--- /dev/null
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright © 2017 Endless Mobile, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Authors:
+ * - Philip Withnall <withnall@endlessm.com>
+ */
+
+#include "config.h"
+
+#include <assert.h>
+#include <gio/gio.h>
+#include <glib.h>
+#include <glib-object.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "ostree-bloom-private.h"
+
+/**
+ * SECTION:bloom
+ * @title: Bloom filter
+ * @short_description: Bloom filter implementation supporting building and
+ * reading filters
+ * @stability: Unstable
+ * @include: libostree/ostree-bloom-private.h
+ *
+ * #OstreeBloom is an implementation of a bloom filter which supports writing to
+ * and loading from a #GBytes bit array. The caller must store metadata about
+ * the bloom filter (its hash function and `k` parameter value) separately, as
+ * the same values must be used when reading from a serialised bit array as were
+ * used to build the array in the first place.
+ *
+ * This is a standard implementation of a bloom filter, and background reading
+ * on the theory can be
+ * [found on Wikipedia](https://en.wikipedia.org/wiki/Bloom_filter). In
+ * particular, a bloom filter is parameterised by `m` and `k` parameters: the
+ * size of the bit array (in bits) is `m`, and the number of hash functions
+ * applied to each element is `k`. Bloom filters require a universal hash
+ * function which can be parameterised by `k`. We have #OstreeBloomHashFunc,
+ * with ostree_str_bloom_hash() being an implementation for strings.
+ *
+ * The serialised output from a bloom filter is guaranteed to be stable across
+ * versions of libostree as long as the same values for `k` and the hash
+ * function are used.
+ *
+ * #OstreeBloom is mutable when constructed with ostree_bloom_new(), and elements
+ * can be added to it using ostree_bloom_add_element(), until ostree_bloom_seal()
+ * is called to serialise it and make it immutable. After then, the bloom filter
+ * can only be queried using ostree_bloom_maybe_contains().
+ *
+ * If constructed with ostree_bloom_new_from_bytes(), the bloom filter is
+ * immutable from construction, and can only be queried.
+ *
+ * Reference:
+ * - https://en.wikipedia.org/wiki/Bloom_filter
+ * - https://llimllib.github.io/bloomfilter-tutorial/
+ *
+ * Since: 2017.8
+ */
+
+struct _OstreeBloom
+{
+ guint ref_count;
+ gsize n_bytes;
+ gboolean is_mutable; /* determines which of [im]mutable_bytes is accessed */
+ union
+ {
+ guint8 *mutable_bytes; /* owned; mutually exclusive */
+ GBytes *immutable_bytes; /* owned; mutually exclusive */
+ };
+ guint8 k;
+ OstreeBloomHashFunc hash_func;
+};
+
+G_DEFINE_BOXED_TYPE (OstreeBloom, ostree_bloom, ostree_bloom_ref, ostree_bloom_unref)
+
+/**
+ * ostree_bloom_new:
+ * @n_bytes: size to make the bloom filter, in bytes
+ * @k: number of hash functions to use
+ * @hash_func: universal hash function to use
+ *
+ * Create a new mutable #OstreeBloom filter, with all its bits initialised to
+ * zero. Set elements in the filter using ostree_bloom_add_element(), and seal
+ * it to return an immutable #GBytes using ostree_bloom_seal().
+ *
+ * To load an #OstreeBloom from an existing #GBytes, use
+ * ostree_bloom_new_from_bytes().
+ *
+ * Note that @n_bytes is in bytes, so is 8 times smaller than the parameter `m`
+ * which is used when describing bloom filters academically.
+ *
+ * Returns: (transfer full): a new mutable bloom filter
+ *
+ * Since: 2017.8
+ */
+OstreeBloom *
+ostree_bloom_new (gsize n_bytes,
+ guint8 k,
+ OstreeBloomHashFunc hash_func)
+{
+ g_autoptr(OstreeBloom) bloom = NULL;
+
+ g_return_val_if_fail (n_bytes > 0, NULL);
+ g_return_val_if_fail (k > 0, NULL);
+ g_return_val_if_fail (hash_func != NULL, NULL);
+
+ bloom = g_new0 (OstreeBloom, 1);
+ bloom->ref_count = 1;
+
+ bloom->is_mutable = TRUE;
+ bloom->mutable_bytes = g_malloc0 (n_bytes);
+ bloom->n_bytes = n_bytes;
+ bloom->k = k;
+ bloom->hash_func = hash_func;
+
+ return g_steal_pointer (&bloom);
+}
+
+/**
+ * ostree_bloom_new_from_bytes:
+ * @bytes: array of bytes containing the filter data
+ * @k: number of hash functions to use
+ * @hash_func: universal hash function to use
+ *
+ * Load an immutable #OstreeBloom filter from the given @bytes. Check whether
+ * elements are probably set in the filter using ostree_bloom_maybe_contains().
