printbuf.h

/*
 * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
 * Michael Clark <michael@metaparadigm.com>
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See COPYING for details.
 *
 *
 * Copyright (c) 2008-2009 Yahoo! Inc.  All rights reserved.
 * The copyrights to the contents of this file are licensed under the MIT License
 * (http://www.opensource.org/licenses/mit-license.php)
 */

#ifndef _fj_printbuf_h_
#define _fj_printbuf_h_

#ifdef __cplusplus
extern "C" {
#endif

struct printbuf {
	char *buf;
	int bpos;
	int size;
};

extern struct printbuf*
printbuf_new(void);

/* As an optimization, printbuf_memappend_fast is defined as a macro
 * that handles copying data if the buffer is large enough; otherwise
 * it invokes printbuf_memappend_real() which performs the heavy
 * lifting of realloc()ing the buffer and copying data.
 * Your code should not use printbuf_memappend directly--use
 * printbuf_memappend_fast instead.
 */
extern int
printbuf_memappend(struct printbuf *p, const char *buf, int size);

#define printbuf_memappend_fast(p, bufptr, bufsize)          \
do {                                                         \
	if ((p->size - p->bpos) > bufsize) {                 \
		memcpy(p->buf + p->bpos, (bufptr), bufsize); \
		p->bpos += bufsize;                          \
		p->buf[p->bpos]= '\0';                       \
	} else {  printbuf_memappend(p, (bufptr), bufsize); }\
} while (0)

/* The following functions provide a printbuf interface where the
 * string terminator '\0' is not always written. This is faster, but
 * the string cannot be used with standard functions while being
 * constructed. To do so, printbuf_terminate_string() must be
 * called first.
 */
void printbuf_memappend_no_nul(struct printbuf *p, const char *buf, int size);
void printbuf_memappend_char(struct printbuf *p, const char c);
void printbuf_terminate_string(struct printbuf *const p);

#define printbuf_length(p) ((p)->bpos)

/**
 * Set len bytes of the buffer to charvalue, starting at offset offset.
 * Similar to calling memset(x, charvalue, len);
 *
 * The memory allocated for the buffer is extended as necessary.
 *
 * If offset is -1, this starts at the end of the current data in the buffer.
 */
extern int
printbuf_memset(struct printbuf *pb, int offset, int charvalue, int len);

extern int
sprintbuf(struct printbuf *p, const char *msg, ...) __attribute__((__format__(__printf__, 2, 3)));

extern void
printbuf_reset(struct printbuf *p);

extern void
printbuf_free(struct printbuf *p);
#ifdef __cplusplus
}
#endif

#endif