lib/sbuf.c

   1 /*
   2  * Simple string buffer
   3  *
   4  * Copyright (C) 2017 Christian Franke
   5  *
   6  * This file is part of FRR.
   7  *
   8  * FRR is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2, or (at your option) any
  11  * later version.
  12  *
  13  * FRR is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with FRR; see the file COPYING.  If not, write to the Free
  20  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  21  * 02111-1307, USA.
  22  */
  23 #include <zebra.h>
  24
  25 #include "printfrr.h"
  26 #include "sbuf.h"
  27 #include "memory.h"
  28
  29 void sbuf_init(struct sbuf *dest, char *buf, size_t size)
  30 {
  31         dest->fixed = (size > 0);
  32         if (dest->fixed) {
  33                 dest->buf = buf;
  34                 dest->size = size;
  35         } else {
  36                 dest->buf = XMALLOC(MTYPE_TMP, 4096);
  37                 dest->size = 4096;
  38         }
  39
  40         dest->pos = 0;
  41         dest->buf[0] = '\0';
  42 }
  43
  44 void sbuf_reset(struct sbuf *dest)
  45 {
  46         dest->pos = 0;
  47         dest->buf[0] = '\0';
  48 }
  49
  50 const char *sbuf_buf(struct sbuf *buf)
  51 {
  52         return buf->buf;
  53 }
  54
  55 void sbuf_free(struct sbuf *buf)
  56 {
  57         if (!buf->fixed)
  58                 XFREE(MTYPE_TMP, buf->buf);
  59 }
  60
  61 void sbuf_push(struct sbuf *buf, int indent, const char *format, ...)
  62 {
  63         va_list args;
  64         int written;
  65
  66         if (!buf->fixed) {
  67                 int written1, written2;
  68                 size_t new_size;
  69
  70                 written1 = indent;
  71                 va_start(args, format);
  72                 written2 = vsnprintfrr(NULL, 0, format, args);
  73                 va_end(args);
  74
  75                 new_size = buf->size;
  76                 if (written1 >= 0 && written2 >= 0) {
  77                         while (buf->pos + written1 + written2 >= new_size)
  78                                 new_size *= 2;
  79                         if (new_size > buf->size) {
  80                                 buf->buf =
  81                                         XREALLOC(MTYPE_TMP, buf->buf, new_size);
  82                                 buf->size = new_size;
  83                         }
  84                 }
  85         }
  86
  87         written = snprintf(buf->buf + buf->pos, buf->size - buf->pos, "%*s",
  88                            indent, "");
  89
  90         if (written >= 0)
  91                 buf->pos += written;
  92         if (buf->pos > buf->size)
  93                 buf->pos = buf->size;
  94
  95         va_start(args, format);
  96         written = vsnprintfrr(buf->buf + buf->pos, buf->size - buf->pos,
  97                               format, args);
  98         va_end(args);
  99
 100         if (written >= 0)
 101                 buf->pos += written;
 102         if (buf->pos > buf->size)
 103                 buf->pos = buf->size;
 104
 105         if (buf->pos == buf->size)
 106                 assert(!"Buffer filled up!");
 107 }