lib/sbuf.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Simple string buffer
   4  *
   5  * Copyright (C) 2017 Christian Franke
   6  */
   7 #include <zebra.h>
   8
   9 #include "printfrr.h"
  10 #include "sbuf.h"
  11 #include "memory.h"
  12
  13 void sbuf_init(struct sbuf *dest, char *buf, size_t size)
  14 {
  15         dest->fixed = (size > 0);
  16         if (dest->fixed) {
  17                 dest->buf = buf;
  18                 dest->size = size;
  19         } else {
  20                 dest->buf = XMALLOC(MTYPE_TMP, SBUF_DEFAULT_SIZE);
  21                 dest->size = SBUF_DEFAULT_SIZE;
  22         }
  23
  24         dest->pos = 0;
  25         dest->buf[0] = '\0';
  26 }
  27
  28 void sbuf_reset(struct sbuf *dest)
  29 {
  30         dest->pos = 0;
  31         dest->buf[0] = '\0';
  32 }
  33
  34 const char *sbuf_buf(struct sbuf *buf)
  35 {
  36         return buf->buf;
  37 }
  38
  39 void sbuf_free(struct sbuf *buf)
  40 {
  41         if (!buf->fixed)
  42                 XFREE(MTYPE_TMP, buf->buf);
  43 }
  44
  45 void sbuf_push(struct sbuf *buf, int indent, const char *format, ...)
  46 {
  47         va_list args;
  48         int written;
  49
  50         if (!buf->fixed) {
  51                 int written1, written2;
  52                 size_t new_size;
  53
  54                 written1 = indent;
  55                 va_start(args, format);
  56                 written2 = vsnprintfrr(NULL, 0, format, args);
  57                 va_end(args);
  58
  59                 new_size = buf->size;
  60                 if (written1 >= 0 && written2 >= 0) {
  61                         while (buf->pos + written1 + written2 >= new_size)
  62                                 new_size *= 2;
  63                         if (new_size > buf->size) {
  64                                 buf->buf =
  65                                         XREALLOC(MTYPE_TMP, buf->buf, new_size);
  66                                 buf->size = new_size;
  67                         }
  68                 }
  69         }
  70
  71         written = snprintf(buf->buf + buf->pos, buf->size - buf->pos, "%*s",
  72                            indent, "");
  73
  74         if (written >= 0)
  75                 buf->pos += written;
  76         if (buf->pos > buf->size)
  77                 buf->pos = buf->size;
  78
  79         va_start(args, format);
  80         written = vsnprintfrr(buf->buf + buf->pos, buf->size - buf->pos,
  81                               format, args);
  82         va_end(args);
  83
  84         if (written >= 0)
  85                 buf->pos += written;
  86         if (buf->pos > buf->size)
  87                 buf->pos = buf->size;
  88
  89         if (buf->pos == buf->size)
  90                 assert(!"Buffer filled up!");
  91 }