+ *
+ * To create a new mutable #OstreeBloom, use ostree_bloom_new().
+ *
+ * Note that all the bits in @bytes are loaded, so the parameter `m` for the
+ * filter (as commonly used in academic literature) is always a multiple of 8.
+ *
+ * Returns: (transfer full): a new immutable bloom filter
+ *
+ * Since: 2017.8
+ */
+OstreeBloom *
+ostree_bloom_new_from_bytes (GBytes *bytes,
+ guint8 k,
+ OstreeBloomHashFunc hash_func)
+{
+ g_autoptr(OstreeBloom) bloom = NULL;
+
+ g_return_val_if_fail (bytes != NULL, NULL);
+ g_return_val_if_fail (g_bytes_get_size (bytes) > 0, NULL);
+ g_return_val_if_fail (k > 0, NULL);
+ g_return_val_if_fail (hash_func != NULL, NULL);
+
+ bloom = g_new0 (OstreeBloom, 1);
+ bloom->ref_count = 1;
+
+ bloom->is_mutable = FALSE;
+ bloom->immutable_bytes = g_bytes_ref (bytes);
+ bloom->n_bytes = g_bytes_get_size (bytes);
+ bloom->k = k;
+ bloom->hash_func = hash_func;
+
+ return g_steal_pointer (&bloom);
+}
+
+/**
+ * ostree_bloom_ref:
+ * @bloom: an #OstreeBloom
+ *
+ * Increase the reference count of @bloom.
+ *
+ * Returns: (transfer full): @bloom
+ * Since: 2017.8
+ */
+OstreeBloom *
+ostree_bloom_ref (OstreeBloom *bloom)
+{
+ g_return_val_if_fail (bloom != NULL, NULL);
+ g_return_val_if_fail (bloom->ref_count >= 1, NULL);
+ g_return_val_if_fail (bloom->ref_count == G_MAXUINT - 1, NULL);
+
+ bloom->ref_count++;
+
+ return bloom;
+}
+
+/**
+ * ostree_bloom_unref:
+ * @bloom: (transfer full): an #OstreeBloom
+ *
+ * Decrement the reference count of @bloom. If it reaches zero, the filter
+ * is destroyed.
+ *
+ * Since: 2017.8
+ */
+void
+ostree_bloom_unref (OstreeBloom *bloom)
+{
+ g_return_if_fail (bloom != NULL);
+ g_return_if_fail (bloom->ref_count >= 1);
+
+ bloom->ref_count--;
+
+ if (bloom->ref_count == 0)
+ {
+ if (bloom->is_mutable)
+ g_clear_pointer (&bloom->mutable_bytes, g_free);
+ else
+ g_clear_pointer (&bloom->immutable_bytes, g_bytes_unref);
+ bloom->n_bytes = 0;
+ g_free (bloom);
+ }
+}
+
+/* @idx is in bits, not bytes. */
+static inline gboolean
+ostree_bloom_get_bit (OstreeBloom *bloom,
+ gsize idx)
+{
+ const guint8 *bytes;
+
+ if (bloom->is_mutable)
+ bytes = bloom->mutable_bytes;
+ else
+ bytes = g_bytes_get_data (bloom->immutable_bytes, NULL);
+
+ g_assert (idx / 8 < bloom->n_bytes);
+ return (bytes[idx / 8] & (1 << (idx % 8)));
+}
+
+/* @idx is in bits, not bytes. */
+static inline void
+ostree_bloom_set_bit (OstreeBloom *bloom,
+ gsize idx)
+{
+ g_assert (bloom->is_mutable);
+ g_assert (idx / 8 < bloom->n_bytes);
+ bloom->mutable_bytes[idx / 8] |= (1 << (idx % 8));
+}
+
+/**
+ * ostree_bloom_maybe_contains:
+ * @bloom: an #OstreeBloom
+ * @element: (nullable): element to check for membership
+ *
+ * Check whether @element is potentially in @bloom, or whether it definitely
+ * isn’t. @element may be %NULL only if the hash function passed to @bloom at
+ * construction time supports %NULL elements.
