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[mLib] / struct / dstr-putf.c

/* -*-c-*-
 *
 * `printf'-style formatting for dynamic strings
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * mLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with mLib; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>

#include "dstr.h"
#include "gprintf.h"

/*----- Main code ---------------------------------------------------------*/

/* --- @dstr_vputf@ --- *
 *
 * Arguments:	@dstr *d@ = pointer to a dynamic string block
 *		@const char *p@ = pointer to @printf@-style format string
 *		@va_list *ap@ = argument handle
 *
 * Returns:	The number of characters written to the string.
 *
 * Use:		As for @dstr_putf@, but may be used as a back-end to user-
 *		supplied functions with @printf@-style interfaces.
 */

static int putch(void *out, int ch)
  { dstr *d = out; DPUTC(d, ch); return (0); }
static int putm(void *out, const char *p, size_t sz)
  { dstr *d = out; DPUTM(d, p, sz); return (0); }

static int nputf(void *out, size_t maxsz, const char *p, ...)
{
  dstr *d = out;
  va_list ap;
  int n;

  va_start(ap, p);
  DENSURE(d, maxsz + 1);
#ifdef HAVE_SNPRINTF
  n = vsnprintf(d->buf + d->len, maxsz + 1, p, ap);
#else
  n = vsprintf(d->buf + d->len, p, ap);
#endif
  assert(0 <= n && n <= maxsz);
  va_end(ap); d->len += n; return (n);
}

const struct gprintf_ops dstr_printops =
  { putch, putm, nputf };

int dstr_vputf(dstr *d, const char *p, va_list *ap)
  { int n = vgprintf(&dstr_printops, d, p, ap); DPUTZ(d); return (n); }

/* --- @dstr_putf@ --- *
 *
 * Arguments:	@dstr *d@ = pointer to a dynamic string block
 *		@const char *p@ = pointer to @printf@-style format string
 *		@...@ = argument handle
 *
 * Returns:	The number of characters written to the string.
 *
 * Use:		Writes a piece of text to a dynamic string, doing @printf@-
 *		style substitutions as it goes.  Intended to be robust if
 *		faced with malicious arguments, but not if the format string
 *		itself is malicious.
 */

int dstr_putf(dstr *d, const char *p, ...)
{
  int n;
  va_list ap;
  va_start(ap, p);
  n = dstr_vputf(d, p, &ap);
  va_end(ap);
  return (n);
}

/*----- That's all, folks -------------------------------------------------*/