MLPL

A library of commonly used functions.

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. Or proper operator overload improves 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

  • An auto 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()