+ *
+ * Returns: %TRUE if @element is potentially in @bloom; %FALSE if it definitely
+ * isn’t
+ * Since: 2017.8
+ */
+gboolean
+ostree_bloom_maybe_contains (OstreeBloom *bloom,
+ gconstpointer element)
+{
+ guint8 i;
+
+ g_return_val_if_fail (bloom != NULL, TRUE);
+ g_return_val_if_fail (bloom->ref_count >= 1, TRUE);
+
+ for (i = 0; i < bloom->k; i++)
+ {
+ gsize idx;
+
+ idx = bloom->hash_func (element, i);
+
+ if (!ostree_bloom_get_bit (bloom, idx % (bloom->n_bytes * 8)))
+ return FALSE; /* definitely not in the set */
+ }
+
+ return TRUE; /* possibly in the set */
+}
+
+/**
+ * ostree_bloom_seal:
+ * @bloom: an #OstreeBloom
+ *
+ * Seal a constructed bloom filter, so that elements may no longer be added to
+ * it, and queries can now be performed against it. The serialised form of the
+ * bloom filter is returned as a bit array. Note that this does not include
+ * information about the filter hash function or parameters; the caller is
+ * responsible for serialising those separately if appropriate.
+ *
+ * It is safe to call this function multiple times.
+ *
+ * Returns: (transfer full): a #GBytes containing the immutable filter data
+ * Since: 2017.8
+ */
+GBytes *
+ostree_bloom_seal (OstreeBloom *bloom)
+{
+ g_return_val_if_fail (bloom != NULL, NULL);
+ g_return_val_if_fail (bloom->ref_count >= 1, NULL);
+
+ if (bloom->is_mutable)
+ {
+ bloom->is_mutable = FALSE;
+ bloom->immutable_bytes = g_bytes_new_take (g_steal_pointer (&bloom->mutable_bytes), bloom->n_bytes);
+ }
+
+ return g_bytes_ref (bloom->immutable_bytes);
+}
+
+/**
+ * ostree_bloom_add_element:
+ * @bloom: an #OstreeBloom
+ * @element: (nullable): element to add to the filter
+ *
+ * Add the given @element to the bloom filter, which must not yet have been
+ * sealed (ostree_bloom_seal()). @element may be %NULL if the hash function
+ * passed to @bloom at construction time supports %NULL elements.
+ *
+ * Since: 2017.8
+ */
+void
+ostree_bloom_add_element (OstreeBloom *bloom,
+ gconstpointer element)
+{
+ guint8 i;
+
+ g_return_if_fail (bloom != NULL);
+ g_return_if_fail (bloom->ref_count >= 1);
+ g_return_if_fail (bloom->is_mutable);
+
+ for (i = 0; i < bloom->k; i++)
+ {
+ gsize idx = bloom->hash_func (element, i);
+ ostree_bloom_set_bit (bloom, idx % (bloom->n_bytes * 8));
+ }
+}
+
+/**
+ * ostree_bloom_get_size:
+ * @bloom: an #OstreeBloom
+ *
+ * Get the size of the #OstreeBloom filter, in bytes, as configured at
+ * construction time.
+ *
+ * Returns: the bloom filter’s size in bytes, guaranteed to be >0
+ * Since: 2017.8
+ */
+gsize
+ostree_bloom_get_size (OstreeBloom *bloom)
+{
+ g_return_val_if_fail (bloom != NULL, 0);
+
+ return bloom->n_bytes;
+}
+
+/**
+ * ostree_bloom_get_k:
+ * @bloom: an #OstreeBloom
+ *
+ * Get the `k` value from the #OstreeBloom filter, as configured at
+ * construction time.
