Parsing C

#define MAXLOG10 10
#define BUFSIZE (128 * 1024)

FILE *fin, *fout;
int p10[MAXLOG10 + 1] = { 0, 1, 10, 100, 1000, 10000, 100000, 1000000,
  10000000, 100000000, 1000000000 }; // santinela pe prima pozitie
int rpos; char rbuf[BUFSIZE];
int wpos; char wbuf[BUFSIZE];

// initializare citire
static inline void initRead() {
  rpos = BUFSIZE - 1;
}

// citire caracter
static inline char readChar() {
  if ( !(rpos = (rpos + 1) & (BUFSIZE - 1)) )
    fread( rbuf, 1, BUFSIZE, fin );
  return rbuf[rpos];
}

// citire intreg cu semn
int readInt() { // citeste un intreg
  int ch, res = 0, semn = 1;

  while ( isspace( ch = readChar() ) );
  if ( ch == '-' ) {
    semn = -1;
    ch = readChar();
  }
  do
    res = 10 * res + ch - '0';
  while ( isdigit( ch = readChar() ) );

  return semn * res;
}

// initializare scriere
static inline void initWrite() {
  wpos = 0;
}

// scriere caracter
static inline void writeChar( char ch ) {
  wbuf[wpos] = ch;
  if ( !(wpos = (wpos + 1) & (BUFSIZE - 1)) )
    fwrite( wbuf, 1, BUFSIZE, fout );
}

// scriere intreg cu semn
void writeInt( int x ) {
  int i, cf;

  if ( x < 0 ) {
    writeChar( '-' );
    x = -x;
  }
  i = MAXLOG10;
  while ( p10[i] > x )
    i--;
  if ( i == 0 )
    writeChar( '0' );
  else
    do {
      cf = '0';
      while ( p10[i] <= x ) {
        x -= p10[i];
        cf++;
      }
      writeChar( cf );
    } while ( --i > 0 );

  writeChar( ' ' ); // separatorul, poate sa difere ('\n'?)
}

// scrie caracterele ramase in buffer
static inline void flushBuf() {
  fwrite( wbuf, 1, wpos, fout );
}


Utilizare:

fin = fopen( "input.in", "r" );
  initRead();
  n = readInt();
  // ... alte citiri
  fclose( fin );

  fout = fopen( "input.out", "w" );
  initWrite();
  writeInt( n );
  // ... alte scrieri
  flushBuf();
  fclose( fout );