json-c/json_util.c

/*
 * $Id: json_util.c,v 1.2 2005/06/14 22:41:51 mclark Exp $
 *
 * Copyright Metaparadigm Pte. Ltd. 2004.
 * Michael Clark <michael@metaparadigm.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public (LGPL)
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * 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: http://www.gnu.org/
 *
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <errno.h>

#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif /* HAVE_SYS_TYPES_H */

#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif /* HAVE_SYS_STAT_H */

#if HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */

#if HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */

#ifdef WIN32
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
# include <io.h>
#endif /* defined(WIN32) */

#include "bits.h"
#include "debug.h"
#include "printbuf.h"
#include "json_object.h"
#include "json_tokener.h"
#include "json_util.h"

struct json_object* json_object_from_file(char *filename)
{
  struct printbuf *pb;
  struct json_object *obj;
  char buf[JSON_FILE_BUF_SIZE];
  int fd, ret;

  if((fd = open(filename, O_RDONLY)) < 0) {
    mc_error("json_object_from_file: error reading file %s: %s\n",
	     filename, strerror(errno));
    return error_ptr(-1);
  }
  if(!(pb = printbuf_new())) {
    mc_error("json_object_from_file: printbuf_new failed\n");
    return error_ptr(-1);
  }
  while((ret = read(fd, buf, JSON_FILE_BUF_SIZE)) > 0) {
    printbuf_memappend(pb, buf, ret);
  }
  close(fd);
  if(ret < 0) {
    mc_abort("json_object_from_file: error reading file %s: %s\n",
	     filename, strerror(errno));
    printbuf_free(pb);
    return error_ptr(-1);
  }
  obj = json_tokener_parse(pb->buf);
  printbuf_free(pb);
  return obj;
}

int json_object_to_file(char *filename, struct json_object *obj)
{
  char *json_str;
  int fd, ret;
  unsigned int wpos, wsize;

  if(!obj) {
    mc_error("json_object_to_file: object is null\n");
    return -1;
  }

  if((fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, 0644)) < 0) {
    mc_error("json_object_to_file: error opening file %s: %s\n",
	     filename, strerror(errno));
    return -1;
  }

  if(!(json_str = json_object_to_json_string(obj))) { return -1; }


  wsize = (unsigned int)(strlen(json_str) & UINT_MAX); /* CAW: probably unnecessary, but the most 64bit safe */
  wpos = 0;
  while(wpos < wsize) {
    if((ret = write(fd, json_str + wpos, wsize-wpos)) < 0) {
      close(fd);
      mc_error("json_object_to_file: error writing file %s: %s\n",
	     filename, strerror(errno));
      return -1;
    }

	/* because of the above check for ret < 0, we can safely cast and add */
    wpos += (unsigned int)ret;
  }

  close(fd);
  return 0;
}