text: // Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef CHROMIUMOS_WIDE_PROFILING_UTILS_H_
  #define CHROMIUMOS_WIDE_PROFILING_UTILS_H_
  
  #include <stdint.h>
  #include <stdlib.h>  // for free()
  
  #include <memory>
  #include <string>
  #include <vector>
  
  #include "base/logging.h"
  
  #include "perf_internals.h"
  #include "quipper_string.h"
  
  namespace quipper {
  
  struct FreeDeleter {
    inline void operator()(void* pointer) {
      free(pointer);
    }
  };
  
  template <typename T>
  using malloced_unique_ptr = std::unique_ptr<T, FreeDeleter>;
  
  // Given a valid open file handle |fp|, returns the size of the file.
  int64_t GetFileSizeFromHandle(FILE* fp);
  
  event_t* CallocMemoryForEvent(size_t size);
  event_t* ReallocMemoryForEvent(event_t* event, size_t new_size);
  
  build_id_event* CallocMemoryForBuildID(size_t size);
  
  bool FileToBuffer(const string& filename, std::vector<char>* contents);
  
  template <typename CharContainer>
  bool BufferToFile(const string& filename, const CharContainer& contents) {
    FILE* fp = fopen(filename.c_str(), "wb");
    if (!fp)
      return false;
    // Do not write anything if |contents| contains nothing.  fopen will create
    // an empty file.
    if (!contents.empty()) {
      CHECK_EQ(fwrite(contents.data(),
                      sizeof(typename CharContainer::value_type),
                      contents.size(),
                      fp),
               contents.size());
    }
    fclose(fp);
    return true;
  }
  
  uint64_t Md5Prefix(const string& input);
  uint64_t Md5Prefix(const std::vector<char>& input);
  
  // Returns a string that represents |array| in hexadecimal.
  string HexToString(const u8* array, size_t length);
  
  // Converts |str| to a hexadecimal number, stored in |array|.  Returns true on
  // success.  Only stores up to |length| bytes - if there are more characters in
  // the string, they are ignored (but the function may still return true).
  bool StringToHex(const string& str, u8* array, size_t length);
  
  // Adjust |size| to blocks of |align_size|.  i.e. returns the smallest multiple
  // of |align_size| that can fit |size|.
  uint64_t AlignSize(uint64_t size, uint32_t align_size);
  
  // Given a general perf sample format |sample_type|, return the fields of that
  // format that are present in a sample for an event of type |event_type|.
  //
  // e.g. FORK and EXIT events have the fields {time, pid/tid, cpu, id}.
  // Given a sample type with fields {ip, time, pid/tid, and period}, return
  // the intersection of these two field sets: {time, pid/tid}.
  //
  // All field formats are bitfields, as defined by enum perf_event_sample_format
  // in kernel/perf_event.h.
  uint64_t GetSampleFieldsForEventType(uint32_t event_type, uint64_t sample_type);
  
  // Returns the offset in bytes within a perf event structure at which the raw
  // perf sample data is located.
  uint64_t GetPerfSampleDataOffset(const event_t& event);
  
  // Returns the size of the 8-byte-aligned memory for storing |string|.
  size_t GetUint64AlignedStringLength(const string& str);
  
  // Returns true iff the file exists.
  bool FileExists(const string& filename);
  
  // Reads the contents of a file into |data|.  Returns true on success, false if
  // it fails.
  bool ReadFileToData(const string& filename, std::vector<char>* data);
  
  // Writes contents of |data| to a file with name |filename|, overwriting any
  // existing file.  Returns true on success, false if it fails.
  bool WriteDataToFile(const std::vector<char>& data, const string& filename);
  
  // Executes |command| and stores stdout output in |output|.  Returns true on
  // success, false otherwise.
  bool RunCommandAndGetStdout(const string& command, std::vector<char>* output);
  
  // Trim leading and trailing whitespace from |str|.
  void TrimWhitespace(string* str);
  
  }  // namespace quipper
  
  #endif  // CHROMIUMOS_WIDE_PROFILING_UTILS_H_
  