--- /dev/null
+#ifndef CCAN_JBITSET_H
+#define CCAN_JBITSET_H
+#include <Judy.h>
+#include <stdbool.h>
+#include <ccan/compiler/compiler.h>
+#include <assert.h>
+
+/**
+ * jbit_new - create a new, empty jbitset.
+ *
+ * See Also:
+ * JBIT_DEFINE_TYPE()
+ *
+ * Example:
+ * struct jbitset *set = jbit_new();
+ * if (!set)
+ * errx(1, "Failed to allocate jbitset");
+ */
+struct jbitset *jbit_new(void);
+
+/**
+ * jbit_free - destroy a jbitset.
+ * @set: the set returned from jbit_new.
+ *
+ * Example:
+ * jbit_free(set);
+ */
+void jbit_free(const struct jbitset *set);
+
+/* This is exposed in the header so we can inline. Treat it as private! */
+struct jbitset {
+ void *judy;
+ JError_t err;
+ const char *errstr;
+};
+const char *COLD_ATTRIBUTE jbit_error_(struct jbitset *set);
+
+/**
+ * jbit_error - test for an error in the a previous jbit_ operation.
+ * @set: the set to test.
+ *
+ * Under normal circumstances, return NULL to indicate no error has occurred.
+ * Otherwise, it will return a string containing the error. This string
+ * can only be freed by jbit_free() on the set.
+ *
+ * Other than out-of-memory, errors are caused by memory corruption or
+ * interface misuse.
+ *
+ * Example:
+ * struct jbitset *set = jbit_new();
+ * const char *errstr;
+ *
+ * if (!set)
+ * err(1, "allocating jbitset");
+ * errstr = jbit_error(set);
+ * if (errstr)
+ * errx(1, "Woah, error on newly created set?! %s", errstr);
+ */
+static inline const char *jbit_error(struct jbitset *set)
+{
+ if (JU_ERRNO(&set->err) <= JU_ERRNO_NFMAX)
+ return NULL;
+ return jbit_error_(set);
+}
+
+/**
+ * jbit_test - test a bit in the bitset.
+ * @set: bitset from jbit_new
+ * @index: the index to test
+ *
+ * Returns true if jbit_set() has been done on this index, false otherwise.
+ *
+ * Example:
+ * assert(!jbit_test(set, 0));
+ */
+static inline bool jbit_test(const struct jbitset *set, size_t index)
+{
+ return Judy1Test(set->judy, index, (JError_t *)&set->err);
+}
+
+/**
+ * jbit_set - set a bit in the bitset.
+ * @set: bitset from jbit_new
+ * @index: the index to set
+ *
+ * Returns false if it was already set (ie. nothing changed)
+ *
+ * Example:
+ * if (jbit_set(set, 0))
+ * err(1, "Bit 0 was already set?!");
+ */
+static inline bool jbit_set(struct jbitset *set, size_t index)
+{
+ return Judy1Set(&set->judy, index, &set->err);
+}
+
+/**
+ * jbit_clear - clear a bit in the bitset.
+ * @set: bitset from jbit_new
+ * @index: the index to set
+ *
+ * Returns the old bit value (ie. false if nothing changed).
+ *
+ * Example:
+ * if (jbit_clear(set, 0))
+ * err(1, "Bit 0 was already clear?!");
+ */
+static inline bool jbit_clear(struct jbitset *set, size_t index)
+{
+ return Judy1Unset(&set->judy, index, &set->err);
+}
+
+/**
+ * jbit_popcount - get population of (some part of) bitset.
+ * @set: bitset from jbit_new
+ * @start: first index to count
+ * @end_incl: last index to count (use -1 for end).
+ *
+ * Example:
+ * assert(jbit_popcount(set, 0, 1000) <= jbit_popcount(set, 0, 2000));
+ */
+static inline size_t jbit_popcount(const struct jbitset *set,
+ size_t start, size_t end_incl)
+{
+ return Judy1Count(set->judy, start, end_incl, (JError_t *)&set->err);
+}
+
+/**
+ * jbit_nth - return the index of the nth bit which is set.
+ * @set: bitset from jbit_new
+ * @n: which bit we are interested in (0-based)
+ * @invalid: what to return if n >= set population
+ *
+ * This normally returns the nth bit in the set, and often there is a
+ * convenient known-invalid value (ie. something which is never in the
+ * set). Otherwise, and a wrapper function like this can be used:
+ *
+ * static bool jbit_nth_index(struct jbitset *set, size_t n, size_t *idx)
+ * {
+ * // Zero might be valid, if it's first in set.
+ * if (n == 0 && jbit_test(set, 0)) {
+ * *idx = 0;
+ * return true;
+ * }
+ * *idx = jbit_nth(set, n, 0);
+ * return (*idx != 0);
+ * }
+ *
+ * Example:
+ * size_t i, val;
+ *
+ * // We know 0 isn't in set.
