mdw@git.distorted.org.uk Git - mLib/blob - struct/dstr-putf.c

   1 /* -*-c-*-
   2  *
   3  * `printf'-style formatting for dynamic strings
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "config.h"
  31
  32 #include <stdarg.h>
  33 #include <stddef.h>
  34 #include <stdio.h>
  35
  36 #include "dstr.h"
  37 #include "gprintf.h"
  38
  39 /*----- Main code ---------------------------------------------------------*/
  40
  41 /* --- @dstr_vputf@ --- *
  42  *
  43  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  44  *              @const char *p@ = pointer to @printf@-style format string
  45  *              @va_list *ap@ = argument handle
  46  *
  47  * Returns:     The number of characters written to the string.
  48  *
  49  * Use:         As for @dstr_putf@, but may be used as a back-end to user-
  50  *              supplied functions with @printf@-style interfaces.
  51  */
  52
  53 static int putch(void *out, int ch)
  54   { dstr *d = out; DPUTC(d, ch); return (0); }
  55 static int putm(void *out, const char *p, size_t sz)
  56   { dstr *d = out; DPUTM(d, p, sz); return (0); }
  57
  58 static int nputf(void *out, size_t maxsz, const char *p, ...)
  59 {
  60   dstr *d = out;
  61   va_list ap;
  62   int n;
  63
  64   va_start(ap, p);
  65   DENSURE(d, maxsz + 1);
  66 #ifdef HAVE_SNPRINTF
  67   n = vsnprintf(d->buf + d->len, maxsz + 1, p, ap);
  68 #else
  69   n = vsprintf(d->buf + d->len, p, ap);
  70 #endif
  71   assert(0 <= n && n <= maxsz);
  72   va_end(ap); d->len += n; return (n);
  73 }
  74
  75 const struct gprintf_ops dstr_printops =
  76   { putch, putm, nputf };
  77
  78 int dstr_vputf(dstr *d, const char *p, va_list *ap)
  79   { int n = vgprintf(&dstr_printops, d, p, ap); DPUTZ(d); return (n); }
  80
  81 /* --- @dstr_putf@ --- *
  82  *
  83  * Arguments:   @dstr *d@ = pointer to a dynamic string block
  84  *              @const char *p@ = pointer to @printf@-style format string
  85  *              @...@ = argument handle
  86  *
  87  * Returns:     The number of characters written to the string.
  88  *
  89  * Use:         Writes a piece of text to a dynamic string, doing @printf@-
  90  *              style substitutions as it goes.  Intended to be robust if
  91  *              faced with malicious arguments, but not if the format string
  92  *              itself is malicious.
  93  */
  94
  95 int dstr_putf(dstr *d, const char *p, ...)
  96 {
  97   int n;
  98   va_list ap;
  99   va_start(ap, p);
 100   n = dstr_vputf(d, p, &ap);
 101   va_end(ap);
 102   return (n);
 103 }
 104
 105 /*----- That's all, folks -------------------------------------------------*/