);
+	void *priv;
+	unsigned int bits;
+	size_t elems, deleted, max, max_with_deleted;
+	/* These are the bits which are the same in all pointers. */
+	uintptr_t common_mask, common_bits;
+	uintptr_t perfect_bit;
+	uintptr_t *table;
+};
+
+#define HTABLE_INITIALIZER(name, rehash, priv)				\
+	{ rehash, priv, 0, 0, 0, 0, 0, -1, 0, 0, &name.perfect_bit }
+
+struct htable_iter {
+	size_t off;
+};
+
+/*
+ * INLINE COPY OF ccan/htable.c
+ */
+
+/* We use 0x1 as deleted marker. */
+#define HTABLE_DELETED (0x1)
+
+/* 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 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_bit;
+}
+
+static 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->perfect_bit;
+}
+
+static void htable_clear(struct htable *ht,
+			 void (*free_cb) (void *entry, void *ctx),
+			 void *ctx)
+{
+	size_t i;
+
+	if (ht->table != &ht->perfect_bit) {
+		if (free_cb) {
+			for (i = 0; i < (size_t)1 << ht->bits; ++i) {
+				if (entry_is_valid(ht->table[i]))
+					free_cb(get_raw_ptr(ht, ht->table[i]),
+						ctx);
+			}
+		}
+
+		free((void *)ht->table);
+	}
+
+	htable_init(ht, ht->rehash, ht->priv);
+}
+
+static void htable_visit(struct htable *ht,
+			 void (*visit_cb) (void *elem, void *ctx),
+			 void *ctx)
+{
+	size_t i;
+
+	if (visit_cb && ht->table != &ht->perfect_bit) {
+		for (i = 0; i < (size_t)1 << ht->bits; ++i) {
+			if (entry_is_valid(ht->table[i]))
+				visit_cb(get_raw_ptr(ht, ht->table[i]), ctx);
+		}
+	}
+}
+
+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;
+}
+
+static 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_bit);
+}
+
+static 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);
+}
+
+/* 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_bit;
+
+	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);
+}
+
+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 = calloc(1 << (ht->bits+1), sizeof(size_t));
+	if (!ht->table) {
+		ht->table = oldtable;
+		return false;
+	}
+	ht->bits++;
+	ht->max = ((size_t)3 << ht->bits) / 4;
+	ht->max_with_deleted = ((size_t)9 << ht->bits) / 10;
+
+	/* If we lost our "perfect bit", get it back now. */
+	if (!ht->perfect_bit && ht->common_mask) {
+		for (i = 0; i < sizeof(ht->common_mask) * CHAR_BIT; i++) {
+			if (ht->common_mask & ((size_t)1 << i)) {
+				ht->perfect_bit = (size_t)1 << i;
+				break;
+			}
+		}
+	}
+
+	if (oldtable != &ht->perfect_bit) {
+		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));
+			}
+		}
+		free(oldtable);
+	}
+	ht->deleted = 0;
+	return true;
+}
+
+static COLD void rehash_table(struct htable *ht)
+{
+	size_t start, i;
+	uintptr_t e;
+
+	/* 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 & ht->perfect_bit)) {
+			void *p = get_raw_ptr(ht, e);
+			ht->table[h] = 0;
+			ht_add(ht, p, ht->rehash(p, ht->priv));
+		}
+	}
+	ht->deleted = 0;
+}
+
+/* We stole some bits, now we need to put them back... */
+static COLD void update_common(struct htable *ht, const void *p)
+{
+	unsigned int i;
+	uintptr_t maskdiff, bitsdiff;
+
+	if (ht->elems == 0) {
+		/* Always reveal one bit of the pointer in the bucket,
+		 * so it's not zero or HTABLE_DELETED (1), even if
+		 * hash happens to be 0.  Assumes (void *)1 is not a
+		 * valid pointer. */
+		for (i = sizeof(uintptr_t)*CHAR_BIT - 1; i > 0; i--) {
+			if ((uintptr_t)p & ((uintptr_t)1 << i))
+				break;
+		}
+
+		ht->common_mask = ~((uintptr_t)1 << i);
