source: doc/papers/concurrency/examples/Format1.c@ f673c13c

#include <stdio.h>

typedef struct {
        void * next;
        char ch;
        int g, b;
} Fmt;

void format( Fmt * f ) {
        if ( __builtin_expect(f->next != 0, 1) ) goto *f->next;
        f->next = &&s1;
        for ( ;; ) {
                for ( f->g = 0; f->g < 5; f->g += 1 ) {                 // groups
                        for ( f->b = 0; f->b < 4; f->b += 1 ) {         // blocks
                                return;
                          s1: ;
                                if ( f->ch == '\0' ) goto fini;                 // EOF ?
                                while ( f->ch == '\n' ) return;                 // ignore
                                printf( "%c", f->ch );                                  // print character
                        }
                        printf( " " );                                                          // block separator
                }
                printf( "\n" );                                                                 // group separator
        }
  fini:
        if ( f->g != 0 || f->b != 0 ) printf( "\n" );
}

int main() {
        Fmt fmt = { NULL };
        format( &fmt );                                                                         // prime
        for ( ;; ) {
                scanf( "%c", &fmt.ch );                                                 // direct read into communication variable
          if ( feof( stdin ) ) break;
                format( &fmt );
        }
        fmt.ch = '\0';
        format( &fmt );
}

// Local Variables: //
// tab-width: 4 //
// compile-command: "gcc-8 Format1.c" //
// End: //