[NETD-BPF#1] Move libnetdutils to frameworks/libs/net/...
libnetdutils is referenced by netd.c and TrafficController.cpp, which
are going to be mainlined. Therefore, move libnetdutils to a common
place where both mainline module and platform code (Netd) can refer to.
Bug: 202086915
Test: build; flash; cd system/netd; atest
Ignore-AOSP-First: the netd change(same topic) would not automerge from
aosp.
No-Typo-Check: Clean code move with no other changes.
BYPASS_INCLUSIVE_LANGUAGE_REASON=Clean code move with no other changes.
Change-Id: I645bfe35f6543149c9a9f894cd4158d27a481abe
diff --git a/staticlibs/netd/libnetdutils/include/netdutils/Slice.h b/staticlibs/netd/libnetdutils/include/netdutils/Slice.h
new file mode 100644
index 0000000..717fbd1
--- /dev/null
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Slice.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2017 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 NETUTILS_SLICE_H
+#define NETUTILS_SLICE_H
+
+#include <algorithm>
+#include <array>
+#include <cstring>
+#include <ostream>
+#include <tuple>
+#include <vector>
+
+namespace android {
+namespace netdutils {
+
+// Immutable wrapper for a linear region of unowned bytes.
+// Slice represents memory as a half-closed interval [base, limit).
+//
+// Note that without manually invoking the Slice() constructor, it is
+// impossible to increase the size of a slice. This guarantees that
+// applications that properly use the slice API will never access
+// memory outside of a slice.
+//
+// Note that const Slice still wraps mutable memory, however copy
+// assignment and move assignment to slice are disabled.
+class Slice {
+ public:
+ Slice() = default;
+
+ // Create a slice beginning at base and continuing to but not including limit
+ Slice(void* base, void* limit) : mBase(toUint8(base)), mLimit(toUint8(limit)) {}
+
+ // Create a slice beginning at base and continuing for size bytes
+ Slice(void* base, size_t size) : Slice(base, toUint8(base) + size) {}
+
+ // Return the address of the first byte in this slice
+ uint8_t* base() const { return mBase; }
+
+ // Return the address of the first byte following this slice
+ uint8_t* limit() const { return mLimit; }
+
+ // Return the size of this slice in bytes
+ size_t size() const { return limit() - base(); }
+
+ // Return true if size() == 0
+ bool empty() const { return base() == limit(); }
+
+ private:
+ static uint8_t* toUint8(void* ptr) { return reinterpret_cast<uint8_t*>(ptr); }
+
+ uint8_t* mBase = nullptr;
+ uint8_t* mLimit = nullptr;
+};
+
+// Return slice representation of ref which must be a POD type
+template <typename T>
+inline const Slice makeSlice(const T& ref) {
+ static_assert(std::is_pod<T>::value, "value must be a POD type");
+ static_assert(!std::is_pointer<T>::value, "value must not be a pointer type");
+ return {const_cast<T*>(&ref), sizeof(ref)};
+}
+
+// Return slice representation of string data()
+inline const Slice makeSlice(const std::string& s) {
+ using ValueT = std::string::value_type;
+ return {const_cast<ValueT*>(s.data()), s.size() * sizeof(ValueT)};
+}
+
+// Return slice representation of vector data()
+template <typename T>
+inline const Slice makeSlice(const std::vector<T>& v) {
+ return {const_cast<T*>(v.data()), v.size() * sizeof(T)};
+}
+
+// Return slice representation of array data()
+template <typename U, size_t V>
+inline const Slice makeSlice(const std::array<U, V>& a) {
+ return {const_cast<U*>(a.data()), a.size() * sizeof(U)};
+}
+
+// Return prefix and suffix of Slice s ending and starting at position cut
+inline std::pair<const Slice, const Slice> split(const Slice s, size_t cut) {
+ const size_t tmp = std::min(cut, s.size());
+ return {{s.base(), s.base() + tmp}, {s.base() + tmp, s.limit()}};
+}
+
+// Return prefix of Slice s ending at position cut
+inline const Slice take(const Slice s, size_t cut) {
+ return std::get<0>(split(s, cut));
+}
+
+// Return suffix of Slice s starting at position cut
+inline const Slice drop(const Slice s, size_t cut) {
+ return std::get<1>(split(s, cut));
+}
+
+// Copy from src into dst. Bytes copied is the lesser of dst.size() and src.size()
+inline size_t copy(const Slice dst, const Slice src) {
+ const auto min = std::min(dst.size(), src.size());
+ memcpy(dst.base(), src.base(), min);
+ return min;
+}
+
+// Base case for variadic extract below
+template <typename Head>
+inline size_t extract(const Slice src, Head& head) {
+ return copy(makeSlice(head), src);
+}
+
+// Copy from src into one or more pointers to POD data. If src.size()
+// is less than the sum of all data pointers a suffix of data will be
+// left unmodified. Return the number of bytes copied.
+template <typename Head, typename... Tail>
+inline size_t extract(const Slice src, Head& head, Tail&... tail) {
+ const auto extracted = extract(src, head);
+ return extracted + extract(drop(src, extracted), tail...);
+}
+
+// Return a string containing a copy of the contents of s
+std::string toString(const Slice s);
+
+// Return a string containing a hexadecimal representation of the contents of s.
+// This function inserts a newline into its output every wrap bytes.
+std::string toHex(const Slice s, int wrap = INT_MAX);
+
+inline bool operator==(const Slice& lhs, const Slice& rhs) {
+ return (lhs.base() == rhs.base()) && (lhs.limit() == rhs.limit());
+}
+
+inline bool operator!=(const Slice& lhs, const Slice& rhs) {
+ return !(lhs == rhs);
+}
+
+std::ostream& operator<<(std::ostream& os, const Slice& slice);
+
+// Return suffix of Slice s starting at the first match of byte c. If no matched
+// byte, return an empty Slice.
+inline const Slice findFirstMatching(const Slice s, uint8_t c) {
+ uint8_t* match = (uint8_t*)memchr(s.base(), c, s.size());
+ if (!match) return Slice();
+ return drop(s, match - s.base());
+}
+
+} // namespace netdutils
+} // namespace android
+
+#endif /* NETUTILS_SLICE_H */