[PATCH 2/9] lib: private string map (associative array) API
David Bremner
david at tethera.net
Sat Aug 6 06:52:32 PDT 2016
The choice of array implementation is deliberate, for future iterator support
---
lib/Makefile.local | 2 +
lib/notmuch-private.h | 11 ++++
lib/string-map.c | 153 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 166 insertions(+)
create mode 100644 lib/string-map.c
diff --git a/lib/Makefile.local b/lib/Makefile.local
index beb9635..c012ed1 100644
--- a/lib/Makefile.local
+++ b/lib/Makefile.local
@@ -40,6 +40,7 @@ libnotmuch_c_srcs = \
$(dir)/messages.c \
$(dir)/sha1.c \
$(dir)/built-with.c \
+ $(dir)/string-map.c \
$(dir)/tags.c
libnotmuch_cxx_srcs = \
@@ -48,6 +49,7 @@ libnotmuch_cxx_srcs = \
$(dir)/directory.cc \
$(dir)/index.cc \
$(dir)/message.cc \
+ $(dir)/message-property.cc \
$(dir)/query.cc \
$(dir)/query-fp.cc \
$(dir)/config.cc \
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index df63905..5abde88 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -540,6 +540,17 @@ _notmuch_string_list_sort (notmuch_string_list_t *list);
/* string-map.c */
typedef struct _notmuch_string_map notmuch_string_map_t;
+notmuch_string_map_t *
+_notmuch_string_map_create (const void *ctx);
+
+void
+_notmuch_string_map_append (notmuch_string_map_t *map,
+ const char *key,
+ const char *value);
+
+const char *
+_notmuch_string_map_get (notmuch_string_map_t *map, const char *key);
+
/* tags.c */
notmuch_tags_t *
diff --git a/lib/string-map.c b/lib/string-map.c
new file mode 100644
index 0000000..0491a10
--- /dev/null
+++ b/lib/string-map.c
@@ -0,0 +1,153 @@
+/* string-map.c - associative arrays of strings
+ *
+ *
+ * Copyright © 2016 David Bremner
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see http://www.gnu.org/licenses/ .
+ *
+ * Author: David Bremner <david at tethera.net>
+ */
+
+#include "notmuch-private.h"
+
+/* Create a new notmuch_string_map_t object, with 'ctx' as its
+ * talloc owner.
+ *
+ * This function can return NULL in case of out-of-memory.
+ */
+
+typedef struct _notmuch_string_pair_t {
+ char *key;
+ char *value;
+} notmuch_string_pair_t;
+
+struct _notmuch_string_map {
+ notmuch_bool_t sorted;
+ size_t length;
+ notmuch_string_pair_t *pairs;
+};
+
+notmuch_string_map_t *
+_notmuch_string_map_create (const void *ctx)
+{
+ notmuch_string_map_t *map;
+
+ map = talloc (ctx, notmuch_string_map_t);
+ if (unlikely (map == NULL))
+ return NULL;
+
+ map->length = 0;
+ map->pairs = NULL;
+ map->sorted = TRUE;
+
+ return map;
+}
+
+void
+_notmuch_string_map_append (notmuch_string_map_t *map,
+ const char *key,
+ const char *value)
+{
+
+ map->length++;
+ map->sorted = FALSE;
+
+ if (map->pairs)
+ map->pairs = talloc_realloc (map, map->pairs, notmuch_string_pair_t, map->length + 1);
+ else
+ map->pairs = talloc_array (map, notmuch_string_pair_t, map->length + 1);
+
+ map->pairs[map->length - 1].key = talloc_strdup (map, key);
+ map->pairs[map->length - 1].value = talloc_strdup (map, value);
+
+ /* Add sentinel */
+ map->pairs[map->length].key = NULL;
+ map->pairs[map->length].value = NULL;
+
+}
+
+static int
+cmppair (const void *pa, const void *pb)
+{
+ notmuch_string_pair_t *a = (notmuch_string_pair_t *) pa;
+ notmuch_string_pair_t *b = (notmuch_string_pair_t *) pb;
+
+ return strcmp (a->key, b->key);
+}
+
+static void
+_notmuch_string_map_sort (notmuch_string_map_t *map)
+{
+ if (map->length == 0)
+ return;
+
+ if (map->sorted)
+ return;
+
+ qsort (map->pairs, map->length, sizeof (notmuch_string_pair_t), cmppair);
+
+ map->sorted = TRUE;
+}
+
+static notmuch_bool_t
+string_cmp (const char *a, const char *b, notmuch_bool_t exact)
+{
+ if (exact)
+ return (strcmp (a, b));
+ else
+ return (strncmp (a, b, strlen (a)));
+}
+
+static notmuch_string_pair_t *
+bsearch_first (notmuch_string_pair_t *array, size_t len, const char *key, notmuch_bool_t exact)
+{
+ size_t first = 0;
+ size_t last = len - 1;
+ size_t mid;
+
+ if (len <= 0)
+ return NULL;
+
+ while (last > first) {
+ mid = (first + last) / 2;
+ int sign = string_cmp (key, array[mid].key, exact);
+
+ if (sign <= 0)
+ last = mid;
+ else
+ first = mid + 1;
+ }
+
+
+ if (string_cmp (key, array[first].key, exact) == 0)
+ return array + first;
+ else
+ return NULL;
+
+}
+
+const char *
+_notmuch_string_map_get (notmuch_string_map_t *map, const char *key)
+{
+ notmuch_string_pair_t *pair;
+
+ /* this means that calling append invalidates iterators */
+ _notmuch_string_map_sort (map);
+
+ pair = bsearch_first (map->pairs, map->length, key, TRUE);
+ if (! pair)
+ return NULL;
+
+ return pair->value;
+}
--
2.8.1
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