MLPL

A library used by Hatohol. However, they provides general functions.　So it is separated from Hatohol itself.

One of the reasons why we created this library is to make code simple by wrapping C-style APIs such as sem_wait(), sprintf() etc. For example, explicit initialization or free can be automated by a constructor and a destructor. In addition, proper operator overloads improve readability.

Classes

• AtomicValue: Atomic operation

  • get(), set(), add(), sub(), etc.

  • internally uses gcc's builtin functions such as __sync_add_and_fetch().

  • We can use instances as if they are native type by operator's overload.

    AtomicValue<int> a, b;
    a = 1;
    b = a;

  • GCC generates the following machine code (gcc 4.8.2 x86_64 w/o optimization). The difference is little. I.e. the implementation is efficient.

    • with __sync_add_and_fetch():
      lock xadd %eax,-0x4(%rbp)

    • normal add operation like a + b;
      add %edx,%eax

• EventSemaphore

  • A semaphore using EventFd, which is one the features of Linux.
  • We can wait for a semaphore with GLibEvent Loop based on poll().

• Logger

  • printf like API: MLPL_X() (X: DBG, INFO, WARN, ERR, CRIT, BUG) that writes a message both to stderr and syslog.

    MLPL_INFO ("My name: %s, Age: %d\n", name, age);

• MutexLock

  • lock(), unlock(), and timedlock().

• ParsableString

  • We can parse a string from the top with specifying a separator.

• ReadWriteLock

  • readLock(), writeLock(), and unlock()

• Reaper

  • A smart pointer helper.

  • deletes an object or a buffer at the end of the block.

  • works even when an exception is thrown.

    MutexLock lock;
    Reaper unlocker(&lock, MutexLock::unlock);

    char *buf = malloc(100);
    Reaper<char *> reaper(buf, free);

• SimpleSemaphore

  • A wrapper class of POSIX semaphore.

• SmartBuffer

  • Utility to handle a buffer.
  • extends the size automatically.
  • provide stream-like APIs such as add8(), add16, etc.
  • helper functions to cast a pointer.

• SmartQueue

  • MT-safe Queue: push() and pop()
  • pop() is blocked when there's no elements.

• SmartTime: holds time (sec and nanosec)

  • Constructor(INIT_CURR_TIME)
  • Constructor(const timespec &ts)
  • Comparators: <, >, <=, >=, ==
  • Add/Sub: +=, -=

• StringUtils

  • Helper functions related to string.
  • sprintf()
  • split()
  • casecmp()
  • isNumber()
  • eraseChars()