+		ht->common_bits = ((uintptr_t)p & ht->common_mask);
+		ht->perfect_bit = 1;
+		return;
+	}
+
+	/* Find bits which are unequal to old common set. */
+	maskdiff = ht->common_bits ^ ((uintptr_t)p & ht->common_mask);
+
+	/* These are the bits which go there in existing entries. */
+	bitsdiff = ht->common_bits & maskdiff;
+
+	for (i = 0; i < (size_t)1 << ht->bits; i++) {
+		if (!entry_is_valid(ht->table[i]))
+			continue;
+		/* Clear the bits no longer in the mask, set them as
+		 * expected. */
+		ht->table[i] &= ~maskdiff;
+		ht->table[i] |= bitsdiff;
+	}
+
+	/* Take away those bits from our mask, bits and perfect bit. */
+	ht->common_mask &= ~maskdiff;
+	ht->common_bits &= ~maskdiff;
+	ht->perfect_bit &= ~maskdiff;
+}
+
+static bool htable_add(struct htable *ht, size_t hash, const void *p)
+{
+	if (ht->elems+1 > ht->max && !double_table(ht))
+		return false;
+	if (ht->elems+1 + ht->deleted > ht->max_with_deleted)
+		rehash_table(ht);
+	assert(p);
+	if (((uintptr_t)p & ht->common_mask) != ht->common_bits)
+		update_common(ht, p);
+
+	ht_add(ht, p, hash);
+	ht->elems++;
+	return true;
+}
+
+static 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--;
+	ht->table[i->off] = HTABLE_DELETED;
+	ht->deleted++;
+}
+
+/*
+ * Wrapper code to make it easier to use this hash-table as map.
+ */
+
+void shl_htable_init(struct shl_htable *htable,
+		     bool (*compare) (const void *a, const void *b),
+		     size_t (*rehash)(const void *elem, void *priv),
+		     void *priv)
+{
+	struct htable *ht = (void*)&htable->htable;
+
+	htable->compare = compare;
+	htable_init(ht, rehash, priv);
+}
+
+void shl_htable_clear(struct shl_htable *htable,
+		      void (*free_cb) (void *elem, void *ctx),
+		      void *ctx)
+{
+	struct htable *ht = (void*)&htable->htable;
+
+	htable_clear(ht, free_cb, ctx);
+}
+
+void shl_htable_visit(struct shl_htable *htable,
+		      void (*visit_cb) (void *elem, void *ctx),
+		      void *ctx)
+{
+	struct htable *ht = (void*)&htable->htable;
+
+	htable_visit(ht, visit_cb, ctx);
+}
+
+bool shl_htable_lookup(struct shl_htable *htable, const void *obj, size_t hash,
+		       void **out)
+{
+	struct htable *ht = (void*)&htable->htable;
+	struct htable_iter i;
+	void *c;
+
+	for (c = htable_firstval(ht, &i, hash);
+	     c;
+	     c = htable_nextval(ht, &i, hash)) {
+		if (htable->compare(obj, c)) {
+			if (out)
+				*out = c;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+int shl_htable_insert(struct shl_htable *htable, const void *obj, size_t hash)
+{
+	struct htable *ht = (void*)&htable->htable;
+	bool b;
+
+	b = htable_add(ht, hash, (void*)obj);
+	return b ? 0 : -ENOMEM;
+}
+
+bool shl_htable_remove(struct shl_htable *htable, const void *obj, size_t hash,
+		       void **out)
+{
+	struct htable *ht = (void*)&htable->htable;
+	struct htable_iter i;
+	void *c;
+
+	for (c = htable_firstval(ht, &i, hash);
+	     c;
+	     c = htable_nextval(ht, &i, hash)) {
+		if (htable->compare(obj, c)) {
+			if (out)
+				*out = c;
+			htable_delval(ht, &i);
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/*
+ * Helpers
+ */
+
+bool shl_htable_compare_ulong(const void *a, const void *b)
+{
+	return *(const unsigned long*)a == *(const unsigned long*)b;
+}
+
+size_t shl_htable_rehash_ulong(const void *elem, void *priv)
+{
+	return (size_t)*(const unsigned long*)elem;
+}
+
+bool shl_htable_compare_str(const void *a, const void *b)
+{
+	return !strcmp(*(char**)a, *(char**)b);
