/**
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef ALGO_ALGORITHMS_ARRAYS_MINMAX_H
#define ALGO_ALGORITHMS_ARRAYS_MINMAX_H
/* NB! This will not play nice if the placeholder `T` is
* not set to a type only containing [0-9A-Za-z_] (and $
* in GNU C). Therefore, with the exception of `char`,
* `short`, `int`, `long`, `float` and `double`, you
* should only use `typedef`:ed types. */
#include <stddef.h>
/**
* Find the minimum and maximum values in an array.
*
* `algo_make_implementation_of_get_bounds(T)` is used to make
* this function available for a particular data type `T`. And
* implementation without modifiers and attributes will be
* expanded. You may add `static`, `inline` and `__attribute__`
* before calling `algo_make_implementation_of_get_bounds(T)`.
*
* `algo_make_prototype_of_get_bounds(T)` is the prototype
* counterpart of `algo_make_implementation_of_get_bounds(T)`.
* It too is will not add any modifiers or attributes by
* default. It will neither add a semicolon at the end of
* the prototype.
*
* `algo_get_bounds(T)` is used to get the version of the
* function that supports the data type `T`.
* `&(algo_get_bounds(T))` gets the address of this function
* and `algo_get_bounds(T)(items, n, min, max)` calls the
* function.
*
* This function is not pure since it will edit the value
* of `min` and `max`. This function does not accept `NULL`
* arguments, if you are using GCC you should add
* `__attribute__((nonnull))` to its prototype.
*
* Undefined behaviour is invoked `n == 0`.
*
* @param items The items over to search.
* @param n The number of elements in `items`.
* @param min Output parameter for the minimum value.
* @param max Output parameter for the maximum value.
*/
//>fun () {
void algo_get_bounds__##T(const T* restrict items, size_t n, T* min, T* max)
{
const T* end = items + n;
T maxv, minv, cur;
size_t i;
max = min = *items++;
while (items != end)
{
cur = *items++;
if (cur > maxv) maxv = cur;
else if (cur < minv) minv = cur;
}
*min = min;
*max = max;
}
//>} ; . ../make_fun
/**
* Find the minimum and maximum values in an array.
*
* This variant of `algo_get_bounds` is suitable for
* non-numeric data.
*
* `algo_make_implementation_of_get_bounds_cmp(T)` is used to make
* this function available for a particular data type `T`. And
* implementation without modifiers and attributes will be
* expanded. You may add `static`, `inline` and `__attribute__`
* before calling `algo_make_implementation_of_get_bounds_cmp(T)`.
*
* `algo_make_prototype_of_get_bounds_cmp(T)` is the prototype
* counterpart of `algo_make_implementation_of_get_bounds_cmp(T)`.
* It too is will not add any modifiers or attributes by
* default. It will neither add a semicolon at the end of
* the prototype.
*
* `algo_get_bounds_cmp(T)` is used to get the version of the
* function that supports the data type `T`.
* `&(algo_get_bounds_cmp(T))` gets the address of this function
* and `algo_get_bounds_cmp(T)(items, n, cmp, min, max)` calls
* the function.
*
* This function is not pure since it will edit the value
* of `min` and `max`, and `cmp` is not necessarily pure.
* This function does not accept `NULL` arguments, if you
* are using GCC you should add `__attribute__((nonnull))`
* to its prototype.
*
* Undefined behaviour is invoked `n == 0`.
*
* @param items The items over to search.
* @param n The number of elements in `items`.
* @param cmp Function used to compare two items, it should return a.
* negative value if its first parameter is the lesser, a.
* positive value if its second parameter is the lesser.
* and zero if the parameters are equal.
* @param min Output parameter for the minimum value.
* @param max Output parameter for the maximum value.
*/
//>fun () {
void algo_get_bounds_cmp__##T(const T* restrict items, size_t n,
int (*cmp)(const T*, const T*),
T* min, T* max)
{
const T* end = items + n;
T maxv, minv, cur;
size_t i;
max = min = *items++;
while (items != end)
{
cur = *items++;
if (cmp(cur, maxv) > 0) maxv = cur;
else if (cmp(cur, minv) < 0) minv = cur;
}
*min = min;
*max = max;
}
//>} ; . ../make_fun
/**
* Find the minimum and maximum values in an array.
*
* This variant of `algo_get_bounds_cmp` allows you to
* store data needed for the comparison in a thread-safe
* way. It is reentrant.
*
* `algo_make_implementation_of_get_bounds_cmp_r(T)` is used to make
* this function available for a particular data type `T`. And
* implementation without modifiers and attributes will be
* expanded. You may add `static`, `inline` and `__attribute__`
* before calling `algo_make_implementation_of_get_bounds_cmp_r(T)`.
*
* `algo_make_prototype_of_get_bounds_cmp(T)` is the prototype
* counterpart of `algo_make_implementation_of_get_bounds_cmp_r(T)`.
* It too is will not add any modifiers or attributes by
* default. It will neither add a semicolon at the end of
* the prototype.
*
* `algo_get_bounds_cmp_r(T)` is used to get the version of the
* function that supports the data type `T`.
* `&(algo_get_bounds_cmp_r(T))` gets the address of this function
* and `algo_get_bounds_cmp_r(T)(items, n, cmp, data, min, max)`
* calls the function.
*
* This function is not pure since it will edit the value
* of `min` and `max`, and `cmp` is not necessarily pure.
* This function does not accept `NULL` arguments, if you
* are using GCC you should add `__attribute__((nonnull))`
* to its prototype.
*
* Undefined behaviour is invoked `n == 0`.
*
* @param items The items over to search.
* @param n The number of elements in `items`.
* @param cmp Function used to compare two items, it should return a
* negative value if its first parameter is the lesser, a
* positive value if its second parameter is the lesser
* and zero if the parameters are equal. `data` will be
* input as `cmp`'s third argument.
* @param data Arbitrary data (may be `NULL`) to pass throught to `cmp`.
* @param min Output parameter for the minimum value.
* @param max Output parameter for the maximum value.
*/
//>fun () {
void algo_get_bounds_cmp_r__##T(const T* restrict items, size_t n,
int (*cmp)(const T*, const T*, void*),
void* data, T* min, T* max)
{
const T* end = items + n;
T maxv, minv, cur;
size_t i;
max = min = *items++;
while (items != end)
{
cur = *items++;
if (cmp(cur, maxv, data) > 0) maxv = cur;
else if (cmp(cur, minv, data) < 0) minv = cur;
}
*min = min;
*max = max;
}
//>} ; . ../make_fun
#endif