+ * assert(!jbit_test(set, 0));
+ * for (i = 0; (val = jbit_nth(set, i, 0)) != 0; i++) {
+ * assert(jbit_popcount(set, 0, val) == i);
+ * printf("Value %zu = %zu\n", i, val);
+ * }
+ */
+static inline size_t jbit_nth(const struct jbitset *set,
+ size_t n, size_t invalid)
+{
+ Word_t index;
+ if (!Judy1ByCount(set->judy, n+1, &index, (JError_t *)&set->err))
+ index = invalid;
+ return index;
+}
+
+/**
+ * jbit_first - return the first bit which is set.
+ * @set: bitset from jbit_new
+ * @invalid: return value if no bits are set at all.
+ *
+ * This is equivalent to jbit_nth(set, 0, invalid).
+ *
+ * Example:
+ * assert(!jbit_test(set, 0));
+ * printf("Set contents (increasing order):");
+ * for (i = jbit_first(set, 0); i; i = jbit_next(set, i, 0))
+ * printf(" %zu", i);
+ * printf("\n");
+ */
+static inline size_t jbit_first(const struct jbitset *set, size_t invalid)
+{
+ Word_t index = 0;
+ if (!Judy1First(set->judy, &index, (JError_t *)&set->err))
+ index = invalid;
+ else
+ assert(index != invalid);
+ return index;
+}
+
+/**
+ * jbit_next - return the next bit which is set.
+ * @set: bitset from jbit_new
+ * @prev: previous index
+ * @invalid: return value if no bits are set at all.
+ *
+ * This is usually used to find an adjacent bit which is set, after
+ * jbit_first.
+ */
+static inline size_t jbit_next(const struct jbitset *set, size_t prev,
+ size_t invalid)
+{
+ if (!Judy1Next(set->judy, (Word_t *)&prev, (JError_t *)&set->err))
+ prev = invalid;
+ else
+ assert(prev != invalid);
+ return prev;
+}
+
+/**
+ * jbit_last - return the last bit which is set.
+ * @set: bitset from jbit_new
+ * @invalid: return value if no bits are set at all.
+ *
+ * Example:
+ * assert(!jbit_test(set, 0));
+ * printf("Set contents (decreasing order):");
+ * for (i = jbit_last(set, 0); i; i = jbit_prev(set, i, 0))
+ * printf(" %zu", i);
+ * printf("\n");
+ */
+static inline size_t jbit_last(const struct jbitset *set, size_t invalid)
+{
+ Word_t index = -1;
+ if (!Judy1Last(set->judy, &index, (JError_t *)&set->err))
+ index = invalid;
+ else
+ assert(index != invalid);
+ return index;
+}
+
+/**
+ * jbit_prev - return the previous bit which is set.
+ * @set: bitset from jbit_new
+ * @prev: previous index
+ * @invalid: return value if no bits are set at all.
+ *
+ * This is usually used to find an adjacent bit which is set, after
+ * jbit_last.
+ */
+static inline size_t jbit_prev(const struct jbitset *set, size_t prev,
+ size_t invalid)
+{
+ if (!Judy1Prev(set->judy, (Word_t *)&prev, (JError_t *)&set->err))
+ prev = invalid;
+ else
+ assert(prev != invalid);
+ return prev;
+}
+
+/**
+ * jbit_first_clear - return the first bit which is unset.
+ * @set: bitset from jbit_new
+ * @invalid: return value if no bits are clear at all.
+ *
+ * This allows for iterating the inverse of the bitmap.
+ */
+static inline size_t jbit_first_clear(const struct jbitset *set,
+ size_t invalid)
+{
+ Word_t index = 0;
+ if (!Judy1FirstEmpty(set->judy, &index, (JError_t *)&set->err))
+ index = invalid;
+ else
+ assert(index != invalid);
+ return index;
+}
+
+static inline size_t jbit_next_clear(const struct jbitset *set, size_t prev,
+ size_t invalid)
+{
+ if (!Judy1NextEmpty(set->judy, (Word_t *)&prev, (JError_t *)&set->err))
+ prev = invalid;
+ else
+ assert(prev != invalid);
+ return prev;
+}
+
+static inline size_t jbit_last_clear(const struct jbitset *set, size_t invalid)
+{
+ Word_t index = -1;
+ if (!Judy1LastEmpty(set->judy, &index, (JError_t *)&set->err))
+ index = invalid;
+ else
+ assert(index != invalid);
+ return index;
+}
+
+static inline size_t jbit_prev_clear(const struct jbitset *set, size_t prev,
+ size_t invalid)
+{
+ if (!Judy1PrevEmpty(set->judy, (Word_t *)&prev, (JError_t *)&set->err))
+ prev = invalid;
+ else
+ assert(prev != invalid);
+ return prev;
+}
+#endif /* CCAN_JBITSET_H */
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