+}
+
+/* DJB's hash function */
+size_t shl_htable_rehash_str(const void *elem, void *priv)
+{
+	const char *str = *(char**)elem;
+	size_t hash = 5381;
+
+	for ( ; *str; ++str)
+		hash = (hash << 5) + hash + (size_t)*str;
+
+	return hash;
+}
diff --git a/src/shl_htable.h b/src/shl_htable.h
new file mode 100644
index 0000000..9591180
--- /dev/null
+++ b/src/shl_htable.h
@@ -0,0 +1,222 @@
+/*
+ * SHL - Dynamic hash-table
+ *
+ * Copyright (c) 2010-2013 David Herrmann <dh.herrmann@gmail.com>
+ * Licensed under LGPLv2+ - see LICENSE_htable file for details
+ */
+
+/*
+ * Dynamic hash-table
+ * Implementation of a self-resizing hashtable to store arbitrary objects.
+ * Entries are not allocated by the table itself but are user-allocated. A
+ * single entry can be stored multiple times in the hashtable. No
+ * maintenance-members need to be embedded in user-allocated objects. However,
+ * the key (and optionally the hash) must be stored in the objects.
+ *
+ * Uses internally the htable from CCAN. See LICENSE_htable.
+ */
+
+#ifndef SHL_HTABLE_H
+#define SHL_HTABLE_H
+
+#include <limits.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/* miscellaneous */
+
+#define shl_htable_offsetof(pointer, type, member) ({ \
+		const typeof(((type*)0)->member) *__ptr = (pointer); \
+		(type*)(((char*)__ptr) - offsetof(type, member)); \
+	})
+
+/* htable */
+
+struct shl_htable_int {
+	size_t (*rehash)(const void *elem, void *priv);
+	void *priv;
+	unsigned int bits;
+	size_t elems, deleted, max, max_with_deleted;
+	/* These are the bits which are the same in all pointers. */
+	uintptr_t common_mask, common_bits;
+	uintptr_t perfect_bit;
+	uintptr_t *table;
+};
+
+struct shl_htable {
+	bool (*compare) (const void *a, const void *b);
+	struct shl_htable_int htable;
+};
+
+#define SHL_HTABLE_INIT(_obj, _compare, _rehash, _priv)		\
+	{							\
+		.compare = (_compare),				\
+		.htable = {					\
+			.rehash = (_rehash),			\
+			.priv = (_priv),			\
+			.bits = 0,				\
+			.elems = 0,				\
+			.deleted = 0,				\
+			.max = 0,				\
+			.max_with_deleted = 0,			\
+			.common_mask = -1,			\
+			.common_bits = 0,			\
+			.perfect_bit = 0,			\
+			.table = &(_obj).htable.perfect_bit	\
+		}						\
+	}
+
+void shl_htable_init(struct shl_htable *htable,
+		     bool (*compare) (const void *a, const void *b),
+		     size_t (*rehash)(const void *elem, void *priv),
+		     void *priv);
+void shl_htable_clear(struct shl_htable *htable,
+		      void (*free_cb) (void *elem, void *ctx),
+		      void *ctx);
+void shl_htable_visit(struct shl_htable *htable,
+		      void (*visit_cb) (void *elem, void *ctx),
+		      void *ctx);
+bool shl_htable_lookup(struct shl_htable *htable, const void *obj, size_t hash,
+		       void **out);
+int shl_htable_insert(struct shl_htable *htable, const void *obj, size_t hash);
+bool shl_htable_remove(struct shl_htable *htable, const void *obj, size_t hash,
+		       void **out);
+
+/* ulong htables */
+
+#if SIZE_MAX < ULONG_MAX
+#  error "'size_t' is smaller than 'unsigned long'"
+#endif
+
+bool shl_htable_compare_ulong(const void *a, const void *b);
+size_t shl_htable_rehash_ulong(const void *elem, void *priv);
+
+#define SHL_HTABLE_INIT_ULONG(_obj)					\
+	SHL_HTABLE_INIT((_obj), shl_htable_compare_ulong,		\
+				shl_htable_rehash_ulong,		\
+				NULL)
+
+static inline void shl_htable_init_ulong(struct shl_htable *htable)
