utilities: bsearch and qsort with additional user_data pointer argument

src/utils.c

@@ -116,3 +116,193 @@ void* obi_get_memory_aligned_on_16(int size, int* shift)
 	return (memory);
 }
 
+
+/*
+ * A generic implementation of binary search for the Linux kernel
+ *
+ * Copyright (C) 2008-2009 Ksplice, Inc.
+ * Author: Tim Abbott <tabbott@ksplice.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2.
+ */
+void* bsearch_user_data(const void* key, const void* base, size_t num, size_t size, const void* user_data,
+              	  	  	int (*cmp)(const void *key, const void *elt, const void* user_data))
+{
+	size_t start = 0;
+	size_t end   = num;
+	size_t mid;
+    int result;
+
+    while (start < end)
+    {
+    	mid = start + (end - start) / 2;
+    	result = cmp(key, base + mid * size, user_data);
+		if (result < 0)
+			end = mid;
+		else if (result > 0)
+			start = mid + 1;
+		else
+			return (void*)base + mid * size;
+    }
+
+    return NULL;
+}
+
+
+/*
+ * Copyright (c) 1992, 1993
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
+ */
+
+#define MIN(a,b) ((a) < (b) ? a : b)
+
+#define swapcode(TYPE, parmi, parmj, n) {               \
+        long i = (n) / sizeof (TYPE);                   \
+        register TYPE *pi = (TYPE *) (parmi);           \
+        register TYPE *pj = (TYPE *) (parmj);           \
+        do {                                            \
+                register TYPE   t = *pi;                \
+                *pi++ = *pj;                            \
+                *pj++ = t;                              \
+        } while (--i > 0);                              \
+}
+
+#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
+        es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
+
+static __inline void
+swapfunc(char *a, char *b, int n, int swaptype)
+{
+        if (swaptype <= 1)
+                swapcode(long, a, b, n)
+        else
+                swapcode(char, a, b, n)
+}
+
+#define swap(a, b)                                      \
+        if (swaptype == 0) {                            \
+                long t = *(long *)(a);                  \
+                *(long *)(a) = *(long *)(b);            \
+                *(long *)(b) = t;                       \
+        } else                                          \
+                swapfunc(a, b, es, swaptype)
+
+#define vecswap(a, b, n)        if ((n) > 0) swapfunc(a, b, n, swaptype)
+
+static __inline char *
+med3(char *a, char *b, char *c, const void *user_data, int (*cmp)(const void *, const void *, const void *))
+{
+        return cmp(a, b, user_data) < 0 ?
+               (cmp(b, c, user_data) < 0 ? b : (cmp(a, c, user_data) < 0 ? c : a ))
+              :(cmp(b, c, user_data) > 0 ? b : (cmp(a, c, user_data) < 0 ? a : c ));
+}
+
+void
+qsort_user_data(void *aa, size_t n, size_t es, const void *user_data, int (*cmp)(const void *, const void *, const void *))
+{
+        char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+        int d, r, swaptype, swap_cnt;
+        register char *a = aa;
+
+loop:   SWAPINIT(a, es);
+        swap_cnt = 0;
+        if (n < 7) {
+                for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
+                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl, user_data) > 0;
+                             pl -= es)
+                                swap(pl, pl - es);
+                return;
+        }
+        pm = (char *)a + (n / 2) * es;
+        if (n > 7) {
+                pl = (char *)a;
+                pn = (char *)a + (n - 1) * es;
+                if (n > 40) {
+                        d = (n / 8) * es;
+                        pl = med3(pl, pl + d, pl + 2 * d, user_data, cmp);
+                        pm = med3(pm - d, pm, pm + d, user_data, cmp);
+                        pn = med3(pn - 2 * d, pn - d, pn, user_data, cmp);
+                }
+                pm = med3(pl, pm, pn, user_data, cmp);
+        }
+        swap(a, pm);
+        pa = pb = (char *)a + es;
+
+        pc = pd = (char *)a + (n - 1) * es;
+        for (;;) {
+                while (pb <= pc && (r = cmp(pb, a, user_data)) <= 0) {
+                        if (r == 0) {
+                                swap_cnt = 1;
+                                swap(pa, pb);
+                                pa += es;
+                        }
+                        pb += es;
+                }
+                while (pb <= pc && (r = cmp(pc, a, user_data)) >= 0) {
+                        if (r == 0) {
+                                swap_cnt = 1;
+                                swap(pc, pd);
+                                pd -= es;
+                        }
+                        pc -= es;
+                }
+                if (pb > pc)
+                        break;
+                swap(pb, pc);
+                swap_cnt = 1;
+                pb += es;
+                pc -= es;
+        }
+        if (swap_cnt == 0) {  /* Switch to insertion sort */
+                for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
+                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl, user_data) > 0;
+                             pl -= es)
+                                swap(pl, pl - es);
+                return;
+        }
+
+        pn = (char *)a + n * es;
+        r = MIN(pa - (char *)a, pb - pa);
+        vecswap(a, pb - r, r);
+        r = MIN((long)(pd - pc), (long)(pn - pd - es));
+        vecswap(pb, pn - r, r);
+        if ((r = pb - pa) > (int)es)
+                qsort_user_data(a, r / es, es, user_data, cmp);
+        if ((r = pd - pc) > (int)es) {
+                /* Iterate rather than recurse to save stack space */
+                a = pn - r;
+                n = r / es;
+                goto loop;
+        }
+/*              qsort(pn - r, r / es, es, cmp);*/
+}
+

src/utils.h

@@ -74,4 +74,41 @@ char* obi_format_date(time_t date);
 void* obi_get_memory_aligned_on_16(int size, int* shift);
 
 
+/**
+ * @brief Version of quick sort modified to allow the user to provide an
+ *        additional pointer sent to the comparison function.
+ *
+ * @param key This is the pointer to the object that serves as key for the search, type-casted as a void*.
+ * @param base This is the pointer to the first object of the array where the search is performed, type-casted as a void*.
+ * @param num This is the number of elements in the array pointed by base.
+ * @param size This is the size in bytes of each element in the array.
+ * @param user_data This is an additional pointer passed to the comparison function.
+ * @param cmp This is the function that compares two elements, eventually with an additional pointer.
+ *
+ * @returns A pointer to an entry in the array that matches the search key.
+ * @retval NULL if key is not found.
+ *
+ * @since January 2017
+ * @author original code modified by Celine Mercier (celine.mercier@metabarcoding.org)
+ */
+void* bsearch_user_data(const void* key, const void* base, size_t num, size_t size, const void* user_data,
+              	  	  	int (*cmp)(const void *key, const void *elt, const void* user_data));
+
+
+/**
+ * @brief Version of quick sort modified to allow the user to provide an
+ *        additional pointer sent to the comparison function.
+ *
+ * @param aa This is the pointer to the first element of the array to be sorted.
+ * @param n This is the number of elements in the array pointed by base.
+ * @param es This is the size in bytes of each element in the array.
+ * @param user_data This is an additional pointer passed to the comparison function.
+ * @param cmp This is the function that compares two elements, eventually with an additional pointer.
+ *
+ * @since January 2017
+ * @author original code modified by Celine Mercier (celine.mercier@metabarcoding.org)
+ */
+void qsort_user_data(void *aa, size_t n, size_t es, const void *user_data, int (*cmp)(const void *, const void *, const void *));
+
+
 #endif /* UTILS_H_ */