Exporting C++ headers from system/core

Moved headers from include/libutils and include/libsysutils to
libutils/include and libsysutils/include respectively, so they can be
exported via these libs. They needed to be moved since Soong does
not allow export from external folder.

Added symlink from old locations. They are needed since Soong
includes system/core/include by default. Once all modules are
cleaned up to explicitly add the required libs, the symlinks will be
removed.

Moved headers of libutils to libutils_headers. They should be used
by modules for header-only inlines. Added libutils_headers as
dependency of libutils.

Split of C++ headers into those that have no dependency and those that
have dependency on libutils.so will be handled in a later CL.

Test: Add above libs to shared lib of local module
Change-Id: I122db72056b26b1f39bad1d9a0c2a1c5efda3550

1 files changed, 54 insertions, 0 deletions

diff --git a/libutils/include/utils/FastStrcmp.h b/libutils/include/utils/FastStrcmp.h
new file mode 100644
index 000000000..3844e7d96
--- /dev/null
+++ b/libutils/include/utils/FastStrcmp.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2014-2016 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.
+ */
+
+#ifndef _ANDROID_UTILS_FASTSTRCMP_H__
+#define _ANDROID_UTILS_FASTSTRCMP_H__
+
+#ifdef __cplusplus
+
+// Optimized for instruction cache locality
+//
+// Template class fastcmp used to create more time-efficient str*cmp
+// functions by pre-checking the first character before resorting
+// to calling the underlying string function.  Profiled with a
+// measurable speedup when used in hot code.  Usage is of the form:
+//
+//  fastcmp<strncmp>(str1, str2, len)
+//
+// NB: Does not work for the case insensitive str*cmp functions.
+// NB: Returns boolean, do not use if expecting to check negative value.
+//     Thus not semantically identical to the expected function behavior.
+
+template <int (*cmp)(const char *l, const char *r, const size_t s)>
+static inline int fastcmp(const char *l, const char *r, const size_t s) {
+    return (*l != *r) || cmp(l + 1, r + 1, s - 1);
+}
+
+template <int (*cmp)(const void *l, const void *r, const size_t s)>
+static inline int fastcmp(const void *lv, const void *rv, const size_t s) {
+    const char *l = static_cast<const char *>(lv);
+    const char *r = static_cast<const char *>(rv);
+    return (*l != *r) || cmp(l + 1, r + 1, s - 1);
+}
+
+template <int (*cmp)(const char *l, const char *r)>
+static inline int fastcmp(const char *l, const char *r) {
+    return (*l != *r) || cmp(l + 1, r + 1);
+}
+
+#endif
+
+#endif // _ANDROID_UTILS_FASTSTRCMP_H__