feat(libc): import qsort implementation
Import qsort implementation from FreeBSD[1] to libc.
[1]: https://cgit.freebsd.org/src/tree/lib/libc/stdlib/qsort.c
Change-Id: Ia0d8e2d1c40c679844c0746db1b669cda672a482
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/include/lib/libc/cdefs.h b/include/lib/libc/cdefs.h
index b11d072..97b7824 100644
--- a/include/lib/libc/cdefs.h
+++ b/include/lib/libc/cdefs.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2018-2022, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2025, Arm Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -36,4 +36,7 @@
#define __STRING(x) #x
#define __XSTRING(x) __STRING(x)
+#define __predict_true(exp) (exp)
+#define __predict_false(exp) (exp)
+
#endif /* CDEFS_H */
diff --git a/include/lib/libc/stdlib.h b/include/lib/libc/stdlib.h
index 4e5a824..cf30ef3 100644
--- a/include/lib/libc/stdlib.h
+++ b/include/lib/libc/stdlib.h
@@ -29,4 +29,6 @@
unsigned long strtoul(const char *nptr, char **endptr, int base);
long long strtoll(const char *nptr, char **endptr, int base);
unsigned long long strtoull(const char *nptr, char **endptr, int base);
+void qsort(void *, size_t, size_t,
+ int (* _Nonnull)(const void *, const void *));
#endif /* STDLIB_H */
diff --git a/lib/libc/libc_common.mk b/lib/libc/libc_common.mk
index 4879818..5f44bd5 100644
--- a/lib/libc/libc_common.mk
+++ b/lib/libc/libc_common.mk
@@ -1,5 +1,5 @@
#
-# Copyright (c) 2024, Arm Limited and Contributors. All rights reserved.
+# Copyright (c) 2024-2025, Arm Limited and Contributors. All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
#
@@ -17,6 +17,7 @@
printf.c \
putchar.c \
puts.c \
+ qsort.c \
snprintf.c \
strchr.c \
strcmp.c \
diff --git a/lib/libc/qsort.c b/lib/libc/qsort.c
new file mode 100644
index 0000000..40569f4
--- /dev/null
+++ b/lib/libc/qsort.c
@@ -0,0 +1,261 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * 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.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(I_AM_QSORT_R)
+typedef int cmp_t(const void *, const void *, void *);
+#elif defined(I_AM_QSORT_R_COMPAT)
+typedef int cmp_t(void *, const void *, const void *);
+#elif defined(I_AM_QSORT_S)
+typedef int cmp_t(const void *, const void *, void *);
+#else
+typedef int cmp_t(const void *, const void *);
+#endif
+static inline char *med3(char *, char *, char *, cmp_t *, void *);
+
+#define MIN(a, b) ((a) < (b) ? a : b)
+
+/*
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
+ */
+
+static inline void
+swapfunc(char *a, char *b, size_t es)
+{
+ char t;
+
+ do {
+ t = *a;
+ *a++ = *b;
+ *b++ = t;
+ } while (--es > 0);
+}
+
+#define vecswap(a, b, n) \
+ if ((n) > 0) swapfunc(a, b, n)
+
+#if defined(I_AM_QSORT_R)
+#define CMP(t, x, y) (cmp((x), (y), (t)))
+#elif defined(I_AM_QSORT_R_COMPAT)
+#define CMP(t, x, y) (cmp((t), (x), (y)))
+#elif defined(I_AM_QSORT_S)
+#define CMP(t, x, y) (cmp((x), (y), (t)))
+#else
+#define CMP(t, x, y) (cmp((x), (y)))
+#endif
+
+static inline char *
+med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
+#if !defined(I_AM_QSORT_R) && !defined(I_AM_QSORT_R_COMPAT) && !defined(I_AM_QSORT_S)
+__unused
+#endif
+)
+{
+ return CMP(thunk, a, b) < 0 ?
+ (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
+ :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
+}
+
+/*
+ * The actual qsort() implementation is static to avoid preemptible calls when
+ * recursing. Also give them different names for improved debugging.
