strset: new module using critbit trees.

[ccan] / ccan / strset / strset.h

diff --git a/ccan/strset/strset.h b/ccan/strset/strset.h
new file mode 100644 (file)
index 0000000..8d0d307
--- /dev/null
+++ b/ccan/strset/strset.h
@@ -0,0 +1,164 @@
+#ifndef CCAN_STRSET_H
+#define CCAN_STRSET_H
+#include "config.h"
+#include <ccan/typesafe_cb/typesafe_cb.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+/**
+ * struct strset - representation of a string set
+ *
+ * It's exposed here to allow you to embed it and so we can inline the
+ * trivial functions.
+ */
+struct strset {
+       union {
+               struct node *n;
+               const char *s;
+       } u;
+};
+
+/**
+ * strset_init - initialize a string set (empty)
+ *
+ * For completeness; if you've arranged for it to be NULL already you don't
+ * need this.
+ *
+ * Example:
+ *     struct strset set;
+ *
+ *     strset_init(&set);
+ */
+static inline void strset_init(struct strset *set)
+{
+       set->u.n = NULL;
+}
+
+/**
+ * strset_empty - is this string set empty?
+ * @set: the set.
+ *
+ * Example:
+ *     if (!strset_empty(&set))
+ *             abort();
+ */
+static inline bool strset_empty(const struct strset *set)
+{
+       return set->u.n == NULL;
+}
+
+/**
+ * strset_test - is this a member of this string set?
+ * @set: the set.
+ * @member: the string to search for.
+ *
+ * Returns the member, or NULL if it isn't in the set.
+ *
+ * Example:
+ *     if (strset_test(&set, "hello"))
+ *             printf("hello is in the set\n");
+ */
+char *strset_test(const struct strset *set, const char *member);
+
+/**
+ * strset_set - place a member in the string set.
+ * @set: the set.
+ * @member: the string to place in the set.
+ *
+ * This returns false if we run out of memory, or (more normally) if that
+ * string already appears in the set.
+ *
+ * Note that the pointer is placed in the set, the string is not copied.  If
+ * you want a copy in the set, use strdup().
+ *
+ * Example:
+ *     if (!strset_set(&set, "goodbye"))
+ *             printf("goodbye was already in the set\n");
+ */
+bool strset_set(struct strset *set, const char *member);
+
+/**
+ * strset_clear - remove a member from the string set.
+ * @set: the set.
+ * @member: the string to remove from the set.
+ *
+ * This returns the string which was passed to strset_set(), or NULL.
+ * This means that if you allocated a string (eg. using strdup()), you can
+ * free it here.
+ *
+ * Example:
+ *     if (!strset_clear(&set, "goodbye"))
+ *             printf("goodbye was not in the set?\n");
+ */
+char *strset_clear(struct strset *set, const char *member);
+
+/**
+ * strset_destroy - remove every member from the set.
+ * @set: the set.
+ *
+ * The set will be empty after this.
+ *
+ * Example:
+ *     strset_destroy(&set);
+ */
+void strset_destroy(struct strset *set);
+
+/**
+ * strset_iterate - ordered iteration over a set
+ * @set: the set.
+ * @handle: the function to call.
+ * @arg: the argument for the function (types should match).
+ *
+ * You should not alter the set within the @handle function!  If it returns
+ * true, the iteration will stop.
+ *
+ * Example:
+ *     static bool dump_some(const char *member, int *num)
+ *     {
+ *             // Only dump out num nodes.
+ *             if (*(num--) == 0)
+ *                     return true;
+ *             printf("%s\n", member);
+ *             return false;
+ *     }
+ *
+ *     static void dump_set(const struct strset *set)
+ *     {
+ *             int max = 100;
+ *             strset_iterate(set, dump_some, &max);
+ *             if (max < 0)
+ *                     printf("... (truncated to 100 entries)\n");
+ *     }
+ */
+#define strset_iterate(set, handle, arg)                               \
+       strset_iterate_((set), typesafe_cb_preargs(bool, void *,        \
+                                                  (handle), (arg),     \
+                                                  const char *),       \
+                       (arg))
+void strset_iterate_(const struct strset *set,
+                    bool (*handle)(const char *, void *), void *data);
+
+
+/**
+ * strset_prefix - return a subset matching a prefix
+ * @set: the set.
+ * @prefix: the prefix.
+ *
+ * This returns a pointer into @set, so don't alter @set while using
+ * the return value.  You can use strset_iterate(), strset_test() or
+ * strset_empty() on the returned pointer.
+ *
+ * Example:
+ *     static void dump_prefix(const struct strset *set, const char *prefix)
+ *     {
+ *             int max = 100;
+ *             printf("Nodes with prefix %s:\n", prefix);
+ *             strset_iterate(strset_prefix(set, prefix), dump_some, &max);
+ *             if (max < 0)
+ *                     printf("... (truncated to 100 entries)\n");
+ *     }
+ */
+const struct strset *strset_prefix(const struct strset *set,
+                                  const char *prefix);
+
+#endif /* CCAN_STRSET_H */