chromiumos-wide-profiling/utils.h

// 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 <byteswap.h>
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>  // for free()

#include <bitset>
#include <memory>
#include <string>
#include <vector>

#include "base/logging.h"

#include "chromiumos-wide-profiling/compat/string.h"
#include "chromiumos-wide-profiling/kernel/perf_internals.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;
}

// Swaps the byte order of 16-bit, 32-bit, and 64-bit unsigned integers.
template <class T>
void ByteSwap(T* input) {
  switch (sizeof(T)) {
  case sizeof(uint8_t):
    LOG(WARNING) << "Attempting to byte swap on a single byte.";
    break;
  case sizeof(uint16_t):
    *input = bswap_16(*input);
    break;
  case sizeof(uint32_t):
    *input = bswap_32(*input);
    break;
  case sizeof(uint64_t):
    *input = bswap_64(*input);
    break;
  default:
    LOG(FATAL) << "Invalid size for byte swap: " << sizeof(T) << " bytes";
    break;
  }
}

// Swaps byte order of |value| if the |swap| flag is set. This function is
// trivial but it avoids filling code with "if (swap) { ... } " statements.
template <typename T>
T MaybeSwap(T value, bool swap) {
  if (swap)
    ByteSwap(&value);
  return value;
}

// Returns the number of bits in a numerical value.
template <typename T>
size_t GetNumBits(const T& value) {
  return std::bitset<sizeof(T) * CHAR_BIT>(value).count();
}

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);

// 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);

// Trim leading and trailing whitespace from |str|.
void TrimWhitespace(string* str);

// Splits a character array by |delimiter| into a vector of strings tokens.
void SplitString(const string& str,
                 char delimiter,
                 std::vector<string>* tokens);

}  // namespace quipper

#endif  // CHROMIUMOS_WIDE_PROFILING_UTILS_H_