132 lines
3.5 KiB
C
132 lines
3.5 KiB
C
#ifndef _UTILS_H
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#define _UTILS_H
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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#include <stdlib.h>
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#define PAGE_SHIFT 12
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#define PAGE_SIZE (1 << PAGE_SHIFT)
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#define PAGE_MASK (~(PAGE_SIZE-1))
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//#define NULL (void *) 0
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#define ___PASTE(a,b) a##b
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//#define __PASTE(a,b) ___PASTE(a,b)
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#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
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#define __min(t1, t2, min1, min2, x, y) ({ \
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t1 min1 = (x); \
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t2 min2 = (y); \
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(void) (&min1 == &min2); \
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min1 < min2 ? min1 : min2; })
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#define min(x, y) \
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__min(typeof(x), typeof(y), \
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__UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \
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x, y)
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#define __max(t1, t2, max1, max2, x, y) ({ \
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t1 max1 = (x); \
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t2 max2 = (y); \
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(void) (&max1 == &max2); \
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max1 > max2 ? max1 : max2; })
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#define max(x, y) \
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__max(typeof(x), typeof(y), \
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__UNIQUE_ID(max1_), __UNIQUE_ID(max2_), \
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x, y)
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#define min3(x, y, z) min((typeof(x))min(x, y), z)
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#define max3(x, y, z) max((typeof(x))max(x, y), z)
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/**
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* min_not_zero - return the minimum that is _not_ zero, unless both are zero
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* @x: value1
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* @y: value2
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*/
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#define min_not_zero(x, y) ({ \
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typeof(x) __x = (x); \
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typeof(y) __y = (y); \
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__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
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/**
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* clamp - return a value clamped to a given range with strict typechecking
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* @val: current value
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* @lo: lowest allowable value
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* @hi: highest allowable value
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*
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* This macro does strict typechecking of lo/hi to make sure they are of the
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* same type as val. See the unnecessary pointer comparisons.
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*/
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#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
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/*
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* ..and if you can't take the strict
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* types, you can specify one yourself.
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*
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* Or not use min/max/clamp at all, of course.
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*/
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#define min_t(type, x, y) \
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__min(type, type, \
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__UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \
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x, y)
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#define max_t(type, x, y) \
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__max(type, type, \
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__UNIQUE_ID(min1_), __UNIQUE_ID(min2_), \
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x, y)
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/**
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* clamp_t - return a value clamped to a given range using a given type
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* @type: the type of variable to use
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* @val: current value
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* @lo: minimum allowable value
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* @hi: maximum allowable value
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*
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* This macro does no typechecking and uses temporary variables of type
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* 'type' to make all the comparisons.
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*/
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#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
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/**
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* clamp_val - return a value clamped to a given range using val's type
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* @val: current value
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* @lo: minimum allowable value
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* @hi: maximum allowable value
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*
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* This macro does no typechecking and uses temporary variables of whatever
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* type the input argument 'val' is. This is useful when val is an unsigned
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* type and min and max are literals that will otherwise be assigned a signed
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* integer type.
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*/
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#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
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/*
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* swap - swap value of @a and @b
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*/
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#define swap(a, b) \
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do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
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/**
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* container_of - cast a member of a structure out to the containing structure
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* @ptr: the pointer to the member.
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* @type: the type of the container struct this is embedded in.
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* @member: the name of the member within the struct.
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*
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*/
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//#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
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#define container_of(ptr, type, member) ({ \
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const typeof( ((type *)0)->member ) *__mptr = (ptr); \
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(type *)( (char *)__mptr - offsetof(type,member) );})
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#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
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#endif
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