+ */
+#if defined(I_AM_QSORT_R)
+#define local_qsort local_qsort_r
+#elif defined(I_AM_QSORT_R_COMPAT)
+#define local_qsort local_qsort_r_compat
+#elif defined(I_AM_QSORT_S)
+#define local_qsort local_qsort_s
+#endif
+static void
+local_qsort(void *a, size_t n, size_t es, cmp_t *cmp, void *thunk)
+{
+ char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+ size_t d1, d2;
+ int cmp_result;
+ int swap_cnt;
+
+ /* if there are less than 2 elements, then sorting is not needed */
+ if (__predict_false(n < 2))
+ return;
+loop:
+ 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(thunk, pl - es, pl) > 0;
+ pl -= es)
+ swapfunc(pl, pl - es, es);
+ return;
+ }
+ pm = (char *)a + (n / 2) * es;
+ if (n > 7) {
+ pl = a;
+ pn = (char *)a + (n - 1) * es;
+ if (n > 40) {
+ size_t d = (n / 8) * es;
+
+ pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
+ pm = med3(pm - d, pm, pm + d, cmp, thunk);
+ pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
+ }
+ pm = med3(pl, pm, pn, cmp, thunk);
+ }
+ swapfunc(a, pm, es);
+ pa = pb = (char *)a + es;
+
+ pc = pd = (char *)a + (n - 1) * es;
+ for (;;) {
+ while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
+ if (cmp_result == 0) {
+ swap_cnt = 1;
+ swapfunc(pa, pb, es);
+ pa += es;
+ }
+ pb += es;
+ }
+ while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
+ if (cmp_result == 0) {
+ swap_cnt = 1;
+ swapfunc(pc, pd, es);
+ pd -= es;
+ }
+ pc -= es;
+ }
+ if (pb > pc)
+ break;
+ swapfunc(pb, pc, es);
+ 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(thunk, pl - es, pl) > 0;
+ pl -= es)
+ swapfunc(pl, pl - es, es);
+ return;
+ }
+
+ pn = (char *)a + n * es;
+ d1 = MIN(pa - (char *)a, pb - pa);
+ vecswap(a, pb - d1, d1);
+ /*
+ * Cast es to preserve signedness of right-hand side of MIN()
+ * expression, to avoid sign ambiguity in the implied comparison. es
+ * is safely within [0, SSIZE_MAX].
+ */
+ d1 = MIN(pd - pc, pn - pd - (ssize_t)es);
+ vecswap(pb, pn - d1, d1);
+
+ d1 = pb - pa;
+ d2 = pd - pc;
+ if (d1 <= d2) {
+ /* Recurse on left partition, then iterate on right partition */
+ if (d1 > es) {
+ local_qsort(a, d1 / es, es, cmp, thunk);
+ }
+ if (d2 > es) {
+ /* Iterate rather than recurse to save stack space */
+ /* qsort(pn - d2, d2 / es, es, cmp); */
+ a = pn - d2;
+ n = d2 / es;
+ goto loop;
+ }
+ } else {
+ /* Recurse on right partition, then iterate on left partition */
+ if (d2 > es) {
+ local_qsort(pn - d2, d2 / es, es, cmp, thunk);
+ }
+ if (d1 > es) {
+ /* Iterate rather than recurse to save stack space */
+ /* qsort(a, d1 / es, es, cmp); */
+ n = d1 / es;
+ goto loop;
+ }
+ }
+}
+
+#if defined(I_AM_QSORT_R)
+void
+(qsort_r)(void *a, size_t n, size_t es, cmp_t *cmp, void *thunk)
+{
+ local_qsort_r(a, n, es, cmp, thunk);
+}
+#elif defined(I_AM_QSORT_R_COMPAT)
+void
+__qsort_r_compat(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
+{
+ local_qsort_r_compat(a, n, es, cmp, thunk);
+}
+#elif defined(I_AM_QSORT_S)
+errno_t
+qsort_s(void *a, rsize_t n, rsize_t es, cmp_t *cmp, void *thunk)
+{
+ if (n > RSIZE_MAX) {
+ __throw_constraint_handler_s("qsort_s : n > RSIZE_MAX", EINVAL);
+ return (EINVAL);
+ } else if (es > RSIZE_MAX) {
+ __throw_constraint_handler_s("qsort_s : es > RSIZE_MAX",
+ EINVAL);
+ return (EINVAL);
+ } else if (n != 0) {
+ if (a == NULL) {
+ __throw_constraint_handler_s("qsort_s : a == NULL",
+ EINVAL);
+ return (EINVAL);
+ } else if (cmp == NULL) {
+ __throw_constraint_handler_s("qsort_s : cmp == NULL",
+ EINVAL);
+ return (EINVAL);
+ } else if (es <= 0) {
+ __throw_constraint_handler_s("qsort_s : es <= 0",
+ EINVAL);
+ return (EINVAL);
+ }
+ }
+
+ local_qsort_s(a, n, es, cmp, thunk);
+ return (0);
+}
+#else
+void
+qsort(void *a, size_t n, size_t es, cmp_t *cmp)
+{
+ local_qsort(a, n, es, cmp, NULL);
+}
+#endif