+{
+	shl_htable_init(htable, shl_htable_compare_ulong,
+			shl_htable_rehash_ulong, NULL);
+}
+
+static inline void shl_htable_clear_ulong(struct shl_htable *htable,
+					  void (*cb) (unsigned long *elem,
+					              void *ctx),
+					  void *ctx)
+{
+	shl_htable_clear(htable, (void (*) (void*, void*))cb, ctx);
+}
+
+static inline void shl_htable_visit_ulong(struct shl_htable *htable,
+					  void (*cb) (unsigned long *elem,
+					              void *ctx),
+					  void *ctx)
+{
+	shl_htable_visit(htable, (void (*) (void*, void*))cb, ctx);
+}
+
+static inline bool shl_htable_lookup_ulong(struct shl_htable *htable,
+					   unsigned long key,
+					   unsigned long **out)
+{
+	return shl_htable_lookup(htable, (const void*)&key, (size_t)key,
+				 (void**)out);
+}
+
+static inline int shl_htable_insert_ulong(struct shl_htable *htable,
+					  const unsigned long *key)
+{
+	return shl_htable_insert(htable, (const void*)key, (size_t)*key);
+}
+
+static inline bool shl_htable_remove_ulong(struct shl_htable *htable,
+					   unsigned long key,
+					   unsigned long **out)
+{
+	return shl_htable_remove(htable, (const void*)&key, (size_t)key,
+				 (void**)out);
+}
+
+/* string htables */
+
+bool shl_htable_compare_str(const void *a, const void *b);
+size_t shl_htable_rehash_str(const void *elem, void *priv);
+
+#define SHL_HTABLE_INIT_STR(_obj)					\
+	SHL_HTABLE_INIT((_obj), shl_htable_compare_str,			\
+				shl_htable_rehash_str,			\
+				NULL)
+
+static inline void shl_htable_init_str(struct shl_htable *htable)
+{
+	shl_htable_init(htable, shl_htable_compare_str,
+			shl_htable_rehash_str, NULL);
+}
+
+static inline void shl_htable_clear_str(struct shl_htable *htable,
+					void (*cb) (char **elem,
+					            void *ctx),
+					void *ctx)
+{
+	shl_htable_clear(htable, (void (*) (void*, void*))cb, ctx);
+}
+
+static inline void shl_htable_visit_str(struct shl_htable *htable,
+					void (*cb) (char **elem,
+					            void *ctx),
+					void *ctx)
+{
+	shl_htable_visit(htable, (void (*) (void*, void*))cb, ctx);
+}
+
+static inline size_t shl_htable_hash_str(struct shl_htable *htable,
+					 const char *str, size_t *hash)
+{
+	size_t h;
+
+	if (hash && *hash) {
+		h = *hash;
+	} else {
+		h = htable->htable.rehash((const void*)&str, NULL);
+		if (hash)
+			*hash = h;
+	}
+
+	return h;
+}
+
+static inline bool shl_htable_lookup_str(struct shl_htable *htable,
+					 const char *str, size_t *hash,
+					 char ***out)
+{
+	size_t h;
+
+	h = shl_htable_hash_str(htable, str, hash);
+	return shl_htable_lookup(htable, (const void*)&str, h, (void**)out);
+}
+
+static inline int shl_htable_insert_str(struct shl_htable *htable,
+					char **str, size_t *hash)
+{
+	size_t h;
+
+	h = shl_htable_hash_str(htable, *str, hash);
+	return shl_htable_insert(htable, (const void*)str, h);
+}
+
+static inline bool shl_htable_remove_str(struct shl_htable *htable,
+					 const char *str, size_t *hash,
+					 char ***out)
+{
+	size_t h;
+
+	h = shl_htable_hash_str(htable, str, hash);
+	return shl_htable_remove(htable, (const void*)&str, h, (void **)out);
+}
+
+#endif /* SHL_HTABLE_H */
diff --git a/src/tsm_unicode.c b/src/tsm_unicode.c
index eb061a2..874915c 100644
--- a/src/tsm_unicode.c
+++ b/src/tsm_unicode.c
@@ -61,7 +61,7 @@
 #include "libtsm.h"
 #include "libtsm_int.h"
 #include "shl_array.h"
-#include "shl_hashtable.h"
+#include "shl_htable.h"
 
