auto import from //depot/cupcake/@135843
diff --git a/tools/apriori/rangesort.h b/tools/apriori/rangesort.h
new file mode 100644
index 0000000..21db357
--- /dev/null
+++ b/tools/apriori/rangesort.h
@@ -0,0 +1,105 @@
+#ifndef RANGESORT_H
+#define RANGESORT_H
+
+/* This implements a simple sorted list of non-overlapping ranges. */
+
+#include <debug.h>
+#include <common.h>
+#include <gelf.h>
+
+typedef enum range_error_t {
+ ERROR_CONTAINS,
+ ERROR_OVERLAPS
+} range_error_t;
+
+typedef struct range_t range_t;
+struct range_t {
+ GElf_Off start;
+ GElf_Off length;
+ void *user;
+ void (*err_fn)(range_error_t, range_t *, range_t *);
+ void (*user_dtor)(void *);
+};
+
+typedef struct range_list_t range_list_t;
+
+range_list_t* init_range_list();
+void destroy_range_list(range_list_t *);
+
+/* Just adds a range to the list. We won't detect whether the range overlaps
+ other ranges or contains them, or is contained by them, till we call
+ sort_ranges(). */
+void add_unique_range_nosort(range_list_t *ranges,
+ GElf_Off start, GElf_Off length,
+ void *user,
+ void (*err_fn)(range_error_t, range_t *, range_t *),
+ void (*user_dtor)(void * ));
+
+/* Sorts the ranges. If there are overlapping ranges or ranges that contain
+ other ranges, it will cause the program to exit with a FAIL. */
+range_list_t* sort_ranges(range_list_t *ranges);
+/* Find which range value falls in. Return that range or NULL if value does
+ not fall within any range. */
+range_t *find_range(range_list_t *ranges, GElf_Off value);
+int get_num_ranges(const range_list_t *ranges);
+range_t *get_sorted_ranges(const range_list_t *ranges, int *num_ranges);
+GElf_Off get_last_address(const range_list_t *ranges);
+
+/* This returns a range_list_t handle that contains ranges composed of the
+ adjacent ranges of the input range list. The user data of each range in
+ the range list is a structure of the type contiguous_range_info_t.
+ This structure contains an array of pointers to copies of the original
+ range_t structures comprising each new contiguous range, as well as the
+ length of that array.
+
+ NOTE: The input range must be sorted!
+
+ NOTE: destroy_range_list() will take care of releasing the data that it
+ allocates as a result of calling get_contiguous_ranges(). Do not free that
+ data yourself.
+
+ NOTE: the user data of the original range_t structures is simply copied, so
+ be careful handling it. You can destroy the range_list_t with
+ destroy_range_list() as usual. On error, the function does not return--the
+ program terminates.
+
+ NOTE: The returned range is not sorted. You must call sort_ranges() if you
+ need to.
+*/
+
+typedef struct {
+ int num_ranges;
+ range_t *ranges;
+} contiguous_range_info_t;
+
+range_list_t* get_contiguous_ranges(const range_list_t *);
+
+/* The function below takes in two range lists: r and s, and subtracts the
+ ranges in s from those in r. For example, if r and s are as follows:
+
+ r = { [0, 10) }
+ s = { [3, 5), [7, 9) }
+
+ Then r - s is { [0, 3), [5, 7), [9, 10) }
+
+ NOTE: Both range lists must be sorted on input. This is guarded by an
+ assertion.
+
+ NOTE: Range s must contain ranges, which are fully contained by the span of
+ range r (the span being the interval between the start of the lowest
+ range in r, inclusive, and the end of the highest range in r,
+ exclusive).
+
+ NOTE: In addition to the requirement above, range s must contain ranges,
+ each of which is a subrange of one of the ranges of r.
+
+ NOTE: There is no user info associated with the resulting range.
+
+ NOTE: The resulting range is not sorted.
+
+ Ther returned list must be destroyed with destroy_range_list().
+*/
+
+range_list_t* subtract_ranges(const range_list_t *r, const range_list_t *s);
+
+#endif/*RANGESORT_H*/