c ports of the array algorithms

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 250 insertions, 0 deletions

diff --git a/csrc/algorithms/arrays/sorted.h b/csrc/algorithms/arrays/sorted.h
new file mode 100644
index 0000000..71037ab
--- /dev/null
+++ b/csrc/algorithms/arrays/sorted.h
@@ -0,0 +1,250 @@
+/**
+ * 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_SORTED_H
+#define ALGO_ALGORITHMS_ARRAYS_SORTED_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>
+
+
+/**
+ * The order elements are sorted in.
+ */
+typedef enum algo_sorted_order
+  {
+    /**
+       The array is not sorted.
+     */
+    UNORDERED,
+    
+    /**
+     * The array is sorted in ascending (normal) order.
+     */
+    ASCENDING_ORDER,
+    
+    /**
+     * The array is sorted in descending (reverse normal) order.
+     */
+    DESCENDING_ORDER,
+    
+    /**
+     * All elements in the array are mutually equal or the array
+     * contains less than two elements. This is the bitwise OR of
+     * `ASCENDING_ORDER` and `DESCENDING_ORDER`.
+     */
+    FLAT
+    
+  } algo_sorted_order_t;
+
+
+/**
+ * Gets whether an array is sorted and in which order it is sorted.
+ * 
+ * `algo_make_implementation_of_is_sorted(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_is_sorted(T)`.
+ * 
+ * `algo_make_prototype_of_is_sorted(T)` is the prototype
+ * counterpart of `algo_make_implementation_of_is_sorted(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_is_sorted(T)` is used to get the version of the
+ * function that supports the data type `T`.
+ * `&(algo_is_sorted(T))` gets the address of this function
+ * and `algo_is_sorted(T)(items, n)` calls the function.
+ * 
+ * This function is pure, if you use GCC you should add
+ * `__attribute__((pure))` to its prototype.
+ * 
+ * @param   items  The items to check if they are ordered.
+ * @param   n      The number of elements in `items`.
+ * @return         The order elements are sorted in.
+ */
+//>fun () {
+algo_sorted_order_t algo_is_sorted__##T(const T* restrict items, size_t n)
+{
+  const T* end = items + n;
+  T last, cur;
+  algo_sorted_order_t order = FLAT;
+  
+  if (n == 0)
+    return FLAT;
+  
+  for (last = *items++; items != end; last = cur)
+    if (cur = *items++, last < cur)
+      {
+	if      (order == FLAT)              order = ASCENDING_ORDER;
+	else if (order == DESCENDING_ORDER)  return UNORDERED;
+      }
+    else if (last > cur)
+      {
+	if      (order == FLAT)             order = DESCENDING_ORDER;
+	else if (order == ASCENDING_ORDER)  return UNORDERED;
+      }
+  
+  return order;
+}
+//>} ; . ../make_fun
+
+
+/**
+ * Gets whether an array is sorted and in which order it is sorted.
+ * 
+ * This variant of `algo_is_sorted` is suitable for
+ * non-numeric data.
+ * 
+ * `algo_make_implementation_of_is_sorted_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_is_sorted_cmp(T)`.
+ * 
+ * `algo_make_prototype_of_is_sorted_cmp(T)` is the prototype
+ * counterpart of `algo_make_implementation_of_is_sorted_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_is_sorted_cmp(T)` is used to get the version of the
+ * function that supports the data type `T`.
+ * `&(algo_is_sorted_cmp(T))` gets the address of this function
+ * and `algo_is_sorted_cmp(T)(items, n, cmp)` calls the function.
+ * 
+ * This function is not pure because `cmp` is not necessarily pure.
+ * 
+ * @param   items  The items to check if they are ordered.
+ * @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.
+ * @return         The order elements are sorted in.
+ */
+//>fun () {
+algo_sorted_order_t algo_is_sorted_cmp__##T(const T* restrict items, size_t n,
+					    int (*cmp)(const T*, const T*))
+{
+  const T* end = items + n;
+  T last, cur;
+  algo_sorted_order_t order = FLAT;
+  int comparison;
+  
+  if (n == 0)
+    return FLAT;
+  
+  for (last = *items++; items != end; last = cur)
+    {
+      comparison = cmp(last, cur = *items++);
+      if (comparison < 0)
+	{
+	  if      (order == FLAT)              order = ASCENDING_ORDER;
+	  else if (order == DESCENDING_ORDER)  return UNORDERED;
+	}
+      else if (comparison > 0)
+	{
+	  if      (order == FLAT)             order = DESCENDING_ORDER;
+	  else if (order == ASCENDING_ORDER)  return UNORDERED;
+	}
+    }
+  
+  return order;
+}
+//>} ; . ../make_fun
+
+
+/**
+ * Gets whether an array is sorted and in which order it is sorted.
+ * 
+ * This variant of `algo_is_sorted_cmp` allows you to
+ * store data needed for the comparison in a thread-safe
+ * way. It is reentrant.
+ * 
+ * `algo_make_implementation_of_is_sorted_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_is_sorted_cmp_r(T)`.
+ * 
+ * `algo_make_prototype_of_is_sorted_cmp_r(T)` is the prototype
+ * counterpart of `algo_make_implementation_of_is_sorted_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_is_sorted_cmp_r(T)` is used to get the version of the
+ * function that supports the data type `T`.
+ * `&(algo_is_sorted_cmp_r(T))` gets the address of this function
+ * and `algo_is_sorted_cmp_r(T)(items, n, cmp)` calls the function.
+ * 
+ * This function is not pure because `cmp` is not necessarily pure.
+ * 
+ * @param   items  The items to check if they are ordered.
+ * @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`.
+ *                 and zero if the parameters are equal.
+ * @return         The order elements are sorted in.
+ */
+//>fun () {
+algo_sorted_order_t algo_is_sorted_cmp_r__##T(const T* restrict items, size_t n,
+					    int (*cmp)(const T*, const T*, void*), void* data)
+{
+  const T* end = items + n;
+  T last, cur;
+  algo_sorted_order_t order = FLAT;
+  int comparison;
+  
+  if (n == 0)
+    return FLAT;
+  
+  for (last = *items++; items != end; last = cur)
+    {
+      comparison = cmp(last, cur = *items++, data);
+      if (comparison < 0)
+	{
+	  if      (order == FLAT)              order = ASCENDING_ORDER;
+	  else if (order == DESCENDING_ORDER)  return UNORDERED;
+	}
+      else if (comparison > 0)
+	{
+	  if      (order == FLAT)             order = DESCENDING_ORDER;
+	  else if (order == ASCENDING_ORDER)  return UNORDERED;
+	}
+    }
+  
+  return order;
+}
+//>} ; . ../make_fun
+
+
+#endif
+