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-rw-r--r--include/linux/util_macros.h53
1 files changed, 53 insertions, 0 deletions
diff --git a/include/linux/util_macros.h b/include/linux/util_macros.h
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+++ b/include/linux/util_macros.h
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+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_HELPER_MACROS_H_
+#define _LINUX_HELPER_MACROS_H_
+
+#define __find_closest(x, a, as, op) \
+({ \
+ typeof(as) __fc_i, __fc_as = (as) - 1; \
+ typeof(x) __fc_x = (x); \
+ typeof(*a) const *__fc_a = (a); \
+ for (__fc_i = 0; __fc_i < __fc_as; __fc_i++) { \
+ if (__fc_x op DIV_ROUND_CLOSEST(__fc_a[__fc_i] + \
+ __fc_a[__fc_i + 1], 2)) \
+ break; \
+ } \
+ (__fc_i); \
+})
+
+/**
+ * find_closest - locate the closest element in a sorted array
+ * @x: The reference value.
+ * @a: The array in which to look for the closest element. Must be sorted
+ * in ascending order.
+ * @as: Size of 'a'.
+ *
+ * Returns the index of the element closest to 'x'.
+ */
+#define find_closest(x, a, as) __find_closest(x, a, as, <=)
+
+/**
+ * find_closest_descending - locate the closest element in a sorted array
+ * @x: The reference value.
+ * @a: The array in which to look for the closest element. Must be sorted
+ * in descending order.
+ * @as: Size of 'a'.
+ *
+ * Similar to find_closest() but 'a' is expected to be sorted in descending
+ * order.
+ */
+#define find_closest_descending(x, a, as) __find_closest(x, a, as, >=)
+
+/**
+ * is_insidevar - check if the @ptr points inside the @var memory range.
+ * @ptr: the pointer to a memory address.
+ * @var: the variable which address and size identify the memory range.
+ *
+ * Evaluates to true if the address in @ptr lies within the memory
+ * range allocated to @var.
+ */
+#define is_insidevar(ptr, var) \
+ ((uintptr_t)(ptr) >= (uintptr_t)(var) && \
+ (uintptr_t)(ptr) < (uintptr_t)(var) + sizeof(var))
+
+#endif