+ *
+ * Returns: the bloom filter’s `k` value, guaranteed to be >0
+ * Since: 2017.8
+ */
+guint8
+ostree_bloom_get_k (OstreeBloom *bloom)
+{
+ g_return_val_if_fail (bloom != NULL, 0);
+
+ return bloom->k;
+}
+
+/**
+ * ostree_bloom_get_hash_func:
+ * @bloom: an #OstreeBloom
+ *
+ * Get the #OstreeBloomHashFunc from the #OstreeBloom filter, as configured at
+ * construction time.
+ *
+ * Returns: the bloom filter’s universal hash function
+ * Since: 2017.8
+ */
+OstreeBloomHashFunc
+ostree_bloom_get_hash_func (OstreeBloom *bloom)
+{
+ g_return_val_if_fail (bloom != NULL, NULL);
+
+ return bloom->hash_func;
+}
+
+/* SipHash code adapted from https://github.com/veorq/SipHash/blob/master/siphash.c */
+
+/*
+ SipHash reference C implementation
+ Copyright (c) 2012-2016 Jean-Philippe Aumasson
+ <jeanphilippe.aumasson@gmail.com>
+ Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+ To the extent possible under law, the author(s) have dedicated all copyright
+ and related and neighboring rights to this software to the public domain
+ worldwide. This software is distributed without any warranty.
+ You should have received a copy of the CC0 Public Domain Dedication along
+ with
+ this software. If not, see
+ <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+/* default: SipHash-2-4 */
+#define cROUNDS 2
+#define dROUNDS 4
+
+#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define U32TO8_LE(p, v) \
+ (p)[0] = (uint8_t)((v)); \
+ (p)[1] = (uint8_t)((v) >> 8); \
+ (p)[2] = (uint8_t)((v) >> 16); \
+ (p)[3] = (uint8_t)((v) >> 24);
+
+#define U64TO8_LE(p, v) \
+ U32TO8_LE((p), (uint32_t)((v))); \
+ U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
+
+#define U8TO64_LE(p) \
+ (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
+ ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
+ ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
+ ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
+
+#define SIPROUND \
+ do { \
+ v0 += v1; \
+ v1 = ROTL(v1, 13); \
+ v1 ^= v0; \
+ v0 = ROTL(v0, 32); \
+ v2 += v3; \
+ v3 = ROTL(v3, 16); \
+ v3 ^= v2; \
+ v0 += v3; \
+ v3 = ROTL(v3, 21); \
+ v3 ^= v0; \
+ v2 += v1; \
+ v1 = ROTL(v1, 17); \
+ v1 ^= v2; \
+ v2 = ROTL(v2, 32); \
+ } while (0)
+
+#ifdef DEBUG
+#define TRACE \
+ do { \
+ printf("(%3d) v0 %08x %08x\n", (int)inlen, (uint32_t)(v0 >> 32), \
+ (uint32_t)v0); \
+ printf("(%3d) v1 %08x %08x\n", (int)inlen, (uint32_t)(v1 >> 32), \
+ (uint32_t)v1); \
+ printf("(%3d) v2 %08x %08x\n", (int)inlen, (uint32_t)(v2 >> 32), \
+ (uint32_t)v2); \
+ printf("(%3d) v3 %08x %08x\n", (int)inlen, (uint32_t)(v3 >> 32), \
+ (uint32_t)v3); \
+ } while (0)
+#else
+#define TRACE
+#endif
+
+static int siphash(const uint8_t *in, const size_t inlen, const uint8_t *k,
+ uint8_t *out, const size_t outlen) {
+
+ assert((outlen == 8) || (outlen == 16));
+ uint64_t v0 = 0x736f6d6570736575ULL;
+ uint64_t v1 = 0x646f72616e646f6dULL;
+ uint64_t v2 = 0x6c7967656e657261ULL;
+ uint64_t v3 = 0x7465646279746573ULL;
+ uint64_t k0 = U8TO64_LE(k);
+ uint64_t k1 = U8TO64_LE(k + 8);
+ uint64_t m;
+ int i;
+ const uint8_t *end = in + inlen - (inlen % sizeof(uint64_t));
+ const int left = inlen & 7;
+ uint64_t b = ((uint64_t)inlen) << 56;
+ v3 ^= k1;
+ v2 ^= k0;
+ v1 ^= k1;
+ v0 ^= k0;
+
