/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2011 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Ilya Moiseenko <iliamo@cs.ucla.edu>
 */

#include "ccn_charbuf.h"

/**
 * @file ccn_charbuf.c
 * @brief Support expandable buffer for counted sequences of arbitrary bytes.
 * 
 * Part of the CCNx C Library.
 *
 * Copyright (C) 2008, 2009 Palo Alto Research Center, Inc.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 * This library 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
 * Lesser General Public License for more details. You should have received
 * a copy of the GNU Lesser General Public License along with this library;
 * if not, write to the Free Software Foundation, Inc., 51 Franklin Street,
 * Fifth Floor, Boston, MA 02110-1301 USA.
 */
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include "ccn_coding.h"

struct ccn_charbuf *
ccn_charbuf_create(void)
{
  struct ccn_charbuf *c;
  c = (ccn_charbuf*)calloc(1, sizeof(*c));
  return(c);
}

void
ccn_charbuf_destroy(struct ccn_charbuf **cbp)
{
  struct ccn_charbuf *c = *cbp;
  if (c != NULL) {
    if (c->buf != NULL)
      free(c->buf);
    free(c);
    *cbp = NULL;
  }
}

/*
 * ccn_charbuf_reserve: expand buffer as necessary to hold n more chars
 */
unsigned char *
ccn_charbuf_reserve(struct ccn_charbuf *c, size_t n)
{
  size_t newsz = n + c->length;
  unsigned char *buf = c->buf;
  if (newsz < n)
    return(NULL);
  if (newsz > c->limit) {
    if (2 * c->limit > newsz)
      newsz = 2 * c->limit;
    buf = (unsigned char*)realloc(c->buf, newsz);
    if (buf == NULL)
      return(NULL);
    memset(buf + c->limit, 0, newsz - c->limit);
    c->buf = buf;
    c->limit = newsz;
  }
  buf += c->length;
  return(buf);
}

void ccn_charbuf_reset(struct ccn_charbuf *c)
{
  if (c == NULL) {
    return;
  } 
  c->length = 0;
}

int
ccn_charbuf_append(struct ccn_charbuf *c, const void *p, size_t n)
{
  unsigned char *dst = ccn_charbuf_reserve(c, n);
  if (dst == NULL)
    return(-1);
  memcpy(dst, p, n);
  c->length += n;
  return(0);
}

int
ccn_charbuf_append_value(struct ccn_charbuf *c, unsigned val, unsigned n)
{
  unsigned char *dst;
  unsigned i;
  if (n > sizeof(val))
    return(-1);
  dst = ccn_charbuf_reserve(c, n);
  if (dst == NULL)
    return(-1);
  for (i = 0; i < n; i++)
    dst[i] = (unsigned char)(val >> (8 * (n-1-i)));
  c->length += n;
  return(0);
}

int
ccn_charbuf_append_charbuf(struct ccn_charbuf *c, const struct ccn_charbuf *in)
{
  return(ccn_charbuf_append(c, in->buf, in->length));
}

int
ccn_charbuf_append_string(struct ccn_charbuf *c, const char *s)
{
  return(ccn_charbuf_append(c, s, strlen(s)));
}

int
ccn_charbuf_putf(struct ccn_charbuf *c, const char *fmt, ...)
{
  int sz;
  va_list ap;
  char *buf;
  buf = (char *)ccn_charbuf_reserve(c, strlen(fmt) + 10); /* estimate */
  if (buf == NULL) return(-1);
  va_start(ap, fmt);
  sz = vsnprintf(buf, c->limit - c->length, fmt, ap);
  va_end(ap);
  if (sz < 0)
    return(sz);
  if (c->length + sz < c->limit) {
    c->length += sz;
    return(sz);
  }
  va_end(ap);
  buf = (char *)ccn_charbuf_reserve(c, sz + 1); /* accurate */
  if (buf == NULL) return(-1);
  va_start(ap, fmt);
  sz = vsnprintf(buf, c->limit - c->length, fmt, ap);
  va_end(ap);
  if (c->length + sz < c->limit) {
    c->length += sz;
    return(sz);
  }
  return(-1);
}

/* This formats time into xs:dateTime format */
int
ccn_charbuf_append_datetime(struct ccn_charbuf *c, time_t secs, int nsecs)
{
  char timestring[32];
  int timelen;
  struct tm time_tm;
  int res;
  
  timelen = strftime(timestring, sizeof(timestring),
                     "%FT%T", gmtime_r(&secs, &time_tm));
  if (timelen >= (int)sizeof(timestring))
    return(-1);
  if (nsecs != 0) {
    if (nsecs < 0 || nsecs >= 1000000000)
      return(-1);
    timelen += snprintf(&timestring[timelen], sizeof(timestring) - timelen,
                        ".%09d", nsecs);
    if (timelen >= (int)sizeof(timestring))
      return(-1);
    while (timestring[timelen - 1] == '0') timelen--;
  }
  timestring[timelen++] = 'Z';
  res = ccn_charbuf_append(c, timestring, timelen);
  return (res);
}

char *
ccn_charbuf_as_string(struct ccn_charbuf *c)
{
  unsigned char *r;
  r = ccn_charbuf_reserve(c, 1);
  if (r == NULL)
    return(NULL);
  r[0] = 0;
  return((char *)c->buf);
}

int
ccn_charbuf_append_closer(struct ccn_charbuf *c)
{
  int res;
  const unsigned char closer = CCN_CLOSE;
  res = ccn_charbuf_append(c, &closer, 1);
  return(res);
}