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Diffstat (limited to 'subprojects/gvdb/gvdb-builder.c')
-rw-r--r-- | subprojects/gvdb/gvdb-builder.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/subprojects/gvdb/gvdb-builder.c b/subprojects/gvdb/gvdb-builder.c new file mode 100644 index 000000000..16a5283dd --- /dev/null +++ b/subprojects/gvdb/gvdb-builder.c @@ -0,0 +1,523 @@ +/* + * Copyright © 2010 Codethink Limited + * + * 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 licence, 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. + * + * Author: Ryan Lortie <desrt@desrt.ca> + */ + +#include "gvdb-builder.h" +#include "gvdb-format.h" + +#include <glib.h> +#include <fcntl.h> +#if !defined(G_OS_WIN32) || !defined(_MSC_VER) +#include <unistd.h> +#endif +#include <string.h> + + +struct _GvdbItem +{ + gchar *key; + guint32 hash_value; + guint32_le assigned_index; + GvdbItem *parent; + GvdbItem *sibling; + GvdbItem *next; + + /* one of: + * this: + */ + GVariant *value; + + /* this: */ + GHashTable *table; + + /* or this: */ + GvdbItem *child; +}; + +static void +gvdb_item_free (gpointer data) +{ + GvdbItem *item = data; + + g_free (item->key); + + if (item->value) + g_variant_unref (item->value); + + if (item->table) + g_hash_table_unref (item->table); + + g_slice_free (GvdbItem, item); +} + +GHashTable * +gvdb_hash_table_new (GHashTable *parent, + const gchar *name_in_parent) +{ + GHashTable *table; + + table = g_hash_table_new_full (g_str_hash, g_str_equal, + g_free, gvdb_item_free); + + if (parent) + { + GvdbItem *item; + + item = gvdb_hash_table_insert (parent, name_in_parent); + gvdb_item_set_hash_table (item, table); + } + + return table; +} + +static guint32 +djb_hash (const gchar *key) +{ + guint32 hash_value = 5381; + + while (*key) + hash_value = hash_value * 33 + *(signed char *)key++; + + return hash_value; +} + +GvdbItem * +gvdb_hash_table_insert (GHashTable *table, + const gchar *key) +{ + GvdbItem *item; + + item = g_slice_new0 (GvdbItem); + item->key = g_strdup (key); + item->hash_value = djb_hash (key); + + g_hash_table_insert (table, g_strdup (key), item); + + return item; +} + +void +gvdb_hash_table_insert_string (GHashTable *table, + const gchar *key, + const gchar *value) +{ + GvdbItem *item; + + item = gvdb_hash_table_insert (table, key); + gvdb_item_set_value (item, g_variant_new_string (value)); +} + +void +gvdb_item_set_value (GvdbItem *item, + GVariant *value) +{ + g_return_if_fail (!item->value && !item->table && !item->child); + + item->value = g_variant_ref_sink (value); +} + +void +gvdb_item_set_hash_table (GvdbItem *item, + GHashTable *table) +{ + g_return_if_fail (!item->value && !item->table && !item->child); + + item->table = g_hash_table_ref (table); +} + +void +gvdb_item_set_parent (GvdbItem *item, + GvdbItem *parent) +{ + GvdbItem **node; + + g_return_if_fail (g_str_has_prefix (item->key, parent->key)); + g_return_if_fail (!parent->value && !parent->table); + g_return_if_fail (!item->parent && !item->sibling); + + for (node = &parent->child; *node; node = &(*node)->sibling) + if (strcmp ((*node)->key, item->key) > 0) + break; + + item->parent = parent; + item->sibling = *node; + *node = item; +} + +typedef struct +{ + GvdbItem **buckets; + gint n_buckets; +} HashTable; + +static HashTable * +hash_table_new (gint n_buckets) +{ + HashTable *table; + + table = g_slice_new (HashTable); + table->buckets = g_new0 (GvdbItem *, n_buckets); + table->n_buckets = n_buckets; + + return table; +} + +static void +hash_table_free (HashTable *table) +{ + g_free (table->buckets); + + g_slice_free (HashTable, table); +} + +static void +hash_table_insert (gpointer key, + gpointer value, + gpointer data) +{ + guint32 hash_value, bucket; + HashTable *table = data; + GvdbItem *item = value; + + hash_value = djb_hash (key); + bucket = hash_value % table->n_buckets; + item->next = table->buckets[bucket]; + table->buckets[bucket] = item; +} + +static guint32_le +item_to_index (GvdbItem *item) +{ + if (item != NULL) + return item->assigned_index; + + return guint32_to_le (-1u); +} + +typedef struct +{ + GQueue *chunks; + guint64 offset; + gboolean byteswap; +} FileBuilder; + +typedef struct +{ + gsize offset; + gsize size; + gpointer data; +} FileChunk; + +static gpointer +file_builder_allocate (FileBuilder *fb, + guint alignment, + gsize size, + struct gvdb_pointer *pointer) +{ + FileChunk *chunk; + + if (size == 0) + return NULL; + + fb->offset += (-fb->offset) & (alignment - 1); + chunk = g_slice_new (FileChunk); + chunk->offset = fb->offset; + chunk->size = size; + chunk->data = g_malloc (size); + + pointer->start = guint32_to_le (fb->offset); + fb->offset += size; + pointer->end = guint32_to_le (fb->offset); + + g_queue_push_tail (fb->chunks, chunk); + + return chunk->data; +} + +static void +file_builder_add_value (FileBuilder *fb, + GVariant *value, + struct gvdb_pointer *pointer) +{ + GVariant *variant, *normal; + gpointer data; + gsize size; + + if (fb->byteswap) + { + value = g_variant_byteswap (value); + variant = g_variant_new_variant (value); + g_variant_unref (value); + } + else + variant = g_variant_new_variant (value); + + normal = g_variant_get_normal_form (variant); + g_variant_unref (variant); + + size = g_variant_get_size (normal); + data = file_builder_allocate (fb, 8, size, pointer); + g_variant_store (normal, data); + g_variant_unref (normal); +} + +static void +file_builder_add_string (FileBuilder *fb, + const gchar *string, + guint32_le *start, + guint16_le *size) +{ + FileChunk *chunk; + gsize length; + + length = strlen (string); + + chunk = g_slice_new (FileChunk); + chunk->offset = fb->offset; + chunk->size = length; + chunk->data = g_malloc (length); + memcpy (chunk->data, string, length); + + *start = guint32_to_le (fb->offset); + *size = guint16_to_le (length); + fb->offset += length; + + g_queue_push_tail (fb->chunks, chunk); +} + +static void +file_builder_allocate_for_hash (FileBuilder *fb, + gsize n_buckets, + gsize n_items, + guint bloom_shift, + gsize n_bloom_words, + guint32_le **bloom_filter, + guint32_le **hash_buckets, + struct gvdb_hash_item **hash_items, + struct gvdb_pointer *pointer) +{ + guint32_le bloom_hdr, table_hdr; + guchar *data; + gsize size; + + g_assert (n_bloom_words < (1u << 27)); + + bloom_hdr = guint32_to_le (bloom_shift << 27 | n_bloom_words); + table_hdr = guint32_to_le (n_buckets); + + size = sizeof bloom_hdr + sizeof table_hdr + + n_bloom_words * sizeof (guint32_le) + + n_buckets * sizeof (guint32_le) + + n_items * sizeof (struct gvdb_hash_item); + + data = file_builder_allocate (fb, 4, size, pointer); + +#define chunk(s) (size -= (s), data += (s), data - (s)) + memcpy (chunk (sizeof bloom_hdr), &bloom_hdr, sizeof bloom_hdr); + memcpy (chunk (sizeof table_hdr), &table_hdr, sizeof table_hdr); + *bloom_filter = (guint32_le *) chunk (n_bloom_words * sizeof (guint32_le)); + *hash_buckets = (guint32_le *) chunk (n_buckets * sizeof (guint32_le)); + *hash_items = (struct gvdb_hash_item *) chunk (n_items * + sizeof (struct gvdb_hash_item)); + g_assert (size == 0); +#undef chunk + + memset (*bloom_filter, 0, n_bloom_words * sizeof (guint32_le)); + + /* NOTE - the code to actually fill in the bloom filter here is missing. + * Patches welcome! + * + * http://en.wikipedia.org/wiki/Bloom_filter + * http://0pointer.de/blog/projects/bloom.html + */ +} + +static void +file_builder_add_hash (FileBuilder *fb, + GHashTable *table, + struct gvdb_pointer *pointer) +{ + guint32_le *buckets, *bloom_filter; + struct gvdb_hash_item *items; + HashTable *mytable; + GvdbItem *item; + guint32 index; + gint bucket; + + mytable = hash_table_new (g_hash_table_size (table)); + g_hash_table_foreach (table, hash_table_insert, mytable); + index = 0; + + for (bucket = 0; bucket < mytable->n_buckets; bucket++) + for (item = mytable->buckets[bucket]; item; item = item->next) + item->assigned_index = guint32_to_le (index++); + + file_builder_allocate_for_hash (fb, mytable->n_buckets, index, 5, 0, + &bloom_filter, &buckets, &items, pointer); + + index = 0; + for (bucket = 0; bucket < mytable->n_buckets; bucket++) + { + buckets[bucket] = guint32_to_le (index); + + for (item = mytable->buckets[bucket]; item; item = item->next) + { + struct gvdb_hash_item *entry = items++; + const gchar *basename; + + g_assert (index == guint32_from_le (item->assigned_index)); + entry->hash_value = guint32_to_le (item->hash_value); + entry->parent = item_to_index (item->parent); + entry->unused = 0; + + if (item->parent != NULL) + basename = item->key + strlen (item->parent->key); + else + basename = item->key; + + file_builder_add_string (fb, basename, + &entry->key_start, + &entry->key_size); + + if (item->value != NULL) + { + g_assert (item->child == NULL && item->table == NULL); + + file_builder_add_value (fb, item->value, &entry->value.pointer); + entry->type = 'v'; + } + + if (item->child != NULL) + { + guint32 children = 0, i = 0; + guint32_le *offsets; + GvdbItem *child; + + g_assert (item->table == NULL); + + for (child = item->child; child; child = child->sibling) + children++; + + offsets = file_builder_allocate (fb, 4, 4 * children, + &entry->value.pointer); + entry->type = 'L'; + + for (child = item->child; child; child = child->sibling) + offsets[i++] = child->assigned_index; + + g_assert (children == i); + } + + if (item->table != NULL) + { + entry->type = 'H'; + file_builder_add_hash (fb, item->table, &entry->value.pointer); + } + + index++; + } + } + + hash_table_free (mytable); +} + +static FileBuilder * +file_builder_new (gboolean byteswap) +{ + FileBuilder *builder; + + builder = g_slice_new (FileBuilder); + builder->chunks = g_queue_new (); + builder->offset = sizeof (struct gvdb_header); + builder->byteswap = byteswap; + + return builder; +} + +static GString * +file_builder_serialise (FileBuilder *fb, + struct gvdb_pointer root) +{ + struct gvdb_header header = { { 0, }, }; + GString *result; + + if (fb->byteswap) + { + header.signature[0] = GVDB_SWAPPED_SIGNATURE0; + header.signature[1] = GVDB_SWAPPED_SIGNATURE1; + } + else + { + header.signature[0] = GVDB_SIGNATURE0; + header.signature[1] = GVDB_SIGNATURE1; + } + + result = g_string_new (NULL); + + header.root = root; + g_string_append_len (result, (gpointer) &header, sizeof header); + + while (!g_queue_is_empty (fb->chunks)) + { + FileChunk *chunk = g_queue_pop_head (fb->chunks); + + if (result->len != chunk->offset) + { + gchar zero[8] = { 0, }; + + g_assert (chunk->offset > result->len); + g_assert (chunk->offset - result->len < 8); + + g_string_append_len (result, zero, chunk->offset - result->len); + g_assert (result->len == chunk->offset); + } + + g_string_append_len (result, chunk->data, chunk->size); + g_free (chunk->data); + + g_slice_free (FileChunk, chunk); + } + + g_queue_free (fb->chunks); + g_slice_free (FileBuilder, fb); + + return result; +} + +gboolean +gvdb_table_write_contents (GHashTable *table, + const gchar *filename, + gboolean byteswap, + GError **error) +{ + struct gvdb_pointer root; + gboolean status; + FileBuilder *fb; + GString *str; + + fb = file_builder_new (byteswap); + file_builder_add_hash (fb, table, &root); + str = file_builder_serialise (fb, root); + + status = g_file_set_contents (filename, str->str, str->len, error); + g_string_free (str, TRUE); + + return status; +} |