upload android base code part6

android/system/extras/simpleperf/build_id.h

@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2015 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 SIMPLE_PERF_BUILD_ID_H_
+#define SIMPLE_PERF_BUILD_ID_H_
+
+#include <string.h>
+#include <algorithm>
+#include <android-base/stringprintf.h>
+
+constexpr size_t BUILD_ID_SIZE = 20;
+
+// Shared libraries can have a section called .note.gnu.build-id, containing
+// a ~20 bytes unique id. Build id is used to compare if two shared libraries
+// are actually the same. BuildId class is the representation of build id in
+// memory.
+class BuildId {
+ public:
+  static size_t Size() {
+    return BUILD_ID_SIZE;
+  }
+
+  BuildId() {
+    memset(data_, '\0', BUILD_ID_SIZE);
+  }
+
+  // Copy build id from a byte array, like {0x76, 0x00, 0x32,...}.
+  BuildId(const void* data, size_t len) : BuildId() {
+    memcpy(data_, data, std::min(len, BUILD_ID_SIZE));
+  }
+
+  // Read build id from a hex string, like "7600329e31058e12b145d153ef27cd40e1a5f7b9".
+  explicit BuildId(const std::string& s) : BuildId() {
+    for (size_t i = 0; i < s.size() && i < BUILD_ID_SIZE * 2; i += 2) {
+      unsigned char ch = 0;
+      for (size_t j = i; j < i + 2; ++j) {
+        ch <<= 4;
+        if (s[j] >= '0' && s[j] <= '9') {
+          ch |= s[j] - '0';
+        } else if (s[j] >= 'a' && s[j] <= 'f') {
+          ch |= s[j] - 'a' + 10;
+        } else if (s[j] >= 'A' && s[j] <= 'F') {
+          ch |= s[j] - 'A' + 10;
+        }
+      }
+      data_[i / 2] = ch;
+    }
+  }
+
+  const unsigned char* Data() const {
+    return data_;
+  }
+
+  std::string ToString() const {
+    std::string s = "0x";
+    for (size_t i = 0; i < BUILD_ID_SIZE; ++i) {
+      s += android::base::StringPrintf("%02x", data_[i]);
+    }
+    return s;
+  }
+
+  bool operator==(const BuildId& build_id) const {
+    return memcmp(data_, build_id.data_, BUILD_ID_SIZE) == 0;
+  }
+
+  bool operator!=(const BuildId& build_id) const {
+    return !(*this == build_id);
+  }
+
+  bool IsEmpty() const {
+    static BuildId empty_build_id;
+    return *this == empty_build_id;
+  }
+
+ private:
+  unsigned char data_[BUILD_ID_SIZE];
+};
+
+#endif  // SIMPLE_PERF_BUILD_ID_H_