boehm-gc/include/ec.h

# ifndef EC_H
# define EC_H

# ifndef CORD_H
#  include "cord.h"
# endif

/* Extensible cords are strings that may be destructively appended to.	*/
/* They allow fast construction of cords from characters that are	*/
/* being read from a stream.						*/
/*
 * A client might look like:
 *
 *	{
 *	    CORD_ec x;
 *	    CORD result;
 *	    char c;
 *	    FILE *f;
 *
 *	    ...
 *	    CORD_ec_init(x);
 *	    while(...) {
 *		c = getc(f);
 *		...
 *		CORD_ec_append(x, c);
 *	    }
 *	    result = CORD_balance(CORD_ec_to_cord(x));
 *
 * If a C string is desired as the final result, the call to CORD_balance
 * may be replaced by a call to CORD_to_char_star.
 */

# ifndef CORD_BUFSZ
#   define CORD_BUFSZ 128
# endif

typedef struct CORD_ec_struct {
    CORD ec_cord;
    char * ec_bufptr;
    char ec_buf[CORD_BUFSZ+1];
} CORD_ec[1];

/* This structure represents the concatenation of ec_cord with		*/
/* ec_buf[0 ... (ec_bufptr-ec_buf-1)]					*/

/* Flush the buffer part of the extended chord into ec_cord.	*/
/* Note that this is almost the only real function, and it is	*/
/* implemented in 6 lines in cordxtra.c				*/
void CORD_ec_flush_buf(CORD_ec x);
      
/* Convert an extensible cord to a cord. */
# define CORD_ec_to_cord(x) (CORD_ec_flush_buf(x), (x)[0].ec_cord)

/* Initialize an extensible cord. */
# define CORD_ec_init(x) ((x)[0].ec_cord = 0, (x)[0].ec_bufptr = (x)[0].ec_buf)

/* Append a character to an extensible cord.	*/
# define CORD_ec_append(x, c) \
    {  \
	if ((x)[0].ec_bufptr == (x)[0].ec_buf + CORD_BUFSZ) { \
	  	CORD_ec_flush_buf(x); \
	} \
	*((x)[0].ec_bufptr)++ = (c); \
    }

/* Append a cord to an extensible cord.  Structure remains shared with 	*/
/* original.								*/
void CORD_ec_append_cord(CORD_ec x, CORD s);

# endif /* EC_H */