Provide portable wrapper for qsort_r.

qsort_r() is declared differently on BSD and GNU libc and
may be absent on other platforms.

Provide qsort_r_compat() which should work everywhere.

Change-Id: I17a9026573b1ed971ff7d79895e7eb41ba108807

include/arch/darwin-x86/AndroidConfig.h

@@ -305,4 +305,14 @@
  */
 #define HAVE_PRINTF_ZD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 1
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 0
+
 #endif /*_ANDROID_CONFIG_H*/

include/arch/freebsd-x86/AndroidConfig.h

@@ -363,4 +363,14 @@
  */
 #define HAVE_PRINTF_ZD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 1
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 0
+
 #endif /*_ANDROID_CONFIG_H*/

include/arch/linux-arm/AndroidConfig.h

@@ -361,4 +361,14 @@
  */
 #define HAVE_PRINTF_ZD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 0
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 0
+
 #endif /* _ANDROID_CONFIG_H */

include/arch/linux-ppc/AndroidConfig.h

@@ -323,4 +323,14 @@
  */
 #define HAVE_PREAD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 0
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 1
+
 #endif /*_ANDROID_CONFIG_H*/

include/arch/linux-sh/AndroidConfig.h

@@ -366,4 +366,14 @@
  */
 #define HAVE_PRINTF_ZD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 0
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 0
+
 #endif /* _ANDROID_CONFIG_H */

include/arch/linux-x86/AndroidConfig.h

@@ -333,4 +333,14 @@
  */
 #define HAVE_PRINTF_ZD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 0
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 1
+
 #endif /*_ANDROID_CONFIG_H*/

include/arch/target_linux-x86/AndroidConfig.h

@@ -350,4 +350,14 @@
  */
 #define HAVE_PRINTF_ZD 1
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 0
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 0
+
 #endif /* _ANDROID_CONFIG_H */

include/arch/windows/AndroidConfig.h

@@ -338,4 +338,14 @@
  */
 /* #define HAVE_PRINTF_ZD 1 */
 
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a BSD style function prototype.
+ */
+#define HAVE_BSD_QSORT_R 0
+
+/*
+ * Define to 1 if <stdlib.h> provides qsort_r() with a GNU style function prototype.
+ */
+#define HAVE_GNU_QSORT_R 0
+
 #endif /*_ANDROID_CONFIG_H*/

include/cutils/qsort_r_compat.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Provides a portable version of qsort_r, called qsort_r_compat, which is a
+ * reentrant variant of qsort that passes a user data pointer to its comparator.
+ * This implementation follows the BSD parameter convention.
+ */
+
+#ifndef _LIBS_CUTILS_QSORT_R_COMPAT_H
+#define _LIBS_CUTILS_QSORT_R_COMPAT_H
+
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
+        int (*compar)(void*, const void* , const void* ));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _LIBS_CUTILS_QSORT_R_COMPAT_H

libcutils/Android.mk

@@ -46,6 +46,7 @@ commonSources := \
 	record_stream.c \
 	process_name.c \
 	properties.c \
+	qsort_r_compat.c \
 	threads.c \
 	sched_policy.c \
 	iosched_policy.c \

libcutils/qsort_r_compat.c

@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <cutils/qsort_r_compat.h>
+
+#if HAVE_BSD_QSORT_R
+
+/*
+ * BSD qsort_r parameter order is as we have defined here.
+ */
+
+void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
+        int (*compar)(void*, const void* , const void*)) {
+    qsort_r(base, nel, width, thunk, compar);
+}
+
+#elif HAVE_GNU_QSORT_R
+
+/*
+ * GNU qsort_r parameter order places the thunk parameter last.
+ */
+
+struct compar_data {
+    void* thunk;
+    int (*compar)(void*, const void* , const void*);
+};
+
+static int compar_wrapper(const void* a, const void* b, void* data) {
+    struct compar_data* compar_data = (struct compar_data*)data;
+    return compar_data->compar(compar_data->thunk, a, b);
+}
+
+void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
+        int (*compar)(void*, const void* , const void*)) {
+    struct compar_data compar_data;
+    compar_data.thunk = thunk;
+    compar_data.compar = compar;
+    qsort_r(base, nel, width, compar_wrapper, &compar_data);
+}
+
+#else
+
+/*
+ * Emulate qsort_r using thread local storage to access the thunk data.
+ */
+
+#include <cutils/threads.h>
+
+static thread_store_t compar_data_key = THREAD_STORE_INITIALIZER;
+
+struct compar_data {
+    void* thunk;
+    int (*compar)(void*, const void* , const void*);
+};
+
+static int compar_wrapper(const void* a, const void* b) {
+    struct compar_data* compar_data = (struct compar_data*)thread_store_get(&compar_data_key);
+    return compar_data->compar(compar_data->thunk, a, b);
+}
+
+void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
+        int (*compar)(void*, const void* , const void*)) {
+    struct compar_data compar_data;
+    compar_data.thunk = thunk;
+    compar_data.compar = compar;
+    thread_store_set(&compar_data_key, &compar_data, NULL);
+    qsort(base, nel, width, compar_wrapper);
+}
+
+#endif