+ if (outlen == 16)
+ v1 ^= 0xee;
+
+ for (; in != end; in += 8) {
+ m = U8TO64_LE(in);
+ v3 ^= m;
+
+ TRACE;
+ for (i = 0; i < cROUNDS; ++i)
+ SIPROUND;
+
+ v0 ^= m;
+ }
+
+ switch (left) {
+ case 7:
+ b |= ((uint64_t)in[6]) << 48;
+ case 6:
+ b |= ((uint64_t)in[5]) << 40;
+ case 5:
+ b |= ((uint64_t)in[4]) << 32;
+ case 4:
+ b |= ((uint64_t)in[3]) << 24;
+ case 3:
+ b |= ((uint64_t)in[2]) << 16;
+ case 2:
+ b |= ((uint64_t)in[1]) << 8;
+ case 1:
+ b |= ((uint64_t)in[0]);
+ break;
+ case 0:
+ break;
+ }
+
+ v3 ^= b;
+
+ TRACE;
+ for (i = 0; i < cROUNDS; ++i)
+ SIPROUND;
+
+ v0 ^= b;
+
+ if (outlen == 16)
+ v2 ^= 0xee;
+ else
+ v2 ^= 0xff;
+
+ TRACE;
+ for (i = 0; i < dROUNDS; ++i)
+ SIPROUND;
+
+ b = v0 ^ v1 ^ v2 ^ v3;
+ U64TO8_LE(out, b);
+
+ if (outlen == 8)
+ return 0;
+
+ v1 ^= 0xdd;
+
+ TRACE;
+ for (i = 0; i < dROUNDS; ++i)
+ SIPROUND;
+
+ b = v0 ^ v1 ^ v2 ^ v3;
+ U64TO8_LE(out + 8, b);
+
+ return 0;
+}
+
+/* End SipHash copied code. */
+
+/**
+ * ostree_str_bloom_hash:
+ * @element: element to calculate the hash for
+ * @k: hash function index
+ *
+ * A universal hash function implementation for strings. It expects @element to
+ * be a pointer to a string (i.e. @element has type `const gchar*`), and expects
+ * @k to be in the range `[0, k_max)`, where `k_max` is the `k` value used to
+ * construct the bloom filter. The output range from this hash function could be
+ * any value in #guint64, and it handles input strings of any length.
+ *
+ * This function does not allow %NULL as a valid value for @element.
+ *
+ * Reference:
+ * - https://www.131002.net/siphash/
+ *
+ * Returns: hash of the string at @element using parameter @k
+ * Since: 2017.8
+ */
+guint64
+ostree_str_bloom_hash (gconstpointer element,
+ guint8 k)
+{
+ const gchar *str = element;
+ gsize str_len;
+ union
+ {
+ guint64 u64;
+ guint8 u8[8];
+ } out_le;
+ guint8 k_array[16];
+ gsize i;
+
+ str_len = strlen (str);
+ for (i = 0; i < G_N_ELEMENTS (k_array); i++)
+ k_array[i] = k;
+
+ siphash ((const guint8 *) str, str_len, k_array, out_le.u8, sizeof (out_le));
+
+ return le64toh (out_le.u64);
+}
--- /dev/null
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright © 2017 Endless Mobile, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Authors:
+ * - Philip Withnall <withnall@endlessm.com>
+ */
+
+#include "config.h"
+
+#include <gio/gio.h>
+#include <glib.h>
+
+#include "ostree-bloom-private.h"
+
+/* Test the two different constructors work at a basic level. */
+static void
+test_bloom_init (void)
+{
+ g_autoptr(OstreeBloom) bloom = NULL;
+ g_autoptr(GBytes) bytes = NULL;
+
+ bloom = ostree_bloom_new (1, 1, ostree_str_bloom_hash);
+ g_assert_cmpuint (ostree_bloom_get_size (bloom), ==, 1);
+ g_assert_cmpuint (ostree_bloom_get_k (bloom), ==, 1);
+ g_assert (ostree_bloom_get_hash_func (bloom) == ostree_str_bloom_hash);
+ g_clear_pointer (&bloom, ostree_bloom_unref);
+
+ bytes = g_bytes_new_take (g_malloc0 (4), 4);
+ bloom = ostree_bloom_new_from_bytes (bytes, 1, ostree_str_bloom_hash);
+ g_assert_cmpuint (ostree_bloom_get_size (bloom), ==, 4);
+ g_assert_cmpuint (ostree_bloom_get_k (bloom), ==, 1);
+ g_assert (ostree_bloom_get_hash_func (bloom) == ostree_str_bloom_hash);
+ g_clear_pointer (&bloom, ostree_bloom_unref);