 /*
  * Unicode Symbol Handling
@@ -103,13 +103,12 @@ struct tsm_symbol_table {
 	unsigned long ref;
 	uint32_t next_id;
 	struct shl_array *index;
-	struct shl_hashtable *symbols;
+	struct shl_htable symbols;
 };
 
-static unsigned int hash_ucs4(const void *key)
+static size_t hash_ucs4(const void *key, void *priv)
 {
-	unsigned int val = 5381;
-	size_t i;
+	size_t i, val = 5381;
 	const uint32_t *ucs4 = key;
 
 	for (i = 0; ucs4[i] <= TSM_UCS4_MAX; ++i)
@@ -134,6 +133,14 @@ static bool cmp_ucs4(const void *a, const void *b)
 	}
 }
 
+static void free_ucs4(void *elem, void *priv)
+{
+	uint32_t *v = elem;
+
+	/* key is prefix with actual value so pass correct pointer */
+	free(--v);
+}
+
 int tsm_symbol_table_new(struct tsm_symbol_table **out)
 {
 	struct tsm_symbol_table *tbl;
@@ -149,6 +156,7 @@ int tsm_symbol_table_new(struct tsm_symbol_table **out)
 	memset(tbl, 0, sizeof(*tbl));
 	tbl->ref = 1;
 	tbl->next_id = TSM_UCS4_MAX + 2;
+	shl_htable_init(&tbl->symbols, cmp_ucs4, hash_ucs4, NULL);
 
 	ret = shl_array_new(&tbl->index, sizeof(uint32_t*), 4);
 	if (ret)
@@ -157,16 +165,9 @@ int tsm_symbol_table_new(struct tsm_symbol_table **out)
 	/* first entry is not used so add dummy */
 	shl_array_push(tbl->index, &val);
 
-	ret = shl_hashtable_new(&tbl->symbols, hash_ucs4, cmp_ucs4,
-				free, NULL);
-	if (ret)
-		goto err_array;
-
 	*out = tbl;
 	return 0;
 
-err_array:
-	shl_array_free(tbl->index);
 err_free:
 	free(tbl);
 	return ret;
@@ -185,7 +186,7 @@ void tsm_symbol_table_unref(struct tsm_symbol_table *tbl)
 	if (!tbl || !tbl->ref || --tbl->ref)
 		return;
 
-	shl_hashtable_free(tbl->symbols);
+	shl_htable_clear(&tbl->symbols, free_ucs4, NULL);
 	shl_array_free(tbl->index);
 	free(tbl);
 }
@@ -250,7 +251,6 @@ tsm_symbol_t tsm_symbol_append(struct tsm_symbol_table *tbl,
 	uint32_t buf[TSM_UCS4_MAXLEN + 1], nsym, *nval;
 	const uint32_t *ptr;
 	size_t s;
-	void *tmp;
 	bool res;
 	int ret;
 
@@ -268,22 +268,32 @@ tsm_symbol_t tsm_symbol_append(struct tsm_symbol_table *tbl,
 	buf[s++] = ucs4;
 	buf[s++] = TSM_UCS4_MAX + 1;
 
-	res = shl_hashtable_find(tbl->symbols, &tmp, buf);
-	if (res)
-		return (uint32_t)(long)tmp;
+	res = shl_htable_lookup(&tbl->symbols, buf, hash_ucs4(buf, NULL),
+				(void**)&nval);
+	if (res) {
+		/* key is prefixed with actual value */
+		return *--nval;
+	}
 
-	nval = malloc(sizeof(uint32_t) * s);
+	/* We save the key in nval and prefix it with the new ID. Note that
+	 * the prefix is hidden, we actually store "++nval" in the htable. */
+	nval = malloc(sizeof(uint32_t) * (s + 1));
 	if (!nval)
 		return sym;
 
+	++nval;
 	memcpy(nval, buf, s * sizeof(uint32_t));
+
 	nsym = tbl->next_id + 1;
 	/* Out of IDs; we actually have 2 Billion IDs so this seems
 	 * very unlikely but lets be safe here */
 	if (nsym <= tbl->next_id++)
 		goto err_id;
 
-	ret = shl_hashtable_insert(tbl->symbols, nval, (void*)(long)nsym);
+	/* store ID hidden before the key */
+	*(nval - 1) = nsym;
+
+	ret = shl_htable_insert(&tbl->symbols, nval, hash_ucs4(nval, NULL));
 	if (ret)
 		goto err_id;
 
@@ -294,7 +304,7 @@ tsm_symbol_t tsm_symbol_append(struct tsm_symbol_table *tbl,
 	return nsym;
 
 err_symbol:
-	shl_hashtable_remove(tbl->symbols, nval);
+	shl_htable_remove(&tbl->symbols, nval, hash_ucs4(nval, NULL), NULL);
 err_id:
 	--tbl->next_id;
 	free(nval);