MediaMetrics: Update and clean proto formatting

Make code compatible with both string
and integer enumeration in the protos.

Test: adb shell dumpsys media.metrics
Test: atest mediametrics_tests
Bug: 149850236
Change-Id: I0a1c21be711f82915f3bb403860b40c695a0587d
diff --git a/services/mediametrics/StringUtils.cpp b/services/mediametrics/StringUtils.cpp
new file mode 100644
index 0000000..50525bc
--- /dev/null
+++ b/services/mediametrics/StringUtils.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "MediaMetricsService::stringutils"
+#include <utils/Log.h>
+
+#include "StringUtils.h"
+
+namespace android::mediametrics::stringutils {
+
+std::string tokenizer(std::string::const_iterator& it,
+        const std::string::const_iterator& end, const char *reserved)
+{
+    // consume leading white space
+    for (; it != end && std::isspace(*it); ++it);
+    if (it == end) return {};
+
+    auto start = it;
+    // parse until we hit a reserved keyword or space
+    if (strchr(reserved, *it)) return {start, ++it};
+    for (;;) {
+        ++it;
+        if (it == end || std::isspace(*it) || strchr(reserved, *it)) return {start, it};
+    }
+}
+
+std::vector<std::string> split(const std::string& flags, const char *delim)
+{
+    std::vector<std::string> result;
+    for (auto it = flags.begin(); ; ) {
+        auto flag = tokenizer(it, flags.end(), delim);
+        if (flag.empty() || !std::isalnum(flag[0])) return result;
+        result.emplace_back(std::move(flag));
+
+        // look for the delimeter and discard
+        auto token = tokenizer(it, flags.end(), delim);
+        if (token.size() != 1 || strchr(delim, token[0]) == nullptr) return result;
+    }
+}
+
+std::vector<std::pair<std::string, std::string>> getDeviceAddressPairs(const std::string& devices)
+{
+    std::vector<std::pair<std::string, std::string>> result;
+
+    // Currently, the device format is EXACTLY
+    // (device1, addr1)|(device2, addr2)|...
+
+    static constexpr char delim[] = "()|,";
+    for (auto it = devices.begin(); ; ) {
+        auto token = tokenizer(it, devices.end(), delim);
+        if (token != "(") return result;
+
+        auto device = tokenizer(it, devices.end(), delim);
+        if (device.empty() || !std::isalnum(device[0])) return result;
+
+        token = tokenizer(it, devices.end(), delim);
+        if (token != ",") return result;
+
+        // special handling here for empty addresses
+        auto address = tokenizer(it, devices.end(), delim);
+        if (address.empty() || !std::isalnum(device[0])) return result;
+        if (address == ")") {  // no address, just the ")"
+            address.clear();
+        } else {
+            token = tokenizer(it, devices.end(), delim);
+            if (token != ")") return result;
+        }
+
+        result.emplace_back(std::move(device), std::move(address));
+
+        token = tokenizer(it, devices.end(), delim);
+        if (token != "|") return result;  // this includes end of string detection
+    }
+}
+
+size_t replace(std::string &str, const char *targetChars, const char replaceChar)
+{
+    size_t replaced = 0;
+    for (char &c : str) {
+        if (strchr(targetChars, c) != nullptr) {
+            c = replaceChar;
+            ++replaced;
+        }
+    }
+    return replaced;
+}
+
+} // namespace android::mediametrics::stringutils