+}
+
+/* Test that building a bloom filter, marshalling it through GBytes, and loading
+ * it again, gives the same element membership. */
+static void
+test_bloom_construction (void)
+{
+ g_autoptr(OstreeBloom) bloom = NULL;
+ g_autoptr(OstreeBloom) immutable_bloom = NULL;
+ g_autoptr(GBytes) bytes = NULL;
+ gsize i;
+ const gchar *members[] =
+ {
+ "hello", "there", "these", "are", "test", "strings"
+ };
+ const gchar *non_members[] =
+ {
+ "not", "an", "element"
+ };
+ const gsize n_bytes = 256;
+ const guint8 k = 8;
+ const OstreeBloomHashFunc hash = ostree_str_bloom_hash;
+
+ /* Build a bloom filter. */
+ bloom = ostree_bloom_new (n_bytes, k, hash);
+
+ for (i = 0; i < G_N_ELEMENTS (members); i++)
+ ostree_bloom_add_element (bloom, members[i]);
+
+ bytes = ostree_bloom_seal (bloom);
+
+ /* Read it back from the GBytes. */
+ immutable_bloom = ostree_bloom_new_from_bytes (bytes, k, hash);
+
+ for (i = 0; i < G_N_ELEMENTS (members); i++)
+ g_assert_true (ostree_bloom_maybe_contains (bloom, members[i]));
+
+ /* This should never fail in future, as we guarantee the hash function will
+ * never change. But given the definition of a bloom filter, it would also
+ * be valid for these calls to return %TRUE. */
+ for (i = 0; i < G_N_ELEMENTS (non_members); i++)
+ g_assert_false (ostree_bloom_maybe_contains (bloom, non_members[i]));
+}
+
+/* Test that an empty bloom filter definitely contains no elements. */
+static void
+test_bloom_empty (void)
+{
+ g_autoptr(OstreeBloom) bloom = NULL;
+ const gsize n_bytes = 256;
+ const guint8 k = 8;
+ const OstreeBloomHashFunc hash = ostree_str_bloom_hash;
+
+ /* Build an empty bloom filter. */
+ bloom = ostree_bloom_new (n_bytes, k, hash);
+
+ g_assert_false (ostree_bloom_maybe_contains (bloom, "hello"));
+ g_assert_false (ostree_bloom_maybe_contains (bloom, "there"));
+}
+
+/* Build a bloom filter, and check the membership of the members as they are
+ * added. */
+static void
+test_bloom_membership_during_construction (void)
+{
+ g_autoptr(OstreeBloom) bloom = NULL;
+ gsize i, j;
+ const gchar *members[] =
+ {
+ "hello", "there", "these", "are", "test", "strings"
+ };
+ const gsize n_bytes = 256;
+ const guint8 k = 8;
+ const OstreeBloomHashFunc hash = ostree_str_bloom_hash;
+
+ /* These membership checks should never fail in future, as we guarantee
+ * the hash function will never change. But given the definition of a bloom
+ * filter, it would also be valid for these checks to fail. */
+ bloom = ostree_bloom_new (n_bytes, k, hash);
+
+ for (i = 0; i < G_N_ELEMENTS (members); i++)
+ {
+ ostree_bloom_add_element (bloom, members[i]);
+
+ for (j = 0; j < G_N_ELEMENTS (members); j++)
+ {
+ if (j <= i)
+ g_assert_true (ostree_bloom_maybe_contains (bloom, members[j]));
+ else
+ g_assert_false (ostree_bloom_maybe_contains (bloom, members[j]));
+ }
+ }
+}
+
+int main (int argc, char **argv)
+{
+ g_test_init (&argc, &argv, NULL);
+
+ g_test_add_func ("/bloom/init", test_bloom_init);
+ g_test_add_func ("/bloom/construction", test_bloom_construction);
+ g_test_add_func ("/bloom/empty", test_bloom_empty);
+ g_test_add_func ("/bloom/membership-during-construction", test_bloom_membership_during_construction);
+
+ return g_test_run();
+}
projects / ostree.git / commitdiff