Added simple string map (hash) utility.

[idzebra-moved-to-github.git] / util / strmap.c

diff --git a/util/strmap.c b/util/strmap.c
new file mode 100644 (file)
index 0000000..8f0b237
--- /dev/null
+++ b/util/strmap.c
@@ -0,0 +1,137 @@
+/* $Id: strmap.c,v 1.1 2007-12-02 11:30:28 adam Exp $
+   Copyright (C) 1995-2007
+   Index Data ApS
+
+This file is part of the Zebra server.
+
+Zebra 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 2, or (at your option) any later
+version.
+
+Zebra 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, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+#include <stddef.h>
+#include <string.h>
+#include <zebra_strmap.h>
+#include <yaz/nmem.h>
+
+struct strmap_entry {
+    char *name;
+    size_t data_len;
+    void *data_buf;
+    struct strmap_entry *next;
+};
+    
+struct zebra_strmap {
+    NMEM nmem_str;
+    NMEM nmem_ent;
+    int hsize;
+    struct strmap_entry **entries;
+    struct strmap_entry *free_entries;
+};
+
+zebra_strmap_t zebra_strmap_create(void)
+{
+    int i;
+    NMEM nmem_ent = nmem_create();
+    zebra_strmap_t st = nmem_malloc(nmem_ent, sizeof(*st));
+    st->nmem_ent = nmem_ent;
+    st->nmem_str = nmem_create();
+    st->hsize = 1001;
+    st->free_entries = 0;
+    st->entries = nmem_malloc(nmem_ent, st->hsize * sizeof(*st->entries));
+    for (i = 0; i < st->hsize; i++)
+        st->entries[i] = 0;
+    return st;
+}
+
+void zebra_strmap_destroy(zebra_strmap_t st)
+{
+    if (st)
+    {
+        nmem_destroy(st->nmem_str);
+        nmem_destroy(st->nmem_ent);
+    }
+}
+
+static struct strmap_entry **hash(zebra_strmap_t st, const char *name)
+{
+    unsigned hash = 0;
+    int i;
+    for (i = 0; name[i]; i++)
+        hash += hash*65519 + name[i];
+    hash = hash % st->hsize;
+    return st->entries + hash;
+}
+
+void zebra_strmap_add(zebra_strmap_t st, const char *name,
+                      void *data_buf, size_t data_len)
+{
+    struct strmap_entry **e = hash(st, name);
+    struct strmap_entry *ne = st->free_entries;
+
+    if (ne)
+        st->free_entries = ne->next;
+    else
+        ne = nmem_malloc(st->nmem_ent, sizeof(*ne));
+    ne->next = *e;
+    *e = ne;
+    ne->name = nmem_strdup(st->nmem_str, name);
+    ne->data_buf = nmem_malloc(st->nmem_str, data_len);
+    memcpy(ne->data_buf, data_buf, data_len);
+    ne->data_len = data_len;
+}
+
+void *zebra_strmap_lookup(zebra_strmap_t st, const char *name, int no,
+                          size_t *data_len)
+{
+    struct strmap_entry *e = *hash(st, name);
+    int i = 0;
+    for (; e ; e = e->next)
+        if (!strcmp(name, e->name))
+        {
+            if (i == no)
+            {
+                if (data_len)
+                    *data_len = e->data_len;
+                return e->data_buf;
+            }
+            i++;
+        }
+    return 0;
+}
+
+int zebra_strmap_remove(zebra_strmap_t st, const char *name)
+{
+    struct strmap_entry **e = hash(st, name);
+    for (; *e ; e = &(*e)->next)
+        if (!strcmp(name, (*e)->name))
+        {
+            struct strmap_entry *tmp = *e;
+            *e = (*e)->next;
+
+            tmp->next = st->free_entries;
+            st->free_entries = tmp;
+            return 1;
+        }
+    return 0;
+}
+                        
+/*
+ * Local variables:
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ * vim: shiftwidth=4 tabstop=8 expandtab
+ */
+