half-edge/src/filereader.c

110 lines
2.5 KiB
C

/*
* Copyright 2011-2014 hasufell
*
* This file is part of a hasufell project.
*
* This program 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 version 2 of the License only.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
/**
* @file filereader.c
* Reading of arbitrary files into strings as well as
* reading specific ones via various parsers.
* @brief reading of different filetypes
*/
#include "common.h"
#include "err.h"
#include "filereader.h"
#include "half_edge.h"
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
/**
* Read an obj file and return a HE_obj
* if parsing worked.
*
* @param filename file to open
* @return the HE_obj or NULL for failure
*/
HE_obj *read_obj_file(char const * const filename)
{
char *string = NULL; /* file content */
HE_obj *obj = NULL;
if (!filename || !*filename)
return NULL;
/* read the whole file into string */
string = read_file(filename);
if (!string)
return NULL;
obj = parse_obj(string);
free(string);
return obj;
}
/**
* Reads a file and returns a newly allocated string.
*
* @param filename file to open
* @return a newly allocated string which must be freed by the caller
* or NULL on failure
*/
char *read_file(char const * const filename)
{
char buf[STD_FILE_BUF],
*string = NULL;
int fd = 0;
size_t str_size = 0;
ssize_t n;
size_t file_length = 0;
fd = open(filename, O_RDONLY);
file_length = lseek(fd, 0, SEEK_END) + 1;
lseek(fd, 0, SEEK_SET);
string = malloc(sizeof(char) * file_length);
if (fd != -1) {
/* read and copy chunks */
while ((n = read(fd, buf, STD_FILE_BUF)) != 0) {
if (n == -1)
ABORT("Failed while reading file descriptor %d\n", fd);
str_size += n; /* count total bytes read */
/* append buffer to string */
memcpy(string + (str_size - n), buf, (size_t)n);
}
/* add trailing NULL byte */
string[str_size] = '\0';
if (close(fd))
ABORT("Failed to close file descripter %d\n", fd);
return string;
} else {
return NULL;
}
}