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 "sbuf.h"
  26 #include "memory.h"
  27
  28 void sbuf_init(struct sbuf *dest, char *buf, size_t size)
  29 {
  30         dest->fixed = (size > 0);
  31         if (dest->fixed) {
  32                 dest->buf = buf;
  33                 dest->size = size;
  34         } else {
  35                 dest->buf = XMALLOC(MTYPE_TMP, 4096);
  36                 dest->size = 4096;
  37         }
  38
  39         dest->pos = 0;
  40         dest->buf[0] = '\0';
  41 }
  42
  43 void sbuf_reset(struct sbuf *dest)
  44 {
  45         dest->pos = 0;
  46         dest->buf[0] = '\0';
  47 }
  48
  49 const char *sbuf_buf(struct sbuf *buf)
  50 {
  51         return buf->buf;
  52 }
  53
  54 void sbuf_free(struct sbuf *buf)
  55 {
  56         if (!buf->fixed)
  57                 XFREE(MTYPE_TMP, buf->buf);
  58 }
  59
  60 void sbuf_push(struct sbuf *buf, int indent, const char *format, ...)
  61 {
  62         va_list args;
  63         int written;
  64
  65         if (!buf->fixed) {
  66                 int written1, written2;
  67                 size_t new_size;
  68
  69                 written1 = indent;
  70                 va_start(args, format);
  71                 written2 = vsnprintf(NULL, 0, format, args);
  72                 va_end(args);
  73
  74                 new_size = buf->size;
  75                 if (written1 >= 0 && written2 >= 0) {
  76                         while (buf->pos + written1 + written2 >= new_size)
  77                                 new_size *= 2;
  78                         if (new_size > buf->size) {
  79                                 buf->buf =
  80                                         XREALLOC(MTYPE_TMP, buf->buf, new_size);
  81                                 buf->size = new_size;
  82                         }
  83                 }
  84         }
  85
  86         written = snprintf(buf->buf + buf->pos, buf->size - buf->pos, "%*s",
  87                            indent, "");
  88
  89         if (written >= 0)
  90                 buf->pos += written;
  91         if (buf->pos > buf->size)
  92                 buf->pos = buf->size;
  93
  94         va_start(args, format);
  95         written = vsnprintf(buf->buf + buf->pos, buf->size - buf->pos, format,
  96                             args);
  97         va_end(args);
  98
  99         if (written >= 0)
 100                 buf->pos += written;
 101         if (buf->pos > buf->size)
 102                 buf->pos = buf->size;
 103
 104         if (buf->pos == buf->size)
 105                 assert(!"Buffer filled up!");
 106 }