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/*
* Simple string buffer
*
* Copyright (C) 2017 Christian Franke
*
* This file is part of FRR.
*
* FRR is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* FRR 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with FRR; see the file COPYING. If not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#ifndef SBUF_H
#define SBUF_H
/*
* sbuf provides a simple string buffer. One application where this comes
* in handy is the parsing of binary data: If there is an error in the parsing
* process due to invalid input data, printing an error message explaining what
* went wrong is definitely useful. However, just printing the actual error,
* without any information about the previous parsing steps, is usually not very
* helpful.
* Using sbuf, the parser can log the whole parsing process into a buffer using
* a printf like API. When an error ocurrs, all the information about previous
* parsing steps is there in the log, without any need for backtracking, and can
* be used to give a detailed and useful error description.
* When parsing completes successfully without any error, the log can just be
* discarded unless debugging is turned on, to not spam the log.
*
* For the described usecase, the code would look something like this:
*
* int sbuf_example(..., char **parser_log)
* {
* struct sbuf logbuf;
*
* sbuf_init(&logbuf, NULL, 0);
* sbuf_push(&logbuf, 0, "Starting parser\n");
*
* int rv = do_parse(&logbuf, ...);
*
* *parser_log = sbuf_buf(&logbuf);
*
* return 1;
* }
*
* In this case, sbuf_example uses a string buffer with undefined size, which
* will
* be allocated on the heap by sbuf. The caller of sbuf_example is expected to
* free
* the string returned in parser_log.
*/
struct sbuf {
bool fixed;
char *buf;
size_t size;
size_t pos;
int indent;
};
void sbuf_init(struct sbuf *dest, char *buf, size_t size);
void sbuf_reset(struct sbuf *buf);
const char *sbuf_buf(struct sbuf *buf);
void sbuf_free(struct sbuf *buf);
#include "lib/log.h"
void sbuf_push(struct sbuf *buf, int indent, const char *format, ...)
PRINTF_ATTRIBUTE(3, 4);
#endif
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